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’
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
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.
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.
- 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.
- 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.
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
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]
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.
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.
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.).
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
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.
- … 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
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.
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?
- Per capita, countries in central South America, the Middle East and both eastern and southern Africa [have some of the lowest national average emissions]
- Per capita, Denmark, Finland and Nigeria were the lowest CO2 emitters in 2016
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
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.
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:
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