Climate Change & Greenhouse Gas Emissions: Causes, Sources, Effects, Solutions & Forecasts

Climate Change: Causes, Sources, Effects, & Solutions

Climate change is one of the most talked about, if not the most talked about global issue.

When we talk about Climate Change, we also usually talk about global warming and greenhouse gases.

In this guide we outline what climate change is, the causes and sources, the effects, and what potential solutions might be on how to prevent it.

We also talk about how global warming and greenhouse gases tie into climate change as a whole.


Summary – What To Know About Climate Change

Climate change in a nutshell is the warming of the earth’s surface (via the sun’s solar radiation, and eventually infrared radiation) – with the warming process being amplified by greenhouse gases such as carbon dioxide (the main gas), but also methane, nitrous oxide and other gases.

From the evidence gathered, climate modelling done, and scientific formulas used – there is a consensus that humans are most likely the primary cause for the warming we are seeing today. Activities such as electricity production (that burns fossil fuels like coal), and vehicles (that burn petroleum) emit huge amounts of GHGs through burning of fossil fuels.

This warming period is usually expressed as the warming that has taken place since around 1950/60.

Temperatures have risen (up to 2019) around 0.8 to 0.9 degrees celcius compared to pre industrial levels, when carbon dioxide levels started increasing rapidly.

This rapid increase in carbon dioxide level (parts per million in the air) coincides with humans’ increased combustion of fossil fuels since the start of the industrial revolution.

What scientists do admit is that there are things they do know about climate change, things they think they might know, and things they are uncertain about that they can only make educated forecasts about with the information available.

They also admit that climate change feedback processes can be complex – leading to warming in some areas, and cooling in others (each area in the world has it’s own local or micro climate).

There’s also variables in the form of what we as humans will do in the future. What we do to mitigate emissions, adapt to changes, and reduce emissions will all impact how climate predictions can be made into the future.

As mentioned above, when it comes to climate change, a good way to look at it might be – what we are fairly certain we know, what we think we might know, and what we might be uncertain about.


What Is Climate Change?

  • Climate change is a change in the pattern of weather, and related changes in oceans, land surfaces and ice sheets, occurring over time scales of decades or longer



What Is Global Warming?

Global warming (i.e. an increase in the earth’s surface temperature) is just one factor in the overall climate change issue.

So, climate change is the all encompassing issue, whereas global warming is a ‘sub factor’ or ‘side effect’ in the overall issue.


What Is The Main Climate Change Problem?

It’s a very wide ranging problem with many factors and sub issues, causes, effects etc. to consider.

These factors and specific issues also differ country by country (and even state by state).

But, the core of the problem is the rise in the earth’s average surface temperature since the industrial revolution and particularly since the late 19th century, which has been largely driven by increased carbon dioxide and other human caused emissions in the atmosphere (carbon dioxide levels have sharply increased to unseen levels from 1950 to the current day).

A big cause for this is the burning of fossil fuels for electricity and heat production, transportation, industry (factories and production of goods and raw materials), and agriculture and clearing of land.


The planet’s average surface temperature has risen about 1.62 degrees Fahrenheit (0.9 degrees Celsius) since the late 19th century.

Most of the warming occurred in the past 35 years, with the five warmest years on record taking place since 2010. Not only was 2016 the warmest year on record, but eight of the 12 months that make up the year — from January through September, with the exception of June — were the warmest on record for those respective months.

Temperature is the one that gets all the attention, but there’s also other issues like:

  • Warming oceans
  • Shrinking ice sheets
  • Glacial retreat
  • Decreased snow cover
  • Sea level rise
  • Declining Arctic sea ice
  • Extreme/severe natural events
  • Ocean acidification
  • + more



What Are Greenhouse Gases?

Greenhouse gases are gases emitted from human and natural sources on earth, that rise up and sit in the earth’s atmosphere like a blanket.

This blanket of greenhouse gases lets through solar radiation from the sun (light). It also absorbs and re-emits infrared radiation (heat) from and back to the earth’s surface.

They get the name greenhouse gas because they have a similar effect that greenhouse glass has whereby the glass traps some IR radiation heat inside the greenhouse.

Greenhouse gases can be divided into two main types:

  • Greenhouse gases being emitted directly by human activities – Carbon dioxide (CO2) is the main one. Then methane (CH4), and nitrous oxide (N2O). Then others include ozone (O3), and synthetic gases (the ‘F’ gases), such as chlorofluorocarbons (CFCs) and hydrofluorocarbons (HFCs)
  • Other greenhouse gases – Water vapour is also a major greenhouse gas, but its concentration in the atmosphere is not influenced directly by human activities (it is influenced indirectly though by the production of carbon dioxide).
  • The most important greenhouse gases are water vapour and carbon dioxide (CO2). Both are present at very small concentrations in the atmosphere.
  • The two most abundant gases in the atmosphere are nitrogen (comprising 78 per cent of the dry atmosphere) and oxygen (21 per cent), but they have almost no greenhouse effects.
  • Water vapour varies considerably in space and time because it has a short ‘lifetime’ in the atmosphere. Because of this variation, it is difficult to measure globally averaged water vapour concentration.
  • Carbon dioxide has a much longer lifetime and is well mixed throughout the atmosphere. The current concentration is about 0.04 per cent.



  • Today, human activities are directly increasing atmospheric concentrations of CO2, methane and nitrous oxide, plus some chemically manufactured greenhouse gases such as halocarbons.
  • These human generated gases enhance the natural greenhouse effect and further warm the surface.
  • In addition to the direct effect, the warming that results from increased concentrations of long-lived greenhouse gases can be amplified by other processes.
  • A key example is water vapour amplification. Human activities are also increasing aerosols in the atmosphere, which reflect some incoming sunlight. This human-induced change offsets some of the warming from greenhouse gases.



What Is The Greenhouse Gas Effect?

There are two main types of greenhouse gas effects:

  • The natural green house gas effect which happens via the natural carbon cycle
  • The enhanced greenhouse gas effect which happens via human activities that add carbon dioxide on top of the natural emission of carbon dioxide

The thing is – we need the natural carbon cycle and natural greenhouse gas effect to make earth habitable. Without it, the earth would be -18ºC (minus 18 degrees) – and the earth would be uninhabitable.

The problem is the enhanced/human induced greenhouse releases carbon into the atmosphere faster than it can be removed by other parts of the carbon cycle.

This is called the ‘greenhouse effect’, and the gases that cause it by interacting with infrared radiation are called greenhouse gases. The most important are water vapour (which humans can’t directly control), carbon dioxide (CO2) and methane.

Since the Industrial Revolution, energy-driven consumption of fossil fuels has led to a rapid increase in CO2 emissions, disrupting the global carbon cycle and leading to a planetary warming impact.



How Does The Greenhouse Effect Actually Work?

What happens in the greenhouse effect it:

  • Solar radiation (light) comes from the sun and is emitted onto the earth’s surface (the sun’s energy intensity and the distance of the sun from earth affect how much solar radiation we get)
  • This solar radiation hits the earth’s surface, is converted to IR radiataion (heat) and warms the earth
  • Some IR radiation is emitted back to space, and some of it does escape into space
  • Some IR radiation gets absorbed by greenhouse gases in the atmosphere and re-emitted back onto the earth’s surface and troposphere – causing more heating than normal
  • Greenhouse gases, particularly carbon, gather in the atmosphere at a higher rate due to human activity like burning fossil fuels than they would during the natural carbon cycle

You can see how this works visually here:

the greenhouse effect

Credit: Philippe Rekacewicz, Emmanuelle Bournay, UNEP/GRID-Arendal

Page Link:


  • The Sun serves as the primary energy source for Earth’s climate.
  • Some of the incoming sunlight is reflected directly back into space, especially by bright surfaces such as ice and clouds, and the rest is absorbed by the surface and the atmosphere.
  • Much of this absorbed solar energy is re-emitted as heat (longwave or infrared radiation).
  • The atmosphere in turn absorbs and re-radiates heat, some of which escapes to space. Any disturbance to this balance of incoming and outgoing energy will affect the climate. For example, small changes in the output of energy from the Sun will affect this balance directly.
  • If all heat energy emitted from the surface passed through the atmosphere directly into space, Earth’s average surface temperature would be tens of degrees colder than today. Greenhouse gases in the atmosphere, including water vapour, carbon dioxide, methane, and nitrous oxide, act to make the surface much warmer than this, because they absorb and emit heat energy in all directions (including downwards), keeping Earth’s surface and lower atmosphere warm.
  • Without this greenhouse effect, life as we know it could not have evolved on our planet.
  • Adding more greenhouse gases to the atmosphere makes it even more effective at preventing heat from escaping into space.
  • When the energy leaving is less than the energy entering, Earth warms until a new balance is established.



What Is The Natural Carbon Cycle, And The Natural Greenhouse Gas Effect?

The natural cycle of carbon emission and absorption into and out of the atmosphere by living things and the natural environment.

All living organisms contain carbon, as do gases (such as carbon dioxide) and minerals (such as diamond, peat and coal). The movement of carbon between large natural reservoirs in rocks, the ocean, the atmosphere, plants, soil and fossil fuels is known as the carbon cycle.

The carbon cycle includes the movement of carbon dioxide:

  • into and out of our atmosphere
  • between the atmosphere, plants and other living organisms through photosynthesis, respiration and decay
  • between the atmosphere and the top of the oceans.

On longer time scales, chemical weathering and limestone and fossil fuel formation decrease atmospheric carbon dioxide levels, whereas volcanoes return carbon to the atmosphere. This is the dominant mechanism of control of carbon dioxide on timescales of millions of years.

Because the carbon cycle is essentially a closed system, any decrease in one reservoir of carbon leads to an increase in others.

For at least the last several hundred thousand years, up until the Industrial Revolution, natural sources of carbon dioxide were in approximate balance with natural ‘sinks’, producing relatively stable levels of atmospheric carbon dioxide.

‘Sinks’ are oceans, plants and soils, which absorb more carbon dioxide than they emit (in contrast, carbon sources emit more than they absorb).



What Is The Human/Enhanced Greenhouse Gas Effect?

Greenhouse gases (mainly carbon dioxide) emitted into the atmosphere mainly by human activity.

Refer to the ’causes’ section below for the sources of these carbon dioxide emissions.

The total carbon cycle is the natural carbon cycle and human carbon cycle together. That can be seen here:

total carbon cycle

Credit: Philippe Rekacewicz, Emmanuelle Bournay, UNEP/GRID-Arendal



Why Is Carbon Dioxide Considered The Main Greenhouse Gas?

There’s two reasons for this:

  • CO2 is responsible for more of an increase in the amount of energy (and therefore heat) reaching Earth’s surface than the other greenhouse gases. Other gases have more potent heat-trapping ability molecule per molecule than CO2 (e.g. methane), but are simply far less abundant in the atmosphere.
  • CO2 remains in the atmosphere longer than the other major heat-trapping gases


Explained in deeper detail…

  • Greenhouse gases are climate drivers
  • By measuring the abundance of heat-trapping gases in ice cores, the atmosphere, and other climate drivers along with models, the IPCC calculated the “radiative forcing” (RF) of each climate driver—in other words, the net increase (or decrease) in the amount of energy reaching Earth’s surface attributable to that climate driver.
  • Positive RF values represent average surface warming and negative values represent average surface cooling. In total, CO2 has the highest positive RF (see Figure 1) of all the human-influenced climate drivers compared by the IPCC.
  • Other gases have more potent heat-trapping ability molecule per molecule than CO2 (e.g. methane), but are simply far less abundant in the atmosphere.
  • CO2 remains in the atmosphere longer than the other major heat-trapping gases emitted as a result of human activities. It takes about a decade for methane (CH4) emissions to leave the atmosphere (it converts into CO2) and about a century for nitrous oxide (N2O).
  • After a pulse of CO2 is emitted into the atmosphere, 40% will remain in the atmosphere for 100 years and 20% will reside for 1000 years, while the final 10% will take 10,000 years to turn over. This literally means that the heat-trapping emissions we release today from our cars and power plants are setting the climate our children and grandchildren will inherit.
  • Water vapor is the most abundant heat-trapping gas, but rarely discussed when considering human-induced climate change. The principal reason is that water vapor has a short cycle in the atmosphere (10 days on average) before it is incorporated into weather events and falls to Earth, so it cannot build up in the atmosphere in the same way as carbon dioxide does.
  • However, a vicious cycle exists with water vapor, in which as more CO2 is emitted into the atmosphere and the Earth’s temperature rises, more water evaporates into the Earth’s atmosphere, which increases the temperature of the planet. The higher temperature atmosphere can then hold more water vapor than before.



Explained in another way…

  • Carbon dioxide is not the only greenhouse gas of concern for global warming and climatic change. There are a range of greenhouse gases, which include methane, nitrous oxide, and a range of smaller concentration trace gases such as the so-called group of ‘F-gases’.
  • Greenhouse gases vary in their relative contributions to global warming; i.e. one tonne of methane does not have the same impact on warming as one tonne of carbon dioxide. These differences can be defined using a metric called ‘Global Warming Potential’ (GWP). GWP can be defined on a range of time-periods, however the most commonly used (and that adopted by the IPCC) is the 100-year timescale (GWP100).
  • You can look at the GWP100 value of key greenhouse gases relative to carbon dioxide. The GWP100metric measures the relative warming impact one molecule or unit mass of a greenhouse gas relative to carbon dioxide over a 100-year timescale. For example, one tonne of methane would have 28 times the warming impact of tonne of carbon dioxide over a 100-year period. GWP100 values are used to combine greenhouse gases into a single metric of emissions called carbon dioxide equivalents (CO2e). CO2e is derived by multiplying the mass of emissions of a specific greenhouse gas by its equivalent GWP100 factor. The sum of all gases in their CO2e form provide a measure of total greenhouse gas emissions.
  • We see the contribution of different gases to total greenhouse gas emissions. These are measured based on their carbon-dioxide equivalent values. Overall we see that carbon dioxide accounts for around three-quarters of total greenhouse gas emissions. However, both methane and nitrous oxide are also important sources, accounting for around 17 and 7 percent of emissions, respectively.
  • Collectively, HFC, PFC and SF6 are known as the ‘F-gases’. Despite having a very strong warming impact per unit mass (i.e. a high global warming potential), these gases are emitted in very small quantities; they therefore make only a small contribution to total warming.



  • Carbon dioxide is the largest single contributor to human-induced climate change. NASA describes it as ‘the principal control knob that governs the temperature of Earth’. Although other factors (such as other long-lived greenhouse gases, water vapour and clouds) contribute to Earth’s greenhouse effect, carbon dioxide is the dominant greenhouse gas that humans can control in the atmosphere.



  • Scientists have determined that, when all human and natural factors are considered, Earth’s climate balance has been altered towards warming, with the biggest contributor being increases in CO2.



Do Humans Only Affect Climate Change Through Greenhouse Gases?


  • Greenhouse gases emitted by human activities alter Earth’s energy balance and thus its climate.
  • But, humans also affect climate by changing the nature of the land surfaces (for example by clearing forests for farming) and through the emission of pollutants that affect the amount and type of particles in the atmosphere.



Causes Of Climate Change (Sources, Sectors & Countries)

The main driver/cause of climate change is carbon emissions from human activity.

These human activities mainly include the burning of fossil fuels – for vehicles, for electricity generation at power plants and so on.

Water vapour accounts for about half the present-day greenhouse effect, but its concentration in the atmosphere is not influenced directly by human activities. The amount of water in the atmosphere is related mainly to changes in the Earth’s temperature. For example, as the atmosphere warms it is able to hold more water. Although water vapour absorbs heat, it does not accumulate in the atmosphere in the same way as other greenhouse gases; it tends to act as part of a feedback loop rather than being a direct cause of climate change.

So, let’s get more specific about where carbon dioxide comes from according to different sources:

EPA tracks total U.S. emissions by publishing the Inventory of U.S. Greenhouse Gas Emissions and Sinks. This annual report estimates the total national greenhouse gas emissions and removals associated with human activities across the United States.

The primary sources of greenhouse gas emissions in the United States are –

  • Transportation – nearly 28.5 percent of 2016 greenhouse gas emissions
  • Electricity Production – 28.4 percent of 2016 greenhouse gas emissions
  • Industry – 22 percent of 2016 greenhouse gas emissions
  • Commercial and residential – 11 percent of 2016 greenhouse gas emissions
  • Agriculture – 9 percent of 2016 greenhouse gas emissions
  • Land Use And Forestry – offset of 11 percent of 2016 greenhouse gas emissions



Combustible fossil fuels such as coal, power plant gas, oil, vehicles and big industry are the largest source of carbon dioxide. The production is from various items such as iron, steel, cement, natural gas, solid waste combustion, lime, ammonia, limestone, cropland, soda ash, aluminum, petrochemical, titanium and phosphoric acid. Carbon dioxide accounts for nearly 85 percent of all emissions and is produced when natural gas, petroleum and coal are used. The major areas where these fuels are used include electricity generation, transportation, industry and in residential and commercial buildings.



87 percent of all human-produced carbon dioxide emissions come from the burning of fossil fuels like coal, natural gas and oil. The remainder results from the clearing of forests and other land use changes (9%), as well as some industrial processes such as cement manufacturing (4%).

– Further breakdown at


Since the Industrial Revolution there has been a large increase in human activities such as fossil fuel burning, land clearing and agriculture, which affect the release and uptake of carbon dioxide.

According to the most recent Emissions Overview, carbon dioxide and other greenhouse gases are produced in NSW (in Australia) by the following activities or sources:

  • stationary energy sources, such as coal-fired power stations (47 per cent)
  • transport (18 per cent)
  • coal mines (12 per cent)
  • agriculture (11 per cent)
  • land use (7 per cent)
  • land change (3 per cent)
  • waste (2 per cent).

Carbon dioxide released into the atmosphere from burning fossil fuels carries a different chemical fingerprint from that released by natural sources such as respiration and volcanoes. This makes it possible to identify the contribution of human activity to greenhouse gas production.

Data collected by CSIRO show that the concentration of carbon dioxide in our atmosphere in 2018 was approximately 404 parts per million. The level of carbon dioxide in the Earth’s atmosphere is now higher than at any time over the past 800,000—and possibly 20 million—years.

Global atmospheric concentrations of the other greenhouse gases (methane and nitrous oxide) also now exceed pre-industrial values.



Global greenhouse gas emissions can be broken down by sectoral sources in these sections:

  • Energy (energy, manufacturing and construction industries and fugitive emissions): emissions are inclusive of public heat and electricity production; other energy industries; fugitive emissions from solid fuels, oil and gas, manufacturing industries and construction.
  • Transport: domestic aviation, road transportation, rail transportation, domestic navigation, other transportation.
  • International bunkers: international aviation; international navigation/shipping.
  • Residential, commercial, institutional and AFF: Residential and other sectors.
  • Industry (industrial processes and product use): production of minerals, chemicals, metals, pulp/paper/food/drink, halocarbons, refrigeration and air conditioning; aerosols and solvents; semicondutor/electronics manufacture; electrical equipment.
  • Waste: solid waste disposal; wastewater handling; waste incineration; other waste handling.
  • Agriculture: methane and nitrous oxide emissions from enteric fermentation; manure management; rice cultivation; synthetic fertilizers; manure applied to soils; manure left on pasture; crop residues; burning crop residues, savanna and cultivation of organic soils.
  • Land use: emissions from the net conversion of forest; cropland; grassland and burning biomass for agriculture or other uses.
  • Other sources: fossil fuel fires; indirect nitrous oxide from non-agricultural NOx and ammonia; other anthropogenic sources.



Emissions by country…

Cumulative emissions –  As of 2014 – China’s rapid growth in emissions over the last few decades now makes it the world’s second largest cumulative emitter, although it still comes in at less than 50% of the US total.

Annual emissions – In 2014, we can see that a number of low to middle income nations are now within the top global emitters. In fact, China is now the largest emitter, followed by (in order) the US, EU-28, India, Russia, Indonesia, Brazil, Japan, Canada and Mexico. Note that a number of nations that are already top emitters are likely to continue to increase emissions as they undergo development.

In contrast to CO2 emissions growth in low to middle income economies, trends across many high income nations have stabilized, and in several cases decreased in recent decades. Despite this downward trend across some nations, emissions growth in transitioning economies dominates the global trend—as such, global annual emissions have continued to increase over this period.

Per Capita emissions – With a few exceptions, there is an important north-south divide in terms of per capita emissions. Most nations across sub-Saharan Africa, South America and South Asia have per capita emissions below five tonnes per year (many have less than 1-2 tonnes). This contrasts with the global north where emissions are typically above five tonnes per person (with North America above 15 tonnes). The monthly emissions per capita in rich countries are mostly higher than the yearly emissions per capita in poorer countries. The largest emitter, Qatar, has per capita emissions of 50 tonnes per year (1243 times that of Chad, the lowest emitter).

Note that carbon dioxide is not the only greenhouse gas which contributes to climate change—nitrous oxide and methane are also greenhouse gases, but are not included here. Food production, especially intensive livestock-rearing for meat and dairy, is a major contributor to both of these non-CO2 GHGs. Since capita meat intake is strongly linked to GDP levels, per capita emissions of nitrous oxide and methane tend to be much larger in high-income nations.

C02 emissions by source vary depending on the country – we are talking about gas, liquid (i.e. oil), solid (coal and biomass), flaring, and cement production. In the present day, solid and liquid fuel dominate, although contributions from gas production are also notable. Cement and flaring at the global level remain comparably small. has some great missions charts and graphs which show total GHG emissions, as well as Carbon Dioxide, Methane and Nitrous Oxide Emissions by sector, activity, country and more as %’s, parts per million etc. –

You can see the stats, as well as trends of emissions.

The EPA has also outlined each sector where greenhouse gases are emitted. You can read more about those sectors and sources for gases in our guide on solutions to climate change.


Effects Of Climate Change

What is important to note is that there are already some effects that have taken place (such as the rise in temperature, shrinking ice etc.

But, future effects can only be forecasted – but not guaranteed.


Climate change affects the world as a whole, but can also affect different countries, and regions within those countries differently.

There are environmental, social and economic effects.

Some of the current and future effects of climate change are…

  • Warming oceans
  • Shrinking ice sheets
  • Glacial retreat
  • Decreased snow cover
  • Sea level rise
  • Declining Arctic sea ice
  • Extreme events
  • Ocean acidification [due to increased carbon levels]



Global warming and a changing climate have a range of potential ecological, physical and health impacts, including extreme weather events (such as floods, droughts, storms, and heatwaves); sea-level rise; altered crop growth; and disrupted water systems.



  • The enhanced greenhouse effect is expected to change many of the basic weather patterns that make up our climate, including wind and rainfall patterns and the incidence and intensity of storms.
  • Every aspect of our lives is in some way influenced by the climate. For example, we depend on water supplies that exist only under certain climatic conditions, and our agriculture requires particular ranges of temperature and rainfall.



  • Ice is melting in both polar ice caps and mountain glaciers. Lakes around the world, including Lake Superior, are warming rapidly — in some cases faster than the surrounding environment. Animals are changing migration patterns and plants are changing the dates of activity, such as trees budding their leaves earlier in the spring and dropping them later in the fall.
  • There’s an increase in average temperatures and the temperature extremes, there’s extreme weather events, there’s ice melt, there’s sea level rise and acidification, plants and animals are affected, and there are social consequences relating to agriculture, food security and health implication just to name a few.



  • Global effects – hotter days, rising sea levels, more frequent and intense extreme weather events, oceans are warming and acidifying. As humans, every aspect of our life is reliant on the natural environment. This includes the food we eat, the air we breathe, the water we drink, the clothes we wear and the products that are made and sold to create jobs and drive the economy. We need a healthy and stable climate for these things.
  • Country Specific effects such as Australia – temperature rises, water shortages, increased fire threats, drought, weed and pest invasions, intense storm damage and salt invasion.
  • Threatening of the Great Barrier Reef.
  • Animals and plants – One in six species is at risk of extinction because of climate change and habitat destruction and environmental change.
  • Food and Farming – Changes to rainfall patterns, increasingly severe drought, more frequent heat waves, flooding and extreme weather make it more difficult for farmers to graze livestock and grow produce, reducing food availability and making it more expensive to buy.
  • Water – Reduced rainfall and increasingly severe droughts may lead to water shortages.
  • Coastal erosion – Rising sea levels and more frequent and intense storm surges will see more erosion of Australia’s coastline, wearing away and inundating community and residential properties.
  • Health – Increasingly severe and frequent heat waves may lead to death and illness, especially among the elderly. Higher temperatures and humidity could also produce more mosquito-borne disease.
  • Damage to homes – Increasingly severe extreme weather events like bushfires, storms, floods, cyclones and coastal erosion, will see increased damage to homes, as well as more costly insurance premiums.
  • Coral bleaching – Rising temperatures and acidity within our oceans is contributing to extreme coral bleaching events, like the 2016 event that destroyed more than one-third of the Great Barrier Reef.
  • Overall – Within Australia, the effects of global warming vary from region to region.
    The impacts of global warming are already being felt across all areas of Australian life, and these will continue to worsen if we do not act now to limit global warming to 1.5°C.



Future effects might be:

Global climate change has already had observable effects on the environment. Glaciers have shrunk, ice on rivers and lakes is breaking up earlier, plant and animal ranges have shifted and trees are flowering sooner.

Scientists have high confidence that global temperatures will continue to rise for decades to come, largely due to greenhouse gases produced by human activities. The Intergovernmental Panel on Climate Change (IPCC), which includes more than 1,300 scientists from the United States and other countries, forecasts a temperature rise of 2.5 to 10 degrees Fahrenheit over the next century.

According to the IPCC, the extent of climate change effects on individual regions will vary over time and with the ability of different societal and environmental systems to mitigate or adapt to change.

The IPCC predicts that increases in global mean temperature of less than 1.8 to 5.4 degrees Fahrenheit (1 to 3 degrees Celsius) above 1990 levels will produce beneficial impacts in some regions and harmful ones in others. Net annual costs will increase over time as global temperatures increase.

“Taken as a whole,” the IPCC states, “the range of published evidence indicates that the net damage costs of climate change are likely to be significant and to increase over time.”

According to the Third and Fourth National Climate Assessment Reports, future effects will be…

  • change through this century and beyond depending on how many greenhouse gases we emit and how sensitive our climate is to them
  • temperatures will continue to rise
  • Frost free season and growing season will lengthen
  • There will be changes in precipitation patterns
  • There will be more droughts and heat waves
  • Hurricanes will become stronger and more intense
  • Sea levels will rise between 1-4 feet by 2100
  • The Arctic is likely to become ice free

NASA also outline the US regional effects so far in Northeast, Northwest, Southeast, Midwest and Southwest. For example, in the Southwest – increased heat, drought and insect outbreaks, all linked to climate change, have increased wildfires. Declining water supplies, reduced agricultural yields, health impacts in cities due to heat, and flooding and erosion in coastal areas are additional concerns.



Evidence That Climate Change Is A Real Issue, & Is A Direct Cause Of Other Problems

In summary, the main points of evidence are:

  • it has been proved how much of a warming effect greenhouse gases like carbon dioxide have on the earth
  • there was a sharp rise in carbon dioxide levels (in parts per million) since the industrial revolution in the 19th century, and in particular since 1950 – most of it from human activity
  • there was rise in average global earth surface (air) temperature in the same time – compared to pre 1950’s levels
  • there has been a change in other events and things in the same time such as sea levels, ice melting, etc. – compared to pre 1950’s levels


So, you have to be able to prove:

  • Greenhouse gases warm the earth and it’s climate
  • Humans are emitting greenhouse gases at certain levels
  • The GHG’s that human are emitting are causing the warming (as opposed to natural emissions causing it)
  • There are negative side effects of this warming (e.g. sea level rise, ice melt etc.)
  • That this warming and these negative side effects wouldn’t be happening, or happening to the extent they are now without the human caused greenhouse gas emissions (essentially comparing what is happening now with excess emissions, to a baseline without these heavy emissions)
  • Some further information explaining this and evidence is…
  • The finding that the climate has warmed in recent decades and that human activities are producing global climate change has been endorsed by every national science academy that has issued a statement on climate change, including the science academies of all of the major industrialized countries.
  • Scientific consensus is normally achieved through communication at conferences, publication in the scientific literature, replication (reproducible results by others), and peer review. In the case of global warming, many governmental reports, the media in many countries, and environmental groups, have stated that there is virtually unanimous scientific agreement that human-caused global warming is real and poses a serious concern.
  • Several studies of the consensus have been undertaken. Among the most-cited is a 2013 study of nearly 12,000 abstracts of peer-reviewed papers on climate science published since 1990, of which just over 4,000 papers expressed an opinion on the cause of recent global warming. Of these, 97% agree, explicitly or implicitly, that global warming is happening and is human-caused. It is “extremely likely” that this warming arises from “… human activities, especially emissions of greenhouse gases …” in the atmosphere. Natural change alone would have had a slight cooling effect rather than a warming effect.



  • [the current warming trend] is extremely likely (greater than 95 percent probability) to be the result of human activity since the mid-20th century and proceeding at a rate that is unprecedented over decades to millennia.

– IPCC Fifth Assessment Report via


  • For 400,000 years, carbon dioxide levels have never been above 280 to 300 parts per million
  • During ice ages, COlevels were around 200 parts per million (ppm), and during the warmer interglacial periods, they hovered around 280 ppm
  • Around 1950, carbon dioxide levels surpassed 300 parts per million, and as of 2013, levels surpassed 400 parts per million
  • This rise in carbon closely mimics our burning of fossil fuels in the same time. What we know about fossil fuels is that they emit carbon dioxide, and 60 percent of fossil-fuel emissions stay in the air.
  • If fossil-fuel burning continues at a business-as-usual rate, such that humanity exhausts the reserves over the next few centuries, CO2 will continue to rise to levels of order of 1500 ppm. The atmosphere would then not return to pre-industrial levels even tens of thousands of years into the future.



  • The Earth’s climate has changed throughout history. Just in the last 650,000 years there have been seven cycles of glacial advance and retreat, with the abrupt end of the last ice age about 7,000 years ago marking the beginning of the modern climate era — and of human civilization. Most of these climate changes are attributed to very small variations in Earth’s orbit that change the amount of solar energy our planet receives.
  • The current warming trend is of particular significance because most of it is extremely likely (greater than 95 percent probability) to be the result of human activity since the mid-20th century and proceeding at a rate that is unprecedented over decades to millennia.
  • Earth-orbiting satellites and other technological advances have enabled scientists to see the big picture, collecting many different types of information about our planet and its climate on a global scale. This body of data, collected over many years, reveals the signals of a changing climate.
  • The heat-trapping nature of carbon dioxide and other gases was demonstrated in the mid-19th century.Their ability to affect the transfer of infrared energy through the atmosphere is the scientific basis of many instruments flown by NASA. There is no question that increased levels of greenhouse gases must cause the Earth to warm in response.
  • Ice cores drawn from Greenland, Antarctica, and tropical mountain glaciers show that the Earth’s climate responds to changes in greenhouse gas levels. Ancient evidence can also be found in tree rings, ocean sediments, coral reefs, and layers of sedimentary rocks. This ancient, or paleoclimate, evidence reveals that current warming is occurring roughly ten times faster than the average rate of ice-age-recovery warming.
  • Further to this, there are these events tied to the above:
  • Global temperature rise – The planet’s average surface temperature has risen about 1.62 degrees Fahrenheit (0.9 degrees Celsius) since the late 19th century, a change driven largely by increased carbon dioxide and other human-made emissions into the atmosphere. Most of the warming occurred in the past 35 years, with the five warmest years on record taking place since 2010. Not only was 2016 the warmest year on record, but eight of the 12 months that make up the year — from January through September, with the exception of June — were the warmest on record for those respective months.
  • Warming Oceans – The oceans have absorbed much of this increased heat, with the top 700 meters (about 2,300 feet) of ocean showing warming of 0.302 degrees Fahrenheit since 1969.
  • Shrinking Ice Sheets – The Greenland and Antarctic ice sheets have decreased in mass. Data from NASA’s Gravity Recovery and Climate Experiment show Greenland lost an average of 281 billion tons of ice per year between 1993 and 2016, while Antarctica lost about 119 billion tons during the same time period. The rate of Antarctica ice mass loss has tripled in the last decade.
  • Glacial Retreat – Glaciers are retreating almost everywhere around the world — including in the Alps, Himalayas, Andes, Rockies, Alaska and Africa.
  • Decreased Snow Cover – Satellite observations reveal that the amount of spring snow cover in the Northern Hemisphere has decreased over the past five decades and that the snow is melting earlier.
  • Sea Level Rise – Global sea level rose about 8 inches in the last century. The rate in the last two decades, however, is nearly double that of the last century.
  • Declining Arctic Sea Ice – Both the extent and thickness of Arctic sea ice has declined rapidly over the last several decades.
  • Extreme Events – The number of record high temperature events in the United States has been increasing, while the number of record low temperature events has been decreasing, since 1950. The U.S. has also witnessed increasing numbers of intense rainfall events.
  • Ocean Acidification – Since the beginning of the Industrial Revolution, the acidity of surface ocean waters has increased by about 30 percent. This increase is the result of humans emitting more carbon dioxide into the atmosphere and hence more being absorbed into the oceans. The amount of carbon dioxide absorbed by the upper layer of the oceans is increasing by about 2 billion tons per year.



  • Look at how the world has warmed since the Industrial Revolution.
  • We see that over the last few decades, temperatures have risen sharply at the global level — to approximately 0.8 degrees celsius higher than our 1961-1990 baseline.
  • When extended back to 1850, we see that temperatures then were a further 0.4 degrees colder than they were in our 1961-1990 baseline.
  • Overall, if we look at the total temperature increase since pre-industrial times, this therefore amounts to approximately 1.2 degrees celcius. We have now surpassed the one-degree mark, an important marker as it brings us more than halfway to the global limit of keeping warming below two degrees celsius.
  • It’s also important to look at trends by hemisphere (North and South), as well as the tropics (defined as 30 degrees above and below the equator).
  • Here we see that the median temperature increase in the North Hemisphere is higher, at closer to 1.4 degrees celcius since 1850, and less in the Southern Hemisphere (closer to 0.8 degrees celcius). Evidence suggests that this distribution is strongly related to ocean circulation patterns (notably the North Atlantic Oscillation) which has resulted in greater warming in the northern hemisphere.



  • Climate change is happening
  • Tens of thousands of scientists in more than a hundred nations have amassed an overwhelming amount of evidence that humans are the cause
  • We are statistically more confident that humans cause climate change than that smoking causes cancer
  • There are nine main independently studied, but physically related, lines of evidence
  • (it is really the first seven that, combined, point to human activities as the only explanation of rising global temperatures since the Industrial Revolution, and the subsequent climate changes (such as ice melt and sea level rise) that have occurred due to this global warming.)
  • Those nine lines of evidence are:
  1. Simple chemistry – when we burn carbon-based materials, carbon dioxide (CO2) is emitted (research beginning in 1900s)
  2. Basic accounting of what we burn, and therefore how much CO2 we emit (data collection beginning in 1970s)
  3. Measuring CO2 in the atmosphere and trapped in ice to find that it is increasing and that the levels are higher than anything we’ve seen in hundreds of thousands of years (measurements beginning in 1950s)
  4. Chemical analysis of the atmospheric CO2 that reveals the increase is coming from burning fossil fuels (research beginning in 1950s)
  5. Basic physics that shows us that CO2 absorbs heat (research beginning in 1820s)
  6. Monitoring climate conditions to find that recent warming of the Earth is correlated to and follows rising CO2 emissions (research beginning in 1930s)
  7. Ruling out natural factors that can influence climate like the sun and ocean cycles (research beginning in 1830s)
  8. Employing computer models to run experiments of natural versus human-influenced simulations of Earth (research beginning in 1960s)
  9. Consensus among scientists who consider all previous lines of evidence and make their own conclusions (polling beginning in 1990s)



  • CO2 keeps the Earth warmer than it would be without it. Humans are adding CO2 to the atmosphere, mainly by burning fossil fuels. And there is empirical evidence that the rising temperatures are being caused by the increased CO2.
  • The reason that the Earth is warm enough to sustain life is because of greenhouse gases in the atmosphere. These gases act like a blanket, keeping the Earth warm by preventing some of the sun’s energy being re-radiated into space. The effect is exactly the same as wrapping yourself in a blanket – it reduces heat loss from your body and keeps you warm. If we add more greenhouse gases to the atmosphere, the effect is like wrapping yourself in a thicker blanket: even less heat is lost.
  • So how can we tell what effect CO2 is having on temperatures, and if the increase in atmospheric CO2 is really making the planet warmer?
  • One way of measuring the effect of CO2 is by using satellites to compare how much energy is arriving from the sun, and how much is leaving the Earth. What scientists have seen over the last few decades is a gradual decrease in the amount of energy being re-radiated back into space. In the same period, the amount of energy arriving from the sun has not changed very much at all. This is the first piece of evidencemore energy is remaining in the atmosphere.
  • The primary greenhouse gases – carbon dioxide (CO2), methane (CH4), water vapour, nitrous oxide and ozone – comprise around 1% of the air. This tiny amount has a very powerful effect, keeping the planet 33°C (59.4°F) warmer than it would be without them. (The main components of the atmosphere – nitrogen and oxygen – are not greenhouse gases, because they are virtually unaffected by long-wave, or infrared, radiation). This is the second piece of evidencea provable mechanism by which energy can be trapped in the atmosphere
  • We now look at the amount of CO2 in the air. We know from bubbles of air trapped in ice cores that before the industrial revolution, the amount of CO2 in the air was approximately 280 parts per million (ppm). In June 2013, the NOAA Earth System Research Laboratory in Hawaii announced that, for the first time in thousands of years, the amount of CO2 in the air had gone up to 400ppm. That information gives us the next piece of evidenceCO2 has increased by nearly 43% in the last 150 years.
  • The final piece of evidence is ‘the smoking gun’, the proof that CO2 is causing the increases in temperature. CO2 traps energy at very specific wavelengths, while other greenhouse gases trap different wavelengths.  In physics, these wavelengths can be measured using a technique called spectroscopy. When looking at the different wavelengths of energy, measured at the Earth’s surface, on a Spectroscopy Graph – among the spikes you can see energy being radiated back to Earth by ozone (O3), methane (CH4), and nitrous oxide (N20). But the spike for CO2 dwarfs all the other greenhouse gases, and tells us something very important: most of the energy being trapped in the atmosphere corresponds exactly to the wavelength of energy captured by CO2.
  • To sum up:
  • 1. What is happening – More energy is remaining in the atmosphere on Earth
  • 2. How is this happening – Greenhouse gases are the mechanism by which energy is trapped in the atmosphere
  • 3. Why is this happening – CO2 has increased by nearly 50% in the last 150 years and the increase is from burning fossil fuels
  • 4. Linking the tw0 – energy being trapped in the atmosphere corresponds exactly to the wavelengths of energy captured by CO2
  • This is empirical evidence that proves, step by step, that man-made carbon dioxide is causing the Earth to warm up.



  • The science on the human contribution to modern warming is quite clear. Humans emissions and activities have caused around 100% of the warming observed since 1950
  • Since 1850, almost all the long-term warming can be explained by greenhouse gas emissions and other human activities.
  • If greenhouse gas emissions alone were warming the planet, we would expect to see about a third more warming than has actually occurred. They are offset by cooling from human-produced atmospheric aerosols.
  • Aerosols are projected to decline significantly by 2100, bringing total warming from all factors closer to warming from greenhouse gases alone.
  • Natural variability in the Earth’s climate is unlikely to play a major role in long-term warming.
  • Some of the findings that back up these results are…
  • Greenhouse gas forcings match actual observed global surface temperature warming – Scientists measure the various factors that affect the amount of energy that reaches and remains in the Earth’s climate. They are known as “radiative forcings”. They can be natural (such as volcanoes) and man made (such as greenhouse gases). When looking at a graph that shows the estimated role of each different climate forcing in changing global surface temperatures since records began in 1850, of all the radiative forcings analysed, only increases in greenhouse gas emissions produce the magnitude of warming experienced over the past 150 years.
  • Human forcings match actual observed global surface temperature warmings
  • Land temperatures are rising faster now – Land temperatures have warmed considerably faster than average global temperatures over the past century, with temperatures reaching around 1.7C above pre-industrial levels in recent years.
  • From the models, future forecasts are that land warms by around 4C by 2100 compared to 3C globally for surface temperature
  • While human factors explain all the long-term warming, there are some specific periods that appear to have warmed or cooled faster than can be explained based on our best estimates of radiative forcing.
  • Short term warming or cooling may occur via natural factors, but long term natural variability to impact long-term warming trends is extremely unlikely
  • Internal variability is likely to have a much larger role in regional temperatures. For example, in producing unusually warm periods in the Arctic and the US in the 1930s.
  • In summary – While there are natural factors that affect the Earth’s climate, the combined influence of volcanoes and changes in solar activity would have resulted in cooling rather than warming over the past 50 years. The global warming witnessed over the past 150 years matches nearly perfectly what is expected from greenhouse gas emissions and other human activity, both in the simple model examined here and in more complex climate models. The best estimate of the human contribution to modern warming is around 100% . Some uncertainty remains due to the role of natural variability, but researchers suggest that ocean fluctuations and similar factors are unlikely to be the cause of more than a small fraction of modern global warming.

– answers many climate change related questions that give evidence of the link between greenhouse gases and climate change at

These questions and answers include:

    • Is the climate warming (lists the range of observations, indications and evidence that show warming has occured)
    • How do scientists know that recent climate change is largely caused by human activities?
    • CO2 is already in the atmosphere naturally, so why are emissions from human activity significant?
    • What role has the Sun played in climate change in recent decades?
    • What do changes in the vertical structure of atmospheric temperature – from the surface up to the stratosphere – tell us about the causes of recent climate change?
    • Climate is always changing. Why is climate change of concern now?
    • Is the current level of atmospheric CO2concentration unprecedented in Earth’s history?
    • Is there a point at which adding more CO2 will not cause further warming?
    • Does the rate of warming vary from one decade to another?
    • Does the recent slowdown of warming mean that climate change is no longer happening?
    • If the world is warming, why are some winters and summers still very cold?
    • Why is Arctic sea ice reducing while Antarctic sea ice is not?
    • How does climate change affect the strength and frequency of floods, droughts, hurricanes and tornadoes?
    • How fast is sea level rising?
    • What is ocean acidification and why does it matter?
    • How confident are scientists that Earth will warm further over the coming century?
    • Are climate changes of a few degrees a cause for concern?
    • What are scientists doing to address key uncertainties in our understanding of the climate system?
      • Are disaster scenarios about tipping points like ‘turning off the Gulf Stream’ and release of methane from the Arctic a cause for concern?
    • If emissions of greenhouse gases were stopped, would the climate return to the conditions of 200 years ago?



Climate Change Evidence Stats

C02 & Other Greenhouse Gas Level Changes

The global mean CO2 level in 2013 was 395 parts per million. This concentration represents a 43 per cent increase from pre-industrial levels; it is likely to be at the highest concentration in at least 2 million years.

Methane and nitrous oxide concentrations, mostly from agriculture, have increased by 150% and 20% respectively since 1750.



Records of air bubbles in ancient Antarctic ice show us that carbon dioxide and other greenhouse gases are now at their highest concentrations for more than 800,000 years.



Global Surface Temperature Change

We have tracked significant increase in global temperatures of at least 0.85°C and a sea level rise of 20cm over the past century.



You can check out global temperature change at 


Global Sea Level Change

We have tracked significant increase in global temperatures of at least 0.85°C and a sea level rise of 20cm over the past century.



You can check out global sea level at 


Average Sea Surface Temperature Change

You can check out average sea surface temperature which is rising at


Looking At Evidence Overall

Overall, you can’t just look at temperature (air temperature, land temperature, water temperature) to diagnose or assess climate change. You also have to look at sea levels, ocean acidity, ice sheets, ecosystem trends, and other factors to get a well rounded answer.


Ways To Monitor The Impact Climate Change Is Having Now & Into The Future

Some of the long-term effects of global climate change in the United States are listed in the Third and Fourth National Climate Assessment Reports.

But, NASA list some of the effects and expected effects of climate change at

(Some effects that scientists had predicted in the past would result from global climate change are now occurring: loss of sea ice, accelerated sea level rise and longer, more intense heat waves.)

Among the impacts to look out for and monitor and link to each other are:

  • Continued C02 parts per million levels rising
  • Continued earth air surface temperature rising
  • Land temperature rising
  • Ocean temperatures rising
  • Glaciers shrinking
  • Ice on rivers and lakes breaking up earlier
  • Plant and animal ranges shifting
  • Trees and plants flowering sooner
  • Loss of sea ice
  • Accelerated sea level rise
  • Longer, more intense heat waves
  • Frost free and growing seasons lengthening (The largest increases in the frost-free season (more than eight weeks) are projected for the western U.S., particularly in high elevation and coastal areas.)
  • Changes in precipitation patterns – trend towards increased heavy precipitation events
  • More droughts, heat waves and hot days (By the end of this century, what have been once-in-20-year extreme heat days (one-day events) are projected to occur every two or three years over most of the nation.)
  • Cold waves to become less intense
  • Hurricanes becoming stronger and more intense (The intensity, frequency and duration of North Atlantic hurricanes, as well as the frequency of the strongest (Category 4 and 5) hurricanes, have all increased since the early 1980s. The relative contributions of human and natural causes to these increases are still uncertain)
  • Sea levels to rise (Global sea level has risen by about 8 inches since reliable record keeping began in 1880. It is projected to rise another 1 to 4 feet by 2100. This is the result of added water from melting land ice and the expansion of seawater as it warms.)
  • Land subsidence to increase (land sinking)
  • Flooding of coastal and sea side land to increase
  • Arctic Ocean to become ice free
  • Infrastructure, agriculture, fisheries and ecosystems will be increasingly compromised
  • Increasing wildfire, insect outbreaks and tree diseases
  • Increasing ocean acidity
  • Decreased freshwater availability
  • Increased erosion



Debate & Disagreement Over Climate Change & Global Warming

You can read more about the debate and controversy over climate change and it’s impact/effects at 


Answers To Skeptical Arguments Against Climate Change

Skeptical Science has a good resource answering common skeptical arguments against climate change:



How Are C02 Concentrations Obtained In Current Time, & From The Past?

More recently, there are observatories that measure air CO2 levels.

But, historic CO2 levels can be found in ice cores, and also rock sediment samples from the ocean and lakes.

There are other ancient samples (such as tree rings, studying ancient organisms etc.) that can also be used to get an idea of CO2 levels from the past.

Read more about how climate change indicators and past CO2 levels are measured in this guide.


Climate Change & Trade/Import Between Developed vs Developing Countries

  • Climate change can lead to lead to widespread drought, disease and desperation in some of the world’s poorest regions
  • Migration by refugees affected by climate change is predicted in the future
  • Richer nations have a lot of carbon emissions contained in the products and materials they import from developing countries
  • Of the carbon emissions that European consumers are personally responsible for, around 22% are allocated elsewhere under conventional carbon accounting practices. For consumers in the US, the figure is around 15%.
  • Heavy industry and the constant demand for consumer goods are key contributors to climate change
  • 30% of global greenhouse gas emissions are produced through the process of converting metal ores and fossil fuels into the cars, washing machines and electronic devices that help prop up richer economies
  • Richer nations have more purchasing power and through their consumption of products, contribute to emissions and pollution
  • For every item bought or sold there is a rise in GDP, and with each 1% increase in GDP there is a corresponding 0.5 to 0.7% rise in carbon emissions
  • For metal ores alone, the extraction rate more than doubled between 1980 and 2008
  • Every time you buy a new car, for instance, you effectively mine 3-7g of “platinum group metals” to coat the catalytic converter. The six elements in the platinum group have the greatest environmental impact of all metals, and producing just one kilo requires the emission of thousands of kilos of CO₂
  • This is only one example of the toll poorer countries are taking to satisfy richer countries
  • The problem is that in poorer countries choose to accept this behavior for a variety of factors, and citizens see it as the only way to get out of poverty (because it provides jobs)
  • Richer nations must start implementing sustainable material strategies that address a product’s entire lifecycle from mining to manufacturing, use, and eventually to disposal. They must consider the well being of the people and environment in the countries they are importing from
  • Consumers can also vote with their dollars and buy from more ethical and sustainable countries



Potential Climate Change Solutions (Mitigation, Adaptation, Carbon Sequestering)

The best solution is to bring emissions to zero as soon as possible.

But, realistically – there is going to need to be a different approach to doing that in each industry and sector of society.

Two big examples are – renewable energy sources in the electricity generation sector, and cleaner cars in the transport sector.

There needs to be an approach that considers employment, the economy and practicality right now, and the future environmental needs of the future.

Building infrastructure, getting funding, transferring to new technologies and power sources – all take time and have technical challenges – so it’s something that requires serious planning and research as to how to best do it.


Some specific solutions might include:

  • More efficient use of residential electronics, and new technology for household electronics
  • More efficient use of residential appliances
  • Retrofit residential HVAC
  • Tillage and residue management
  • Insulation retrofits for residential
  • Hybrid cars
  • Waste recycling
  • Lighting – switch from incandescent to LED lights (residential)
  • Retrofit insulation (commercial)
  • Better motor systems efficiency
  • Cropland nutrient management
  • Clinker substitution by fly ash
  • Electricity from landfill gas
  • Efficiency improvements by different industries
  • Rice management
  • 1st generation biofuels
  • Small hydro
  • Reduced slash and burn agriculture conversion
  • Reduced pastureland conversion
  • Grassland management
  • Geothermal energy
  • Organic soil restoration
  • Building energy efficiency in new builds
  • 2nd gen biofuels
  • Degraded land restoration
  • Pastureland afforestation
  • Nuclear energy
  • Degraded forest reforestation
  • Low penetration wind technology and energy
  • Solar CSP technology and energy
  • Solar PV technology and energy
  • High penetration wind technology and energy
  • Reduced intensive agriculture conversion
  • Power plant biomass co-firing
  • Coal CCS new build
  • Iron and steel CCS new build
  • Coal CCS retrofit
  • Gas plant CCS retrofit



Also according to

  • To keep global temperature rise below the agreed 2°C, global carbon emission must peak in the next decade and from 2070 onward must be negative
  • The goal, with the Paris Agreement in mind, is limiting warming to 2℃ above pre-industrial levels. The Paris Agreement went further, aiming to “pursue efforts” towards a more ambitious goal of just 1.5℃. Given we’re already at around 1℃ of warming, that’s a relatively short-term goal.
  • The warming will slow to a potentially manageable pace only when human emissions are reduced to zero. The good news is that they are now falling in many countries as a result of programs like fuel-economy standards for cars, stricter building codes and emissions limits for power plants. But experts say the energy transition needs to speed up drastically to head off the worst effects of climate change
  • The energy sources with the lowest emissions include wind turbines, solar panels, hydroelectric dams and nuclear power stations. Power plants burning natural gas also produce fewer emissions than those burning coal. Using renewables can be costlier in the short term
  • Burning gas instead of coal in power plants reduces emissions in the short run, though gas is still a fossil fuel and will have to be phased out in the long run
  • “Clean coal” is an approach in which the emissions from coal-burning power plants would be captured and pumped underground. It has yet to be proven to work economically, but some experts think it could eventually play a major role.



Mitigation of climate change are actions to reduce greenhouse gas emissions, or enhance the capacity of carbon sinks to absorb greenhouse gases from the atmosphere.

There is a large potential for future reductions in emissions by a combination of activities, including energy conservation and increased energy efficiency; the use of low-carbon energy technologies, such as renewable energy, nuclear energy, and carbon capture and storage; and enhancing carbon sinks through, for example, reforestation and preventing deforestation.

A 2015 report by Citibank concluded that transitioning to a low carbon economy would yield positive return on investments.

Apart from mitigation, adaptation and climate engineering are other options for responses.



Cost Of Pursuing Climate Change Mitigation

According to OurWorldInData, these are very loose and very roughly estimated costs to pursue climate change mitigation. These costs have lots of variables:

The possible cost-benefit of taking global and regional action on climate change is often a major influencing factor on the effectiveness of mitigation agreements and measures.

If we aggressively pursue all of the low-cost abatement opportunities currently available, the total global economic cost would be €200-350 billion per year by 2030. This is less than one percent of the forecasted global GDP in 2030.

If we include these additional opportunities, our maximum technical abatement potential by 2030 totals 47 billion tonnes of CO2e per year. Our maximum global potential is therefore a 65-70% reduction relative to our current projected pathway.



Recent Greenhouse Gas Trends (Total Greenhouse Gas Emissions)

Since 1990, gross U.S. greenhouse gas emissions have increased by about 2 percent. From year to year, emissions can rise and fall due to changes in the economy, the price of fuel, and other factors.

In 2016, U.S. greenhouse gas emissions decreased compared to 2015 levels. This decrease was largely driven by a decrease in emissions from fossil fuel combustion, which was a result of multiple factors including substitution from coal to natural gas consumption in the electric power sector; warmer winter conditions that reduced demand for heating fuel in the residential and commercial sectors.

You can see total US GHG emissions between 1990 and 2016 at



EPA also shows the total global and national GG emissions by %:

  • National –
  • Global –

In the US you can see carbon dioxide emissions have been gradually decreasing since around 2007 to 2016.


Forecast For Climate Change Into The Future

Climate change and it’s effects can be forecasted into the future, but not with an absolute guarantee (some forecasts from the past weren’t completely accurate).

There variables that can impact how quickly warming takes place, and how the earth and different indicators in different parts of the world react.

Climate models can forecast for 100’s of different scenarios based on these variables.

There may be warming in some parts of the world, and there may be cooling in others just as one example.

It’s more realistic to be aware of the indicators and causes, understand what potential future scenarios might be, and continue to monitor them and adjust expectations accordingly.

What most experts do agree on though is that it’s in our best interests to decrease human GHG emissions as soon as possible.



  • The continued burning of fossil fuels will inevitably lead to further climate warming. The complexity of the climate system is such that the extent of this warming is difficult to predict, particularly as the largest unknown is how much greenhouse gas we keep emitting.
  • The IPCC has developed a range of emissions scenarios or Representative Concentration Pathways (RCPs) to examine the possible range of future climate change.
  • Using scenarios ranging from business-as-usual to strong longer-term managed decline in emissions, the climate model projections suggest the global mean surface temperature could rise by between 2.8°C and 5.4°C by the end of the 21st century. Even if all the current country pledges submitted to the Paris conference are achieved we would still only just be at the bottom end of this range.
  • The sea level is projected to rise by between 52cm and 98cm by 2100, threatening coastal cities, low-lying deltas and small island nations. Snow cover and sea ice are projected to continue to reduce, and some models suggest that the Arctic could be ice-free in late summer by the latter part of the 21st century.
  • Heat waves, droughts, extreme rain and flash flood risks are projected to increase, threatening ecosystems and human settlements, health and security. One major worry is that increased heat and humidity could make physical work outside impossible.
  • Changes in precipitation are also expected to vary from place to place. In the high-latitude regions (central and northern regions of Europe, Asia and North America) the year-round average precipitation is projected to increase, while in most sub-tropical land regions it is projected to decrease by as much as 20%, increasing the risk of drought.
  • In many other parts of the world, species and ecosystems may experience climatic conditions at the limits of their optimal or tolerable ranges or beyond.
  • Human land use conversion for food, fuel, fibre and fodder, combined with targeted hunting and harvesting, has resulted in species extinctions some 100 to 1000 times higher than background rates. Climate change will only speed things up.
  • This is the challenge our world leaders face. To keep global temperature rise below the agreed 2°C, global carbon emission must peak in the next decade and from 2070 onward must be negative: we must start sucking out carbon dioxide from the atmosphere.
  • Despite 30 years of climate change negotiations there has been no deviation in greenhouse gas emissions from the business-as-usual pathway, so many feel keeping global warming to less than 2°C will prove impossible.
  • Previous failures, most notably at Copenhagen in 2009, set back meaningful global cuts in emissions by at least a decade. Paris, however, offers a glimmer of hope.



  • Near- and long-term trends in the global energy system are inconsistent with limiting global warming at below 1.5 or 2 °C, relative to pre-industrial levels. Pledges made as part of the Cancún agreements are broadly consistent with having a likely chance (66 to 100% probability) of limiting global warming (in the 21st century) at below 3 °C, relative to pre-industrial levels.



What does the future of our carbon dioxide and greenhouse gas emissions look like? [here are] … a range of potential future scenarios of global greenhouse gas emissions (measured in gigatonnes of carbon dioxide equivalents), based on data from Climate Action Tracker. Here, five scenarios are shown:

  • No climate policies: projected future emissions if no climate policies were implemented; this would result in an estimated 4.1-4.8°C warming by 2100 (relative to pre-industrial temperatures)
  • Current climate policies: projected warming of 3.1-3.7°C by 2100 based on current implemented climate policies
  • National pledges: if all countries achieve their current targets/pledges set within the Paris climate agreement, it’s estimated average warming by 2100 will be 2.6-3.2°C. This will go well beyond the overall target of the Paris Agreement to keep warming “well below 2°C”.
  • 2°C consistent: there are a range of emissions pathways that would be compatible with limiting average warming to 2°C by 2100. This would require a significant increase in ambition of the current pledges within the Paris Agreement.
  • 1.5°C consistent: there are a range of emissions pathways that would be compatible with limiting average warming to 1.5°C by 2100. However, all would require a very urgent and rapid reduction in global greenhouse gas emissions.



Climate Change Overall Is A Complex Process – It Has Drivers, Amplifiers, Diminishers & Feedbacks That All Interact With Each Other

Based just on the physics of the amount of energy that CO2 absorbs and emits, a doubling of atmospheric CO2 concentration from pre-industrial levels (up to about 560 ppm) would, by itself, cause a global average temperature increase of about 1 °C (1.8 °F).

In the overall climate system, however, things are more complex; warming leads to further effects (feedbacks) that either amplify or diminish the initial warming.

The most important feedbacks involve various forms of water.

A warmer atmosphere generally contains more water vapour.

Water vapour is a potent greenhouse gas, thus causing more warming; its short lifetime in the atmosphere keeps its increase largely in step with warming. Thus, water vapour is treated as an amplifier, and not a driver, of climate change.

Higher temperatures in the polar regions melt sea ice and reduce seasonal snow cover, exposing a darker ocean and land surface that can absorb more heat, causing further warming.

Another important but uncertain feedback concerns changes in clouds. Warming and increases in water vapour together may cause cloud cover to increase or decrease which can either amplify or dampen temperature change depending on the changes in the horizontal extent, altitude, and properties of clouds.

The latest assessment of the science indicates that the overall net global effect of cloud changes is likely to be to amplify warming.

The ocean moderates climate change. The ocean is a huge heat reservoir, but it is difficult to heat its full depth because warm water tends to stay near the surface. The rate at which heat is transferred to the deep ocean is therefore slow; it varies from year to year and from decade to decade, and helps to determine the pace of warming at the surface.

Observations of the sub-surface ocean are limited prior to about 1970, but since then, warming of the upper 700 m (2,300 feet) is readily apparent. There is also evidence of deeper warming.

Surface temperatures and rainfall in most regions vary greatly from the global average because of geographical location, in particular latitude and continental position.

Both the average values of temperature, rainfall, and their extremes (which generally have the largest impacts on natural systems and human infrastructure), are also strongly affected by local patterns of winds.

Estimating the effects of feedback processes, the pace of the warming, and regional climate change requires the use of mathematical models of the atmosphere, ocean, land, and ice (the cryosphere) built upon established laws of physics and the latest understanding of the physical, chemical and biological processes affecting climate, and run on powerful computers.

Models vary in their projections of how much additional warming to expect (depending on the type of model and on assumptions used in simulating certain climate processes, particularly cloud formation and ocean mixing), but all such models agree that the overall net effect of feedbacks is to amplify warming.



Other Notes & Stats On Climate Change, C02 & Greenhouse Emissions

C02 and Economic development

Historically, CO2 emissions have been primarily driven by increasing fuel consumption. This energy driver has been, and continues to be, a fundamental pillar of economic growth and poverty alleviation. As a result, there is a strong correlation between per capita CO2 emissions and GDP per capita for countries.

There are also noticeable within-country inequalities in greenhouse gas emissions



C02 and Poverty alleviation

The link between economic growth and CO2 described above raises an important question: do we actually want the emissions of low-income countries to grow despite trying to reduce global emissions? In our historical and current energy system (which has been primarily built on fossil fuels), CO2 emissions have been an almost unavoidable consequence of the energy access necessary for development and poverty alleviation.

In general, we see a very similar correlation in both CO2 and energy: higher emissions and energy access are correlated to lower levels of extreme poverty. Energy access is therefore an essential component in improved living standards and poverty alleviation.

In an ideal world, this energy could be provided through 100% renewable energy: in such a world, CO2emissions could be an avoidable consequence of development. However, currently we would expect that some of this energy access will have to come from fossil fuel consumption (although potentially with a higher mix of renewables than older industrial economies). Therefore, although the global challenge is to reduce emissions, some growth in per capita emissions from the world’s poorest countries remains a sign of progress in terms of changing living conditions and poverty alleviation.



C02 Intensity Of Economies 

If economic growth is historically linked to growing CO2 emissions, why do countries have differing levels of per capita CO2 emissions despite having similar GDP per capita levels? These differences are captured by the differences in the CO2 intensity of economies; CO2 intensity measures the amount of CO2 emitted per unit of GDP (kgCO2 per int-$). There are two key variables which can affect the CO2 intensity of an economy:

  • Energy efficiency: the amount of energy needed for one unit of GDP output. This is often related to productivity and technology efficiency, but can also be related to the type of economic activity underpinning output. If a country’s economy transitions from manufacturing to service-based output, less energy is needed in production, therefore less energy is used per unit of GDP.
  • Carbon efficiency: the amount of CO2 emitted per unit energy (grams of CO2 emitted per kilowatt-hour). This is largely related to a country’s energy mix. An economy powered by coal-fired energy will produce higher CO2 emissions per unit of energy versus an energy system with a high percentage of renewable energy. As economies increase their share of renewable capacity, efficiency improves and the amount of CO2 emitted per unit energy falls.

Global CO2 intensity has been steadily falling since 1990.17 This is likely thanks to both improved energy and technology efficiency, and increases in the capacity of renewables. The carbon intensity of nearly all national economies has also fallen in recent decades. Today, we see the highest intensities in Asia, Eastern Europe, and South Africa. This is likely to be a compounded effect of coal-dominated energy systems and heavily industrialized economies.



C02 Intensity and Prosperity 

On average, we see low carbon intensities at low incomes; carbon intensity rises as countries transition from low-to-middle incomes, especially in rapidly growing industrial economies; and as countries move towards higher incomes, carbon intensity falls again.



C02 intensity of goods imported and exported by country

Some countries take on emissions via trade.

The net emissions transfers here is the COembedded in imported goods minus the COembedded in exported goods. This tells us whether a country is a net exporter or importer of emissions.

Based on the updated data gathered by Peters et al. (2012) and the Global Carbon Project, if we switched to a consumption-based reporting system (which corrects for this trade), in 2014 the annual CO2 emissions of many European economies would increase by more than 30% (the UK by 38%; Sweden by 66%; and Belgium’s emissions would nearly double); and the USA’s emissions would increase by 7%.

On the other hand, China’s emissions would decrease by 13%; India’s by 9%; Russia’s by 14% and South Africa by 29%. The goods exported from Russia, China, India, and the Middle East typically have a high carbon intensity, reflecting the fact that their exports are often manufactured goods.

In contrast, we see that exports from the UK, France, Germany and Italy are low; this is likely to be the higher share of export of service-based exports relative to those produced from heavy industry.

Production vs consumption based emissions – If a country’s consumption-based emissions are higher than its production-based emissions then it is a net importer of CO2. If production-based emissions are higher, it is a net exporter.






3. Hannah Ritchie and Max Roser (2018) – “CO₂ and other Greenhouse Gas Emissions”. Published online at Retrieved from: ‘’ [Online Resource]































Potential Solutions To Freshwater Depletion & Scarcity

Solutions To Freshwater Depletion, Scarcity, Stress & Shortages

The world’s freshwater supplies are limited, and in a lot of cases depleting.

Depletion of these sources of freshwater include one off natural events, and more permanent problems like overpopulation and climate change (plus other factors).

Dry countries with hotter climates, and lower income countries with water access issues in particular face big freshwater issues that cause a severe impact on people, the economy, animals and the natural environment.

We’ve collated some of the best and most innovative ideas being used, or that might be worth developing further to solve issues like freshwater depletion, scarcity, stress and shortages.

Let’s take a look


Summary – Solutions To Freshwater Depletion

Some of the biggest positive changes might be see by addressing:

  • The Agricultural, Industrial & Household sectors – the three main areas we use freshwater in society
  • Population growth – more people means more demand for water directly, and also for all the indirect uses of water such as growing food, manufacturing products, producing energy, and running households
  • Capture waste/sewage/industrial/energy production/agricultural and household water, treat it, and re-use/recycle it where possible – waste water and grey water re-use and recycling, once treated, is one of the biggest potential ways to make better use of the water we use
  • Find more ways to capture/harvest rainwater – increased harvesting rainwater on farms, industrially, and at the household level, can give us more access to freshwater
  • Improve irrigation efficiency in agriculture – like for example drip irrigation and installing timers and sensors on irrigation systems. Making irrigation more efficient, and addressing water waste via irrigation, can save a lot of water
  • Improve industrial/commercial and energy production water efficiency – these two sectors use farm more water than the household sector. Becoming more efficient in these sectors can provide significant returns 
  • Reduce water waste, especially from water pipes and water infrastructure – at the household level, more water is wasted BEFORE it gets to our houses. Upgrading and improving water pipes and water infrastructure is one way to address this, as well as installing more water pipe damage software and sensors – just as some examples
  • Explore how to be more energy efficient with water desalination (and less costly) – desalination is currently very energy intensive and expensive. Reducing energy consumptions requirements (and cost) for desalination, or developing technology that allows desalination to occur with sustainable energy and green energy would go a long way to addressing this
  • Address water pollution – water pollution and contamination reduces the overall amount of freshwater available to our growing populations
  • Consider the impact of climate change on natural water replenishment – climate and temperature impacts the natural water replenishment cycle via evaporation, precipitation and so on


Specific Ways To Address Freshwater Depletion


Per (note: we’ve paraphrased the descriptions):

… Population growth, urban development, farm production and climate change are increasing competition for fresh water and producing shortages.

Here’s a look at the first 19 areas where experts feel needed solutions will come.

[these are areas where solutions for coping with water scarcity in business and industry may come based on a] … poll of more than 1200 leading international experts in 80 countries)


1. Educate people on the various water issues, and help people change consumption habits

Educate people on how important water is, how much of it we have, how much to use, where we use it and the consequences if we don’t address the issue and become sustainable with our use of it.

Specifically we want to educate people, and motivate them to change their behavior when it comes to consuming water

At all levels, and across the sections of society where we use the most water, we have to change consumption habits

We’ve got to use less water, and/or use water more efficiently


2. Invest in new water conservation technologies

Groundwater is drying up, and rainfalls are becoming inconsistent

Manufacturing equipment, waste water capture and re-use equipment, household equipment – all use water

Invest in technology that saves, re captures, cleans and re-uses water

Make sure new technologies are energy efficient, as energy use with water conservation or purification tech can be an issue


3. Recycle waste water

From industries, agriculture and households

Find a way to treat waste water and re-use/recycle it. Some places like Singapore are trying to find ways to treat and recycle wastewater for drinking for example


4. Improve agricultural and irrigation practices

These activities use a lot of water – up to 70% of total usage in some countries

Getting more efficient, using less water, and growing/producing different foods and crops can help

We can either create new practices and technology, or improve existing ones (such as existing irrigation technology – like they’ve done in California)


5. Increase the price of water 

If we stop making non drinking fresh water so cheap – maybe we can make people and businesses use less of it

It may also decrease water waste and pollution


6. Develop energy efficient water desalination

Desalination uses ALOT of energy – this is one of the major drawbacks to it

Considering 97% of the world’s water is saline water – if we get this technology right – it opens things up a lot

Renewable energy desalination plants are a good option – such as solar powered plants

Having said this – a country needs money in the first place to experiment with this type of technology, so it’s not an option for low income countries


7. Improve water catchment and harvesting

Water catchment and water harvesting can help us catch more freshwater that falls on the land and on structures

The more water we catch and harvest, the more we have available to use. You see this in dams that get extended

This is important for places struck by climate change, places with irregular rainfall, and places with low freshwater supplies


8. Look to community based governments and partnerships

Local governments and communities have power to empower people at a grassroots level

It can filter up to the national level when change occurs here


9. Develop, enact and maintain better laws and regulations

There’s the Clean Water Act in the US for example – which the US government is thinking of expanding

Whatever the case, national and state governments worldwide have an important part to play with both legislature, and their policies and decisions on how to manage freshwater sources

Many people believe it’s the government’s responsibility to provide us with freshwater


10. Holistically manage ecosystems

We are talking about economic, cultural, and ecological systems

This is making systems work together instead of just on their own

Good examples of holistic management are communities that operate sewage treatment plants while pursuing partnerships with clean energy producers to use wastewater to fertilize algae and other biofuel crops.

The crops, in turn, soak up nutrients and purify wastewater, significantly reducing pumping and treatment costs.


11. Improve distribution infrastructure

Poor water infrastructure can cause health, pollution/contamination and economic problems

We are talking about pipe bursts, lack of treatment facilities, sewage and wastewater overflows and malfunction


12. Shrink corporate water footprints

We are talking about producing products and goods, and sustainable manufacturing

Business activity and industrial activity (factories, manufacturing facilities etc.) uses up a large amount of water

Bottled water is one industry that is highly questioned – if we improve drinking water infrastructure – why do we need bottled water in the first place? Why don’t people refill their existing water bottles?


13. Build international frameworks and institutional cooperation

Work together to have better binding watter agreements and behaviors between countries

Hold each other to higher standards

Regional agreements regarding transboundary or shared water bodies, and treaties need more attention


14. Address water pollution (and contamination)

We are specifically talking about creating and maintaining better water quality

Poor water quality leads to human health and biodiversity issues

Contamination includes things like bacteria – E coli is an example

Pollution includes things like oil pollution, agricultural pollution and wastewater and sewage pollution


15. Public common resources/equitable access

Access to drinking water has to be a right for everyone in every country

Governments need to find a way to do this at least, even if water use for other purposes isn’t as efficient as it can be

The water crisis in lower income countries shows us what happens when drinking water is hard to come by or access


16. R&D/Innovation

Public private partnerships between business and governments

One example— cities that operate sewage treatment plants are likely to pursue partnerships with clean energy producers to fertilize algae and other biofuel crops with wastewater.


17. Water projects in developing countries/transfer of technology

Climate change and water scarcity are producing the most dramatic consequences in developing regions

One proposed solution is to transfer water conservation technologies from developed countries to these dry areas.

Doing so is tricky because economies are weak and there are gaps in skills that often compel government and business authorities to impose these changes on local citizens.


18. Climate change mitigation

Climate change (greenhouse gases in particular) and water scarcity go hand-in-hand

As renewable energy options are pursued, the water consumption of these mitigation tactics must be considered in producing alternatives ranging from bio-energy crops to hydropower and solar power plants.


19. Population growth control

Because of the accelerating growth in global population, parts of the world could see a supply-demand gap of up to 65 percent in water resources by 2030.

Currently, more than one billion people don’t have access to clean water.

And with 70 percent of the world’s freshwater used for agriculture, water’s critical role in food production must be considered as climate and resource conditions change.



1. Solar Powered Water Purifiers

Make more contaminated water drinkable

Use zinc oxide and titanium dioxide in containers that expose it to ultraviolet radiation and cleanse the water – making it suitable to drink


2. Water leak software and monitors

Almost a third of water is wasted even before it reaches a home – at failed and leaking pipelines. And, then obviously at the household level there can be over usage and wastage.

Water leak monitors and software with a central operating hub/control centre can help against this.


3. Replacing water cleaning, with CO2 cleaning

We use a lot of water in cleaning in manufacturing

To give you an idea of how much, manufacturing a car requires nearly 40,000 gallons of water

CO2 cleaning involves the use of carbon dioxide in solid form, highly propelled dry ice particles out of a nozzle to clean a variety of different surfaces.

The technology can be used for composite aircraft and automotive structures, cleaning complex medical equipment, and dry cleaning operations in an eco-friendly way.

The CO2 required for these machines is recycled from other industrial uses, so not only does it contribute to solving the water shortage crisis, but also helps with climate change.


4. Lifesaver bottles

For emergencies and short term water issues.

It’s a special bottle that can instantly make water potable. It uses a pump to push the water through a 15-nanometer filter which cleans it of any bacteria or viruses.

Has a low financial and environmental cost


5. Improving shower water saving technology

Technology that helps shower water heat up quicker, and technology that collects wasted cold water and refilters it in at the right temperature


6. Showering without water

A lotion has been made that has a blend of chemicals that get rid of odors, bioflavonoids and essential oils. The lotion can be applied right onto the skin and is as effective as taking a regular shower.

Dry Bathing can help save 4 liters of water per person which can add up to many millions every single year and help billions of people who don’t have access to water stay clean and avoid the life-threatening bacteria that’s often found in the stagnant water some of these people use to bathe.




The 2030 Water Resources Group has brought together case studies from around the world of currently available, replicable and practical solutions for water use transformation.

Some of these solutions include:

  • Waterless dying technology in textile processing
  • Installation of soil moisture monitoring system to improve productivity
  • Resource efficient cleaner production in sugar factories
  • Balancing supply and demand through water metering
  • Public private partnerships for water system upgrades
  • Partnerships for cleaner textile production
  • Institutional reform in irrigation management
  • Reducing the cost of water re-use in the textile sector
  • Integrated irrigation modernisation projects
  • Basin based approach for groundwater management
  • Innovative financing arrangements
  • Active supply chain management in the textile industry
  • Effluent treatment and aquifer storage for agricultural use
  • Innovative PPP to improve water quality and availability
  • Corporate water efficiency targets in the mining industry
  • Reducing water use in fish and seafood processing
  • Zero liquid discharge and water reuse at a coal power plant
  • PPP to address regional water issues
  • Adapting to water scarcity at farm level
  • Community implemented aquifer recharge scheme
  • Institutional capacity building approach to managing industrial water use
  • Integrated water resource management in agriculutre
  • Water management in copper and gold mines
  • Reuse of municipal effluent at a petrochemical complex
  • New water from fog catchingReducing water and energy consumption in a chemical plant
  • Satellite based spatial data to aid in irrigation
  • Micro irrigation for food security
  • Creation of ‘new water’ from saline aquifer
  • High frequency intermittent drip irrigation
  • Water free milk powder factory
  • Maximising water reuse at a brewery
  • Social norms based customer engagement on water efficiency
  • Installation of drip irrigation systems
  • Emergency response to drought crisis
  • Air flow dyeing machines in textile production
  • Water use reduction strategy in food sector
  • Water reuse in the textile sector
  • Water reuse in the power and steel production sector
  • Water recycling in the food sector
  • Water recycling in paper production
  • Water reclamation for reuse and groundwater recharge
  • Water optimisation in the mining sector
  • Use of seawater in dual municipal water supply
  • Regional water conservation program
  • Wastewater reclamation and reuse network
  • Water loss management programs
  • Water efficiency audits of steam systems
  • Reducing water losses in a large distribution network
  • Water demand management strategy
  • Water demand management scheme
  • Reducing business risk through municipal leakage reduction
  • Water authority conservation program
  • Pressure management in municipalities
  • Wastewater reclamation to meet potable water demand
  • Pilot low cost irrigation scheduling
  • Managing evapotranspiration using quotas
  • Mine water recycling
  • Leakage reduction in primary schools
  • Leakage reduction in cities
  • Metering of non revenue water
  • Irrigation scheduling in grape farming
  • Managing water towards zero discharge
  • Irrigation optimisation
  • Irrigation network renewal
  • Irrigation management
  • Integrated watershed management
  • Improving water availability through wastewater treatment
  • Improved water management for sugar cane production
  • Improved water distribution management
  • Groundwater recharge
  • Groundwater conservation
  • Emergency water demand management
  • Domestic and business retrofit project
  • Direct dry cooling in the power sector
  • Behavioral change initiative
  • Aquifer recharge with stormwater
  • Advanced pressure management



  • Farmers are partnering with scientists and conservationists to recharge groundwater by inundating farm fields with wintertime floodwater, which then seeps through the soil to the aquifer below
  • … Another neglected water source can be found right below our feet. The world’s soils can hold eight times more water than all rivers combined, yet agricultural practices deplete soils, causing that critical water reservoir to shrink.  But this can be fixed by rebuilding soil health.  
  • By eliminating tillage and planting cover crops, farmers can build the soil’s carbon content and enable it to store more water. Even a one percentage-point increase in soil organic carbon can increase water-holding capacity by some 18,000 gallons per acre. Yet farmers plant cover crops on less than 3% of US farmland and practice conservation agriculture on only about seven percent of cropland worldwide.


Further Ideas & Solutions

1. Consider changing our production and purchasing habits

Specifically with food and clothing.

Meat production, and cotton plants for example use a lot of water.

Switching to vegetarian diets, and switching to bamboo, hemp, lyocell and similar less water intensive fabrics – can all help.


2. Decrease water contamination, and invest more cheap/efficient water contamination technology

Water contamination, particularly with E coli and bacteria, is a big problem

If we can decrease contamination (protect water sources better) and get better at treating water contamination in it – more water will be available in contaminated water sources


3. Decrease water pollution

Mostly pollution from agriculture (fertiliser, herbicide and pesticide) and waste water and sewage treatment pollutes water

Decrease this pollution, and get better at cleaning up pollution







Freshwater Supply & Usage Around The World: How Much Freshwater We Have, How Much We Use, & How We Use It

Freshwater Supply & Usage Around The World: How Much Freshwater We Have, How Much We Use, & How We Use It

Freshwater supplies and usage/withdrawal rates around the world differ by country.

How much freshwater we have, how much of it we use and what we use it on are all important stats and trends to look at so we can manage our water resources within each country.

We take a look at these stats and certain trends and patterns in this guide.


Summary Of Freshwater Worldwide

  • We have different types of freshwater sources in the world – some are more renewable than others
  • Freshwater is distributed unequally all over the world – some countries have huge natural freshwater supplies, and some are very water scarce
  • Freshwater usage is only increasing as population increases 
  • Freshwater is used in the three following areas in society – agriculture, industry (energy generation and business), and municipal (household). Agriculture usually uses the most (around 70% of total), but in some countries industry uses almost as much as agriculture. Household usually uses about 10% or less.


Different Types Of Freshwater Sources

One of the most important freshwater sources to know about is renewable water resources.

These are defined as the average manual flow of rivers and recharge of aquifers generated from precipitation (precipitation from the atmosphere is what fills freshwater sources).

In layman’s terms – these are sources that are regenerated from the natural water cycle of rainfall, use and evaporation – and the cycle repeats itself.

From a sustainability perspective, if withdrawal rates (how much freshwater a country uses) stays within the renewable water supply rate, a country should have a better chance of staying out of water stress or water shortage territory (but there’s also natural events, climate change, socio-economic factors and other factors that can affect water supply).


According to, there are different types of freshwater sources such as:

  • Renewable freshwater sources – renewed by the water cycle. They represent the long-term average annual flow of rivers (surface water) and groundwater.
  • Non renewable freshwater sources – groundwater bodies (deep aquifers) that have a negligible rate of recharge on the human time-scale and thus can be considered non-renewable.
  • Natural freshwater sources – the total amount of a country’s water resources (internal and external resources), both surface water and groundwater, which is generated through the hydrological cycle
  • Human (actual) influenced freshwater sources – the sum of internal renewable resources (IRWR) and external renewable resources (ERWR), taking into consideration the quantity of flow reserved to upstream and downstream countries through formal or informal agreements or treaties and possible reduction of external flow due to upstream water abstraction. Unlike natural renewable water resources, actual renewable water resources vary with time and consumption patterns and, therefore, must be associated to a specific year.
  • Internal freshwater sources – water resources (surface water and groundwater) generated from endogenous precipitation i.e. water from within the country itself
  • External freshwater sources –  the part of a country’s renewable water resources that enter from upstream countries through rivers (external surface water) or aquifers (external groundwater resources) i.e. water from other countries
  • Surface Freshwater – rivers, lakes, streams etc. that are above ground
  • Groundwater Freshwater – underground aquifers of water


When freshwater sources are talked about, often the water quality is not taken into consideration i.e. whether it is contaminated, polluted or not suitable to drink or use.

Freshwater though does naturally contain a very little amount of dissolved salts and naturally occurs on the surface of the earth in lakes, rivers, caps, streams, ponds, icebergs, glaciers, and ponds.

Freshwater sources do not usually account for brackish, saline and non-conventional water sources.

You can read more about the different types of freshwater sources here – 


Freshwater Supply By Country

According to, total freshwater supplies in kilometres cubed (km3) are:

  1. Brazil – 8233
  2. Russia – 4508
  3. United States – 3069
  4. Canada – 2902
  5. China – 2840
  6. Colombia – 2132
  7. European Union – 2057
  8. Indonesia – 2019
  9. Peru – 1913
  10. India – 1911
  11. Democratic Republic Of The Congo – 1283
  12. Venezuela – 1233
  13. Bangladesh – 1227
  14. Myanmar – 1168
  15. Nigeria – 950

WorldAtlas describes where most of the freshwater in each of these countries is found, so their guide is worth a read.


Wikipedia also shows an extended list of 172 countries (which you can find in the sources part of this guide).


According to Food and Agriculture Organization, AQUASTAT data, and via, Renewable internal freshwater resources (internal river flows and groundwater from rainfall) per capita (per person, in cubic metres) worldwide are as follows:

5Papua New Guinea103,277.802014
9Solomon Islands77,671.052014
11New Zealand72,510.372014


How Is Freshwater Distributed By Sources


Of the Earth’s water, 97 percent is saline while 3 percent is freshwater (with low concentrations of dissolved salts and other total dissolved solids).

  • Nearly 69 percent is held in glaciers and ice caps.
  • Another 30 percent is groundwater that is held in underground soil and rock crevices
  • The remaining one percent is surface water and other sources.
  • Of that water considered to be surface water, 87 percent exists in lakes, 11 percent in swamps, and 2 percent in rivers.
  • The American Great Lakes account for 21 percent of the Earth’s surface fresh water.
  • Lake Baikal in Russia is considered the deepest, oldest freshwater lake in the world. It holds about 20 percent of the Earth’s unfrozen surface fresh water, the largest volume in the world.
  • Lake Victoria, which spreads across the African countries of Kenya, Uganda, and Tanzania, is the second largest freshwater lake in the world by surface area.
  • Africa’s Lake Tanganyika is the second deepest freshwater lake, and holds the second largest volume of fresh water. It’s the longest lake, and extends across Burundi, Zambia, Tanzania, and the Democratic Republic of Congo.

Different countries and states across the globe have their freshwater located in different sources, and access their usable and drinkable water from different sources.

If we take Indiana in the US as an example, groundwater supplies approximately 60 percent of the treated water delivered to homes and businesses for drinking, bathing, chores, and more. In a 2 year span, Indiana American Water proactively invested more than $130 million in its water and wastewater infrastructure around the state –

You can read more about how much water we have on earth


Variables That Can Affect Available Freshwater Supplies

A country may have enough freshwater for drinking and use, but people and businesses in that country may not get access to the water.

A country may also have declining freshwater supplies year on year despite not being a high usage country.

Why does this happen? Well, it can be for a few reasons:

  • Barriers to freshwater access – barriers can be physical or economic. Freshwater sources may be difficult from a logistical level to access, or the country may be a low income/low GDP country and may not financially be able to build and maintain water access infrastructure and equipment
  • Contamination and pollution of freshwater sources which lessens water quality – there may be access to freshwater, but those freshwater sources might not be well protected against potential contaminants (especially bacteria like E coli) and pollution
  • Poor governance and freshwater management plans – there may be enough freshwater supply and access to the water, but the water usage and management plans in place may not be adequate
  • Natural events – droughts, heat waves, floods (can cause contamination), change of seasons and monsoons, can all temporarily affect water supply levels
  • Human induced events – climate change and global warming can decrease freshwater supply levels

There are several water based issues we face on a global and at country levels that have their own set of problems, solutions and limitations 


Freshwater Usage On A Global Level

  • A growing global population and economic shift towards more resource-intensive consumption patterns means global freshwater use — that is, freshwater withdrawals for agriculture, industry and municipal uses — has increased nearly six-fold since 1900.
  • Rates of global freshwater use increased sharply from the 1950s onwards, but since 2000 appears to be plateauing, or at least slowing.
  • Evidence of that can be seen by looking at 2004 where the global population used 3.85 trillion cubic metres of freshwater, and 2014 where the global population used 3.99 trillion cubic metres of freshwater



Freshwater Usage/Withdrawal By Country (Withdrawal Rate)

Total Freshwater Withdrawals

Per, in 2014, the biggest users of freshwater were:

  • India had the largest freshwater withdrawals at over 760 billion cubic metres per year.
  • This was followed by China at just over 600 billion m
  • United States at 480-90 billion m3
  • Pakistan at 183.5 billion m3
  • and, Indonesia at 113.3 billion m3


Freshwater Withdrawals Per Capita, Per Year

Per, in 2010, the biggest users of freshwater per person were:

  • Iceland – 11,042 cubic metres (per person, per year)
  • Turkmenistan – 5,753 cubic metres
  • Chile – 2152 cubic metres
  • Uzbekistan – 2106 cubic metres


Renewable Internal Freshwater Withdrawals Per Capita

Renewable internal freshwater resources refers to the quantity of internal freshwater from inflowing river basins and recharging ground water aquifers.

According to OurWorldInData:

Per capita renewable resources depend on two factors: the total quantity of renewable flows, and the size of the population.

If renewable resources decline — as can happen frequently in countries with large annual variability in rainfall, such as monsoon seasons — then per capita renewable withdrawals will also fall. Similarly, if total renewable sources remain constant, per capita levels can fall if a country’s population is growing.

The trends we see for a lot of countries is a slow decline in renewable internal freshwater supplies based on withdrawal rates.

Brazil by far has the biggest per capita supply decrease from 1962 to 2014, going from over 70,000 cubic metres of water, to under 30,000 cubic metres.

In that same time span, the United States has gone from 15,106 cubic metres to 8,845 cubic metres.

China has gone from 4,225 cubic metres, to 2,016 cubic metres.

Average per person, per year, renewable freshwater withdrawal rates by region are as follows (in cubic metres):

  • South America – 30,428
  • Oceania – 29,225
  • Eastern Europe – 21,383
  • North America – 12,537
  • Central America and Caribbean – 8,397
  • Western & Central Europe – 4,006
  • Sub Saharan Africa – 3,879


Freshwater Usage/Withdrawal By Industry & Sectors (How & Where We Use Water)

Per findings and stats by 


Agriculture Water Usage/Withdrawal

Water is used in agriculture (food crop, livestock, biofuels, or other non-food crop production) from both rainfall, and pumped irrigation.

In 2010 India was the world’s largest agricultural water consumer at nearly 700 billion m3 per year. India’s agricultural water consumption has been growing rapidly  — almost doubling between 1975 and 2010 — as its population and total food demand continues to increase. China is the world’s second largest user, at approximately 385 billion min 2015, although its agricultural freshwater use has approximately plateaued in the recent past.

Globally we use approximately 70 percent of freshwater withdrawals for agriculture.

  • However, this share varies significantly by country – as shown in the chart below which measures the percentage of total freshwater withdrawals used for agriculture. Here we see large variations geographically and by income level. The average agricultural water use for low-income countries is 90 percent; 79 percent for middle income and only 41 percent at high incomes.
  • There are a number of countries across South Asia, Africa and Latin America which use more than 90 percent of water withdrawals for agriculture. The highest is Afghanistan at 99 percent. Countries in the global north tend to use a much lower share of water for agriculture; Germany and the Netherlands use less than one percent.


Irrigation Water Usage/Withdrawal 

Irrigation is the deliberate provision or controlled flooding of agricultural land with water.

The share of total agricultural area (which is the combination of arable and grazing land) which is irrigated:

  • is particularly prevalent across South & East Asia and the Middle East;  Pakistan, Bangladesh and South Korea all irrigate more than half of their agricultural area. India irrigates 35 percent of its agricultural area.
  • Levels of irrigation in Sub-Saharan Africa have increased, and continue to have, lower levels  of irrigation relative to South Asia and the Middle East & North Africa. Poorer progress in increasing crop yields in recent decades in Sub-Saharan Africa has been partly attributed (among other factors including fertilizer application rates and crop varieties) to lower uptake of irrigation in Sub-Saharan Africa.


Industrial (Business) Water Usage/Withdrawal

Water is used in industries and business in dilution, steam generation, washing, and cooling of manufacturing equipment. as well as cooling water for energy generation in fossil fuel and nuclear power plants (hydropower generation is not included in this category), or as wastewater from certain industrial processes.

  • The United States is the largest user of industrial water, withdrawing over 300 billion m³ per year.
  • This is significantly greater than China, the second largest, at 140 billion m³
  • Most countries across the Americas, Europe and East Asia & Pacific regions use more one billion m³ for industrial uses per year. Rates are typically much lower across Sub-Saharan Africa and some parts of South Asia where most use less than 500 million m³.

Globally, just under 20 percent (18-19 percent) of total water withdrawals are used for industrial purposes.

  • In contrast to the global distribution for agricultural water withdrawals, industrial water tends to dominate in high-income countries (with an average of 44 percent), and is small in low-income countries on average 3 percent).
  • Estonia uses the greater share of withdrawals for industrial applications at 96 percent. The share in Central and Eastern Europe tends to be greater than 70 percent; 80 percent in Canada; and approximately half in the United States. Across Sub-Saharan Africa and South Asia, this tends to contribute less than 10 percent to total withdrawals.


Municipal (household) Water Usage/Withdrawal 

The water we use for domestic, household purposes or public services. This is typically the most ‘visible’ form of water: the water we use for drinking, cleaning, washing, and cooking.

  • With the largest population, China’s domestic water demands are highest at over 70 billion m³ per year.
  • India, the next largest populace is the third largest municipal water user.
  • The United States, despite having a much lower population, is the second largest user as a result of higher per capita water demands.

Despite being the most visible use of freshwater, domestic demands for most countries are small relative to agricultural and industrial applications. Globally around 11 percent of withdrawals are used for municipal purposes.

  • The majority of countries use less than 30 percent of withdrawals for domestic purposes.
  • The share of municipal water in some countries across Sub-Saharan Africa can be high as a result of very low demands for agricultural and industrial withdrawals.
  • Domestic uses of water withdrawals can also dominate in some countries across Europe with high rainfall, such as the United Kingdom and Ireland where agricultural production is often largely rain fed and industrial output is low.



1. Hannah Ritchie and Max Roser (2018) – “Water Access, Resources & Sanitation”. Published online at Retrieved from: ‘’ [Online Resource]








The Water Crisis: Access To Usable Freshwater, & Clean/Safe Drinking Water

Lack Of Access To Clean/Usable Water, & Drinking Water

There are a number of different issues when it comes to water as a resource in different parts of the world.

One of those issues is being able to access safe/clean freshwater, to both use and drink.

Some countries have never had access to, or have had problems accessing safe/clean water to drink and to use – and these countries are sometimes referred to as being in a ‘water crisis’.

In this guide we discuss what the water crisis is, what causes access issues, the effects of a lack of sufficient access to non contaminated water, countries most affected, and how we can solve and prevent these water crisis issues.


Summary – What To Know About The Water Crisis

The water crisis is when there is a lack of access to safe and clean freshwater to either use or drink.

Low income and poverty stricken countries, those with high water pollution and contamination rates, those with small freshwater reserves (water scarce countries), rural areas, and high populated place can have issues with clean water access, and supply of fresh drinking water.

The solution depends on the circumstances of the water crisis – but it is usually multi pronged.

What is clear though is that clean and safe water is critical to any society to function and grow.

The impacts of having a lack of freshwater or clean drinking water are wide ranging and can be both life threatening and catastrophic.


The Different Global Water Issues

Before we get into talking about the water crisis in more depth, it’s important to get a general idea of the different water issues.

You can read a guide detailing the different global water issues and terms/phrases used to describe them here.

It’s really water access, and water quality we are talking about when we talk about the water crisis.

To put it in layman’s terms, the main steps finding for water to use or drink are:

  • find a freshwater source or sources
  • access it < main part of the water crisis
  • assess the quality of the water to make sure it’s suitable to use or drink, and treat it if necessary before using or drinking < part of the water crisis
  • make sure it stays protected from contamination or pollution while in use < part of the water crisis
  • manage the water source in terms of supply, withdrawal rates, natural events like droughts, growth in population, climate change etc.


The Water Crisis: Access To Usable Freshwater, & Clean/Safe Drinking Water

When we talk about the water crisis, we are mainly focussing on countries and regions that:

  • Don’t have sufficient physical or economic access to freshwater
  • Don’t have sufficiently protected freshwater to drink (protected against contamination or pollution that might make it unsafe to drink)
  • Don’t have sufficiently protected freshwater to use (protected against contamination or pollution that might make it unsafe to use). Note that water can be unsafe to drink, but safe to use for cleaning for example
  • Or, a combination of these factors/issues

The water crisis mainly affects low income/developing countries with access issues, but water quality in particular can affect developed countries (like the Flint, Michigan event).

It’s very important to note that there can be access/improved access to freshwater, but that doesn’t mean the water is of a quality to use or drink. Water quality is a separate issue to water access.


Improved Water Sources, & ‘Safe’ Water Sources For Drinking

One of the goals with water access is to get access to an improved water source. This can be defined as:

  • “An improved drinking water source includes piped water on premises (piped household water connection located inside the user’s dwelling, plot or yard), and other improved drinking water sources (public taps or standpipes, tube wells or boreholes, protected dug wells, protected springs, and rainwater collection).
  • Access to drinking water from an improved source does not ensure that the water is safe or adequate, as these characteristics are not tested at the time of survey.
  • But improved drinking water technologies are more likely than those characterized as unimproved to provide safe drinking water and to prevent contact with human excreta.
  • While information on access to an improved water source is widely used, it is extremely subjective, and such terms as safe, improved, adequate, and reasonable may have different meanings in different countries despite official WHO definitions.
  • Even in high-income countries treated water may not always be safe to drink.
  • Access to an improved water source is equated with connection to a supply system; it does not take into account variations in the quality and cost (broadly defined) of the service.”

– WorldBank, & UNICEF/WHO, via


Per WHO/UNICEF, via the

  • Some sources protect against contamination, but it still might not be safe to drink the water.
  • To be considered “safe”, a source of drinking water must be free from pathogens and high levels of harmful substances. Globally, the main health concern is faecal contamination, which is identified by the presence of bacteria such as E.coli.
  • In many places, a water point is designed to protect against contamination, but the water from it might still have traces of E.coli – the groundwater may be contaminated by faulty latrines, or the containers people use to carry and store water may contain traces of the bacteria.
  • In Nepal, 91% of the population drink from an improved water source, but E.coli has still been detected.


Causes Of Lack Of Access To Usable Freshwater, & Clean/Safe Drinking Water

Some of the major causes of a lack of clean usable water and safe drinking water in a country or region are:

  • Being a low income/low GDP country – not having the economic/financial capacity to set up and maintain safe access to freshwater. This is the main cause and it affects many African countries
  • Having high rates of water contamination and pollution – even if there is access to water, contamination lessens the water quality for use and drinking (e.g. it might have bacteria or pathogens in it, or get waste regularly dumped in it)
  • Not having large renewable freshwater reserves – limits the total available amount of freshwater accessible to use or drink
  • Living in a rural area – rural areas generally have bigger access issues than urban areas
  • Population growth and overpopulation – places increased economic and logistical strain on water access


Effects Of Lack Of Access To Usable Freshwater, & Clean/Safe Drinking Water

Humans depend on freshwater for almost every major thing we do in our societies, with notable things being:

  • Drinking
  • Cleaning
  • Food Production and Agriculture
  • Industrial & Commercial Output (Business Activity)

On top of that, the animals and natural environment around us need clean water to survive and thrive.


When there is a lack of clean usable water or drinking water, the following effects can occur:

  • Poor Human Health – examples are malnutrition (not drinking enough water), and higher rates of the transmission of infectious diseases such as diarrhoea, cholera, dysentery, typhoid, and polio. This is particularly the case with contaminated water and when there is a lack of water for proper sanitation –
  • Higher Spending on Public Health – more water access or water quality related health problems means more of a government’s expenditure must go towards health when it could go to other things.
  • Death and Higher Mortality Rates – Particularly with children. The WHO estimates that in 2015, the deaths of 361,000 children under 5-years-old could have been avoided by addressing water and sanitation risk factors. – WHO/
  • Poverty and Lack of Economic Growth – water access and water quality related issues contribute to poverty because obviously people either can’t work at all, or can’t work productively. In addition, the freshwater supplies aren’t there to run and grow business and economic activity. It’s worth noting that in countries where people have to walk longer distances to get water, this cuts into time they could spend working and earning money. Women and children in particular spend 258 million hours every day worldwide collecting water. This is time spent not working, caring for family members or attending school. –
  • Lack of Sanitation and Hygienesanitation and hygiene depend on available clean water
  • Lack Of Safety – walking long distances to get water can increase the risk of being assaulted or harmed – especially for women and children
  • Lack Of Education – if children have to walk to get water for themselves and their families, they miss out on school to do this


Trends And Progress In Access To Improved Water Sources, & Drinking Water


  • Access to improved water sources is increasing across the world overall, rising from 76 percent of the global population in 1990 to 91 percent in 2015.
  • This marks significant progress since 1990 where most countries across Latin America, East and South Asia, and Sub-Saharan Africa were often well below 90 percent.
  • In 1990, 1.26 billion people across the world did not have access to an improved drinking water source. By 2015, this had nearly halved to 666 million.
  • In 1990, 4 billion people had access to an improved water source; by 2015 this had increased to 6.7 billion. This means that over these 25 years the average increase of the number of people with access to improved drinking water was 107 million every year. These are on average 290,000 people who gained access to drinking water every single day.
  • In 1990 nearly 42 percent of those without access to an improved water source were in East Asia & the Pacific. By 2015, this had fallen to 20 percent. In contrast, Sub-Saharan Africa was host to 22 percent of those without water access in 1990; by 2015 this had increased to nearly half of the global total.
  • The absolute number of people without access has fallen across all regions over this 25-year period with the exception of Sub-Saharan Africa. The number of people in Sub-Saharan Africa without access to an improved water source has increased from 271 million to 326 million in 2015.
  • Access in current times remains lowest in Sub-Saharan Africa where rates typically range from 40 to 80 percent of households.
  • The share of rural households with improved water sources was lower than the total population in 2015, with 85 percent access. Gaining access to improved water sources can often require infrastructural investment and connection to municipal water networks; this is can be more challenging in rural areas hence we may expect access to be lower. Nonetheless, rural access has risen at a faster rate (based on the relative increase in the share of the population) than total access, increasing by 22 percent since 1990. –
  • Globally 97 percent of urban households had improved water access, with most nations now having close to 100 percent penetration.


Per, in 2018:

  • In 2015, 71% of the global population (5.2 billion people) used a safely managed drinking-water service – that is, one located on premises, available when needed, and free from contamination.
  • 89% of the global population (6.5 billion people) used at least a basic service. A basic service is an improved drinking-water source within a round trip of 30 minutes to collect water.
  • 844 million people lack even a basic drinking-water service, including 159 million people who are dependent on surface water.
  • Globally, at least 2 billion people use a drinking water source contaminated with faeces.
  • Contaminated water can transmit diseases such diarrhoea, cholera, dysentery, typhoid, and polio. Contaminated drinking water is estimated to cause 502 000 diarrhoeal deaths each year.
  • By 2025, half of the world’s population will be living in water-stressed areas.
  • In low- and middle-income countries, 38% of health care facilities lack an improved water source, 19% do not have improved sanitation, and 35% lack water and soap for handwashing.


Also per

  • 1.3 billion people with basic services, meaning an improved water source located within a round trip of 30 minutes
  • 263 million people with limited services, or an improved water source requiring more than 30 minutes to collect water
  • 423 million people taking water from unprotected wells and springs
  • 159 million people collecting untreated surface water from lakes, ponds, rivers and streams.


Per WHO/UNICEF, via the In 2015:

  • 663 million people – one in 10 – still drank water from unprotected sources (a protected source protects against contamination, whereas an unprotected one doesn’t).
  • In 41 countries, a fifth of people drink water from a source that is not protected from contamination
  • In most countries, the majority of people spend less than 30 minutes collecting water, or have a piped supply within their home. But in some regions, especially sub-Saharan Africa, many people spend more than 30 minutes – and some more than an hour – on each trip to collect water. This burden still falls mainly on women and girls – they are responsible for this task in eight in 10 households that don’t have a piped supply.
  • Mongolia is the only country where men and boys have primary responsibility for collecting water
  • In many parts of the world, water isn’t available all day everyday. In some provinces of South Africa, water supply in 60% of households has been interrupted for two days or more. In South Africa in 2014, a fifth of households with municipal piped water had interruptions that lasted for more than two days. This was three times higher in some regions of the country. Few countries have water available continuously, but in many parts of the world a less than 24-hour supply is still considered sufficient. Countries use a wide range of different measures to assess availability and these must match up so that comparisons of service levels can be made across countries and over time.
  • The cost of drinking water and sanitation is different in different countries – In Tanzania, 10% of the population spend more than 5% of their expenditure on drinking water


Countries & Places Without Access To Drinking Water

Access in 2015 remains lowest in Sub-Saharan Africa where rates typically range from 40 to 80 percent of households. 

The number of people in Sub-Saharan Africa without access to an improved water source has increased from 271 million in 2990, to 326 million in 2015. 

To put these numbers in context, almost half of people drinking water from unprotected sources worldwide live in sub-Saharan Africa, and eight in 10 live in rural areas.

East Asia and The Pacific make up 133 million, and South Asia also makes up 133 million. 



Countries With Water Pollution & Contamination Issues

Read more about water pollution and countries with water pollution issues in this guide 


Potential Solutions To Lack Of Clean Water, & Lack Of Drinking Water

Potential solution to manage and solve the water crisis might be:

  • Specifically provide aid and donations to low income countries and regions to help improve clean water access with infrastructure and water treatment technology
  • Aid, and investment in low income countries to help build them up economically so they can build and maintain clean water access equipment and technology
  • Reduce and better manage water pollution and contamination
  • Use water more efficiently at the household and business/commercial/industrial levels – particularly in high water stress countries
  • Better water management plans from the government level – particularly in high water stress countries
  • Adjust household, business and food production/agriculture activity in water stressed countries to activity that doesn’t use as much water e.g. switch to growing food that uses less water
  • Invest in freshwater supply technology (like desalination plants) – particularly in highly water stressed countries
  • Re-use of wastewater, to recover water, nutrients, or energy, is becoming an important strategy. Increasingly countries are using wastewater for irrigation – in developing countries this represents 7% of irrigated land. While this practice if done inappropriately poses health risks, safe management of wastewater can yield multiple benefits, including increased food production.
  • Invest more in low-cost techniques to test the quality of water people drink, especially for those who are not connected to regulated piped networks.


When looking at a water crisis solution, these notes can be considered:

  • Access to improved water sources generally increases with income of the country
  • Urban areas generally have better access to freshwater than rural areas
  • Agricultural water withdrawals tend to be higher at lower incomes
  • Globally, 70 percent of water withdrawals are used for agriculture. However, water requirements vary significantly depending on food type. Different foods have different water footprints
  • Different industries and sectors have different water footprints e.g. agriculture and textile industries are big water users



1. Hannah Ritchie and Max Roser (2018) – “Water Access, Resources & Sanitation”. Published online at Retrieved from: ‘’ [Online Resource]










Lack Of Access To Improved/Basic Sanitation, Hygiene & Open Defecation

World Sanitation, Hygiene & Open Defecation Issues

Availability of, and access to clean, safe water is an issue of it’s own.

But, it is closely linked to and also a cause of lack of sufficient and safe sanitation, and hygiene.

Open defecation is also an issue related to lack of sanitation.

In this guide we look at what these issues are, examples of them, why they happen, and what might be done to improve them.


Summary – What To Know About Sanitation, Hygiene & Open Defecation

Much of the world’s worst issues with sanitation, hygiene and particularly open defecation occur in developing (or under developed) countries in the lower GDP brackets (particularly in rural areas).

There’s dangerous human health and disease consequences because of these issues – particularly with young children.

Investing in access to clean water infrastructure, as well as human waste and hygiene facilities is obviously the big solution.

Having and directing the funds on the government and individual levels are the big barrier to making this happen.

Minimising water pollution and contamination will help, as well as finding better ways to spend external funding, and finding ways to stimulate the economy.

Access to clean water (that isn’t contaminated or polluted) is also important to sanitation, hygiene and human waste systems.


What Are The Lack Of Access To Improved/Basic Sanitation, Hygiene & Open Defecation Issues?

Lack Of Access To Basic Sanitation, & Improved Access To Sanitation

The lack of access to basic sanitation issue is essentially the percentage of people that do not have access to sanitation conditions or facilities to dispose of their waste safely and hygienically.

For places with a lack of access to sanitation, there is an aim for improved access to sanitation.


  • “An improved sanitation facility is defined as one that hygienically separates human excreta from human contact. They include flush/pour flush (to piped sewer system, septic tank, pit latrine), ventilated improved pit (VIP) latrine, pit latrine with slab, and composting toilet.
  • Improved sanitation facilities range from simple but protected pit latrines to flush toilets with a sewerage connection. To be effective, facilities must be correctly constructed and properly maintained.”

– WorldBank & WHO/UNICEF, via


  • Improved sanitation facilities include: flush or pour-flush to piped sewer system, septic tank or pit latrine; ventilated improved pit latrine; pit latrine with slab; and composting toilet.
  • Unimproved sanitation facilities include: flush or pour–flush to elsewhere; pit latrine without slab or open pit; bucket; hanging toilet or hanging latrine; no facilities or bush or field. 
  • The word ‘sanitation’ also refers to the maintenance of hygienic conditions, through services such as garbage collection and wastewater disposal. 



Open Defecation

  • “Refers to the percentage of the population defecating in the open, such as in fields, forest, bushes, open bodies of water, on beaches, in other open spaces or disposed of with solid waste.”



Types Of Sanitation

According to

  • Basic sanitation – refers to the management of human feces at the household level. Basic sanitation is the same as improved sanitation. This is facilities that ensure hygienic separation of human excreta from human contact. They include:
    • Flush or pour-flush toilet/latrine to a piped sewer system, a septic tank or a pit latrine.
    • Ventilated improved pit latrine.
    • Pit latrine with slab.
    • Composting toilet.
  • On-site sanitation – the collection and treatment of waste is done where it is deposited. Examples are the use of pit latrines, septic tanks, and Imhoff tanks.


Causes Of Lack Of Access To Basic Sanitation, & Open Defecation

Some of the overall causes of lack of access to sanitation, lack of access to improved sanitation and open defecation are:

  • Lack of access to clean, safe, fresh water (which is linked to sanitation because sanitation uses water)
  • Pollution or contamination of accessible freshwater sources
  • Not enough money to build sanitation facilities and infrastructure, and keep them maintained
  • Being a low income, poverty stricken, low GDP or less developed country or region (note that due to the health effects of poor sanitation and hygiene – poverty and lack of access to improved sanitation can be a cause of each other, which is a vicious cycle)
  • Living in rural areas as opposed to urban areas


Consider these findings from (

  • There is a general link between income level/GDP of a country and freshwater access
  • In addition to the large inequalities in water access between countries, there are can also be large differences within country
  • [rural areas compared to urban areas tend to have a lower share of sanitation facilities]
  • [The provision of sanitation facilities tends to increase with income]
  • [open defecation is mainly a rural issues] … Open defecation in urban areas is typically below 20 percent of the population. For rural populations, however, the share of the population practicing open defecation can range from less than 20 percent to almost 90 percent. 


Effects Of Lack Of Access To Basic Sanitation, & Open Defecation

There’s many effects, both direct and indirect, from not having access to sanitation, not having access to improved sanitation, and open defecation. Some of these include:

  • Overall lower human health and hygiene
  • Disease – transmission of infectious diseases such as diarrhoea, cholera, dysentery, typhoid, and polio.
  • Higher mortality rates, especially of children
  • Higher poverty rates, or lack of improvement in poverty rates
  • Severe impacts on malnutrition
  • In particular with open defecation, this can increase the rate of pathogens, toxins, nitrates and phosphates in the environment and harm the natural environment and ecosystem


Some more findings from & WHO in the impacts are:

  • The WHO estimates that in 2015, the deaths of 361,000 children under 5-years-old could have been avoided by addressing water and sanitation risk factors.
  • There are a number of important contributing factors to child mortality, including nutrition, healthcare and other living standards … But, in countries where open defecation is greater than 10 percent, typically more than 20 children per 1,000 die before their 5th birthday.
  • Contaminated drinking water, poor sanitation facilities and open defecation contribute to the transmission of infectious diseases such as diarrhoea, cholera, dysentery, typhoid, and polio, and can also have severe impacts on malnutrition.
  • Stunting — determined as having a height which falls below the median height-for-age WHO Child Growth Standards — is a sign of chronic malnutrition … [but is also linked to poor sanitation and hygience]


Other stats and findings on the effects of lack of sanitation are:

  • discusses a case study of lack of sanitation in Cape Town settlements –
  • Poor water and sanitation is the leading cause of diarrhoea, which is the second biggest cause of death among children under five, killing 760,000 each year. –
  • Poor water and sanitation can severely erode health and wellbeing gains made by food and nutrition programs. –
  • Illness and time spent collecting water also reduces school attendance and adults’ capacity to work and earn income. A 2012 World Bank study of 18 African countries found they lose 1-2.5 percent of GDP – around US$5.5 billion – every year due to poor sanitation. –
  • 272 school days are lost each year due to water related diseases –
  • 80% of childhood disease is related in some way to unsafe drinking water, inadequate hygiene and poor sanitation –
  • Every 20 seconds a child dies as a result of poor sanitation. –


How Many People Lack Of Access To Improved/Basic Sanitation, & Progress On The Issue

From (which has great charts and data on access to sanitation and open defecation + water access):

  • The total number of people without access to improved sanitation has remained almost constant from 1990 to 2015: in 1990 this figure was 2.49 billion, and in 2015 it reduced to 2.39 billion.
  • Total world population has of course grown in total though over this period
  • This means the % of the population without access has decreased (which is an improvement)
  • This population growth also means the total number with access has increased from 2.8 billion in 1990 to nearly 5 billion in 2015.
  • From 1990-2015, a share of 29 percent of the global population gained access to sanitation.
  • But, share of people gaining access to improved sanitation is growing at different rates in different countries and regions and better effort needs to be made that countries and areas lagging behind are helped out


From –  844 million people lack access to safe water, while 2.5 billion people live without improved sanitation. have a good fact sheet on access to sanitation and open defecation – 


Access To Safe Sanitation By Country, & Regions


  • Of the total number of people without access to improved sanitation facilities by region, over 90 percent of those without access in 2015 resided in Asia, the Pacific or Sub-Saharan Africa.
  • The largest region share was from South Asia, accounting for 40 percent and nearly one billion without access. This was followed by Sub-Saharan Africa with nearly 30 percent (706 million), and East Asia & Pacific with around 22 percent (520 million).
  • There remains large inequalities in levels of access to improved sanitation across the countries in the world
  • In 2015, the total share of the population with access to improved sanitation across Europe, North America, North Africa and some of Latin America is typically greater than 90 percent (and in most cases between 99 and 100 percent).
  • Between 80 and 90 percent of households in Latin America and the Caribbean have improved sanitation.
  • Access is slightly lower across Central and East Asia, typically between 70 and 80 percent.
  • In South Asia, progress has been varied. Sri Lanka has achieved a 95 percent access rate; Pakistan and Bangladesh both have access of over 60 percent; whereas India lags behind in this regard with just under 40 percent.
  • Regionally, access is lowest in Sub-Saharan Africa where most countries have less than 40 percent access rates.
  • In South Sudan, only 6-7 percent of the population had improved sanitation in 2015.
  • Within each country, rural areas generally have lesser access to sanitation than urban areas


In Which Countries Are Open Defecation Rates Highest?


  • In 2015, 15 percent of the world’s population were still practicing open defecation, presenting a reduction of approximately half since 1990
  • Prevalence was highest in South Asia where the average share is 36 percent. India in particular still has high rates, with nearly 45 percent still using open defecation.
  • In Sub-Saharan Africa, this rate was 23 percent. However, some countries in particular — such as Niger, Chad, South Sudan and Eritrea — still have a prevalence between 60-80 percent.


According to, in 2011, 1.04 billion people still practiced open defecation. 


Potential Solutions To Lack Of Access To Improved Sanitation, Hygiene & Open Defecation Issues

Potential ways to increase access to improved sanitation and decrease open defecation are:

  • To increase access to safe freshwater
  • To manage water usage in water stressed countries more efficiently
  • To develop technology or develop plans in water stressed countries, or countries where water security is poor, to increase the amount of available and usable freshwater
  • To minimise water pollution and contamination of freshwater in countries where this is a problem
  • To develop, invest in and aid low income/low GDP countries economically so they can afford new water and sanitation facilities and infrastructure, and so they can maintain it. According to the United Nations World Health Organization (2014), every dollar invested in water and sanitation results in a $4.30 return in the form of reduced healthcare costs. –
  • Place specific focus on rural areas who lag in both sanitation and open defecation rates says:

  • “Reaching the Sustainable Development Goal (SDG) of access to safely managed water and sanitation services by 2030 will require countries to spend $150 billion per year. A fourfold increase in water supply, sanitation, and hygiene (WASH) investments compared to what is spent today, this is out of reach for many countries, threatening progress on poverty eradication.”


  • An example of an organisation helping with the sanitation issue is UNICEF. UNICEF’s water, sanitation and hygiene (WASH) team works in over 100 countries worldwide to improve water and sanitation services, as well as basic hygiene practices.
  • In one year, UNICEF’s efforts provided nearly 14 million people with clean water and over 11 million with basic toilets.




1. Hannah Ritchie and Max Roser (2018) – “Water Access, Resources & Sanitation”. Published online at Retrieved from: ‘’ [Online Resource]








Water Pollution: Causes, Sources, Effects & Prevention/Solutions

Water Pollution: Causes, Sources, Effects & Prevention/Solutions

Water pollution is one of the leading environmental issues in the world.

Pollution includes both fresh water pollution (lakes, rivers and groundwater), and ocean/marine water pollution.

In this guide, we’ve outlined what water pollution is, as well the types, causes, sources, examples, effects & prevention/solutions of water pollution.


Summary – What To Know About Water Pollution

  • Water pollution can involve pollution of ground water (freshwater), surface water (freshwater), or the ocean (saltwater)
  • Water can become polluted from a number of sources and in a number of ways
  • Agricultural run off (fertilizers, pesticides, agricultural chemicals, and animal waste) is the main cause of freshwater pollution
  • Sewage and wastewater are the main causes of ocean water pollution (More than 80 percent of the world’s wastewater flows back into the environment without being treated or reused)
  • These causes differ between developed and developing countries – in developing countries, lack of sewage waste treatment and lack of sanitation can lead to water pollution
  • Water pollution impacts humans who can experience a lack of drinking water or freshwater to use. It impacts animals who live in and drink the water. And there are environmental effects.
  • Water pollution is tied to other environmental issues like  eutrophication (oxygen dead spots in water where aquatic life can’t live), ocean acidification (carbon uptake by the ocean of the atmosphere’s carbon in the air), acid rain (rains down on water sources) and other environmental issues
  • Potential solutions on the social level might be aimed at addressing agricultural pollution, and wastewater and sewage pollution 


What Is Water Pollution?

  • Water pollution occurs when harmful substances—often chemicals or microorganisms—contaminate a stream, river, lake, ocean, aquifer, or other body of water, degrading water quality and rendering it toxic to humans or the environment.



Types Of Water Pollution

Three types:

  • Surface water pollution (includes freshwater sources like rivers and lakes)
  • Ground water pollution (underground freshwater sources. Over time, water from rain and rivers seeps into the ground and accumulates within cracks or pores in the rocks (aquifers), forming groundwater under the earth’s surface.)
  • Salt water/ocean water (self explanatory)


Surface Water Pollution

  • Surface water from freshwater sources accounts for more than 60 percent of the water delivered to American homes. 



  • According to the most recent surveys on national water quality from the U.S. Environmental Protection Agency, nearly half of the rivers and streams, and more than one-third of the lakes are polluted and unfit for swimming, fishing, and drinking.



  • In specific numbers, a 2000 survey published in EPA’s National Water Quality Inventory found almost 40 percent of U.S. rivers and 45 percent of lakes are polluted
  • A major cause of this pollution in surface freshwater sources is fertilizer, pesticides and animal waste from agriculture. A lot of this pollution simply runs off the land and is nonpoint (coming from not one point, but many points) source pollution



You can read more about surface water pollution and contamination here – 


Groundwater Pollution

  • Nearly 40 percent of Americans rely on groundwater, pumped to the earth’s surface, for drinking water. For some people in rural areas, it’s their only freshwater source.



  • Some figures say groundwater use for drinking use in the USA is as high as 50%



  • Groundwater gets polluted when contaminants—from pesticides and fertilizers to waste leached from landfills and septic systems—make their way into an aquifer, rendering it unsafe for human use.
  • Ridding groundwater of contaminants can be both difficult and costly.
  • Once polluted, an aquifer/groundwater source may be unusable for decades, or even thousands of years.
  • Groundwater can also spread contamination far from the original polluting source as it seeps into streams, lakes, and oceans.



You can read more about groundwater contamination and pollution here – 


Marine/Ocean Water Pollution

  • Eighty percent of ocean pollution originates on land—whether along the coast or far inland.



  • Contaminants such as chemicals, nutrients, and heavy metals are carried from farms, factories, and cities by streams and rivers into bays and estuaries; from there they travel out to sea. 
  • Meanwhile, marine debris—particularly plastic and other waste—is blown in by the wind or washed in via storm drains and sewers.
  • Seas also suffer oil pollution (spills, and general oil pollution from cars and household) and are consistently soaking up carbon pollution from the air. The ocean absorbs as much as a quarter of man-made carbon emissions.



You can read more about ocean/marine water pollution facts here – 


The Point At Which Water Is Polluted

Water isn’t always polluted at one single source or point. The points at which water is polluted are:

  • Point Source (pollution from a single point/source)
  • Non Point Source (pollution from multiple points/sources)
  • Transboundary (pollution from over the border/another country)


Point Source Water Pollution

  • Examples include wastewater (also called effluent) discharged legally or illegally by a manufacturer, oil refinery, or wastewater treatment facility, as well as contamination from leaking septic systems, chemical and oil spills, and illegal dumping.



Nonpoint Source Water Pollution

  • Nonpoint source pollution is contamination derived from diffuse (spread out or scattered) sources. These may include agricultural or stormwater runoff or debris blown into waterways from land.



  • Nonpoint source pollution is the leading cause of water pollution in U.S. waters, but it’s difficult to regulate, since there’s no single, identifiable culprit.



Transboundary Water Pollution

  • Transboundary pollution is the result of contaminated water from one country spilling into the waters of another.
  • Contamination can result from a disaster—like an oil spill—or the slow, downriver creep of industrial, agricultural, or municipal discharge.



  • Another way to say it is, sometimes pollution that enters the environment in one place has an effect hundreds or even thousands of miles away.
  • One example is the way radioactive waste travels through the oceans from nuclear reprocessing plants in England and France to nearby countries such as Ireland and Norway.



Causes & Sources Of Water Pollution (Human, & Natural)

Causes of water pollution can be natural, or anthropogenic (caused by humans).

Read more about the causes of water pollution and contamination in this guide.


  • Natural causes include things like naturally decaying plant matter, naturally occurring water bacteria and organisms, animal waste (from wild animals), and natural events like volcano eruptions, earthquakes, flooding and tsunamis that contaminate water sources.
  • However, by far and away … human based sources … are the main contributors to water pollution.



Some of the most common and major causes and sources of human based water pollution are:

  • Agricultural pollution (a major cause of pollution in freshwater lakes, rivers etc.)
  • Sewage and wastewater pollution (a major cause of pollution in oceans)
  • Oil pollution
  • Radioactive pollution
  • Chemical waste
  • Plastic Waste
  • Alien species pollution
  • Heat/Thermal pollution
  • Sediment pollution
  • Air pollution
  • + more

You can read more about each of these in the FAO, NRDC, EPA, UNESCO,


Agricultural Pollution

  • Around the world, agriculture is the leading cause of water degradation. 

– FAO/


  • In the United States, agricultural pollution is the top source of contamination in rivers and streams, the second-biggest source in wetlands, and the third main source in lakes. It’s also a major contributor of contamination to estuaries and groundwater. 



  • Every time it rains, fertilizers, pesticides, and animal waste from farms and livestock operations wash nutrients and pathogens—such bacteria and viruses—into our waterways.
  • They often seep from the soil they absorb into, into these water sources.
  • Nutrient pollution, caused by excess nitrogen (nitrates) and phosphorus (phosphates) in water or air, is the number-one threat to water quality worldwide and can cause algal blooms, a toxic soup of blue-green algae that can be harmful to people and wildlife.



  • Nutrient pollution is the leading type of contamination for freshwater sources (rivers, lakes, streams etc.) in particular. While plants and animals need these nutrients to grow, they have become a major pollutant due to farm waste and fertilizer runoff. 



Together, fertilizers AND sewage can cause a massive increase in the growth of algae or plankton that overwhelms huge areas of oceans, lakes, or rivers.

Eutrophication is when a body of water becomes overly enriched with minerals and nutrients that induce excessive growth of plants and algae. Eutrophication is almost always induced by the discharge of nitrate or phosphate – containing detergents, fertilizers, or sewage into an aquatic system.


Sewage and Wastewater Pollution

  • Used water is wastewater. It comes from sinks, showers, and toilets (think sewage) and from commercial, industrial (factories), and agricultural activities (think metals, solvents, and toxic sludge).
  • The term also includes stormwater runoff, which occurs when rainfall carries road salts, oil, grease, chemicals, and debris from impermeable surfaces into our waterways.



  • More than 80 percent of the world’s wastewater flows back into the environment without being treated or reused, according to the United Nations; in some least-developed countries, the figure tops 95 percent.



  • Sewage contains all kinds of other chemicals, from the pharmaceutical drugs people take to the paper, plastic, and other wastes they flush down their toilets.
  • When people are sick with viruses, the sewage they produce carries those viruses into the environment. It is possible to catch illnesses such as hepatitis, typhoid, and cholera from river and sea water.



  • In the United States, wastewater treatment facilities process about 34 billion gallons of wastewater per day. These facilities reduce the amount of pollutants such as pathogens, phosphorus, and nitrogen in sewage, as well as heavy metals and toxic chemicals in industrial waste, before discharging the treated waters back into waterways. 
  • That’s when all goes well. But according to EPA estimates, the USA’s aging and easily overwhelmed sewage treatment systems also release more than 850 billion gallons of untreated wastewater each year.



  • Another way to say the above is – around half of all ocean pollution is caused by sewage and waste water. 
  • Each year, the world generates perhaps 5–10 billion tons of industrial waste, much of which is pumped untreated into rivers, oceans, and other waterways. In the United States alone, around 400,000 factories take clean water from rivers, and many pump polluted waters back in their place. 
  • However, there have been major improvements in waste water treatment recently. Since 1970, in the United States, the Environmental Protection Agency (EPA) has invested about $70 billion in improving water treatment plants that, as of 2015, serve around 88 percent of the US population (compared to just 69 percent in 1972). 
  • However, another $271 billion is still needed to update and upgrade the system. 
  • Factories are point sources of water pollution, but quite a lot of water is polluted by ordinary people from nonpoint sources; this is how ordinary water becomes waste water in the first place. 



Oil Pollution 

  • Consumers account for the vast majority of oil pollution in our seas, including oil and gasoline that drips from millions of cars and trucks every day.



  • Nearly half of the estimated 1 million tons of oil that makes its way into marine environments each year comes not from tanker spills but from land-based sources such as factories, farms, and cities.



  • At sea, tanker spills account for about 10 percent of the oil in waters around the world, while regular operations of the shipping industry—through both legal and illegal discharges—contribute about one-third.



  • Oil is also naturally released from under the ocean floor through fractures known as seeps.



Radioactive Substance Pollution (Nuclear Pollution)

  • Radioactive waste is any pollution that emits radiation beyond what is naturally released by the environment. 
  • It’s generated by uranium mining, nuclear power plants, and the production and testing of military weapons, as well as by universities and hospitals that use radioactive materials for research and medicine. 
  • Radioactive waste can persist in the environment for thousands of years, making disposal a major challenge.



  • The decommissioned Hanford nuclear weapons production site in Washington cleanup of 56 million gallons of radioactive waste is expected to cost more than $100 billion and last through 2060.



  • Accidentally released or improperly disposed of contaminants threaten groundwater, surface water, and marine resources.



  • At high enough concentrations it can kill; in lower concentrations it can cause cancers and other illnesses.
  • The biggest sources of radioactive pollution in Europe are two factories that reprocess waste fuel from nuclear power plants: Sellafield on the north-west coast of Britain and Cap La Hague on the north coast of France.
  • Both discharge radioactive waste water into the sea, which ocean currents then carry around the world. Countries such as Norway, which lie downstream from Britain, receive significant doses of radioactive pollution from Sellafield. 
  • The Norwegian government has repeatedly complained that Sellafield has increased radiation levels along its coast by 6–10 times. Both the Irish and Norwegian governments continue to press for the plant’s closure. 



Other Water Pollution Causes & Sources…

Some of these sources are related to the above sources, whilst some are their alone separate sources:

Chemical Waste Pollution

According to

  • Chemical waste can come in varying forms and extremities.
  • They can come from households – like detergents and cleaning products.
  • But, they can come from commercial and industrial sources like factories, plants, and mines. We are talking about asbestos, lead, mercury, petrochemicals etc.
  • Detergents are relatively mild substances, while at the opposite end of the spectrum are highly toxic chemicals such as polychlorinated biphenyls (PCBs).( They were once widely used to manufacture electronic circuit boards)
  • Another kind of toxic pollution comes from heavy metals, such as lead, cadmium, and mercury. Lead was once commonly used in gasoline (petrol), though its use is now restricted in some countries.
  • Mercury and cadmium are still used in batteries (though some brands now use other metals instead). Until recently, a highly toxic chemical called tributyltin (TBT) was used in paints to protect boats from the ravaging effects of the oceans.
  • Ironically, however, TBT was gradually recognized as a pollutant: boats painted with it were doing as much damage to the oceans as the oceans were doing to the boats.



  • Virtually everyone pours chemicals of one sort or another down their drains or toilets. Even detergents used in washing machines and dishwashers eventually end up in rivers and oceans. So do the pesticides people use on their gardens. 
  • A lot of toxic and chemical pollution also enters waste water from highway runoff. Highways are typically covered with toxic chemicals—everything from spilled fuel and brake fluids to bits of worn tires (themselves made from chemical additives) and exhaust emissions. 
  • When it rains, these chemicals wash into drains and rivers. It is not unusual for heavy summer rainstorms to wash toxic chemicals into rivers in such concentrations that they kill large numbers of fish overnight. 
  • It has been estimated that, in one year, the highway runoff from a single large city leaks as much oil into our water environment as a typical tanker spill. Some highway runoff runs away into drains; others can pollute groundwater or accumulate in the land next to a road, making it increasingly toxic as the years go by. 



Plastic & Waste Pollution

Plastic is one of the most common things that washes up on a beach.

There are three reasons for this:

  • plastic is one of the most common materials, used for making virtually every kind of manufactured object from clothing to automobile parts;
  • plastic is light and floats easily so it can travel enormous distances across the oceans;
  • most plastics are not biodegradable (they do not break down naturally in the environment), which means that things like plastic bottle tops can survive in the marine environment for a long time. (A plastic bottle can survive an estimated 450 years in the ocean and plastic fishing line can last up to 600 years.).

While plastics are not toxic in quite the same way as poisonous chemicals, they nevertheless present a major hazard to seabirds, fish, and other marine creatures.



When we look at waste in general, littering, improper waste disposal and dumping in landfills can cause waste to spill over into water sources.

In addition to plastic, glass, aluminum, styrofoam, cigarette butts and more can be found in water sources. 


Alien Species Pollution (Biological Pollution)

  • Most people’s idea of water pollution involves things like sewage, toxic metals, or oil slicks, but pollution can be biological as well as chemical.
  • In some parts of the world, alien species are a major problem. Alien species (sometimes known as invasive species) are animals or plants from one region that have been introduced into a different ecosystem where they do not belong.
  • Outside their normal environment, they have no natural predators, so they rapidly run wild, crowding out the usual animals or plants that thrive there. Examples are Zebra Mussels, algae, jellyfish, clams etc.  In 1999, Cornell University’s David Pimentel estimated that alien invaders like this cost the US economy $123 billion a year.



Heat Or Thermal Pollution

  • Heat or thermal pollution from factories and power plants also causes problems in rivers.
  • By raising the temperature, it reduces the amount of oxygen dissolved in the water, thus also reducing the level of aquatic life that the river can support.



Sediment Pollution

  • Another type of pollution involves the disruption of sediments (fine-grained powders) that flow from rivers into the sea.
  • Dams built for hydroelectric power or water reservoirs can reduce the sediment flow. This reduces the formation of beaches, increases coastal erosion (the natural destruction of cliffs by the sea), and reduces the flow of nutrients from rivers into seas (potentially reducing coastal fish stocks).
  • Increased sediments can also present a problem. During construction work, soil, rock, and other fine powders sometimes enters nearby rivers in large quantities, causing it to become turbid (muddy or silted).
  • The extra sediment can block the gills of fish, effectively suffocating them. Construction firms often now take precautions to prevent this kind of pollution from happening.



Air Pollution 

Air pollution can cause water pollution in some of the following ways:

  • Ocean Acidification –  is the ongoing decrease in the pH of the Earth’s oceans, caused by the uptake of carbon dioxide (CO2) from the atmosphere. – Wikipedia –
  • Acid rain – SO2 and NOX  emitted into the air from fossil fuel burning, vehicles and manufacturing react with water, oxygen and other chemicals to form sulfuric and nitric acids.  These then mix with water and other materials before falling to the ground. It can get into water sources via the soil it has polluted and fallen onto –
  • Global Warming –  a result of greenhouse gases like carbon dioxide contributing to climate change and causing an increase in water temperature 


Other Pollutants

  • Underground storage leakages
  • Damming of rivers –
  • Deforestation


Summary Of Pollutants 

  • Microorganisms, toxins, pathogens – from waste water, sewage, animal waste (agriculture)
  • Chemicals & Nutrients – fertilizer, pesticides/herbicides, detergents, cleaning products, oils (oil spills, household oils, and car oil), PTBs, phosphates, nitrates
  • Heavy Metals – lead, mercury, cadmium etc,
  • Hard Waste – plastic, aluminium, cigarette butts, glass etc.
  • Air Pollution – carbon, other air pollutants that mix together
  • Soil Pollution – seep and runoff from soil
  • Natural Pollution – plant decay, natural waste and bacteria, natural events

This is not an extensive list – just some of the main contaminants.


Ocean/Marine Water Pollution

  • As a summary to the above for saltwater – around half of all ocean pollution is caused by sewage and waste water



Freshwater Pollution

  • As a summary to the above for freshwater – agricultural pollution (fertilisers, pesticides/herbicides and animal waste) is the top source of contamination in rivers and streams, the second-biggest source in wetlands, and the third main source in lakes. It’s also a major contributor of contamination to estuaries and groundwater.



Effects Of Water Pollution

Some water pollution is inevitable as a result of human and economic activity – it can’t completely be eliminated.

However, water pollution also has human, environmental and economic costs – so it’s in everyone’s best interests to minimise it or find a way to address it.


Some of the effects are as follows:

Human Health Effects

  • Water pollution can cause death. It caused 1.8 million deaths in 2015, according to a study published in The Lancet.



  • Contaminated water can also make you ill. Every year, unsafe water sickens about 1 billion people. And low-income communities are disproportionately at risk because their homes are often closest to the most polluting industries.



Pathogens are found in polluted/contaminated water and diseases spread in the water include cholera, giardia, and typhoid.


  • Thousands of people across the United States are sickened every year by Legionnaires’ disease (a severe form of pneumonia contracted from water sources like cooling towers and piped water), with cases cropping up from California’s Disneyland to Manhattan’s Upper East Side.



  • Flint, Michigan was the result of cost-cutting measures and aging water infrastructure creating a lead contamination crisis



  • The problem goes far beyond Flint and involves much more than lead, as a wide range of chemical pollutants—from heavy metals such as arsenic and mercury to pesticides and nitrate fertilizers—are getting into water supplies. Once they’re ingested, these toxins can cause a host of health issues, from cancer to hormone disruption to altered brain function. Children and pregnant women are particularly at risk.



  • Even swimming can pose a risk. Every year, 3.5 million Americans contract health issues such as skin rashes, pinkeye, respiratory infections, and hepatitis from sewage-laden coastal waters, according to EPA estimates.



Environmental Effects

  • Interruption with how animals, plants, bacteria, and fungi in an ecosystem interact with each other
  • [algal blooms from excess nutrients like fertilizers can cause oxygen depleted dead spots in water – which aquatic animals can’t live in]
  • Chemicals and heavy metals from industrial and municipal wastewater contaminate waterways as well. These contaminants are toxic to aquatic life [and can find their way up the food chain when big animals eat smaller ones]



  • Marine ecosystems are also threatened by marine debris, which can strangle, suffocate, and starve animals. [plastic and fishing gear are two big examples of this]



  • Meanwhile, ocean acidification is making it tougher for shellfish and coral to survive. Though they absorb about a quarter of the carbon pollution created each year by burning fossil fuels, oceans are becoming more acidic. 



Economic Effects

On top of the human health and environmental effects of water pollution, there are also economic effects such as:

  • Cleaning up oil spills
  • Killing fish which harms the fishing industry
  • Treating humans who get sick from water pollution
  • Costs to lost tourism
  • Costs of lower supplies of freshwater – restriction or increased prices can restrict business growth and employment

Plus much more. 


How To Measure Water Quality

It should be noted that water quality depends on the purpose for the water, or what you want to use it for.

For example, water that could be unfit for human consumption could be still usable in industrial or agriculture applications like irrigation.


Once you know the purpose of the water, there are two main ways of measuring the quality of water:

Chemical Indicators

  • One is to take samples of the water and measure the concentrations of different chemicals that it contains.


Biological Indicators

  • Another way to measure water quality involves examining the fish, insects, and other invertebrates that the water will support.
  • If many different types of creatures can live in a river, the quality is likely to be very good; if the river supports no fish life at all, the quality is obviously much poorer.


Water Pollution & Quality – Developing vs Developed Countries

Access to, and availability of safe drinking and usable water (and also sanitation) is certainly an issue in developing countries.

A lack of income certainly plays a role in this – not being able to purchase and set up drinkable and useable water infrastructure, and having the same financial restrictions with sanitation and waste water/sewage treatment facilities and infrastructure.

However, water pollution is more of a country by country issue which depends on a lot of factors.

Water quality in developing countries is often hampered by lack of or limited enforcement of:

  • emission standards
  • water quality standards
  • chemical controls
  • non-point source controls (e.g. agricultural runoff)
  • market based incentives for pollution control/water treatment
  • follow-up and legal enforcement
  • integration with other related concerns (solid waste management)
  • trans-boundary regulation on shared water bodies
  • environmental agency capacity (due to resources or lack of political will)
  • understanding/awareness of issues and laws

– Wikipedia


Having said this, developed countries also face significant issues of their own with an excess of resources at the consumer and household level producing contaminants and waste, and the various business, industries and agriculture sectors doing the same.


Countries That Pollute Water The Most

According to, the 7 biggest water polluting countries are:

  1. China
  2. United States
  3. India
  4. Japan
  5. Germany
  6. Indonesia
  7. Brazil


  • As an example in China, 54% of the Hai River basin surface water is so polluted that it is considered un-usable



  • Another example is India, where 80% of the health issues come from waterborne diseases. Part of this challenge includes addressing the pollution of the Ganges (Ganga) river, which is home to about 400 million people.
  • The river receives about over 1.3 billion litres of domestic waste, along with 260 million litres of industrial waste, run off from 6 million tons of fertilizers and 9,000 tons of pesticides used in agriculture, thousands of animal carcasses and several hundred human corpses released into the river every day for spiritual rebirth.
  • Two-thirds of this waste is released into the river untreated.

– GlobalWaterForum/Treehugger/Wikipedia


Countries With Some Of The Worst Water Quality

According to, the 10 countries with the poorest water quality in 2017 are:

  1. India
  2. Nigeria
  3. Democratic Republic Of The Congo
  4. Papua New Guinea
  5. China
  6. Haiti
  7. Russia
  8. Ethiopia
  9. Indonesia
  10. Afghanistan


Potential Water Pollution Solutions, & How To Prevent It

You can read more about potential solutions to water pollution in this guide.


On an individual level – we can use environmentally friendly detergents and household products, not pour oil and harmful chemicals down drains, maintain our cars and make sure they don’t leak, reduce pesticides and fertilisers in our gardens, recycle as opposed to use plastic, and so on.

We can take community action too, by helping out on beach cleans. We can also take action as countries to support and pass laws and regulations (like the the Clean Water Rule, which clarifies the Clean Water Act’s scope and protects the drinking water of one in three Americans) that will make pollution harder and the world less polluted.














Outdoor Air Pollution: Causes, Sources, Effects & Prevention/Solutions

Outdoor Air Pollution: Causes, Sources, Effects & Prevention/Solutions

When it comes to air pollution, there are two main types – indoor air pollution, and outdoor air pollution.

This guide focuses on ambient outdoor air pollution, and we look at causes, sources, examples, effects and potential ways to prevent or solve it.


(*It should be noted that general ambient outdoor air pollution is a lower atmosphere issue which has a separate set of sub issues to deal with than upper atmosphere Greenhouse Gases, Carbon emissions and Climate Change/Global Warming (all of which also affects the outside air environment).

This is a guide specifically about lower atmosphere (non Greenhouse gas) ambient outdoor air pollution.)


Summary – What To Know About Outdoor Air Pollution

First off, outdoor air pollution should be distinguished from greenhouse gas emissions (an upper atmosphere air issue) and global warming – these are separate issues.

Outdoor air pollution is mainly the release of air contaminants into the air that not only lower air quality and contribute to a range of human illnesses (and related deaths), but also contribute to other environmental issues like acid rain for example.

Combustion of fossil fuels in the generation of electricity, industrial activities, and the operation of vehicles/cars are huge emitters of air pollutants. In cities and densely populated areas – vehicles and road transport is the main source.

Air pollution is particularly heavy around cities and heavily populated areas, as it’s mainly an issue caused by humans.

We can measure the levels of outdoor air pollution with outdoor air quality indexes, amongst other measures.

Side effects can be lowering in air quality for humans, which can have health effects, but also environmental side effects like acid rain for example.

The World Health Organisation (WHO) highlights air pollution as the greatest environmental risk to human health – but a changing climate may be the biggest risk in the future.

Cleaner electricity sources like wind and solar, and cleaner vehicle technology (developing electric battery, hybrid, hydrogen and other vehicle types) could go a long way to helping us decrease outdoor air pollution.

You can read about examples of cities that have done something about their air pollution in this guide.


What Is Outdoor (Ambient) Air Pollution?

  • Air pollution in general can be defined as the ’emission of harmful substances to the atmosphere [i.e. the outside environment]’

– OurWorldInData


[Outdoor air pollution] usually has a harmful effect on the living and non-living things that breathe in, absorb or come into contact with that air – such as humans, animals and even the ocean.


Air Pollution Contaminants

When we talk about outdoor air pollution, we are usually talking about the following pollutants:

  • particulate matter (PM10, & PM2.5) (small suspended particles of varying sizes)
  • sulphur dioxide (SO2)
  • nitrogen oxides (NOx)
  • ozone (O3)
  • carbon monoxide (CO)
  • and volatile organic compounds (VOCs)


  • Some of these pollutants are emitted singularly, but some form when two or more pollutants mix together.
  • For example, SO2 and NOx can react in the Earth’s atmosphere to form particulate matter (PM) compounds

– OurWorldInData


  • Note that carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), ozone (O3), and synthetic gases, such as chlorofluorocarbons (CFCs) and hydrofluorocarbons (HFCs) are more likely to be treated as upper atmosphere/ozone greenhouse gases



Causes, Sources & Examples Of Outdoor Air Pollution

  • The sources and causes of the pollutants listed above can vary
  • They can come from both non-natural, and natural sources.
  • However, most are generally linked to human sources like fuel combustion and industrial (factories, business etc.) activities; pollutants are released as by-products of these processes

– OurWorldInData


  • Examples [of sources might] include petrol and diesel vehicles, burning fuel in houses for cooking and heating (Cookers, heaters, stoves and open fires), emissions from power generation, factories and business, and agriculture.

– British Lung Foundation


Specific examples of air contaminants include:

  • sulphur dioxide (SO2) – About 99% of the sulfur dioxide in air comes from human sources. The main source of sulfur dioxide in the air is industrial activity that processes materials that contain sulfur, eg the generation of electricity from coal, oil or gas that contains sulfur. [and, industrial activities and motor vehicles] –
  • Sulphur dioxide can also be produced by volcanoes – Wikipedia


  • nitrogen oxides (NOx) – comes from the burning of fossil fuels like coal, oil and gas. Most of the nitrogen dioxide in cities comes from motor vehicle exhaust (about 80%) – Can also come from electrical storms via electrical discharge, and plants, soil and water – although only a very small amount comes from these natural sources. Other sources of nitrogen dioxide are petrol and metal refining, electricity generation from coal-fired power stations, other manufacturing industries and food processing. Unflued gas heaters and cookers are the major sources of nitrogen dioxide in Australian homes –


  • ozone (O3) – Tropospheric, or ground level ozone, is not emitted directly into the air, but is created by chemical reactions between oxides of nitrogen (NOx) and volatile organic compounds (VOC). It is formed when pollutants emitted by cars, power plants, industrial boilers, refineries, chemical plants, and other sources chemically react in the presence of sunlight –


  • particulate matter (PM10, & PM2.5) (small suspended particles of varying sizes) – Particulate matter, also known as particle pollution or PM, is a term that describes extremely small solid particles and liquid droplets suspended in air. Particulate matter can be made up of a variety of components including nitrates, sulphates, organic chemicals, metals, soil or dust particles, and allergens (such as fragments of pollen or mould spores). Particle pollution mainly comes from motor vehicles, wood burning heaters and industry – Health.NSW.Gov.Au. 
  • Most particles form in the atmosphere as a result of complex reactions of chemicals such as sulfur dioxide and nitrogen oxides, which are pollutants emitted from power plants, industries and automobiles. Some are emitted directly from a source, such as construction sites, unpaved roads, fields, smokestacks or fires. –
  • The friction of brakes and tyres on the road also creates particulate matter. – British Lung Foundation


  • carbon monoxide (CO) – It is a product of combustion of fuel such as natural gas, coal or wood. Vehicular exhaust contributes to the majority of carbon monoxide let into our atmosphere. In 2013, more than half of the carbon monoxide emitted into our atmosphere was from vehicle traffic and burning one gallon of gas will often emit over 20 pounds of carbon monoxide into the air. – Wikipedia/Union Of Concerned Scientists, is produced in the incomplete combustion of carbon-containing fuels, such as gasoline, natural gas, oil, coal, and wood. The largest anthropogenic source of CO in the United States is vehicle emissions. –


  • volatile organic compounds (VOCs) – VOCs comprise volatile hydrocarbons and other organic molecules released into the atmosphere. They may have biogenic or anthropogenic sources. In the UK it is estimated that less than 5% of the VOCs (2.3 million tonnes per year, expressed in terms of carbon) emitted into the atmosphere are emitted from vegetation. The rest comes from transport, including distribution and extraction losses (50%), solvent use (30%) and other industrial processes (15%). Road transport alone accounts for 30% of VOC emissions. –
  • Common VOCs include acetone, benzene, ethylene glycol, formaldehyde, methylene chloride, perchloroethylene, toluene and xylene. –


  • Overall, in towns and cities, the main source of air pollution is road transport

– British Lung Foundation


  • Other more minor sources may include smoke from bushfires, windblown dust, and biogenic emissions from vegetation (pollen and mould spores)

– NSW Government


How Much Outdoor Air Pollution Is Released Each Year, & What Are The Trends (Increasing or Decreasing)?

Obviously different cities and countries release different amounts of outdoor air pollution and have different policies and measures in place to control outdoor air pollution.

But, here are some amounts and trends from different countries:

  • sulphur dioxide (SO2) – In the US, sulfur dioxide emissions have been decreasing, and are down to 2709 thousand tons in 2016 –
  • Air quality regarding sulfur dioxide in improving in the US –
  • In Australia, the amount of sulfur dioxide in air is at acceptable low levels in most Australian towns and cities. – In Australia, the highest concentrations of sulfur dioxide in the air are found around petrol refineries, chemical manufacturing industries, mineral ore processing plants and power stations. –


  • nitrogen oxides (NOx) – There’s been a 60% decrease in the US national average of nitrogen dioxide from 1980 to 2017 –
  • In the US, there was 12,412 thousand tons of nitrogen oxide emissions in 2014 –
  • In Australia, since the early 1990s, even the highest levels of nitrogen dioxide reached in most Australian towns and cities are thought to be acceptable for humans. –


  • ozone (O3) – there’s been a 32% decrease in ground level ozone national average in the US from 1980 to 2017 –


  • particulate matter (PM10, & PM2.5) (small suspended particles of varying sizes) – there’s been a 41% decrease in the particulate matter 2.5 national average in the US from 1980 to 2017. There’s also been a 34% decrease in the particulate matter 10 national average in the US from 1980 to 2017  – 
  • Particle pollution is a major air quality issue in Australia. –


  • carbon monoxide (CO) – there’s been a 84% decrease in the carbon monoxide national average in the US from 1980 to 2017 – 
  • In most Australian towns and cities, the levels of carbon monoxide in air are below levels that are hazardous for human health. Only larger cities, like some capital cities, have the potential to have harmful levels of carbon monoxide. –


  • and volatile organic compounds (VOCs) – there are different VOC’s such as Butadiene, Dichlorobenzene,  Benzene, Chloroform, Methylene Chloride, m,p-Xylene, o-Xylene, and Toluene.
  • has done some studies on the levels of these VOCs across the NY state. VOCs particularly affect indoor air quality—concentrations of many VOCs are consistently higher indoors (up to 10 times higher) than outdoors. –


OurWorldInData also shows levels of the different levels of different air pollutants over the years. You can see that there was a huge increase up until 1970/1980 for most regions, followed by a steady decline –

Although some pollutants have decreased since 1980, there has been small increases or flatlines in progress in the years before 2017. Particulate matter 10 levels are one example of this – with minimal progress being made since 2004.


Effects Of Outdoor Air Pollution

  • Outdoor air pollution can have an impact on human health, damage to ecosystems, food crops and the built environment 
  • The World Health Organisation (WHO) highlights air pollution as the greatest environmental risk to human health (note that this is based on current risk, and that longer-term environmental threats such as climate change may exceed this in the future). 
  • The World Health Organization estimates that 3 million people die from ambient outdoor pollution every year

– OurWorldInData/WHO


  • Although that number can vary by up to a million depending on the source and year you read it from.
  • It is important to emphasize the difficulties in directly attributing deaths to air pollution. A ‘death’ from air pollution is defined as someone who dies prematurely (could be in the range of months or years) than would be expected in the absence of air pollution.
  • In many cases, air pollution exacerbates pre-existing cardiorespiratory illnesses—individuals suffering from asthma, for example, are particularly vulnerable.

– OurWorldInData/


The three key sources of air pollution deaths are from the indoor burning of solid fuels (indoor air/household pollution), exposure to ambient outdoor ozone (O3), and ambient outdoor particulate matter (PM) pollution.

In 2015, deaths from these 3 pollutants were as follows (as total %’s):

  • Ozone – 3.45%
  • Particulate Matter – 57.54%
  • Indoor Air Pollution/Solid Fuels – 38.72%

– OurWorldInData


Aside from death, ambient outdoor air pollution can cause other health related problems such as:

  • sulphur dioxide (SO2) – affects people when it is breathed in. People most at risk are those with asthma or breathing conditions. It irritates the nose, throat, and airways to cause coughing, wheezing, shortness of breath, or a tight feeling around the chest. –


  • nitrogen oxides (NOx) – causes increased likelihood of respiratory problems. Nitrogen dioxide inflames the lining of the lungs, and it can reduce immunity to lung infections. This can cause problems such as wheezing, coughing, colds, flu and bronchitis. People with asthma, and in particular children and older people are most at risk. –


  • ozone (O3) – ground level ozone can cause the muscles in the airways to constrict, trapping air in the alveoli. This leads to wheezing and shortness of breath. People with asthma and children, older adults, and people who are active outdoors, especially outdoor workers are most at risk. There are other health issues ground ozone can cause as well –


  • particulate matter (PM10, & PM2.5) (small suspended particles of varying sizes) – Studies have linked exposure to particle pollution to a number of health problems including respiratory illnesses (such as asthma and bronchitis) and cardiovascular disease. In addition, the chemical components of some particles, particularly combustion products, have been shown to cause cancer. These effects are often more pronounced for vulnerable groups, such as the very young and the elderly. Particle pollution is the major cause of reduced visibility. –


  • carbon monoxide (CO) – Increased levels of carbon monoxide reduce the amount of oxygen carried by haemoglobin around the body in red blood cells. The result is that vital organs, such as the brain, nervous tissues and the heart, do not receive enough oxygen to work properly. For healthy people, the most likely impact of a small increase in the level of carbon monoxide is that they will have trouble concentrating. Some people might become a bit clumsy as their coordination is affected, and they could get tired more easily. People with heart problems are likely to suffer from more frequent and longer angina attacks, and they would be at greater risk of heart attack. Children and unborn babies are particularly at risk because they are smaller and their bodies are still growing and developing. –


  • volatile organic compounds (VOCs) – Different VOCs have different health effects, and range from those that are highly toxic to those with no known health effect. Breathing low levels of VOCs for long periods of time may increase some people’s risk of health problems. Several studies suggest that exposure to VOCs may make symptoms worse in people who have asthma or are particularly sensitive to chemicals. –


Countries Where Outdoor Air Pollution Can Be An Issue

Some interesting trends in air pollution related deaths according to OurWorldInData are:

  • Death rates from air pollution—across countries of all income levels—have shown a general decline over the last few decades. [usually] by more than 50 percent.
  • Globally, it’s estimated that outdoor air pollution resulted in 4.2 million deaths in 2016; this represents an increase from 3.4 million in 1990. Overall, we see that the majority of pollution-related deaths are in Asia – South, Southeast and East Asia alone accounted for nearly 3 million in 2016.

You can read more about air pollution related deaths by type, country and more here – 


We’ve also put together a guide that details the countries where outdoor and indoor air pollution might be the worst.


Measuring Outdoor Air Pollution – Air Quality Index

  • One way to measure and keep track of outdoor air pollution in a particular area or city is with an Air Quality Index.
  • An Air Quality Index can give you a range of information, but should usually tell you the main pollutants in an area and give you a general health rating for the air in that area.
  • There are large online sites that keep track of the Air Quality Index (such as WAQI, Airnow and AQICN), and individual governments also have their own tracking programs.
  • The NSW Government in Australia for example has their own air monitoring networks where they measure particles (PM10, PM2.5), sulfur dioxide (SO2), carbon monoxide (CO), ozone (O3), nitrogen dioxide (NO2) and visibility. Wind speed and direction, air temperature and humidity are also recorded


  • In metropolitan areas (greater Sydney, Newcastle, and Wollongong regions), the main air pollutants of concern are ozone (O3) and particles (particulate matter or PM). For regional areas in NSW, particle pollution is the main concern.

– NSW Government


Countries & Cities With The Most & Least Polluted Outdoor Air In The World

Obviously pollution can vary from city to city within a country, and even from year to year.


  • For example, the most polluted city in a 2016 report, Zabol in Iran, has had its pollution level cut fourfold in the latest version of the database, and now appears to be cleaner than Australia’s capital Canberra
  • Based on the amount of particulate matter under 2.5 micrograms found in every cubic metre of air, Indian regions and cities are the most polluted in the world in 2018, followed by China. Some places in Saudi Arabia are also highly polluted



  • Egypt, Mauritania, Libya, Niger, Cameroon and Pakistan also show high mean annual averages of migrograms per cubic meter of PM 2.5 air pollution in 2015 
  • Some of the least polluted countries in the world in terms of mean annual averages of migrograms per cubic meter of PM 2.5 air pollution in 2015 are Kirbati, Samoa, Brunei, Solomon Islands, Sweden, Finland, Australia, Canada, United States, New Zealand, Norway, Spain, and Iceland. 
  • It’s important to note that there is an additional key factor at play, which has some impact on pollution concentrations over time and space: the weather. Local weather conditions, and seasonal and weather patterns have an important influence on the year-round fluctuations in exposure levels reported in each place

– OurWorldInData


Potential Solutions To, & Prevention Of Outdoor Air Pollution

Solutions to, and prevention of outdoor air pollution involves a wide ranging approach.

It’s definitely not a simple issue with one simple solution, and no solution is perfect.

It really does centre around reducing, or finding alternatives to fuel combustion and other human related air pollution producing activities, and becoming more environmentally friendly with the way we run our households and businesses/industries.


Some things that might be done to reduce the level of outdoor air pollution and lower pollutant emissions are:

  • Switching to electric vehicles
  • Reducing reliance on vehicles in heavily populated cities, and favoring public transport and walking/bikes
  • Switching to cleaner renewable energy over fossil fuels for households and business/industry, and agriculture
  • Switch to diets and agriculture that produces less air contaminants, or becoming more environmentally friendly with production

People can also check air quality websites to see how polluted the air is in the city or area they are living. Moving to places with less air pollution can be an option for better short term and long term health.



1. Hannah Ritchie and Max Roser (2018) – “Air Pollution”. Published online at Retrieved from: ‘’ [Online Resource]


























Indoor Air Pollution: Causes, Sources, Effects & Prevention/Solutions

Indoor Air Pollution: Causes, Sources, Effects & Prevention/Solutions

When it comes to air pollution, there are two main types – indoor, and outdoor air pollution.

This guide focuses on indoor air pollution, and specifically in parts of the world where it causes the most harm – which is mostly the poorer/lower income countries and regions.

We look at causes, sources, examples, effects and potential ways to prevent or solve it.


Summary – What To Know About Indoor Air Pollution

It’s goes without saying that indoor air pollution happens inside dwellings and buildings, and not out in the atmosphere.

Much of the most harmful indoor air pollution happens in developing countries where people don’t have access to safe electricity and energy production (natural gas or renewable energy, for example).

People use solid fuels (like wood and organic matter) for cooking, cleaning, heating etc.

A range of health related diseases and illnesses can occur as a result of particulates and other air contaminants that enter the air.

Providing cleaner, safer energy to people to use within dwellings and their houses could go a long way towards helping with the issue of indoor air pollution.


What Is Indoor Air Pollution?

Indoor air pollution is a change in the Indoor Air Quality, usually by the introduction of an air contaminant, that has a harmful effect on any living thing that consumes that air


  • Indoor Air Quality ‘refers to the air quality within and around buildings and structures, especially as it relates to the health and comfort of building occupants’



There’s really two distinct types of indoor air pollution – indoor air pollution in developed countries, and indoor air pollution in poorer parts of the world.


Causes, Sources & Examples Of Indoor Air Pollution

  • Indoor air pollution in poorer parts of the world is far more severe, and is usually caused by the inefficient use of solid fuels for cooking and cleaning [and heating]
  • There is smoke and other contaminants released from burning non modern energy sources inside the house like wood, crop residues, dung, charcoal, coal and kerosene.

– OurWorldInData. 


  • In 2018, around 3 billion people still cook using polluting open fires or simple stoves fuelled by these types of fuels
  • Small particulate matter in smoke is one of the main indoor air pollutants [Small particles of less than 10 microns in diameter (PM10), are among the most dangerous]



  • Indoor air pollution in developed countries is less severe (but can still causes short and long term health problems) and is caused by things like mold, household sprays (aerosols for example), cleaning chemicals, garden sprays (insecticides for example) and so on.
  • Particulate matter, carbon monoxide and VOC’s also come from things like second hand tobacco smoke, the use of space heaters and paints/coatings.

– Wikipedia


Effects Of Indoor Air Pollution

Indoor air pollution can lead:

  • … acute lower respiratory disease, chronic obstructive pulmonary disease, cancers, and other illnesses.



  • In total, 2.6 million people died prematurely in 2016 from illness attributable to household air pollution

– OurWorldInData/Institute for Health Metrics and Evaluation (IHME)


The World Health Organisation says ‘close to 4 million people die prematurely from illness attributable to household air pollution from inefficient cooking practices using polluting stoves paired with solid fuels and kerosene. Household air pollution causes noncommunicable diseases including stroke, ischaemic heart disease, chronic obstructive pulmonary disease (COPD) and lung cancer’

Deaths are attributable to the following diseases in the following %’s:

  • 27% are due to pneumonia
  • 18% from stroke
  • 27% from ischaemic heart disease
  • 20% from chronic obstructive pulmonary disease (COPD)
  • 8% from lung cancer.

– World Health Organization (WHO)


  • Close to half of deaths due to pneumonia among children under 5 years of age are caused by particulate matter (soot) inhaled from household air pollution



The trends with indoor air pollution is:

  • Overall, ‘we see a decline in the number of pollution-related deaths since 1990, falling from 3.7 million to 2.6 million in 2016.’
  • It is predominantly women and young children who are killed by indoor air pollution

– OurWorldInData


Countries Where Indoor Air Pollution Can Be An Issue

  • Deaths from air pollution are ‘largely concentrated in Asia and Africa. Approximately three-quarters of all deaths in 2016 were in Asia, with 22-23 percent in Africa & the Middle East, and only a couple of percent across the Americas and Europe (with most of these originating in Latin America & the Caribbean)’. 
  • At the country level – ‘India followed by China had the highest mortality figures in 2016 with 783,000 and 605,000 respectively. These numbers have, however, shown a significant decline in recent years. In the last decade alone the number of deaths from household air pollution in China has approximately halved.’ 
  • This decline is ‘also true for countries in Sub-Saharan Africa (SSA) with high mortality figures. Ethiopia and Nigeria – who have the two highest death tolls in SSA – have both seen a inverse-U trend of increase-peak-decline since 1990. This is however not true everywhere: the Democratic Republic of Congo appears to still be on the upward slope of this pattern.’

– OurWorldInData

You can read more about indoor air pollution related death rates, overall trends, and how different countries are affected here –, and here 


Indoor Air Pollution In Developed Countries

Indoor air pollution in developed countries tends not to be anywhere near as severe:

  • … it might only usually result in short term side effects such as irritation of the eyes, nose, and throat, headaches, dizziness, and fatigue. But, some more severe cases can also cause long term health side effects.
  • People most at risk might be people who may be exposed to indoor air pollutants for the longest periods of time such as the young, the elderly and the chronically ill, especially those suffering from respiratory or cardiovascular disease. People with breathing conditions like asthma also
  • In developed countries, ‘while pollutant levels from individual sources may not pose a significant health risk by themselves, most homes have more than one source that contributes to indoor air pollution. There can be a serious risk from the cumulative effects of these sources.’



Potential Solutions For Indoor Air Pollution/How To Prevent It

  • In developing countries and poorer countries, the best way to prevent indoor air pollution and it’s harmful effects it is to switch to modern energy sources which don’t release smoke and other harmful indoor air contaminants.
  • This involves switching to non solid fuels for heating and cooking such as natural gas, ethanol or electric technologies.

– OurWorldInData


An example of where and how this might be occurring is with the AKON Lighting Africa Project, which is replacing solid fuels with clean and affordable electricity in the form of solar panels/solar energy.

Specifically, the following demographics may need more help with indoor air pollution prevention:

  • Low income countries and areas (that don’t have access to, or can’t afford cleaner energy)
  • Women and children
  • People in more isolated rural areas (vs more highly populated urban areas for example)

Improved design of stoves and ventilation systems can also reduce indoor air pollution in many poor communities, as well as raising more awareness about the issue to those most at risk



In developed countries, limiting the number of contaminants in or around your house, having proper ventilation, and keeping at risk people (those who spend a lot of time inside) in a part of the house with high air quality can help minimise the effects of indoor air pollution.




2. Max Roser and Hannah Ritchie (2018) – “Indoor Air Pollution”. Published online at Retrieved from: ‘’ [Online Resource]






A List Of Different Global Water Issues Words/Phrases, & What They Might Mean

The Different Phrases/Words Used To Describe Global Water Issues, & What They Mean

When we talk about global water issues, there are more than a few different phrases and words used to describe them.

The problem you may encounter, especially if you’re learning about these water issues for the first time, is that different sources use the same phrases to describe different issues to each other.

Because the phrases are used in different contexts in different industries, and by different organisations or individuals – there is no consensus definition/meaning for some or even most of them.

What we’ve tried to do in this guide is gather a general meaning on each phrase so you at least have a starting idea of what they might mean in relation to one another.

We hope this enables you to understand each water issue better and more clearly.

*We should differentiate between ocean (saltwater) and freshwater (drinkable/potable water) issues – this guide is mainly about freshwater and drinkable water issues

*Also note that we treat sanitation as separate (but equally important) to most water issues, because, although sanitation involves water, it also usually involves other factors like human waste, plumbing and pipe infrastructure for example


Water Availability

  • Water Availability is having fresh water sources (which may or may not be accessible) physically present within an area (like a city)
  • Very hot/dry or very cold/snowy regions for example may have lesser water availability


Water Access

  • Water Access is being able to physically and economically access the available fresh water in an area
  • There’s two types of water access – physical water access, and economic water access
  • Physical Water Access is being able to physically get to and use the available fresh water in an area
  • Fresh water is usually physically accessible as surface water (such as lakes, rivers, reservoirs) and less commonly in groundwater (found underground in rock or soil layers, and accessed through wells or natural springs), but not in snow, ice and glaciers
  • Fresh water might also be too far away, too deep in the ground, or you may not be able to create infrastructure or devices suitable enough to physically use/consume the water
  • Economic Water Access is whether a group of people have enough money to access the available fresh water around them, or build infrastructure to access the available water. This usually affects low income regions, and/or places with political instability


Water Quality

  • Water Quality essentially refers to whether the fresh water is safe to use or consume – either directly or after fresh water treatment
  • Fresh water sources can be contaminated for example with certain pollutants like chemicals and bacteria


Water Pollution

  • Water Pollution is any chemical, physical or biological change in the quality of water that has a harmful effect on any living thing that drinks, uses or lives (in) it – Lentech
  • Water pollution can be natural or caused by human activity


Water Resource Improvement, & Water Quality Improvement

  • Water Resource Improvement is improving water accessibility usually by improving water infrastructure or innovating (with water packs, water wells etc.)
  • Water Quality Improvement is improving water quality by cleaning up pollution and contaminants in a fresh water source, managing the source of the pollution to reduce or eliminate it, or creating polluted water treatment devices or systems (such as water purifiers)


Water Scarcity (A Lack Of Water Supply To Meet Demand)

  • You can read more in depth about water scarcity in this guide
  • Water Scarcity is more extreme than water stress, and occurs when water demand exceeds internal water resources


  • If the amount of renewable water in a country is below 1,700 m3 per person per year, that country is said to be experiencing water stress; below 1,000 m3 it is said to be experiencing water scarcity; and below 500 m3, absolute water scarcity.
  • An area could conceivably be highly water stressed, but not water scarce, if, for example, it had significant water pollution, but plentiful supplies of contaminated water

– Pacinst


Water Stress (Water Demand/Use Vs Supply Ratio)


  • Water stress is the ratio of total withdrawals to total renewable supply in a given area. A higher percentage means more water users are competing for limited water supplies, and therefore that area/country is more stressed 



  • Compared to Water Scarcity, Water Stress is a more inclusive and broader concept. It considers several physical aspects related to water resources, including water scarcity, but also water quality, environmental flows, and the accessibility of water

– Pacinst


  • Countries scarce on fresh water supply, or dry countries, are usually most likely to be water stressed because they have a smaller quantity of fresh water available, and therefore a smaller quantity of fresh water to use and consume. The more water they use and consume, the more water stressed they become
  • Water Stress is also a term used to describe countries that are using more fresh water than is being renewed annually – they can be stressing their water supply with high water use
  • If a country is using/withdrawing 80% or more of their total water supply, they might be classified as ‘highly water stressed’. You can read more about country water stress levels at
  • Some of the world’s projected most water stressed countries by 2040 are Bahrain, Kuwait, Qatar, San Marino, Singapore, United Arab Emirates and Israel – World Resources Institute. Read more about them at


The World Resources Institute (WRI) define baseline water stress based on the ratio of annual water withdrawals to renewable resources.

It defines water stress categories based on this percentage (% of withdrawals to renewable resources) as follows:

  • <10% = low stress
  • 10-20% = low-to-medium stress
  • 20-40% = medium-to-high stress
  • 40-80% = high stress
  • >80% = extremely high stress

– OurWorldInData/WRI


Water Shortage

  • A Water Shortage is when an area’s total quantity of clean fresh water is getting close to zero
  • Water Shortages can be created by many factors such as water use, water scarcity, water pollution, water stress, and more

You can read a case study of the Cape Town water shortage in this guide.


Water Security

  • Water Security is ‘the capacity of a population to safeguard sustainable access to adequate quantities of acceptable quality water for sustaining livelihoods, human well-being, and socio-economic development, for ensuring protection against water-borne pollution and water-related disasters, and for preserving ecosystems in a climate of peace and political stability’

– UN-Water


  • Water Security can be made up of water access (especially economic access), water scarcity, water pollution, water quality and other factors
  • You might say a country has good Water Security if they have high amounts of fresh water sources, good access to that water, and low usage/withdrawal rates (lower than annual average renewable supply levels)
  • High Water Stress countries tend to have poorer water security


Water Risk

  • Water Risk refers to the possibility [or probability] of an entity experiencing a water-related challenge (e.g. water scarcity, water stress, flooding, infrastructure decay, drought) 


  • The extent of risk is a function of the likelihood of a specific challenge occurring and the severity of the challenge’s impact 
  • The severity of impact itself depends on the intensity of the challenge, as well as the vulnerability of the actor [the area or country in question]

– CEOWaterMandate


  • Companies and organizations and governments cannot gain robust insight into water risk unless they have a firm understanding of the various components of water stress (i.e., water scarcity, accessibility, environmental flows, and water quality), as well as additional factors, such as water governance
  • Many water-related conditions, such as water scarcity, pollution, poor governance, inadequate infrastructure, climate change, and others, create water risk for many different sectors and organizations simultaneously

– Pacinst


The Water Crisis

  • A Water Crisis (or The Water Crisis) is a term generally used to describe a situation where people lack access to safe water, or access to a toilet 
  • In 2018, 1 in 9 people lack access to safe water, and 1 in 3 people lack access to a toilet 
  • There can be serious consequences to places experiencing a water crisis such as serious short term and long term health implications, and/or death
  • Areas in Africa, Asia & Latin America are where significant work is being done to improve the Water Crisis situation





2. Hannah Ritchie and Max Roser (2018) – “Water Access, Resources & Sanitation”. Published online at Retrieved from: ‘’ [Online Resource]









How Much Land Is There On Earth, & What Is It Used For?

How Much Land Is There On Earth? - Total, Inhabitable, Arable, Agricultural & Cultivated

This is a guide about how much land there is on earth.

Below we’ve outlined some of the more important land quantity and usage stats such as total land, habitable land, agricultural land and arable land.

We’ve also noted what arable land is used for, and countries that have the most cultivated land in total.

Note that these numbers are estimates, and are to be used as a general guide only.


Summary – How Much Land Is There On Earth?

  • About 29% of the total surface of the earth is land (the rest is water)
  • Of that, there is habitable land (that we can live on) and non habitable land, and agricultural (including land that livestock can be produced on) and arable land (more fertile land with topsoil for growing crops)


How Much Land Is There On Earth/In The World In Total?

  • Of the land’s total surface, about 29% of that surface is land, and 71% is ocean

The quantities that make up those %’s are:

  • Land – 149 million km², or 92.5 million mi.²
  • Ocean – 361 million km², or 224.3 million mi.²

– OurWorldInData/FAO


You can read more about the how much water there is on earth in this guide.


How Much Habitable Land Is There On Earth?

About 71% of the total land surface on earth is habitable, with the rest being glaciers (10%) and barren land (19%).

The quantities that make up those %’s are:

  • Habitable Land – 104 million km², or 64.6 million mi.²
  • Glaciers – 15 million km², or 9.32 million mi.²
  • Barren Land – 28 million km², 17.3 million mi.²

– OurWorldInData/FAO


How Much Agricultural/Farmable Land Is There On Earth?

Agricultural land includes arable land for crops, but also land that can be used for rearing livestock.


  • According to World Bank data, in 2015, approximately 37% of the world’s land surface was agricultural land.



  • Roughly between 32 and 36 million square kilometers (12 and 14 million square miles) of land is used to raise livestock

– Sciencing/University of Wisconsin-Madison


How Much Arable Land Is There On Earth?

Arable land just includes land that can be used for growing crops, and not livestock rearing land.


  • According to World Bank data, in 2015, approximately almost 11% of the world’s land surface was arable land.



  • Approximately 17.6 million square kilometers (6.8 million square miles) of land is used to grow crops

– Sciencing/University of Wisconsin-Madison


What Is The World’s Habitable Land Used For?

  • About 50% of the world’s habitable land is used for agriculture, 37% for forests, 11% for shrubland, 1% for urban development, and 1% is freshwater

– OurWorldInData/FAO


The quantities that make up those %’s are:

  • Agriculture – 51 million km², or 31.6 million mi.²
  • Forests – 39 million km², or 24.2 million mi.²
  • Shrubs – 12 million km², or 7.4 million mi.²
  • Urban – 1.5 million km², or 0.93 million mi.²
  • Freshwater – 1.5 million km², or 0.93 million mi.²


What Is The World’s Agricultural Land Used For?

  • Of the world’s land that is used for agriculture, about 77% is used for livestock rearing/meat and dairy production, and 23% is used for growing crops.

– OurWorldInData/FAO


The quantities that make up those %’s are:

  • Livestock – 40 million km², or 24.8 million mi.²
  • Crops – 11 million km², or 6.83 million mi.²

Even with the above numbers, it’s interesting to note that 83% of the world’s caloric consumption supply comes from plant based food, whilst only 17% comes from meat and dairy production. 

Likewise, about 67% of the world’s protein consumption supply comes from plant based food, whilst only 33% comes from meat and dairy. 

– OurWorldInData/FAO


  • Current estimates (as of 2017) put the remaining amount of farmable land at about 27 million square kilometers (10.5 million square miles), most of which is concentrated in Africa and Central and South America. 

– Sciencing


Of course, population growth significantly affects how much land we can or are using for agriculture at any one time.


What Is The World’s Arable Land Used For?

You can view a list of the world’s most valuable crops, and crop production by metric tonnes here –


In order, some of the top value producing crops are (not including meat and dairy):

  1. Rice, paddy
  2. Wheat
  3. Soybean
  4. Tomatoes
  5. Sugarcane
  6. Maize (corn)
  7. Potatoes
  8. Vegetables (not listed elsewhere)
  9. Grapes
  10. Cotton
  11. Apples
  12. Bananas
  13. Cassava (yuca)
  14. Mangos, Mangosteens, Guava
  15. Coffee
  16. Palm Oil
  17. Onion, dry
  18. Beans, dry and green
  19. Peanuts
  20. Olives

– Wikipedia/FAO


What Do Different Countries Use Their Cultivated Land For?

You can view a list of land use statistics by country here – 


In order, the countries with the most total cultivated land area are:

  1. India
  2. United States
  3. China
  4. Russia
  5. Brazil
  6. Canada
  7. Australia
  8. Indonesia
  9. Nigeria
  10. Argentina
  11. Ukraine
  12. Sudan
  13. Mexico
  14. Kazakhstan
  15. Turkey
  16. Pakistan
  17. France
  18. Thailand
  19. Iran
  20. Ethiopia

– Wikipedia/CIA World Factbook


Will We Have Enough Agricultural Land To Grow Food In The Future?

Read more in this guide about the future availability and capacity of agricultural land to grow/produce food into the future.



1. ( by Hannah Ritchie)