Better Meets Reality

Australia is one of the driest countries on Earth, and Perth is one of the driest cities in the world.

In this guide, we provide a case study on Perth’s water scarcity problems, and how they have addressed them (solutions)

Other dry countries and cities might be able to get ideas for their water scarcity issues.

Summary – Perth Water Scarcity Problems & Solutions

• Perth faced many of the same challenges as Cape Town (who experienced a recent water shortage) as a city – a rapidly growing population, a dry climate, the possible effects of climate change, decreasing rainfall and being drought prone, decrease of stream flows and flows into dams, a reliance on dams, and other factors.
• But, Perth was in a position to invest long term in options like large desalination plants and groundwater replenishment [whereas Cape Town didn’t … they relied on their dams]
• Perth’s drinking water supplies are now secure, but non potable water supply levels are decreasing 
• Several sources say that Perth’s long term approach should strongly lean towards treating and re-using the waste water that is dumped from the city into the ocean and other locations, and that more desalination plants are not necessarily the right answer (desalination plants come with their own drawbacks)
• Ultimately, what will be the best water scarcity solutions for a city in both the short and long term depends on local characteristics of the city (geology/geography, and hydrology), finances, and the social, economic, and environmental impact of the different water supply options
• Diversifying water sources, and less reliance on rainfall or natural/climate based factors for water supply is a good approach for all cities for the future, as it diversifies risk and makes a city less vulnerable to climate change and global warming
• Region and state officials and water managers from places like California have visited Perth to get ideas for their own water scarcity issues

First – Define What Type Of Water Is Scarce

Water supplies can be divided into potable (drinking) water, and non potable (non drinking) water.

These types of water can be sourced from different water sources, and these different water sources can be more scarce than another.

In Perth’s case:

• Drinking water is not running out for Perth, but non potable water is

– theconversation.com

Factors Contributing To Water Scarcity For Perth

The following factors contribute to Perth’s water scarcity issues:

• A Growing Population – a growing population can mean more of a demand for water over the long term. Perth’s population grew by more than a third from roughly 2004 to 2014 (bbc.com). We say ‘over the long term’ because year to year demand can actually decrease sometimes depending on things like water restrictions and water policy, with demand for water down by 8% [in 2013] compared with 2003 in Perth.
• Despite a rising population, water consumption has fallen from 191,000 litres to 131,000 litres per capita per year over the past decade in [Perth]. In comparison, for example, San Diego’s consumption is an estimated 249,000 litres per capita per year. (theguardian.com)
• Climate Change May Be Contributing To Dry Perth Climate – climate change and global warming may be major reasons making Perth’s climate drier, with declining rainfall and increased likelihood of droughts being a side effect of climate change
• Decreasing Rainfall/Precipitation Levels – average rainfall levels have decreased in the past few decades (bbc.com)
• Perth’s annual rainfall has been declining by about 3mm per year on average (theconversation.com)
• Decreasing Rain Into Water Supply Sources – decreasing rainfall means less rain is flowing into dams and other water supply sources … about one sixth of the water is currently flowing into dams compared to the past (bbc.com)
• Water flow from rainfall into Perth’s dams has slumped by 80% since the 1970s (theguardian.com)
• [Perth’s] rainfall has declined almost 20 per cent since the 1970s, and the amount of water flowing into the city’s dams has fallen from an average of 300 billion litres a year to just 25 billion litres. (abc.net.au)
• Rising Evaporation Rates – rising evaporation rates (which increase consumption and reduce water yields). The overall effect is that soils and vegetation are often dry, meaning that rainfall will be lost to evapotranspiration rather than running off into rivers and dams, or recharging underground aquifers (theconversation.com)
• Previous Supplies Of Freshwater Did Not Have Sufficient Capacity – [In 2013] Perth’s dams received just 72.4bn litres of water – far less than the 300bn currently demanded by Perth’s two million-strong population (theguardian.com)
• Annual Mean Temperature Anomaly Has Increased – by 1℃ in southwest Western Australia in the past 40 years (theconversation.com)
• Groundwater Levels In Perth Are Decreasing, & Aquifer/Groundwater Recharge Rates Are Unknown – Perth’s hydrology means that they can use their local natural sands and aquifers to store excess run-off from roads and roads. But, there’s been less excess water from winter rains. Unlike dam inflows, we don’t yet know the full scale of the reduction in natural groundwater recharge rates. About 70% of local road runoff and half of roof runoff already recharges the shallow unconfined aquifer, because it is the cheapest way to dispose of excess water in areas with sandy soils. As well as reducing discharge costs, this practice helps to ensure that bores do not run dry in summer. Perth also has large main drains that are designed to lower groundwater levels in swampy areas and prevent inundation. Some of these waters could be redirected into the aquifer where there is a suitable site [to help in recharging groundwater aquifers] (theconversation.com)

Where Does Majority Of Perth’s Water Supply Now Come From?

• Perth now relies chiefly on groundwater and desalination rather than dams
• Although both are much more expensive than dam water, desalination and groundwater replenishment look set to secure Perth’s drinking supply, because seawater is virtually unlimited, and wastewater availability increases in line with the city’s growth

– theconversation.com

• As of 2018, desalination provides almost half of Perth’s water needs while the other half comes from ground water

– abc.net.au

How Perth Is Solving Their Water Scarcity Problems 

Non Potable Water Supplies (non drinking water)

• Injecting Wastewater Into Groundwater Aquifers (Known as Groundwater Replenishment) – this is a method of recycling wastewater, where the waste water pass through sandy soil for filtering first (or gets treated separately), and then gets mixed with groundwater in aquifers, before clean water is extracted for drinking and irrigation. This has been a decade long trial for Perth that has turned out to be successful
• … treated wastewater is added to these aquifers where it blends with the groundwater and is extracted later for water supplies (theconversation.com)
• [the] treated wastewater … injected into underground supplies [has also been] re-used as drinking water (abc.net.au)
• Separate Wastewater Treatment Plants – an advanced water recycling plant can be expanded to produce 28bn litres of water each year when required … Groundwater replenishment could supply up to 20% of Perth’s drinking water needs by 2060 (theguardian.com)

Potable/Drink Water Supplies

• Desalination Plants – Large water desalination plants using sea water from the Indian Ocean via. Perth can get up to half it’s drinking water from these [two] desalination plants (bbc.com)
• These plants use reverse osmosis seawater desalination technology and provide nearly half of the city’s water supplies (theconversation.com)
• As of 2018, these plants have been able to provide one-trillion-litres of water (abc.net.au)

General Water Supply Solutions

• Awareness, & Cultural/Social View Of Water – Perth citizens see water as a scarce, valuable resource that is not to be wasted. This means they are theoretically less likely to waste it than if cultural and social norms didn’t place a high value on water.
• Openness to Drinking Recycled Water – citizens have to be open to drinking recycled water … this is easier to do if citizens view water as a valuable resource.
• Water Restrictions – for households (particularly for gardens, lawns and sprinklers) and per person. 
• Backyard Bores – some citizens in Perth have backyard bores … more than a quarter have them for watering their gardens.
• Recycling (Treating & Re-using) Wastewater – instead of dumping it or releasing it into the ocean. If we can filter/clean it, and re-use it sustainably – this opens up much more available water for water supply.
• Using Natural Environment For Water Supply Processing – such as natural sands for filtering, and groundwater aquifers as storage locations.
• Become Less Reliant On Rainfall – rainfall is usually relied upon to top up groundwater and above surface water sources like lakes, rivers etc. Becoming less reliant on rainfall takes natural water replenishment means a city can shield itself from the effects of climate change more effectively.
• Diversify Water Supply Sources – relying on 2, 3 or more water supply sources is just smart from a percentages standpoint. If one water supply is diminishing, there are other options. It also helps if these water supply sources depend on both natural and man made production and replenishment for more diversification – because you are then not reliant on the climate for water supply.
• Monitor Per Capita Water Usage – this is an indicator of how effectively water is being used. Knowing both potable and non potable water per capita water usage can help cities more effectively track their water management.
• Water Saving Training, Schemes & Fines – provide businesses with free training, help in data-gathering, and a certification scheme that allows them to promote themselves as water-conscious companies. Businesses and organisations that don’t meet requirements risk fines and will be ineligible for the recognition scheme. A total of 330 businesses have reportedly saved enough water to fill the equivalent of 20,000 Olympic-sized swimming pools since the Water Corporation started this project in 2007
• Water Saving Technology – organisations have made use of acoustic listening equipment to locate pipe leaks, helping to reducing water use by 10%, & other organisations have cut their water use by 25% by reducing the flow of their taps and installing dual-flush toilets, among other things. Perth’s largest theme park, Adventure World, checks water levels and pressure using real-time monitoring. If a leak is detected, maintenance to resolve the problem can be quickly deployed. Around 30m litres of water have been saved in the past two years this way. The theme park has also installed two new filters, at A$100,000 (£46,700) a piece, saving 30,000 litres of water a day in peak season (will take 5 years to pay itself off). (theguardian.com)
• Emphasise the importance of corporate social responsibility – for businesses and organisations to save water or use it efficiently.

Long Term Questions & Concerns With Perth’s Current Water Scarcity Solutions

The above solutions and approaches Perth has chosen to address their water scarcity problems aren’t perfect. They come with long term pros and cons to consider …

Desalination Plants

• Can be expensive to build and operate – desalination plants, depending on the size, can cost billions to build, and can be very expensive to operate.
• [plants] remain costly to maintain, even if they do not supply desalinated water [and they are only on standy by mode]
• Are energy intensive – this is especially a problem when running on fossil fuel combustion.
• Can contribute to climate change – if desalination plants run on fossil fuels and not primarily renewable energy, greenhouse gases are emitted. Wind and solar energy can help with this – but these forms of energy generation can be variable and hard to use as a primary energy source for such an energy intensive process as desalination.
• Western Australian carbon emissions per capita are now the highest in Australia and among the highest in the developed world [and, desalination plants only add to this] (theconversation.com)
• Cause increases water rates/prices – use of desalination plants can increase water bills for households because of the cost to run them and the energy they use.
• The average Perth household’s water bill has tripled since 2005–06 [up to 2015], even though water consumption per capita has dropped substantially over the past decade. This adds to cost of living. (theconversation.com)
• Can damage the environment – The marine environments of Perth’s desalination plants are sensitive to the hypersaline discharge that is produced in the purification process (theconversation.com)
• Can give people a false sense that there will be fresh water available forever – this is not the case … desalination plants are not an unlimited sustainable source of water for various reasons. They still have their drawbacks and concerns for long term use.

Recycling Wastewater By Natural Filtration & Injecting Into Groundwater Aquifers

• This process relies on local factors that may not be available every where or all the time – for a city or town to use this approach, they need sandy soil in the area that can naturally filter the wastewater, and aquifers that can take the waste water too. Other cities could build wastewater recycling plants, but there would be cost and feasibility questions to answer first. The way Perth has replenished the Gnangara groundwater resource seems more of a sustainable approach

Backyard Boreholes

• Boreholes bored into groundwater sources can deplete the aquifer they withdraw from – Citizens having backyard boreholes can compromise the water available to the public supply via groundwater and aquifers

In General

• All water supply sources have their own set of factors to consider short term and long term – New water sources for a city depend on when the water source is required (in terms of a timeline – how quickly), and the economics in terms of funding available and how much new water sources cost to create. You also have to consider social, environmental and economic impact overall.

What’s The Best Long Term & Sustainable Approach To Perth’s Water Scarcity Problems? – Can The Current Approach Be Improved Upon?

Several sources say an increased emphasis on treating and re-using/recycling waste water that is currently dumped into the ocean might be a more sustainable and feasible approach compared to the long term use of desalination plants …

Perth professors argue that treating and recycling waste water is a better long term approach than desalinations plants:

• [Perth has a large amount of waste water that goes straight into the ocean]
• [Perth should be sending waste water] into recharge or treatment to produce good water for public open space, even potable water
• The technology is there to treat any water — waste-water, storm water, any kind of water can be treated to perfection

– abc.net.au

On re-using more waste water instead of dumping it:

• About 140 billion litres of treated wastewater are discharged into the ocean every year in the Perth-Peel region. A further 7 billion litres are infiltrated into the sands as a means of disposal where there isn’t an option for ocean outfall. Recent investigations of these land disposal sites have shown them to be effective in protecting wetlands from drying and providing water for public and private irrigation.
• Investigations have also shown that the quality of treated wastewater can be greatly improved when infiltrated through the yellow sands into the limestone aquifer in the western part of Perth. It is suitable for irrigation after a few weeks’ residence within the aquifer.
• Without these kinds of measures, local governments will struggle to water parks and sports ovals, to protect Perth’s remaining wetlands, and to safeguard the trees that help keep us cool.
• So while drinking water supplies for an affluent city like Perth are reasonably secure, [the] vital non-drinking water supplies need to be augmented using some of the water [Perth] currently discharges into the ocean. As Perth gets even hotter and drier, and green spaces and wetlands are needed to provide much-needed cooling, [Perth] can no longer afford to let any water go to waste.

(theconversation.com)

Perth & Cape Town Have Similar Water Scarcity Causes, But Have Had Different Approaches To Their Situations

• [Perth faces] very similar climatic conditions to Cape Town.
• The difference between Cape Town and Perth is that [Perth has] been in a position to make long-term decisions to deal with climate change
• [In the midst of Cape Town’s water shortage, there was] Strict water restrictions amounting to 50 litres per person per day — Perth residents use an average of 335 litres a day
• Perth, much like Cape Town, was once almost entirely reliant on its dams.

– abc.net.au

• Perth is half the size of Cape Town in terms of population, but, inflows to water reservoirs are decreasing as a result of decreased rainfall and river inflows
• There’s also been significant population growth [in both Perth and Cape Town over the last few years to decades, and more population growth is expected]
• Perth has progressively sourced more and more of its supply from desalination and from groundwater extraction – [while] Cape Town has not done this

– theconversation.com

• Cape Town has small water capacity/supply per person from it’s dams
• Brisbane has 2,220,150 ML storage capacity for its 2.2 million residents. That amounts to just over one million litres per resident when storages are full.
• In comparison, Cape Town’s four million residents have a full storage capacity of 900,000 ML. That’s 225,000 litres per resident
• Cape Town is building a number of small desalination plants to deal with this 

– theconversation.com

Sources

1. https://www.bbc.com/news/world-asia-27225396

2. https://theconversation.com/drought-proofing-perth-the-long-view-of-western-australian-water-36349

3. https://www.abc.net.au/news/2018-06-21/how-perth-dodged-its-own-water-crisis-like-day-zero-in-cape-town/9891472

4. https://www.theguardian.com/sustainable-business/2015/oct/06/perth-western-australia-drought-climate-change-water

5. https://theconversation.com/cape-town-is-almost-out-of-water-could-australian-cities-suffer-the-same-fate-90933

6. https://theconversation.com/is-perth-really-running-out-of-water-well-yes-and-no-90857

You’ve been told before that water is important to society…but, have you been told the exact reasons why?

In this guide, we outline some of the most important reasons.

Summary – Why Water Is So Important To Society

• The reality is – there is a water footprint (the direct and indirect water it takes to produce, supply something from start to finish) for everything you do
• Water is used across all aspects of society, and those countries who don’t have access to clean and safe fresh water experience all sorts of serious problems
• Water comes in two main types – potable (drinking water), and non potable
• Water comes from various sources depending on the city – dams, ground water aquifers, lakes/rivers and lately desalination plants, are some of the main sources various developed countries use
• Water is used broadly across the agricultural, industrial and municipal (household) levels of society

Drinking Water

An obvious reason why we need water – to drink.

Drinking water should meet certain safety and quality standards set out in regulations and guidelines in a particular state/province or country.

Some countries and states can have contamination or safety issues with their public drinking water supply.

Although access to drinking water has improved for many people worldwide since 1990, the fact remains that:

• 785 million people lack even a basic drinking-water service, including 144 million people who are dependent on surface water.
• Globally, at least 2 billion people use a drinking water source contaminated with faeces

– who.int

Countries and regions that lack access to clean and safe drinking water face severe health and social problems.

Children are particularly at risk of sickness, disease and death in these places.

Health, Hygiene and Sanitation

Washing and human waste are key components of health, hygiene and sanitation. 

We need water for showers, baths, toilets, taps, and so on.

Developed countries tend not to have an issue with this, apart from those with contaminated public water supplies.

Lesser developed regions of the world are a different story though:

• In least developed countries, 22% of health care facilities have no water service, 21% no sanitation service, and 22% no waste management service
• 74% of the world’s population (5.5 billion people) used at least a basic sanitation service.
• 2.0 billion people still do not have basic sanitation facilities such as toilets or latrines.
• Of these, 673 million still defecate in the open, for example in street gutters, behind bushes or into open bodies of water.

– who.int

Spread of disease and sickness is huge in countries and regions without proper water supplies for health, hygiene and sanitation.

Agriculture

In most countries, irrigation for agriculture uses a majority of the annual fresh water consumption.

Food and fibers like livestock, crops, and cotton are some of the main consumers of water supplies.

Dry climates particularly rely on irrigation as they don’t usually have the rainfall levels required for rain fed farming.

Electricity Generation

Part of the industrial sector (the industrial sector, and electricity generation are usually the second biggest consumers of water, but can be equal to agriculture or slightly more in some countries.)

Some people don’t realise that the electricity we use can take a lot of water to produce.

Thermal plants usually have cooling towers that use water to cool the steam that passes through and spins the turbines.

But, newer cooling systems are making use of dry cooling, and lower water use technology, or even recycled or alternate water use methods. Some use air cooling too.

Transport

Manufacturing cars requires more water usage than most other products.

Water is also used at various points in the petroleum sourcing and refining process.

Water is also used to clean, service and repair cars and other vehicles.

Other Areas & Sectors That Use Water

Mining, construction, textiles, government, raw material production and supply, and many other sectors use water in everyday society.

It’s accurate to say all successful and healthy communities and countries need fresh water.

Sources

1. https://www.who.int/news-room/fact-sheets/detail/drinking-water

2. https://www.who.int/en/news-room/fact-sheets/detail/sanitation

3. Various Better Meets Reality Water Guides

The topics of Climate Change and Global Warming can take a significant amount of time to research for the average person.

This guide is a summary of all the key pieces of information relating to those issues.

It’s our most complete and updated guide that we’ve aimed at significantly cutting down the research time required for the average person to get an understanding of these issues and topics.

Summary – Climate Change & Global Warming 

Some of the key points to be aware of with climate change and global warming are:

• Since 1880 up until the present, the Earth has experienced a rate of climate warming that Earth has not seen in some time. Over that time, Earth’s climate has risen by between 0.8 to 1 degree celcius
• In the same time period, carbon dioxide levels (measured in parts per million) have risen to 411ppm. These are carbon dioxide levels we estimate we have not seen in at least the last 800,000 years (based on ice cores, deep sea sediment samples, tree rings and other ancient forms of Earth’s climate records), where carbon dioxide levels have averaged somewhere between 200 to 300 ppm
• In this time period, we also know how much of the carbon dioxide in the atmosphere is due to the burning of fossil fuels by humans
• Scientists have analysed many lines of data and evidence across various aspects of Earth’s climate
• Scientists have a good idea of all the natural, and non natural factors that impact the Earth’s climate at any point in Earth’s history
• Scientists currently have a lot of modern technology set up (satellites, sensors, buoys, gauges etc) to observe and record various measurements of the Earth’s climate and indicators/vital signs in the environment (ppm, sea level, surface temperature, ocean temperature etc.)
• Scientists have also run climate models simulating Earth’s past climate, and forecasting Earth’s future climate (climate models run on data, calculations, and assumptions fed into them by researchers/modellers)
• Based on all the data available, and the data that has been studied and analysed, various scientists and scientific organisation across the world think it is very likely Earth’s climate has been warmed over the last century or so by greenhouse gas emissions from human activity (burning of fossil fuels for energy like electricity, transport, industrial activity, and so on)
• It is put forward by some sources that if Earth’s climate was primarily being influenced by natural factors right now, the Earth would actually be cooling, not warming. We actually were in a cooling period for the last 6000 years before the current warming trend
• It should be noted that the Earth has been around for about 4.5 billion years in total, and we think we have a good idea of Earth’s temperature and climate stretching back as far as hundreds of millions of years (based on data from ice cores in Greenland and Antarctica, deep sea sediment samples, tree rings and other ancient forms of Earth’s climate records)
• But, to an extent, the strength of what we know about climate change now, is subject to the reliability/accuracy of these ancient Earth samples, climate models, and other lines of data, evidence, calculations, modelling, observations, Earth monitoring (with current day technology), and so on
• One way to look at climate change might be what we definitely know, what we think we know, and what we have some uncertainty about (because we can only forecast or make calculated guesses about some things due to variables and future unknown factors)
• Further to that, although it may not be able to be proved 100% that humans are directly sending Earth heading towards catastrophic levels of warming and climate change (where, for example, environmental feedback processes compound the warming cycle to a level where reducing our emissions will no longer matter), what the science and available data may indicate is that directly protecting against the risk of that scenario by significantly reducing our emissions is the smartest decision humans can make to protect their long term future and livelihood (rather than wait to be 99 or 100% sure we are the cause, and to wait and see what climate conditions are when that time comes)

What Is The Main Question Posed About Climate Change?

• Whether the recent warming trend we are seeing since 1880 (where global average surface temperature has increased 0.8 to 1 degree celcius up until the present – 2019) is caused primarily by greenhouse gas emissions from human activities (mainly from the burning of fossil fuels), or whether it’s primarily from natural factors/natural variability

What Is The Current Consensus On Climate Change?

• There is currently a consensus (from various scientists and organisations), based on all the lines of data and evidence available to us that have been studied and processed, that human emissions are extremely likely the cause of the climate warming over the last century or so (and natural factors are not)

Definition Of 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 [usually at least 30 years or more]
• [Climate can be contrasted with weather which is] the state of the atmosphere—its temperature, humidity, wind, rainfall and so on—over hours to weeks. It is influenced by the oceans, land surfaces and ice sheets, which together with the atmosphere form what is called the ‘climate system’

– science.org.au

So, the weather is part of what makes up the climate.

Some people unofficially describe the climate as the weather averaged out over the period of decades to centuries.

Definition Of Global Warming

• Global warming is a long-term rise in the average temperature of the Earth’s climate system, an aspect of climate change shown by temperature measurements and by multiple effects of the warming

– wikipedia.org

So, global warming is one aspect of climate change.

A Key Measurement Of The Earth’s Warming – Global Average Surface Temperature

• When sources refer to the warming trend, they usually reference …
• Global average above land surface temperature – which is the temperature of the air immediately above the ground

[Sometimes, sources also refer to the] Sea surface temperature – which can either be the temperature of the air immediately above the ocean water surface, or of the top millimeter to top 20 metres of water in various parts of the ocean (depending on the methodology being used)

You can keep up with the global above land surface temperature at https://climate.nasa.gov/vital-signs/global-temperature/

You can keep up with sea surface temperature at a site like https://earthobservatory.nasa.gov/global-maps/MYD28M

How Much Has The Earth’s Climate Warmed In The Last Century Or So?

• According to an ongoing temperature analysis … the average global temperature on Earth has increased by about 0.8° Celsius (1.4° Fahrenheit) since 1880. Two-thirds of the warming has occurred since 1975, at a rate of roughly 0.15-0.20°C per decade.

– earthobservatory.nasa.gov

Since 1990, there are various sources that indicate we have had some of our warmest years on record when compared to the last century or so.

For example:

• Earth’s global surface temperature in 2018 was the fourth warmest since modern record keeping began in 1880. Global temperatures in 2018 were 1.5 degrees Fahrenheit (0.83 degrees Celsius) warmer than the 1951 to 1980 mean
• Globally, 2018’s temperatures rank behind those of 2016, 2017 and 2015. The past five years are, collectively, the warmest years in the modern record.

– climate.nasa.gov

• Eighteen of the 19 warmest years all have occurred since 2001, with the exception of 1998. The year 2016 ranks as the warmest on record. 

– climate.nasa.gov

What Makes The Recent Warming Trend Concerning?

There’s a few things, but just to note some of the more concerning points:

• The period of warming has happened quite quickly (since 1880), and, even more quickly if you look at the period from 1950 or 1990 until the present day. So, the rate of warming is relatively fast
• Based on natural climate factors, some sources say we should actually be in a cooling period now, and not warming (we were in a 6,000 year cooling period before we started this recent warming period in the last century or so)
• A rise in global temperature of 1 degree takes a huge amount of energy and heat being reflected back onto the Earth’s surface and oceans from greenhouse gas layers – pointing to how significant the impact humans have had on the Earth’s climate might be in such a short space of time
• Scientists have a good idea of what was happening on Earth when rapid temperature change or abrupt climate change events happened in the past, and those events might be similar to what is happening now (huge and rapid carbon emissions, a big rapid jump in global temperatures, rising sea levels, ocean acidification, widespread oxygen-starved zones in the oceans etc.) are all happening today with human-caused climate change
• In the past, changes in Earth’s climate (usually drops in climate) of just 1 or 2 degrees celcius have led to significant events that could have a significant impact of life on Earth for humans (a plunge into a freezing ice age for example)
• Continued warming and continued GHG emissions at the current rate increases the risk that Earth’s climate reaches a point where feedback processes and loops continually warm the Earth, no matter how much humans reduce their emissions – essentially, once we pass a certain threshold, we may not be able to impact or control the climate on Earth anymore, which could impact our survival as a species

An Asterisk On The Recent Warming Trend (A Short Period Of Cooling Amongst The Long Term Warming Trend)

Over the long term since 1880 to the present, global average surface temperature has risen.

• But, there was a period, roughly from 1998 to 2012, where the Earth’s global average temperature did cool temporarily.
• It it thought various natural factors such as La Niña events were part of the cause of this cooling … shifting some excess heat into the ocean

– climate.gov

One of the clear aspects of climate change science is that natural factors can influence the Earth’s climate over the course of one or several decades, but non natural factors are responsible for long term climate impact (at least in the last century or so). 

Global vs Regional Climate Change

It’s important to note that there is a difference between global and regional climates.

Regional climates tend to be subject to local weather patterns, and other unique local factors.

Global climate however, takes into account average temperature over the entire surface of the planet.

This is why the Earth’s average temperature can be rising, while some regions of the world may be actually experiencing continued cooling.

What Is The Significance Of The Year 1880?

• 1880 is when modern record keeping started for Earth’s global surface temperature [observations did not sufficiently cover enough of the planet prior to that time]

– climate.nasa.gov

This is also roughly around the time (1870) the second industrial revolution is recognised as having started in the US, and also when we began burning/consuming fossil fuels like coal, oil and natural gas at a greater rate (this really increased around 1950 too).

What Is The Significance Of The 1950-1980 Baseline/Mean?

• The period of 1951-1980 was chosen largely because the U.S. National Weather Service uses a three-decade period to define “normal” or average temperature. The GISS temperature analysis effort began around 1980, so the most recent 30 years was 1951-1980. It is also a period when many of today’s adults grew up, so it is a common reference that many people can remember.

– earthobservatory.nasa.gov

Has Earth’s Climate Change Before, And, How Much Has Earth’s Climate Warmed Throughout History?

Yes, Earth’s climate has changed before, and scientists usually know why.

Earth’s climate is split into various periods where the climate underwent different trends and patterns.

The last 800,000 years ago has been categorised by recurring ice ages consisting of glacials (cooling) and interglacials (warming).

Prior to that, there was an extended ice age, and prior to that, Earth’s climate could be more unpredictable.

You can read more in these two guides:

• How Warm Did The Climate/Temperatures Get Throughout Earth’s History?
• What Earth’s Climate Was Like In The Past: Last Century, Thousand, Million & Billions Of Years (Earth Climate History Timeline)

How Fast Did The Earth’s Climate Change In The Past, & What Are Abrupt Climate Change Events?

The Earth’s climate has usually changed gradually over hundreds of years or millenia, with periods of extended glacials (cooling), mixed in with interglacials (warming).

Abrupt climate change, however, is a significant change in the climate over the course of a few years, a decade, or a human lifetime i.e. a much quicker change than the gradual change.

There’s been several events where there has been abrupt climate over Earth’s history.

As one example, the global mean temperature about 65 millions years ago seems to have risen by as much as 5-8 °C (9-14 °F) to an average temperature as high as 23 °C (73 °F), in contrast to the global average temperature of today at just under 15 °C (60 °F).

Factors that may have impacted or caused abrupt climate change events from the past might have been:

• huge volcanic eruptions in India
• changes in ocean currents and ocean circulation patterns (thermohaline circulation)
• the collapse of ice sheets
• release of methane from frozen methane ices at the bottom of oceans

Experts think an abrupt climate change event is unlikely at least for the next 100 years, but, human emissions may make an event like this more likely.

Read more in this guide about abrupt climate change and how quickly the Earth’s climate changed in the past.

What Factors Cause Earth’s Climate To Change?

There’s many factors, natural and man made, that can impact the Earth’s climate. Some of these are:

• Natural Factors – the Earth’s orbit in relation to the sun, the brightness of the sun, volcanic eruptions (small and large eruptions), the natural level of greenhouse gases in the atmosphere (CO2, methane, nitrous oxide and so on), the ozone layer, stratospheric water vapour, linear contrails, methane release from termite mounds and other sources, how reflective the Earth’s surface is (which can be impacted by the level of snow cover for example), and natural factors involved in the carbon cycle such as the absorption of CO2 in the atmosphere by soil and plants
• Non Natural Factors – release of greenhouse gases from the burning of fossil fuels (for electricity generation and transport, being big sources), and changes to land cover such as deforestation, agriculture and land use

At different points in the Earth’s timeline/history, different factors can be impacting the climate, with different variables. That’s why what is impacting the Earth’s climate today might be different than 40 million years ago (because of the brightness of the sun, because of man made emissions, etc.).

Read more about the natural and non natural factors that cause the Earth’s climate to change.

What Are Greenhouse Gases?

Greenhouse gases occur naturally and through human activities.

The primary greenhouse gases in Earth’s atmosphere are water vapor, carbon dioxide, methane, nitrous oxide and ozone.

They are responsible for the greenhouse effect, whereby these gases rise to the top of the atmosphere, and reflect and re-emit some infrared radiation back to the Earth’s surface – warming the Earth.

What Are The Sources Of Greenhouse Gas Emissions?

GHGs can occur naturally in the atmosphere through various sources, such as the natural carbon and nitrogen cycles, volcanic eruptions, and other natural processes and events.

You can read more about how some of the natural sources of greenhouse gases work at https://www.neefusa.org/weather-and-climate/climate-change/principal-greenhouse-gases-and-their-sources

But, man made greenhouse gas sources are the main area to be concerned about.

Sources of greenhouse gases from humans vary depending on if you are talking about the city, country or global level.

Mainly, greenhouse gases from humans are caused by the burning of fossil fuels such as coal, oil and natural gas (in that order).

Electricity, transportation, and the industrial sector tend to be big emitters of carbon dioxide.

Agriculture and land use is a big emitter of methane and nitrous oxide.

Forestry is a carbon sink – which is why deforestation and land clearing can be a problem (amongst other issues like loss of biodiversity and land degradation).

As mentioned above, each city and country might be different in terms of the greenhouse gas profile they have (i.e. which gases are emitted from which sectors in which quantities). Developing countries might have different GHG profiles to developed countries.

On the global level – you are really taking the average of all countries, so there’s limited specific information you can take from this.

Each fuel source – coal, oil, natural gas, nuclear, renewables etc. – has it’s own carbon footprint to consider in manufacture and operation.

More Information About Greenhouse Gases

Read more about greenhouse gases in this guide:

• Which Greenhouse Gas Is The Worst
• How Long Do Greenhouse Gases Stay In The Atmosphere
• Which Greenhouse Gas Traps The Most Heat & Is Most Potent?
• Which Greenhouse Gas Is Emitted The Most
• Summary Of Global Greenhouse Gas Emissions

Why Is Carbon Dioxide So Important To Track?

• There are various factors why carbon dioxide is so important in terms of global warming
• But, mainly because of the sheer quantity of it that we emit annually (mainly from burning fossil fuels like coal, oil and natural gas) compared to other GHGs, and because of how long carbon dioxide stays in the atmosphere once it is emitted

What Are CO2 Levels (PPM) Right Now?

CO2 levels today in 2019 are 411 ppm.

You can keep track of current CO2 ppm levels at https://climate.nasa.gov/vital-signs/carbon-dioxide/.

What Have Been Carbon Dioxide Levels Throughout Earth’s History?

You can read more about carbon dioxide levels throughout Earth’s history here:

• A History Of Earth’s Carbon Dioxide Levels Over Time (Carbon Dioxide Level Timeline), & How Fast C02 Levels Are Increasing

What we think from looking at ice cores and ancient data samples of CO2 levels is that today’s CO2 levels are higher than at any point through the last 800,000 years.

Over the last 800,000 years, it’s thought CO2 levels fluctuated between about 200 and 300ppm, before significantly increasing up to today’s levels.

You can look at a graph of the last 800,000 years of CO2 levels here – https://climate.nasa.gov/climate_resources/24/graphic-the-relentless-rise-of-carbon-dioxide/

Are Ice Cores Reliable/Accurate?

Ice cores have been taken from ice sheets worldwide, but also from Greenland and Antarctica specifically.

Generally, for finding out accumulation, air temperature and air chemistry from another time in Earth’s history, they can be reliable:

• Ice cores provide detailed records of carbon dioxide, methane and nitrous oxide going back over 650,000 years. Ice core records globally agree on these levels, and they match instrumented measurements from the 1950s onwards, confirming their reliability. Carbon dioxide measurements from older ice in Greenland is less reliable, as meltwater layers have elevated carbon dioxide (CO₂ is highly soluble in water). Older records of carbon dioxide are therefore best taken from Antarctic ice cores.
• … [although] ice cores can also have other complexities 

– antarcticglaciers.org

Are Climate Models Reliable?

Climate models can tell us certain things, but do have limitations and uncertainties in telling us other things.

Model supporters will say although they aren’t perfect, they have gotten far more better and accurate over the years, and are great at identifying overall trends (they may also say model contrarians are yet to produce a model of their own that successfully models past climate change).

Model contrarians may say models don’t match up exactly with reality, use calculations and formulas that serve to confirm the models’ creators beliefs, and haven’t been accurate in the past and forecasting future climate change.

The best way to view models might be one line of evidence and information among many lines of evidence and information across the climate change/global warming topic (so, they aren’t the one thing to rely on in making a conclusion about climate change, but, one of many pieces of evidence or one of many tools).

A summary of current day climate models might be:

• While there are uncertainties with climate models, they successfully reproduce the past [by successfully reproducing temperatures since 1900 globally, by land, in the air and the ocean] and have made predictions that have been subsequently confirmed by observations
• Models have evolved to the point where they successfully predict long-term trends and are now developing the ability to predict more chaotic, short-term changes
• … Models don’t need to be exact in every respect to give us an accurate overall trend and its major effects – and we have that now.
• If you knew there were a 90% chance you’d be in a car crash, you wouldn’t get in the car (or at the very least, you’d wear a seatbelt). 
• The IPCC concludes, with a greater than 90% probability, that humans are causing global warming. To wait for 100% certainty before acting is recklessly irresponsible.

– skepticalscience.com

• … climate models are not good predictors of specific climate effects, such as the melting of Arctic sea ice or the frequency of major hurricanes in the north Atlantic
• … There are two types of widely used climate models: large, complicated, planetary-scale models [also known as general circulation models] … and [smaller] higher-resolution models
• … general circulation models are more accurate for long-term, worldwide forecasts, including the key measure of climate sensitivity—the amount of warming, in global mean temperature, that will happen when the amount of carbon in the atmosphere doubles from pre-industrial levels.
• … The smaller, high-resolution models are better for examining the likely regional effects of climate change.
• models continue to get better … in the sense that they simulate many processes more realistically … But most climate scientists acknowledge that there are limits: no matter how sophisticated our models become, there will always be an irreducible element of chaos in the earth’s climate system that no supercomputer will ever eliminate
• [developing better climate models has not helped] … in decreasing the uncertainty in future projections

– technologyreview.com

Resources that outline some of the limitations or flaws with climate models are:

• https://www.hoover.org/research/flawed-climate-models (lists the various flaws and errors with modern climate models)
• https://notrickszone.com/2018/12/06/scientists-falsified-climate-models-do-not-employ-known-physics-fullydont-agree-with-reality/ (states that climate model results conflict with one another, diverge from observations, and aren’t fully rooted in established physics)
• https://wattsupwiththat.com/2017/06/28/173948/ (climate models and reality vary)

What Is The Carbon Budget, & Is It Reliable?

A ‘carbon budget’ is the amount of carbon dioxide that can be emitted before the world is expected to reach a certain temperature of warming. It is also sometimes expressed as the amount of time before we reach a certain temperature based on current rates of emissions.

It should be noted though that carbon budgets are only a very very rough guide.

They can change and be updated (expand or decrease) based on various factors such as:

• changes in emission rates
• changes a country’s emission reporting
• uncertainties with different aspects of climate science
• updates or changes in calculations used to estimate budgets, or other climate science
• + more

Read more about carbon budgets in this guide.

What Other Lines Of Evidence Have We Used To Link Humans As The Primary Cause Of Recent Global Warming

• Basic chemistry – we know that when we burn fossil fuels, CO2 is emitted in the atmosphere
• Basic physics – shows us that CO2 absorbs heat, and we can use spectroscopy to see that most of the energy being trapped in the atmosphere corresponds exactly to the wavelength of energy captured by CO2
• Basic accounting – we know how much fossil fuel we’ve consumed, and the quantity of our emissions
• Chemical analysis – analysing CO2 already in the atmosphere shows us that it is coming from fossil fuels
• Measurements of CO2 in the atmosphere – at observatories, and from looking at ice cores
• Modern technology – using modern technology in the air, on land and in the ocean such as satellites, buoys, ships, sensors and more to measure global average above land surface temperature, above ocean surface temperature, and more
• Analysing ancient Earth data – such as deep sea sediments, ice cores (from Antarctica and Greenland), and tree rings to get an idea of CO2 levels and Earth’s average global temperature in the past
• Using climate modelling – to model how natural and human factors impact the climate over the long term (models use calculations, formulas, data and assumptions fed into the models by humans)
• Observing environmental events and trends – such as shrinking glaciers, sea levels rising, ocean warming, ocean acidification, snow cover loss, and so on
• Scientists also know general fingerprints that natural vs man made climate factors leave on the climate and environment.

Read more about the evidence linking humans together with global warming in this guide.

Which Countries Emit The Most Greenhouse Gases?

• You can read more in this guide about the countries that emit the most greenhouse gases
• The United States has emitted to most cumulative greenhouse gases throughout history (as of the year 2019). You can read a summary of the United States’ greenhouse gas emissions here
• China (in 2019) currently emits the most annual greenhouse gases (and leads the second placed United States by about double the quantity of annual emissions). You can read a summary of China’s greenhouse gas emission here
• Different reports show different countries as leaders for per capita GHG emissions

Which Countries Emit The Least Greenhouse Gases?

You can read more in this guide about the countries that emit the least greenhouse gases

• Per capita, countries in central South America, the Middle East and both eastern and southern Africa [have some of the lowest national average emissions]

– skepticalscience.com

• Per capita, Denmark, Finland and Nigeria were the lowest CO2 emitters in 2016

– telegraph.co.uk

Which Countries Might Be Affected The Most By Climate Change & Global Warming?

• … the countries most severely impacted by climate change contributed the least to greenhouse gas emissions
• … highly vulnerable regions included central South America, the Middle East and both eastern and southern Africa.
• Less vulnerable regions were largely in the northern part of the Northern Hemisphere

– skepticalscience.com

Note – a different question to ‘who might be most impacted by climate change’ would be ‘who is least able to adapt to climate change and who is therefore most vulnerable?’. Poor and under developed countries are obviously at risk in this regard, as well as coastal and island regions (due to factors like sea level rise).

Which Countries Might Need To Do More To Reduce Their Greenhouse Gases?

• There’s various ways we might assess the countries that need to be doing more, or need to be making more of an effort, to do their ‘fair share’ to address climate change
• You can read this guide which outlines countries countries that might need to do more to address climate change

How Can We Track How Different Countries Are Managing Their Greenhouse Gas Emissions Over Time?

There are sites like climateactiontracker.org that provide various tracking indicators, methodology and forecasts to communicate how different countries are tracking with their greenhouse gas emissions over time.

Check out https://climateactiontracker.org/countries/ for more info.

Which Cities Emit The Most Greenhouse Gases?

• You can read more in this guide for the full list of cities that emit the most greenhouse gases in total, and per capita

• In 2019 Seoul, Guangzhou and New York were the top 3 emitters in total GHGs
• In 2019, Hong Kong SAR, Mohammed Bin Zayed City, and Abu Dhabi were the top 3 emitters in per capita GHGs

Which Cities Have Already Reduced Their Emissions?

As of 2019, there’s already 27 of the world’s biggest cities that have reduced emissions below 10% of what their peak emission quantity was.

You can read more in this guide about the cities that have reduced emissions, and in general, how cities can reduce emissions and address climate change.

How Can We Track How Different Cities Are Managing Their Greenhouse Gas Emissions Over Time?

One place you can go to see how some cities are tracking in terms of how they are addressing greenhouse gas emissions & sustainability is:

• https://www.c40.org/cities

What Are The Main Solutions To Addressing Climate Change & Global Warming?

Some of the major approaches to addressing climate change and global warming are:

• Mitigation (reduction and elimination of GHGs)
• Sequestration (absorbing CO2 already in the atmosphere)
• Adaptation (adapting to the changes/impact caused by warming)

These approaches can happen on a city, state/province or national level.

There are also other options to addressing climate change.

Specific Solutions & Ways To Address Climate Change & Reduce Emissions

Every city, country and sector within those cities and countries are going to have their own custom solutions that should be pursued to address climate change.

This is because each sector within those cities and countries is going to emit different greenhouse gases, in different quantities, and in different ways.

But, in general, some solutions to the main sectors might be found in these guides:

• Potential Solutions For Reducing Greenhouse Gas & CO2 Emissions In The Transport Sector
• Potential Solutions For Reducing Greenhouse Gas & CO2 Emissions In Energy (Power) & Electricity Production
• Potential Solutions For Reducing Greenhouse Gas & CO2 Emissions In The Residential & Commercial Sectors
• Potential Solutions For Reducing Greenhouse Gas & CO2 Emissions In The Industrial Sector
• Potential Solutions For Reducing Greenhouse Gas & CO2 Emissions In Agriculture, Forestry & Other Land Use Sources (AFOLU)

Some of the main solutions posed for addressing climate change are the use of renewable and green energy (solar, wind, water, hydro, nuclear etc.), and the use of electric, hybrid and alternate vehicles (like hydrogen).

But, there’s also now a growing idea that these solutions won’t be enough on their own and a decrease in overall consumption of resources is what’s needed i.e. sustainability, efficient use of resources and even more minimalist lifestyle are further strategies.

A growing world population (which means more demand for electricity, transport, food and agriculture, desalination plants etc.) and developing countries increasing their energy use from industrial development, also makes it more likely greenhouse gas emissions aren’t reduced, if there aren’t significant changes made soon.

So, a single solution or single approach to addressing climate change won’t work – it needs to be multi tiered and there needs to be buy in from multiple cities, countries and key decision makers.

Uncertainties Related To Climate Change & Global Warming

A good climate expert or climate scientist/researcher should admit there are still some things that we are uncertain about when it comes to knowing the full picture with climate change and global warming. Some of these thing include:

• The limitations in using climate models 
• How accurately we can forecast climate change in the future (because of huge variables like global climate policy into the future, human GHG emissions into the future, the behavior of the Sun into the future, short term disturbances like El Niño or volcanic eruptions) – just to name a few things.
• How accurately we can forecast the impact (on humans, the economy, different regions of the world, animals, the environment etc.) of a changing climate in the future – it is freely admitted that the impact could be worse or better than predicted
• To what extent we can rely on the conclusions we can draw from ancient Earth data like ice cores, deep sea sediments, rock samples, tree rings, etc. – this is especially true the further back in Earth’s past we go
• How sensitive Earth’s climate really is 
• How El Niño or La Niña events are linked to climate change
• How rainforests and other eco systems might actually respond to climate change 
• + more

Answers To Some Of The Most Common Arguments Made Against Climate Change & Global Warming

Skeptical Science has pretty good resources on some of the most common arguments made against various aspects of climate change.

You can read their answers to these arguments at https://skepticalscience.com/argument.php

Sources

1. https://climate.nasa.gov/climate_resources/139/graphic-global-warming-from-1880-to-2018/

2. https://earthobservatory.nasa.gov/world-of-change/DecadalTemp

3. https://climateactiontracker.org/countries/

4. https://www.c40.org/cities

5. https://www.bettermeetsreality.com/how-cities-might-reduce-greenhouse-gases-address-climate-change-solutions-strategies-as-well-as-examples-of-cities-who-have-already-reduced-emissions/

6. https://www.bettermeetsreality.com/cities-that-emit-the-most-greenhouse-gases/

7. https://climate.nasa.gov/vital-signs/global-temperature/

8. https://earthobservatory.nasa.gov/global-maps/MYD28M

9. https://skepticalscience.com/Those-who-contribute-the-least-greenhouse-gases-will-be-most-impacted-by-climate-change.html

10. https://www.bettermeetsreality.com/which-countries-need-to-do-more-to-reduce-their-greenhouse-gas-emissions-better-help-address-climate-change/

11. https://www.telegraph.co.uk/travel/maps-and-graphics/mapped-the-countries-that-use-the-most-electricity/

12. https://www.bettermeetsreality.com/a-history-of-earths-carbon-dioxide-levels-over-time-carbon-dioxide-level-timeline-how-fast-c02-levels-are-increasing/

13. https://www.bettermeetsreality.com/what-earths-climate-was-like-in-the-past-last-century-thousand-million-billions-of-years-earth-climate-history-timeline/

14. https://www.bettermeetsreality.com/how-warm-did-climate-temperatures-get-throughout-earths-history/

15. https://climate.nasa.gov/vital-signs/carbon-dioxide/

16. https://www.science.org.au/learning/general-audience/science-climate-change/1-what-is-climate-change

17. https://en.wikipedia.org/wiki/Global_warming

18. https://www.bettermeetsreality.com/factors-natural-human-that-impact-affect-climate-change-drivers-forcings/

19. https://www.bettermeetsreality.com/how-fast-did-earths-climate-change-in-the-past-abrupt-climate-change-events/

20. https://www.climate.gov/news-features/climate-qa/why-did-earth%E2%80%99s-surface-temperature-stop-rising-past-decade

21. https://earthobservatory.nasa.gov/world-of-change/DecadalTemp

22. https://climate.nasa.gov/climate_resources/24/graphic-the-relentless-rise-of-carbon-dioxide/

23. https://www.bettermeetsreality.com/which-greenhouse-gas-is-the-worst/

24. https://www.bettermeetsreality.com/how-long-do-greenhouse-gases-stay-in-the-atmosphere/

25. https://www.bettermeetsreality.com/which-greenhouse-gas-traps-the-most-heat-is-most-potent/

26. https://www.bettermeetsreality.com/which-type-of-greenhouse-gas-is-emitted-the-most-volume/

27. https://www.bettermeetsreality.com/summary-greenhouse-gas-emissions-worldwide-globally-past-present-future/

28. http://www.antarcticglaciers.org/glaciers-and-climate/ice-cores/ice-core-basics/

29. https://skepticalscience.com/argument.php

30. https://www.bettermeetsreality.com/the-evidence-linking-greenhouse-gas-emissions-from-human-activity-climate-change-global-warming-together/

31. https://skepticalscience.com/climate-models-intermediate.htm

32. https://www.technologyreview.com/s/543546/why-climate-models-arent-better/

33. https://www.hoover.org/research/flawed-climate-models

34. https://notrickszone.com/2018/12/06/scientists-falsified-climate-models-do-not-employ-known-physics-fullydont-agree-with-reality/

35. https://wattsupwiththat.com/2017/06/28/173948/

36. https://www.neefusa.org/weather-and-climate/climate-change/principal-greenhouse-gases-and-their-sources

37. https://www.bettermeetsreality.com/summary-greenhouse-gas-emissions-united-states-past-present-future/

38. https://www.bettermeetsreality.com/summary-greenhouse-gas-emissions-in-china-past-present-future/

39. https://www.bettermeetsreality.com/potential-options-solutions-for-reducing-greenhouse-gas-emissions-in-transport-industry/

40. https://www.bettermeetsreality.com/potential-options-solutions-for-reducing-greenhouse-gas-c02-emissions-from-energy-power-electricity-production/

41. https://www.bettermeetsreality.com/potential-options-solutions-for-reducing-greenhouse-gas-co2-emissions-in-the-residential-commercial-sectors/

42. https://www.bettermeetsreality.com/potential-options-solutions-for-reducing-greenhouse-gas-co2-emissions-from-industry-industrial-activities/

43. https://www.bettermeetsreality.com/potential-options-solutions-for-reducing-greenhouse-gas-co2-emissions-in-agriculture-land-use-forestry/

A lot of the research and data on greenhouse gas emissions in the past has been at the country/national or global level.

Now, more information is coming out about the significance of cities and CBD or heavily urbanized areas in the emissions picture.

This guide outlines how important it is for us to focus on cities going forward, in addition to countries and the world as a whole.

Summary – GHG Emissions & Carbon Footprints From Cities

• The biggest and most well developed cities in the world are the source of a significant % of global greenhouse gas emissions (in total emissions, and usually per capita emissions too)
• Roughly 70% of global greenhouse gas emissions come from cities (some sources say it’s higher when accounting for all production and consumption emissions)
• The top 100 emitting cities in the world make up about 20% of global emissions just by themselves
• Developing cities in the future are expecting to make up around 90% of the increase in carbon emissions that we will see from energy use
• All these stats and figures point to cities, and specifically the most well developed, urbanized and affluent cities, being a focus if we want to address climate change and global warming in the future
• Every city has it’s own GHG emission and carbon footprint profile though – so each city needs a different approach/strategy, and solutions. Mitigation (reducing emissions), adaptation and sequestration are all options
• You can read more about how cities might be able to reduce emissions and address climate change in the future in this guide
• You can also read this guide about the cities with the highest greenhouse gas emissions in the world (top 500 cities in total emissions, and per capita)

Development in emerging cities, and modification in existing cities, should both focus on sustainability principles that address a range of sustainability issues and not just greenhouse emissions e.g. supply of freshwater, air quality, land degradation, over population, and so on.

How Much Cities Contribute To Global Greenhouse Gas Emissions

• Cities consume over two-thirds of the world’s energy and account for more than 70% of global CO2 emissions.

– c40.org

• Cities consume as much as 80 percent of energy production worldwide and account for a roughly equal share of global greenhouse gas emissions.

– siteresources.worldbank.org

• Cities emit about 70% of the world’s greenhouse gases – but that figure only accounts for production [and not consumption]

– news.nationalgeographic.com

• [just] 100 cities [in the world] drive 18% of global emissions

– citycarbonfootprints.info

• Residents of just 100 cities (out of 13,000 studied in the world) account for 20 percent of humanity’s overall carbon footprint

– scientificamerican.com

More Information On The Carbon Footprint Of, & Greenhouse Gas Emissions From Cities

We’ve paraphrased and listed ideas from various sources below (and expanded them, or connected them to other ideas ourselves). Check out the resources list for the full resource if you’re interested.

• Economic growth and urbanization tend to lead to higher greenhouse gas emissions – richer and more developed cities tend to have higher emission footprints
• Lifestyle and level of affluence can impact GHG emission totals – the higher the affluence, the higher the GHG emissions
• Population growth can be a reason for GHG increases
• It’s expected that by 2050, 70% of the world’s population will live in cities – making them people dense areas to focus on. Urban population is expected to double by 2030 as well
• Cities consume roughly 80% of the world’s energy production and are responsible for roughly the same amount of GHG emissions
• A trend that is noticed in cities is that when a city is developing, GHGs come more from the industrial sector
• Once a city is reasonably well developed, GHGs tend to come more from energy for lighting, heating, and cooling (in buildings)
• Developing countries in the future will play a major role in the increase in CO2 emissions from energy – about 89% 
• Building out (urban sprawl) and not up increases energy requirements for a city. Dense living (more people in smaller land surface areas), and building up and not out – are two ways to decrease emissions
• The energy source mix within a city plays a huge role in the GHGs emitted
• Richer cities, less dense cities, and cities that depend predominantly on coal to produce energy all emit more greenhouse gases.
• There’s total greenhouse gas emissions, and there’s per capita emissions – both can be a helpful measurement or indicator
• Per capita emissions tend to be lower in efficient and well planned cities
• To promote growth and also mitigate climate change, cities will need to shift energy sources, improve energy efficiency, and increase city density
• At some point we have to decrease consumption too – not just look to green up energy sources or move to electric vehicles (these solutions can only address some of the problem)
• Energy use in buildings and how electricity is produced are usually huge drivers of climate change
• Spatial organisation of living areas also contributes to GHGs. Single family homes, further away from services and with private cars, have higher emissions than multi unit buildings that are built up, close to public transport and services
• Cities require concentrated electricity production but with short distances to power plants so there are shorter transmission lines and less transmission losses
• Trucks, automobiles, and aircraft also need concentrated energy
• In the future, cities with more electric vehicles and desalination plants will need more energy from electricity generation
• Fossil fuels, hydroelectric and nuclear are not expected to be replaced by solar and wind in most big cities in the short to mid term future
• Less energy use/more efficient energy use, more efficient buildings and less vehicle use will be important to reducing greenhouse gas emissions
• Coal and oil are worse than gas for emissions
• City greenhouse gas emissions reflect the structure of a city, its energy sources, and its residents’ lifestyles. Resource use, water consumption, wastewater production, toxic releases, and solid waste generation are all linked among themselves and with greenhouse gas emissions as well.
• You have to define a city’s scope and geographical boundaries for GHGs when calculating the footprint
• Emissions can come from both production and consumption, inside and outside of the city
• Export and importation of GHG emissions should be accounted for
• Variables like deforestation and mining can be difficult to factor into carbon footprints
• Per capita emissions can be influenced by factors like a cold climate
• Per capita emissions can be influenced by a variety of physical, economic, and social factors specific to the unique urban life of each city.
• Infrastructure investments quickly become longterm sunk costs. The transportation system that a city develops largely defines the final shape of the city, as influenced by local geography. Roads and public transit lines are the bones of a city, with water, wastewater and power services fleshing out the city. Once buildings grow around transportation and service nodes, they are all but locked-in.
• Compact cities are more sustainable than sprawling cities
• The variation in per capita emissions in cities results from differences in wealth, sectoral specialization, energy sources, the general climate, and the structural efficiency of the urban form, which includes buildings and transport infrastructure
• Overall, cities should be aware of the factors they do and don’t have control over to mitigate emissions or sequester them, and to adapt to the impact of warming or cooling 

– siteresources.worldbank.org

• Emissions can come from within the city boundary, from off site energy production (like a power plant feeding into the grid), and from outside the city boundary (like when a city member flies out of the city)
• Sectors might be divided up into agriculture, forestry and land use, stationary fuel consumption, waste generated and disposed, industrial processes, in boundary transport, grid supplied energy, indirect emissions and so on
• There’s a difference between production and consumption both inside and outside the city
• Consumption = production – export + import
• Imported goods that were produced outside the city tend to have the biggest footprint, followed by within the city for both consumption and production, and lastly production inside the city but exported outside
• Consumer cities are responsible for about 80% of GHG emissions, while producer cities are for 20%
• Different regions and countries in the world have different profiles for both consumption and production, and also the sectors of their city that make up their total footprint
• Capital and buildings, utilities and housing, food, beverage and tobacco, Public transport, private transport and government tend to have the biggest carbon footprints
• This is followed by clothing, furnishing and household equipment, restaurants, hotels, recreation and culture, communications, education and health, miscellaneous goods and services, and other sources of emissions
• Be aware of exported and imported emissions
• There are good reasons why most cities focus on sector-based GHG emissions. They occur from sources over which cities often have more direct influence; are easier and more reliable to estimate and monitor
• … cities may not have much direct influence over the carbon intensity of power used in the manufacturing process of an imported product, or whether that product is transported by train or truck, as end users and centres of innovation and change
• Cities need to work with other cities that they trade with – this can address emissions that aren’t being accounted for
• Cities rely heavily on the supply of goods and services from outside their physical boundaries. The results of this study show that the GHG emissions associated with these supply chains are significant, particularly for C40 cities in Europe, North America and Oceania. Over 70% of consumption-based GHG emissions come from utilities and housing, capital, transportation, food supply and government services.

– c40.org

• Carbon footprints of cities are higher when production and consumption emissions are counted inside and outside the city, and not just for products produced or used inside the city
• Wealthy “consumer cities” such as London, Paris, New York, Toronto, or Sydney that no longer have large industrial sectors have significantly reduced their local emissions. However, when the emissions associated with their consumption of goods and services are included, these cities’ emissions have grown substantially and are among the highest in the world on a per person basis
• Meanwhile, “producer” cities in India, Pakistan, or Bangladesh generate lots of industrial pollution and carbon emissions in the manufacture of products that will be sold and consumed in Europe and North America.
• Food, clothing, electronic equipment, air travel, delivery trucks, and construction industries are examples of consumption activities
• Emissions can be outsourced from one city to another – so we have to be mindful of the complete carbon footprint picture, and not just what is produced or consumed within the city limits
• Service-based economies that consume the things that other cities make can rank better for emissions – so new carbon footprint calculations need to take into account inside and outside city emissions, and local production vs foreign production

– news.nationalgeographic.com

• The bulk of a country’s consumption-related carbon emissions can be concentrated in just a few cities
• For example, residents of South Korea’s capital, Seoul, account for about 45 percent of that nation’s overall carbon emissions; in the U.K., London, Manchester and Birmingham combined contribute more than 20 percent of national output; whereas in the U.S. people living in Chicago, New York and Los Angeles combine to account for nearly 10 percent of the country’s overall footprint.
• … roughly one third of an urban resident’s footprint is determined by that city’s public transportation options and building infrastructure

– scientificamerican.com

• There are lists for the top 500 emitting cities – in total, and per capita
• Globally, carbon footprints are highly concentrated into a small number of dense, high-income cities and affluent suburbs
• 100 cities drive 18% of global emissions
• In most countries (98 of 187 assessed), the top three urban areas drive more than one-quarter of national emissions
• … in practice mapping footprints to local jurisdictional bounds is complex
• 41 of the top 200 cities are in countries where total and per capita emissions are low e.g. Dhaka, Cairo, Lima). In these cities population and affluence combine to drive footprints at a similar scale as the highest income cities

– citycarbonfootprints.info/

Sources

1. http://siteresources.worldbank.org/INTUWM/Resources/340232-1205330656272/4768406-1291309208465/PartIII.pdf

2. https://www.c40.org/why_cities

3. https://news.nationalgeographic.com/2018/03/city-consumption-greenhouse-gases-carbon-c40-spd/

4. https://www.scientificamerican.com/article/heres-how-much-cities-contribute-to-the-worlds-carbon-footprint/?redirect=1

5. http://citycarbonfootprints.info/

6. Moran, D., Kanemoto K; Jiborn, M., Wood, R., Többen, J., and Seto, K.C. (2018) Carbon footprints of 13,000 cities. Environmental Research Letters DOI: 10.1088/1748-9326/aac72a.

7. https://www.c40.org/researches/consumption-based-emissions

We’ve already written previously about potential solutions and ideas for addressing climate change at the country and global level.

This is a guide about how cities might address climate change at the city level.

Summary – Reducing Emissions In Cities 

• CBD and heavily urbanized areas have a different carbon footprint to suburban and rural areas
• Every city also has it’s own unique carbon footprint
• The most developed cities in the world have the highest total footprints
• Per capita footprint tends to be lower in denser cities that are built up instead of out, and that are more compact and efficient in their design
• Reducing consumption may be the best way to reduce emissions
• But, specific sectors to focus on within a city might be …
• Having a cleaner energy mix (renewables and greener non fossil fuel energy – or, at least a bigger contribution from cleaner energy)
• More of a focus on mass transit, and walking, biking and public transport, as opposed to single person vehicles
• Efficient building energy systems and designs (especially with the consumption of electricity for heating, cooling, refrigeration and lighting)
• There can be other sectors and areas to focus on as well such as food consumption, food waste and loss, waste management, government, road, pathways and infrastructure, health and education, and so on
• Production, consumption, exported, imported, inside the city boundaries, and outside the city boundaries emissions all need to be considered in arriving at a carbon footprint measurement
• Population growth can be one multiplier factor in a city that can grow direct and indirect emissions

Ultimately, every city is different, and every city will need it’s own custom approach not only to addressing climate change, but to becoming more sustainable to address broad sustainability issues like water supply, air pollution, land degradation, overpopulation, and so on.

The Different Types Of Cities & Their Carbon Footprints

Rural, urban and CBD/built up city areas all tend to have different emission rates.

When it comes to cities and urban areas, it’s important to know that different types of cities tend to have different carbon footprint profiles in their own right.

Emissions can be measured by total emissions, or emissions per capita.

The cities that emit the most total greenhouse gas emissions in total tend to be some of the biggest, most economically developed, urbanized and affluent/richest (in terms of lifestyle) cities.

There’s about 100 of these types of cities that make up around 20% of total global greenhouse gas emissions. 

These cities tend to be consumer cities (outsourcing production elsewhere but consuming inside the city boundaries), whilst developing cities tend to tilt towards being production cities.

The more developed a city becomes, the more their industrial sector emissions might reduce, and the more their emissions from building energy might increase (heating, cooling, refrigeration, lighting etc.).

Developing cities tend to have lower overall emissions, but more of their emissions tend to come from the industrial sector (which makes sense as they are building and developing their city). 

Having said that, in the future, around 90% of the emissions from energy use are forecasted to come from developing cities.

There’s also other factors and variables that contribute to the unique carbon footprint and emissions profile of different cities

Ideally, solutions and strategies to reduce emissions or address climate change would be suited to the profile of the city – developed vs developing, consumer city vs producer city, and identifying the sectors and activities in the city that emit the most GHGs and where there is most potential for positive results.

Overall, it would make sense to not only implement policies, strategies and solutions that bring about mitigation, adaptation, and sequestration for climate change, but are sustainable in general so they can address other issues like air pollution, over population, waste management, and so on.

Cities are well placed in this regard as solutions and strategies may be able to be implemented more quickly and effectively than at the national or even state/province wide level.

Solutions & Strategies For Reducing Emissions & Addressing Climate Change In Cities

We’ve paraphrased and listed ideas from various sources below (and expanded them, or connected them to other ideas ourselves). Check out the resources list for the full resource if you’re interested.

• The real key to reducing emissions from cities in the future might not be renewable/green energy or electric vehicles – but, a reduction in consumption overall

• Decreasing consumption of goods and services, improving electricity efficiency, and decreasing the use of single person cars and transport and encouraging ride sharing, mass transport and clean transport, are just some ways to reduce consumption
• Increasing urban density can lower emissions per capita
• Improving urban design to avoid sprawl can lower emissions per capita
• Improving city public transit and mass transit can reduce overall emissions
• Changing building practices and increasing building efficiency can reduce emissions overall
• Changing sources of energy to more efficient, greener, renewable and cleaner energy sources can reduce overall emissions
• Compact cities tend to be the most efficient in terms of emissions per capita, compared to sprawling urban areas

• Be aware that population increase within a city not only increases emissions directly (for example through electricity usage), but increases demand on resources like freshwater which may in turn increase energy required to deliver more water, and even energy to run desalination plants (both of which can result in greenhouse gas emissions)
• Place a focus on cities that are highly developed, urbanized, and rich/affluent for addressing high greenhouse gas emissions right now
• When it comes to increases in greenhouse gas emissions from energy in the future, understand that developing cities might be where we place most focus
• Place a focus on greenhouse gas emissions from the industrial sector of developing cities in the future
• Understand that developed countries tend to have a higher amount of emissions coming from buildings, their energy use, and heating, cooling, refrigeration and lighting > this might be where we have the most potential to reduce emissions
• Higher city densities (more people using less land surface area) tends to result in less emissions per capita
• Building up (tall buildings) instead of out (urban sprawl) is one way to increase per capita carbon emission efficiency
• Social norms and culture within cities can impact emissions – if more people buy into the concept of sustainable cities, emissions might be lower based on behavior and other factors
• The energy mix within a city is usually directly proportionate to the greenhouse gas emissions produced – so, focus on cleaner energy mixes. Coal tends to be the dirtiest fuel, followed by oil, and then natural gas behind that. Renewables, hydroelectricity and nuclear are some of the cleanest
• Understand that more electric vehicles and desalination plants in the future will only means more energy consumption and higher potential for an increase in GHG emissions
• Spatial organization of cities and urban areas matter – single family homes, further away from services and with private cars, tend to have higher emissions than multi unit buildings that are built up, close to public transport and services
• Shorter electricity transmissions lines might mean less loss of power in delivering energy, which might be a save on emissions
• Limiting the number of trucks, automobiles, and aircrafts coming in and out of the city limits the need for more concentrated energy within city limits (after looking at electricity generation, this is probably the second biggest way a city can ensure they are monitoring where their emissions come from)

• Look at every aspect of the city for an idea of where emissions are coming from i.e. all sectors – Resource use, water consumption, wastewater production, toxic releases, and solid waste generation, and so on.
• Food waste and loss, waste generation and disposal and other areas are important
• Get an accurate picture of the geographic boundaries of a city for an idea of where emissions are happening
• Understand how far up the production and supply chain you are counting emissions – indirect supply, transport, delivery and manufacturing chain can all be included or excluded
• Variables like deforestation and mining can be difficult to factor into carbon footprints for cities because of how disconnected they can be from final consumption
• Per capita emissions can be influenced by factors like a cold climate
• Per capita emissions can be influenced by a variety of physical, economic, and social factors specific to the unique urban life of each city
• Infrastructure investments quickly become longterm sunk costs. The transportation system that a city develops largely defines the final shape of the city, as influenced by local geography. Roads and public transit lines are the bones of a city, with water, wastewater and power services fleshing out the city. Once buildings grow around transportation and service nodes, they are all but locked-in. Understand these factors as factors that might be hard to change and may limit a city’s final emission footprint.
• The variation in per capita emissions in cities results from differences in wealth, sectoral specialization, energy sources, the general climate, and the structural efficiency of the urban form, which includes buildings and transport infrastructure

– siteresources.worldbank.org

• It’s important to know where the boundaries are of a city when you are calculating emission footprints
• Look at emissions both in the city boundary and outside (on site and off site emissions)
• Look at emissions from both consumption and production – goods and services can be produced outside the city and consumed inside, they can be both produced and consumed inside the city, or they can be produced inside the city and consumer outside the city boundaries
• To calculation consumption = production – export + import
• Imported goods that were produced outside the city tend to have the biggest footprint, followed by within the city for both, and then produced inside and exported outside – so focus on imported goods and what can be done there
• Consumer cities are responsible for about 80% of GHG emissions, while producer cities are for 20% – so focus on consumer type cities
• Look at emissions from both imported and exported goods and services
• Cities need to work with other cities that they trade with otherwise supply chain emissions will rarely be counted or addressed
• Look at supply chains all the way through – deforestation and land clearing, mining, sourcing, manufacturing, processing, delivery and transport, waste and loss etc.
• Look at emissions across all city sectors and activities
• Capital and buildings, utilities and housing, food, beverage and tobacco, Public transport, private transport and government tend to have the biggest carbon footprints
• This is followed by clothing, furnishing and household equipment, restaurants, hotels, recreation and culture, communications, education and health, miscellaneous goods and services, and other sources of emissions
• Over 70% of consumption-based GHG emissions come from utilities and housing, capital, transportation, food supply and government services – so this may be where a focus in placed
• There are good reasons why most cities focus on sector-based GHG emissions. They occur from sources over which cities often have more direct influence; are easier and more reliable to estimate and monitor
• Cities may not have much direct influence over the carbon intensity of power used in the manufacturing process of an imported product, or whether that product is transported by train or truck, as end users and centres of innovation and change
• Different regions and countries in the world have different profiles for both consumption and production, and also the sectors of their city that make up their total footprint – so, understand what type of city you are looking at and what makes it unique from an emissions perspective
• [The biggest or most developed] Cities rely heavily on the supply of goods and services from outside their physical boundaries. The results of this study show that the GHG emissions associated with these supply chains are significant, particularly for C40 cities in Europe, North America and Oceania.

– c40.org

• We can come up with ways to make tourism to and inside of some cities more sustainable – more train travel and less plane and car travel for example
• Understand that cities like London, Paris, New York, Toronto, or Sydney are consumer cities who no longer have large industrial sectors – their emissions come from consumption, but also from the production of products outside of the city boundaries
• Understand that cities like India, Pakistan, or Bangladesh generate lots of industrial pollution and carbon emissions in the manufacture of products that will be sold and consumed in Europe and North America.
• We can’t just outsource emissions to other cities and think we are making an impact by minimising emissions within our own city
• We are going the wrong direction with climate change – the next step is to reduce consumption – not using more renewable energy and mass transit
• Smarter purchasing, buying local, and reducing waste are part of what can be done to reduce consumption emissions
• Service-based economies that consume the things that other cities make can rank better for emissions – so new carbon footprint calculations need to take into account inside and outside city emissions. We also need to take into account other factors like local production which is better than foreign production
• We can change our diets to reduce emissions at the agricultural, forestry and land use level [reducing food waste and loss is also another opportunity to do this]
• Retrofit buildings and ensure new buildings are efficient – another way to reduce emissions in developed cities

– nationalgeographic.com

• a very small number of cities, about 100, emit about 20% of the world’s total greenhouse gas emissions. So, we might focus on these cities as a priority
• … within countries, The bulk of a country’s consumption-related carbon emissions can be concentrated in just a few cities … For example, residents of South Korea’s capital, Seoul, account for about 45 percent of that nation’s overall carbon emissions; in the U.K., London, Manchester and Birmingham combined contribute more than 20 percent of national output; whereas in the U.S. people living in Chicago, New York and Los Angeles combine to account for nearly 10 percent of the country’s overall footprint.
• … roughly one third of an urban resident’s footprint is determined by that city’s public transportation options and building infrastructure … If cities would switch to a more efficient energy source or make their public buses electric … they could slash their emissions by at least 25 percent …There is a lot of power in cities … and … at the more local level of government you can take faster action than at the national level

– scientificamerican.com

• Place a focus on the top 100 to 500 cities for addressing total emissions
• Place a focus on the top 100 to 500 cities for addressing per capita emissions
• Radical decarbonization measures (limiting non-electric vehicles; requiring 100% renewable electricity) can induce substantial emissions reductions beyond city boundaries. In wealthy, high-consumption, high-footprint localities such measures may require only a small investment relative to median income, yet accomplish large reductions in total footprint emissions
• Local action at the city and state level can meaningfully affect national and global emissions
• You have to know the scope included in the final footprint – what emissions are being counted, what source are they coming from, are they counted inside or outside the city, and how far back in the manufacture or supply process is being counted (just as examples)

– citycarbonfootprints.info

When addressing climate change involves mitigation, adaptation and sustainability strategies … areas to focus on for solutions might be:

• Adaptation and implementation – connecting cities, cool cities, urban flooding
• Improving Air Quality – minimising air pollution and emissions
• Energy and buildings – Clean Energy, Municipal Building Efficiency, New Building Efficiency, Private Building Efficiency
• Transport – Land Use Planning, Mass Transit, Mobility Management, Walking & Cycling, Zero Emission Vehicles
• Food, waste and water – Food Systems, Sustainable Waste Systems, Waste to Resources

– c40.org/networks

• It’s also worth noting that sequestration of GHGs in the air might be achieved through sequestration technology, or simply greening up cities with more plant and vegetation matter
• Some cities do this on building rooftops, on building facades or even have sequestration towers built
• Some cities are also starting to have a much heavier emphasis on walking, biking and non vehicular movement and transport

Examples Of Cities That Have Already Reduced Greenhouse Gas Emissions

You can find examples of cities that have already got results or done something to reduce greenhouse gas emissions at:

• https://www.c40.org/press_releases/27-cities-have-reached-peak-greenhouse-gas-emissions-whilst-populations-increase-and-economies-grow

An excerpt from this page that mentions results seen already from cities attempting to reduce emissions:

• 27 of the world’s greatest cities, representing 54 million urban citizens and $6 trillion in GDP have peaked their greenhouse gas emissions. New analysis reveals that the cities have seen emissions fall over a 5 year period, and are now at least 10% lower than their peak.
• The cities are: Barcelona, Basel, Berlin, Boston, Chicago, Copenhagen, Heidelberg, London, Los Angeles, Madrid, Melbourne, Milan, Montréal, New Orleans, New York City, Oslo, Paris, Philadelphia, Portland, Rome, San Francisco, Stockholm, Sydney, Toronto, Vancouver, Warsaw, Washington D.C.

Tracking How Cities Are Addressing Climate Change & Sustainability

One place you can go to see how some cities are tracking in terms of how they are addressing greenhouse gas emissions & sustainability is:

• https://www.c40.org/cities

Sources

1. http://siteresources.worldbank.org/INTUWM/Resources/340232-1205330656272/4768406-1291309208465/PartIII.pdf

2. https://news.nationalgeographic.com/2018/03/city-consumption-greenhouse-gases-carbon-c40-spd/

3. https://www.c40.org/researches/consumption-based-emissions

4. https://www.c40.org/press_releases/27-cities-have-reached-peak-greenhouse-gas-emissions-whilst-populations-increase-and-economies-grow

5. Moran, D., Kanemoto K; Jiborn, M., Wood, R., Többen, J., and Seto, K.C. (2018) Carbon footprints of 13,000 cities. Environmental Research Letters DOI: 10.1088/1748-9326/aac72a

6. http://citycarbonfootprints.info/

7. https://www.scientificamerican.com/article/heres-how-much-cities-contribute-to-the-worlds-carbon-footprint/?redirect=1

8. https://www.c40.org/cities

9. https://www.c40.org/networks

Recent studies and research in the last few years gives us a better idea of carbon footprints from cities.

In the past, there’s been focus on global emission numbers, as well as country wide data.

This begs the questions – should we be focussing on cities over entire countries if we want to address climate change?

Summary – Should We Focus On The City Or Country Level When Addressing Climate Change?

• When comparing emission data and trends between cities and countries, there’s some overlap in results, but there’s also some differences
• Both sets of data appear to be valuable in terms of reducing emissions and addressing climate change
• Country wide data is important from the perspective that national policy and national government is at play
• Whereas city data is important as it can help us get an idea of emission trends in locations where humans are most heavily populating the country, as well as address emissions on a more specific, and either local or state/province based level (with state or province based government and councils)
• There’s not only the difference between countries and cities in emissions data and trends, and the governments and policies that might be at play – but, there’s also a difference between rural, urban (suburbs), and inner city and CBD living within countries. Each of these areas within countries might require slightly different approaches in regards to coming up with solutions to lower emissions, along with other mitigation, adaptation and sequestering strategies. There’s also the fact that some countries are represented in top emitting city lists, but not tp emitting country lists.
• So, in summary, city based data on emissions is very helpful, but country based data is too
• They offer a complement to each other in addressing the overall climate change issue
• Focussing on both, either at the same time or in alternation, is beneficial to coming up with solutions 

What Have We Found Out About Emissions From Countries?

When we break down emissions by country, there’s several measurements that identify countries with the largest emissions footprints.

China is the leader in terms of total annual emissions by almost double what the second place US emits.

We can also get an idea of which countries might need to do more to reduce their emissions by looking at cumulative emissions, per capita emissions and how countries are tracking according to ‘fair effort’ and how they are progressing with their emission targets. We see that Russia, Saudi Arabia, Turkey, the Ukraine and Qatar appear among these measurements.

If we use the US and China as examples for a moment when looking at where their emissions come from:

• China – mostly from coal, and mostly from the power generation and industrial sectors are responsible for carbon emissions in China
• The US – the US has more mixed emission sources, and most of their greenhouse gas emissions came from transportation, electricity generation and the industrial sector in 2010

With China in particular, on a country wide/national level, we know China are going to continue their coal consumption for the short term future, and will face some challenges in transitioning to cleaner energy in the future.

What Have We Found Out About Emissions From Cities?

When we look at the top emitting cities list, we see a number of countries represented even in the top 30 cities, that aren’t on the top emitting countries list.

South Korea, the Country Of Singapore and Japan are just a few examples of cities 

Also, what we know about the most developed cities in the world, is that on a more granular level, we can see that a large portion of their carbon footprint comes from goods and services that are imported from outside the city limits, but consumed within the city.

We can also see that consumption happens in several more specific areas and activities than what we can see on the country level.

Capital (commercial buildings and other buildings), utilities (electricity for example) and housing, food, beverage and tobacco, public transport, private transport and government are some of those activities.

Some of these activities line up with national sectors such as power generation and transport.

With cities, what we know for sure is that the most developed cities are highly concentrated places for greenhouse gas emissions:

• Residents of just 100 cities (out of 13,000 studied) account for 20 percent of humanity’s overall carbon footprint (scientificamerican.com)

Sources

1. https://www.bettermeetsreality.com/countries-that-emit-the-most-greenhouse-gases-carbon-dioxide/

2. https://www.bettermeetsreality.com/which-countries-need-to-do-more-to-reduce-their-greenhouse-gas-emissions-better-help-address-climate-change/

3. https://www.bettermeetsreality.com/summary-greenhouse-gas-emissions-in-china-past-present-future/

4. https://www.bettermeetsreality.com/summary-greenhouse-gas-emissions-united-states-past-present-future/

5. https://www.bettermeetsreality.com/the-challenges-with-chinas-transition-from-coal-to-natural-gas-renewable-energy/

6. https://www.bettermeetsreality.com/cities-that-emit-the-most-greenhouse-gases/

7. https://www.scientificamerican.com/article/heres-how-much-cities-contribute-to-the-worlds-carbon-footprint/?redirect=1

Recent studies and reports are outlining the carbon footprints of cities worldwide. 

In this guide, we list the cities with the largest carbon footprints.

Identifying the top greenhouse gas emitting cities is a good start in being able to come up with solutions for reducing greenhouse gases via various solutions and strategies.

Cities That Emit The Most Greenhouse Gases & Carbon Dioxide (In Total)

The top 30 cities with the largest carbon footprints (in total carbon dioxide emissions) are:

• Seoul
• Guangzhou
• New York
• Hong Kong SAR 
• Los Angeles
• Shanghai
• Country Of Singapore
• Chicago
• Tokyo/Yokohama
• Riyadh
• Dubai
• Wuxi
• Johannesburg
• Tehran
• Moscow
• London
• Benha
• Beijing
• Jakarta
• Al-Ahmadi
• Miami
• Samut Prakan
• Paris
• Dallas
• Tianjin
• Istanbul
• Detroit
• Philadelphia
• San Jose
• New Delhi

View the full list of the top 500 cities at http://citycarbonfootprints.info/ 

Cities That Emit The Most Greenhouse Gases & Carbon Dioxide (Per Person/Per Capita)

The top 30 cities with the largest carbon footprints per capita/person are:

• Hong Kong SAR
• Mohammed Bin Zayed City
• Abu Dhabi
• Country of Singapore
• Hulun Buir
• Al-Ahmadi
• Doha
• Hinggan
• Chifeng
• Al-Jahrah
• Litong
• New Orleans
• Detroit
• Tongliao
• Yinchuan
• Al Ain
• Cleveland
• Ulanqab
• St Louis
• Dalad
• Pittsburgh
• Toledo
• Kansas City
• Gold Coast
• Grand Rapids
• Cincinnati
• Tulsa
• Akron
• Dubai
• Huhot

View the full list of the top 500 cities at http://citycarbonfootprints.info/

A Note On Calculating The Carbon Footprints Of Cities

Calculations for carbon footprints are a guide only because of the data that might be included and because of how complex and time consuming calculations can be.

For example, carbon footprints can be calculated with emissions from the production stage of goods and services (for example manufacturing a car), and also emissions from the consumption stage of goods and services (for example driving the car, getting it repaired, maintaining it, etc.). Some footprints only include one stage of the carbon lifecycle.

Also note that energy can be consumed and emissions produced within the city, off site at power plants, and off site at other locations (like people taking plane travel from the city to another location, waste being taken from the city and disposed of at landfills, and so on). Some calculations might only include emissions within the city. 

Emissions can also be imported and exported between cities with the exportations and importation or outsourcing of goods and services.

There’s many calculations and variables that can make up a 100% accurate/precise city carbon footprint.

Always look at exactly what data and calculations a footprint involves to get an idea of what it’s representing.

Sources

1. http://citycarbonfootprints.info/

2. https://www.c40.org/researches/consumption-based-emissions

3. Moran, D., Kanemoto K; Jiborn, M., Wood, R., Többen, J., and Seto, K.C. (2018) Carbon footprints of 13,000 cities. Environmental Research Letters DOI: 10.1088/1748-9326/aac72a.

This is not a guide about pointing fingers or blaming specific countries for climate change and global warming.

It is however a guide where we can get a better idea of which countries might be contributing in different ways to climate change via their greenhouse emissions across various measures and indicators.

Summary – Which Countries (Might) Need To Do More To Reduce Their Greenhouse Gas Emissions?

• As outlined – this is more a guide about which countries ‘might’ need to do more about emissions rather than saying that the countries listed below definitely need to reduce emissions. 
• There’s probably four indicators/measurements (that we can think of) that give a better idea of which countries need to do more to reduce emissions…
• Look at annual total emissions (total emissions per year), annual % of global emissions (what % that country makes up compared to other countries), per capita emissions (emissions per person per year), and look at reports/ratings about each countries’ effort and commitment to doing their ‘fair share’ to address climate change
• There is an asterisk on cumulative emissions as an indicator/measurement – the US has the most cumulative emissions over history by far. This is something to note – but obviously it’s something that reflects past behavior more than current behavior.
• We would also note that there are variables to emissions indicators – such as whether you are measuring all greenhouse gases or a specific one like carbon dioxide for example. Examples of other variables might include that some countries have cleaner coal than others, or, even that there is question over the accuracy of the reporting of some countries’ emission total
• But, with the data we have, the results are …
• Annual total greenhouse emissions – China currently leads all countries, and essentially doubles the second places US’s emissions
• Annual % of global emissions – China lead all countries in 2017 with 28.3% of emissions, over second placed United States with 15.2%
• Per capita emissions – According to multiple sources, Qatar leads per capita emissions with 47.83 tonnes of CO2 per person (a wide margin in front of other countries)
• According to some reports in 2019, these countries rate as critically insufficient when it comes to doing their fair share to reduce global emissions, or committing to targets to hold warming to below 2 degrees – Russia, Saudi Arabia, Turkey, USA, Ukraine
• According to some reports in 2019, these countries rate as highly insufficient when it comes to doing their fair share to reduce global emissions, or committing to targets to hold warming to below 2 degrees – Argentina, Canada, Chile, China, Indonesia, Japan, Singapore, South Africa, South Korea, United Arab Emirates
• According to some reports in 2019, these countries rate as insufficient when it comes to doing their fair share to reduce global emissions, or committing to targets to hold warming to below 2 degrees – Australia, Brazil, the EU, Kazakhstan, Mexico, New Zealand, Norway, Peru, Switzerland

Overall, the global emissions picture really needs to be broken down on a country specific, and even city specific level, along with looking at how clean current energy sources are, consumption of fossil fuels, investment and effort to set up renewable and clean energy forms, transition strategies to clean energy, progress on meeting emissions targets, emission policies and more.

This guide is more a generalisation and not an in depth analysis of all those factors.

Annual Total Greenhouse Gas Emissions (By Country)

The countries that lead in terms of total sum of C02 emissions per year in 2016, measured in millions of tonnes, are:

• China – 10,283.51 (Mt)
• US – 5,565.49 (Mt)
• EU-28 – a mix of european countries (Germany features high on the list)
• India – 2,236.55 (Mt)
• Russia – 1,669.6 (Mt)
• Japan – 1266.6 (Mt)

– ourworldindata.org

In 2014, the top countries for C02 emissions were:

• China – 30%
• Other – 30%
• United States – 15%
• EU-28 – 9%
• India – 7%
• Russia – 5%
• Japan – 4%

– epa.gov

Annual % Of Global Emission (By Country)

In the year 2017, the share of global CO2 emissions expressed as a % was:

• China – 28.3%
• Rest Of World – 28.2%
• OECD Countries – 21.2%
• USA – 15.2%
• India – 7.1%

– chinapower.csis.org

In the year 2016, the share of global CO2 emissions expressed as a % was:

• China – 29.1%
• US – 15.2%
• India – 6.9%
• Brazil – 1.4%
• UK – 1.1%

– ourworldindata.org

Per Capita/Per Person Emissions (By Country)

The countries with the highest per capita (C02 emissions per person in the population), measured in tonnes per person per year, are:

• Qatar – 47.83 (tonnes per person per year)
• Trinidad & Tobago – 30.06
• Kuwait – 25.81
• United Arab Emirates – 25.79
• Bahrain – 24.51
• Brunei – 23.7
• Saudi Arabia – 19.66
• New Caledonia – 18.2
• Australia – 16.5
• Luxembourg – 16.47
• United States –  16.44
• 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)

– ourworldindata.org

1. Qatar
2. Curacao
3. Latvia
4. Bahrain
5. United Arab Emirates
6. Trinidad and Tobago
7. Malaysia
8. Saudi Arabia
9. Guatemala
10. United States

– telegraph.co.uk

Rating Each Countries’ Effort, Commitment & ‘Fair Share’ To Address Climate Change

climateactiontracker.org has developed some ratings to assess the level of commitment and effort different countries are putting towards climate change and reducing greenhouse gas emissions.

Note that these ratings use a custom methodology – so not everyone may agree with it. Also note that countries can change their targets, policies and actions, which would then require an updating of the ratings over time.

But, the results/findings as of mid 2019 were:

Countries Rated Critically Insufficient

Commitments within this range fall well outside the ‘fair share’ range and are not consistent and are not consistent with holding warming below 2 degrees celcius.

If all government targets were within this range – warming would exceed 4 degrees celcius.

Countries include Russia, Saudi Arabia, Turkey, USA, Ukraine

Countries Rated Highly Insufficient

Commitments within this range fall outside the ‘fair share’ range and are not consistent with holding warming below 2 degrees celcius.

If all government targets were within this range – warming would fall between 3 and 4 degrees celcius.

Countries include Argentina, Canada, Chile, China, Indonesia, Japan, Singapore, South Africa, South Korea, United Arab Emirates

Countries Rated Insufficient

Commitments with this rating are in the least stringest part of their fair share range and not consistent with holding warming below 2 degrees celcius.

If all government targets were in this range, warming would reach between 2 and 3 degrees celcius.

Countries include Australia, Brazil, the EU, Kazakhstan, Mexico, New Zealand, Norway, Peru, Switzerland

Cumulative Emissions (By Country)

The countries that lead in terms of total sum of C02 emissions since 1751 and up to 2014, measured in millions of tonnes, are:

• United States – 376,212.65 (Mt)
• China – 174,874.89 (Mt)
• Germany – 86,536.42 (Mt)
• United Kingdom – 75,237.98 (Mt)
• India – 41,784.24 (Mt)

– ourworldindata.org

Sources

1. https://climateactiontracker.org/methodology/comparability-of-effort/

2. https://chinapower.csis.org/china-greenhouse-gas-emissions/

3. https://www.telegraph.co.uk/travel/maps-and-graphics/mapped-the-countries-that-use-the-most-electricity/

4. https://www.economicshelp.org/blog/6131/economics/list-of-co2-emissions-per-capita/

5. https://www.bettermeetsreality.com/what-are-the-targets-for-climate-change-global-warming/

6. https://ourworldindata.org/co2-and-other-greenhouse-gas-emissions

7. https://www.epa.gov/ghgemissions/global-greenhouse-gas-emissions-data

8. https://www.bettermeetsreality.com/countries-that-emit-the-most-greenhouse-gases-carbon-dioxide/

9. https://www.bettermeetsreality.com/what-are-the-targets-for-climate-change-global-warming/

10. https://climateactiontracker.org/countries/

Some people fully support some type of transition to renewable energy, whilst others don’t.

In this guide, we list various reasons why we don’t use more renewable energy right now worldwide (or on a country by country basis).

Summary – Reasons Why We Don’t Use More Renewable Energy Worldwide

Some of the reasons include: 

• Financial reasons (lack of funding or investment)
• A reliance in the past on fossil fuels to grow the economy
• There is significant existing investment in coal or another fossil fuel energy source
• Existing electricity infrastructure (such as the power grid) is designed and set up to take fossil fuel energy right now
• The past 15 years or past number of years of energy strategy is in implementation now, and there is a lag between strategy proposal and implementation
•  The profit margin of coal and other fossil fuel energy is high in some countries (for mining companies, coal plant investors and so on)
• Subsidies and protectionism of fossil fuels
• Environmental laws and regulations are too relaxed when it comes to dirtier energy sources
• Fines and penalties for dirtier energy aren’t big enough, and don’t dissuade companies and individuals from using these dirtier energy sources
• Technology (and variability) can be a limiting factor
• Speed of transition can cause job losses and other issues
• Some small populations and towns are reliant on fossil fuels for their livelihood
• Geographical unsuitability
• The use of renewables can introduce other environmental and sustainability issues
• Conflict of interest, questionable motives/intentions or even corruption from those making key decisions on energy supply
• Renewable energy being more expensive than fossil fuels in some countries
• Additional renewable equipment like batteries can add to the cost of renewables
• Politicians and key decision makers might believe their careers are tied to the support of the fossil fuel industry
• Politicians or key decision makers don’t understand or believe in the negative environmental impact of fossil fuel compared to renewables
• The general public/society has cultural or social beliefs that fossil fuels are a better option right now than renewables
• There is a perceived risk or uncertainty with renewables
• Cities/countries might be choosing to transition to natural gas or nuclear first before renewables
• Importing energy that is sourced from renewable sources has barriers
• Some cities or countries simply don’t have the natural or renewable resources for some types of renewable energy
• There can be misleading reports published about renewable energy by those with vested interest in fossil fuel industries

Overall, from the data, it makes sense that most cities and countries should consider renewable energy at the very least as a partial component of their entire energy mix i.e. as a supplementary or complementary source.

Some countries may even benefit from making renewables the majority of where they get their energy from (although they have to factor in the variability of some renewable sources like wind and solar, and complement it with a consistent energy source like hydropower, nuclear or existing fossil fuels for example).

Air contamination (outdoor air pollution and lowering of air quality), emission of greenhouse gases, potential future scarcity of non renewable resources, and other issues should be considered with continuing to use fossil fuels.

*Note – the reasons for pursuing different energy mixes is a city specific or country specific choice. Each city or country usually has different variables/factors to consider when choosing how their energy sources will be set up, and how they will run. This is how we end up with different timelines for energy supply mixes, and overall different energy supply mixes in each city worldwide.

1. Financial reasons (lack of funding or investment)

• A simple reason is that some countries of cities simply don’t have the finances or investment available to fund new renewable energy development.
• This could be because their budget is going towards existing energy sources, or they just lack the money in general (especially true for unstable economies, or lower income countries)

2. A reliance in the past on fossil fuels for economic growth

• Countries like China in particular have relied on coal to increase their economic growth in recent decades 
• Fossil fuels can be an option that some believe deliver better security and performance for a growing economy

3. There is significant existing investment in coal or another fossil fuel source

• There is a lot of existing heavy investment in coal in a country like China for example
• Heavy investment generally means there is already a surplus or over supply of coal power plants
• This investment also means that if there is a switch to renewables, there can be stranded/sunk investments in the form of coal power plants and coal infrastructure – so people are losing money or not getting their money back

4. Existing electricity and grid infrastructure is set up for fossil fuel 

• Existing energy infrastructure (mainly the power grid) can be designed and set up to take fossil fuel energy
• As a result, there can be technical or other issues connecting into the grid with renewables. It also creates a path dependency that relies on fossil fuels in the present
• There can also be renewable power lost or wasted because of this because for example solar panel farms might not be able to feed all their collected energy into the grid 
• Retrofitting and modifying existing infrastructure can be costly financially and from a time perspective

5. The existing power supply can be a result of the last 15 years of energy development strategy

• In some cases in some countries, energy sector implementation lags behind strategy by many year – up to 15 years in the case of some cities (this is particularly applicable on large scale projects and modification)
• If you want renewable energy now, you should have been strategizing to implement it years prior to prevent a lag

6. Coal in some instances can have a high profit margin (for investors and those funding it)

• The profit incentive in some countries to continue with coal is strong
• This is especially true considering how cheap coal is in some countries
• Mining companies and coal plant investors can benefit immensely from this

7. Government subsidies and protection for coal and fossil fuels

• The government can subsidise and protect coal and other fossil fuels in different ways (through laws, concessions, tax cuts or advantages etc.) in some countries
• The same may not be done for set up and installation of new renewable energy equipment comparatively (incentives for citizens to install solar for example may be decreased)
• This gives an advantage to setting up and continuing to run fossil fuel energy
• One example of a country that gave huge incentive to it’s citizens to install household solar was Germany

8. There can be a relaxation on environmental laws regulating dirtier energy

• If laws aren’t strict enough or well enough enforced for fossil fuel energy or dirtier energy (that contaminates the air and emits greenhouse gases) – these energy sources will continue to prosper
• Environmental laws need to balance jobs and the economy, but also serve society in the short and long term environmentally

9. Fines and penalties for dirty energy in some instances aren’t big enough

• If fines and penalties for dirtier energy aren’t heavy enough, companies will be willing to pay fines over implementing cleaner energy strategies and using cleaner energy sources

10. Technology of renewables can sometimes be a limiting factor

• In some countries, the technological aspect of renewable energy can impact it’s efficiency, operation and maintenance costs in many ways
• Variability of power supply can also be an issue with renewable energy, and technology and other energy sources have to be available or sufficiently developed to deliver a consistent power supply
• For example, solar can be fed into the grid directly from solar farms, but can also be stored in batteries when panels are installed on family homes and buildings. Batteries big enough to store lots of energy are expensive, and batteries are good for short, rapid bursts of power but not sustained non variable energy (pumped hydropower is one way of getting around this)

11. Speed of transition can lead to other issues like job loss, loss of disposable income and so on

• Sometimes, a city might propose to transition too fast
• This can cause various issues that citizens haven’t had time to prepare for – such as a loss of a job in the fossil fuel industry, or an increase in energy prices
• Price reforms to the cost of energy can be a problem (energy prices might be increased which can really affect low income earners)

12. Some small populations and towns have almost a complete reliance on fossil fuels for their livelihood

• There can also be job loss and a loss of disposable income from shutting down fossil fuel operations in – this can particularly cripple smaller towns and communities with a reliance on it – whether it’s in the mining industry or working for a fossil fuel plant or energy provider

13. Geographical (un)suitability 

• As one example of geographical suitability (or unsuitability) … Many of the massive showcase renewable projects in the outer provinces of China are too far away from the energy-hungry cities and industrial centres of the east, and transmission lines and the grid haven’t been upgraded to utilise the power

14. Renewable energy can cause other environmental/sustainability issues

• Solar farms can degrade land, contribute to land scarcity or exacerbate existing environmental problems in places where these issues already exist (such as land scarce towns in China)
• Renewable equipment like solar panels or batteries also use precious/rare metals – so there can be short term or long term supply issues if alternatives aren’t developed or there are other supply issues

15. Questionable motives/intentions and conflict of interest from those making decisions on energy supply 

• In some countries, business and political elites are making millions and billions from fossil fuel industries
• Some call this corruption, whilst others call it questionable motives/bad intentions or a conflict of interest

16. In some countries, renewable electricity is expensive compared to fossil fuel

• Renewable energy can be more expensive than renewable energy in some cities and countries compared to coal
• This happens for various reasons, with overall demand being low, or technology not yet being advanced enough being a few examples

17. Unless energy is fed into the grid, some renewables need batteries, which add to the price

• There’s two ways to use some renewable energy – storing energy in batteries, and feeding energy straight into the grid.
• When using batteries, they can be expensive because of how big they are
• Additionally, batteries are usually only good for short term energy supply before they have to be recharged or topped up. So, a more consistent power supply is needed in this case

18. Politicians and key decision makers might believe their careers are tied to the support of the fossil fuel industry

• Some politicians and key decision makers may believe their career prospects and livelihood is linked to supporting fossil fuels over renewables
• This may influence them to make decisions in favor of fossil fuels over renewables

19. Politicians or key decision makers don’t understand, or believe in the negative environmental impact of fossil fuel compared to renewables

• Some decision makers may still be in doubt , or are skeptical about the role fossil fuels in issues like air pollution, carbon emissions and other environmental and sustainability issues.
• This can influence their decision making on energy supply strategy 
• Some politicians even believe the strength of support around renewables might be in some way a conspiracy by other major countries to sabotage their economy (although this is just hearsay)

20. The general public/society has cultural or social beliefs that fossil fuels are a better option right now than renewables

• For reasons such as employment, keeping the economy strong, jobs, reliability, certainty etc.
• This obviously impacts how people vote for their governments

21. There is a perceived risk or uncertainty with renewables

• That it will be unreliable or not cost effective
• Especially by governments or business or investors
• Investors and energy suppliers want to know they will get their money back and make a profit for sure over a certain period of time

22. Cities/countries might be choosing to transition to natural gas or nuclear first before renewables

• If a city or country has a transition plan, then transition to renewables might be scheduled to happen after an initial transition to natural gas or nuclear first
• This can be for variability reasons, power density or power output reasons, or many other reasons

23. Importing energy that is sourced from renewable sources can have barriers

• Some cities and countries import a portion of their energy
• Importing renewable energy might have barriers or difficulties that make it difficult

24. Some cities or countries simply don’t have the natural or renewable resources for some types of renewable energy

• Iceland is an example of country with good natural resources for geothermal energy and hydroelectricity energy – which they use a lot of
• But some countries or cities don’t have enough natural resources for some types of renewables
• For example, they might not have enough land for solar farms, enough sun for solar in general, enough wind for wind energy in general, enough suitable places for hydroelectricity damn installation and so on

25. There can be misleading reports published about renewable energy by those with vested interest in fossil fuel industries

• This is more of a subjective reason, but some sources indicate that some reports on renewable energy might be misleading information that gets published by fossil fuel companies or those with a vested interest in fossil fuels and other non renewable energy. These reports obviously change people’s opinions and mislead them

Sources

1. https://www.bettermeetsreality.com/the-challenges-with-chinas-transition-from-coal-to-natural-gas-renewable-energy/ 

2. https://www.cnet.com/news/if-renewable-energy-can-power-entire-countries-why-isnt-everyone-doing-it/ 

3. https://en.wikipedia.org/wiki/100%25_renewable_energy

Energy sources can be primary or secondary.

In this guide we explain what they are and give examples of each.

What Are Primary Energy Sources?

Primary energy sources are usually either natural or refined resources.

They undergo an energy conversion process to produce a secondary (usually more convenient) form of energy.

What Are Secondary Energy Sources?

Secondary energy sources are forms of energy produced from the above mentioned energy conversion process of primary energy sources.

Secondary energy sources are the ones we as humans usually directly use in a more convenient way e.g. the burning of coal at coal power plants is the primary energy source that delivers us the secondary energy source of electricity to use at work, in our homes etc.

Secondary energy sources are also referred to as energy carriers, because they move energy in a useable form from one place to another [secondary energy is essentially a good that has been changed from it’s original state to another state for ease of consumption]. The two most well-known energy carriers are electricity and hydrogen.

– userwikis.fu-berlin.de

What Are Examples Of Primary & Secondary Energy Sources?

• coal, raw oil, natural gas, wind, sun, streaming water, [… and uranium are all examples of primary energy sources]

– userwikis.fu-berlin.de

• Gasoline is a secondary product better suited for motor transport uses than crude oil, the primary product from which it is made.
• Electricity production based on hydropower, solar PV, wind and ocean energy is considered to be primary energy.
• For geothermal and solar thermal, however, heat is the primary energy, which can be transformed into secondary geothermal or solar electricity.
• [Bioenergy is a more complicated/complex form of energy as not all bioenergy sources are primary energy products]

– hub.globalccsinstitute.com

• Primary sources can be used directly, as they appear in the natural environment: coal, oil, natural gas and wood, nuclear fuels (uranium), the sun, the wind, tides, mountain lakes, the rivers (from which hydroelectric energy can be obtained) and the Earth heat that supplies geothermal energy.
• Secondary sources derive from the transformation of primary energy sources: for example petrol, that derives from the treatment of crude oil and electric energy, obtained from the conversion of mechanical energy (hydroelectric plants, Aeolian plants), chemical plants (thermoelectric), or nuclear (nuclear plants). Electric energy is produced by electric plants, i.e. suitable installations that can transform primary energy (non-transformed) into electric energy.

– eniscuola.net

• People make electricity and hydrogen [which are secondary energy sources] from primary energy sources such as coal, natural gas, nuclear energy, petroleum, and renewable energy sources (biomass, geothermal, hydropower, solar energy, and wind energy).

– eia.gov

• Crude oil must be put through an oil refinery before it turns into secondary fuel (useable fuel) like gasoline, diesel or kerosene.
• Coal is usually put into a coal-fired power plant to generate electricity
• Wind must be harnessed by a wind turbine before it can generate electricity

– energyeducation.ca

• Primary energy sources take many forms, including nuclear energy, fossil energy – like oil, coal and natural gas – and renewable sources like wind, solar, geothermal and hydropower. These primary sources are converted to electricity, a secondary energy source, which flows through power lines and other transmission infrastructure to your home and business.

– energy.gov

There’s some good examples of primary energy sources, energy breakdown processes and secondary energy sources at:

• https://en.wikipedia.org/wiki/Primary_energy

What Does It Mean To Say That Electricity Is A Secondary Energy Source?

It means that electricity is the source of energy being used by the consumer, but it has come from a primary energy source such as coal (that has undergone an energy conversion process at a coal power plant) for example.

Sources

1. https://userwikis.fu-berlin.de/display/energywiki/secondary+energy

2. https://hub.globalccsinstitute.com/publications/statistical-issues-bioenergy-and-distributed-renewable-energy/primary-and-secondary-renewable-energy-sources

3. http://www.eniscuola.net/en/argomento/energy-knowledge/energy-sources/primary-and-secondary-sources/

4. https://en.wikipedia.org/wiki/Primary_energy

5. https://www.eia.gov/energyexplained/?page=secondary_home

6. https://www.originenergy.com.au/about/community/energy-for-schools/students/what-is-energy-years-7-8.html

7. https://energyeducation.ca/encyclopedia/Primary_energy

8. https://www.energy.gov/science-innovation/energy-sources

9. http://needtoknow.nas.edu/energy/energy-sources/electricity/

10. https://shodhganga.inflibnet.ac.in/bitstream/10603/15703/8/08_chapter%202.pdf