Climate Change: The Scientific Facts

We describe the primary and secondary factors that influence our climate, including the use of fossil fuels. We also look at the main effects of climate change, as well as the advice being offered by the UN and the IPCC on preventing and cushioning its impacts.
Australian bushfires: Kangaroo survives
After climate change has finished off the animals, we’ll be next. Photo: © Jo-Anne McArthur/Unsplash

What is Climate Change?

The term “climate change” means any significant change in the average rainfall, winds or temperature of the Earth – irrespective of the cause – which lasts for 30 years or longer. Examples of past climate changes include the catastrophic loss of sunlight and consequent rapid cooling of Earth, caused by the impact of the Chicxulub asteroid, which wiped out the dinosaurs 66 million years ago, as well as the five major ice ages of prehistory.

Today, the term is used to describe the recent surge in global temperature (1975-present) – known as global warming – caused by man-made emissions of heat-trapping ‘greenhouse gases’, like carbon dioxide, from the burning of fossil fuels. 1 This recent surge in Earth’s temperature has captured the urgent attention of climatologists around the world. As a result, the term “climate change” has become the ’official’ name for global warming, as underlined by its incorporation into the title of the Intergovernmental Panel on Climate Change (IPCC) and the UN Framework Convention on Climate Change (UNFCCC).

NOTE: For a short explanation of global warming, see our: Climate Change Essay in 1,000 words. For answers to frequently asked questions, see: 50 Climate Change FAQs and also: 50 FAQs About Global Warming.

Tropical depression thunderstorms destroy houses, United States
In 2020 Hurricane Laura, a category 4 storm weakened to a tropical depression when it hit the Chattanooga region, Tennessee, causing significant damage to homes and businesses. Photo © Kelly Lacy/ Pexels

What’s The Difference Between Global Warming And Climate Change?

“Global warming” refers to the increase in Earth’s temperature caused by human action. In other words, it’s global and it causes an increase in temperature. “Climate change”, on the other hand, may refer to a period of cooling (such as an ice age) as well as warming, and it’s not necessarily global: it may refer only to a region or part of a region. Lastly, it also embraces natural as well as man-made climate change. In practice though, both terms are commonly used to describe our present climate warming.

Of course, the term climate change hardly does justice to the environmental and ecological dangers posed by global warming, whose adverse effects on the Earth’s oceans, cryosphere and atmosphere are now apparent in every corner of the globe. The planet’s entire biosphere is under threat, thanks to our overconsumption of fossil fuel energy. A more accurate description is climate crisis, because unless we switch to cleaner energy, global warming could turn out to be global extinction.

The Role Of The Sun

Icebergs Reflect Sunlight Thus Regulating Climate Change
Icebergs help control global warming by reflecting back sunlight. Image: NASA

The sun is the primary energy source for our climate system. Solar energy is transmitted by the sun in the form of light at the speed of light. It takes roughly 8 minutes to travel the 90 million miles to Earth. About 29 percent of all sunlight (solar or light energy) that arrives at the edge of Earth’s atmosphere is reflected back into space by clouds or reflective particles in the atmosphere, or by ice and snow on the Earth’s surface. The surviving 71 percent is absorbed by the Earth’s surface and atmosphere: 23 percent is absorbed by the atmosphere; 48 percent is absorbed by Earth’s land and sea. (Note: Energy comes to Earth in the form of light but leaves as heat. This is why incoming sunlight is reflected by clouds but outgoing infrared heat energy is absorbed by them.)

The Energy Balance

The laws of physics dictate that all objects that receive an amount of energy must emit an equivalent amount of energy, in order to maintain their energy balance. Therefore, in order to maintain a stable temperature and stop itself from overheating, the Earth must now expel the solar energy it receives from the sun (that is, the 48 percent it absorbs). For more on this, see: Earth’s Energy Balance.

The Greenhouse Effect

But as Earth emits the solar energy it absorbs into space, a significant amount of it is trapped by greenhouse gases in the atmosphere (like water vapor and carbon dioxide), in a process known as the “Greenhouse Effect“. The greenhouse gases then re-radiate the trapped energy in all directions, including back towards the Earth’s surface. This greenhouse effect helps to maintain life on Earth. Without it, the average temperature on the surface of the planet would be about minus 18°C (0 °F), instead of the current average of 15 °C (59 °F).

Fossil Fuels Have Destabilized The Greenhouse Effect

For the last 10,000 years or more – ever since the end of the last Ice Age – the Earth has maintained a fairly stable temperature and a stable level of greenhouse gases. But things changed from about 1750 onwards, when new inventions in Europe triggered what became known as The Industrial Revolution.

During this phase of industrial development, new machines and factory processes were introduced, which consumed large amounts of fossil fuel. Coal was the world’s foremost fossil fuel until the 1950s. Its precursor, peat, was popular in countries like Russia, Canada and Ireland. Petroleum became an important source of energy from the 1860s onwards, followed later by natural gas.

Ever since the Industrial Revolution, the burning of coal and other carbon-rich fossil fuels has led directly to growing levels of carbon dioxide (CO2) in the atmosphere. In turn, this has resulted in more and more trapped heat, destabilizing the greenhouse effect and raising temperatures to levels not seen for thousands of years.

So how much has the Earth’s temperature increased? According to scientists at NASA’s Goddard Institute for Space Studies, the average surface temperature of the planet has risen by approximately 1.1 degrees Celsius (2.0 degrees Fahrenheit) since 1900. 2 It may not sound a lot, but it is. For more on this, see: Why a half-degree rise in temperature matters

What Are The Primary Causes Of Climate Change?

Over the past 2-3 billion years, the three most important causes of climate change (known as ‘drivers’ or ‘forcings’) have been: (a) changes in the amount of solar energy received, or fluctuations in the Earth’s orbit around the Sun, (b) volcanic eruptions or tectonic events, and (c) meteorite collisions with Earth. All three are naturally occurring events over which we have no control.

However, the main driver of today’s warming is the man-made surge in greenhouse gases, caused by the burning of fossil fuels. 3

For a challenging viewpoint, see: What is the Root Cause of Climate Change?

What Is The Main Cause Of Today’s Climate Change?

  • The IPCC’s Fourth Assessment Report (2007) states that increases in anthropogenic greenhouse gas levels are “very likely to have caused most of the increases in global average temperatures since the mid-20th century.”
  • In 2017, U.S. greenhouse gas concentrations were made up of the following chemicals: Carbon dioxide 82 percent; Methane 9 percent; Nitrous Oxide 6 percent; fluorinated gases 3 percent. In total, a whopping 76 percent of these chemical discharges derived from fossil fuel combustion – specifically the burning of coal, oil, and natural gas, and also wood burning.
  • In 1750, the atmospheric level of carbon dioxide (CO2) was about 280 ppm (parts per million). It is now around 414 ppm, which means that CO2 levels today are higher than at any point in the past 800,000 years. 4 5
  • In 1750, the atmospheric level of methane (CH4) was about 790 ppb (parts per billion). It is now around 1860 ppb, which means that CH4 levels today are higher than at any point in at least the past 650,000 years. 6
  • The evidence is unmistakable. Fossil fuel-based greenhouse gas emissions are the primary cause of climate warming.

Greenhouse Gas Emissions

Here is a short summary of where the main man-made greenhouse gases (GHGs) come from, together with details of their global warming potential (GWP). 7 8

Carbon Dioxide (CO2)

Man-made emissions of carbon dioxide (CO2) derive from burning fossil fuels like coal, petroleum and gas and peat. The biggest CO2 emitters are coal-fired power stations and motor vehicles. Cement industry CO2 emissions are also huge.

Deforestation is another culprit, releasing nearly a billion tons of carbon into the atmosphere per year. 9 Carbon dioxide has a major influence on warming because of its abundance in the atmosphere. In 2018, according to the EPA, CO2 made up 81 percent of U.S. greenhouse gas emissions (65 percent of global emissions). CO2 is one of the most long-lived GHGs. Around 20 percent remains active in the atmosphere for hundreds, sometimes thousands of years.

Methane (CH4)

Man-made emissions of methane (CH4) derive mainly from livestock, landfills and leaks from natural gas infrastructure, like pipelines. In 2018, according to the EPA, methane CH4 made up roughly 10 percent of US greenhouse gas emissions (16 percent of global emissions). Over 20 years, methane traps 84 times more heat than carbon dioxide. Over 100 years, 28-36 times as much. However, it is only fully active for about 10 years.

Nitrous Oxide (N2O)

Man-made emissions of nitrous oxide (N2O) result from the use of nitrogen fertilizers, fossil fuel combustion and from certain factory and waste management processes. In 2018, according to the EPA, nitrous oxide (N2O) made up around 7 percent of US greenhouse gas emissions (6 percent of global emissions). N2O has a GWP 265–298 times greater that of CO2. (EPA) Like methane, N2O remains active for more than 100 years.

Synthetic Fluorinated Gases

Synthetic F-gases, such as Chlorofluorocarbons (CFCs) (now banned by the Montreal Protocol), Hydrofluorocarbons (HFCs), Perfluorocarbons (PFCs), Sulfur Hexafluoride and Nitrogen Trifluoride, are man-made compounds found in refrigerants, air conditioning units, solvents, insulating foams, fire extinguishers and aerosol propellants. They are also found in the electronics and microelectronics industries, as well as the pharmaceutical and cosmetics sectors.

Emissions of F-gases typically occur during manufacturing and maintenance processes. Although emitted in very small quantities, F-gases have a global warming potential up to 23,000 times greater than carbon dioxide.

Latest Statistics On Greenhouse Gas Emissions

The latest figures on global greenhouse gas emissions are as follows: total emissions for the year 2019 amounted to 59.1 GtCO2e (billion tons of CO2 equivalent). Of these, 38.0 GtCO2 came from fossil fuels and industry; 6.8 GtCO2 came from deforestation and land use; 9.8 GtCO2e came from man-made methane emissions; 2.8 GtCO2e came from man-made nitrous oxide; 1.7 GtCO2e came from fluorinated gases. [Note: like all statistics on GHG emissions, these figures are approximate only. Source: UN Emissions Gap Report 2020.] See also: Greenhouse Gas Statistics Lack Consistency.

How Dependent Are We On Fossil Fuels?

Very. At present, about 11 percent of the world’s energy requirements are met by renewable energies like wind, solar or hydroelectric.

Primary Energy by Fuel Type 2020
Source: BP Statistical Review of World Energy 2020
US Primary Energy By Fuel Source

How Do Aerosols Affect Global Warming?

Carbon dioxide emissions are also associated with atmospheric aerosols, a type of air pollution that causes a number of environmental and health problems. See: What exactly are aerosols and how do they affect global warming?

“Aerosols” is an umbrella term for small bits of solid matter or liquid particles that end up suspended in the atmosphere. (Think “airborne stuff”.) Produced by a variety of industrial factory processes or entirely natural processes, they can be microscopically small or large enough to see with the naked eye. They include things like sea salt, material discharged by volcanic eruptions, anthropogenic or natural dust, droplets of acid, black carbon from the combustion of fossil fuels, and so on.

The effect of aerosols on global warming can be beneficial or harmful. In general, bright-colored or translucent particles reflect sunlight (cooling the planet), while darker aerosols absorb light (warming the planet via the greenhouse effect).

However, dark particles also tend to shade the Earth’s surface, making it cooler. (See, for example, the Asian Brown Cloud that appears in India during the winter dry season.) But, if dark particles fall on areas of snow or ice they will reduce the latter’s light-reflecting ability (lowering the so-called albedo effect) and warm the planet as a result. In the Arctic, for instance, aerosols from wildfires and industrial pollution are accelerating ice melt.

Confusingly, aerosols also stimulate cloud formation (water droplets form more readily around particles), and since white clouds reflect incoming sun this has a cooling effect. On the other hand, clouds also absorb heat via the greenhouse effect, thus adding to global warming. (For more, see: How do Clouds Affect Climate?)

From 1940 to the late 1950s the Earth’s average temperature fell by about 0.2°C. Later, from about 1960 to 1990, a gradual fall in the amount of sunlight reaching the Earth’s surface was observed – known as global dimming. Climatologists attributed both these events to the effect of aerosols. Some even suggested that this cooling effect might predominate over the warming impact of CO2. However, following more thorough studies as well as a switch to cleaner fossil fuels, scientists now believe that, overall, aerosols have at best a neutral effect on climate change. This may not be the last word on this subject. Of the 25 climate models reviewed by the Fourth Intergovernmental Panel on Climate Change (2007), the vast majority involved sulphate aerosols, a type noted for its cooling tendency.

What Are The Health Risks Of Aerosols And Air Pollution?

Aerosol pollution generated by the combustion of fossil fuels like coal, petroleum and other factory combustibles – see the environmental effects of fossil fuels – is associated with an increased risk of asthma and lung disease, as well as heart disease, stroke, cancer, certain birth defects and even Alzheimer’s disease.

A recent estimate by the World Health Organization (WHO) states that fine particles in the air – notably “PM2.5”: particulate matter less than 2.5 microns in diameter – resulted in 4.2 million premature deaths around the world in 2016. The health risks from breathing in this type of particle are highest in urban areas of Asia – examples: Beijing (from coal burning), New Delhi (crop stubble fires) and Ulaanbaatar (coal stoves) – and overall WHO says that 91 percent of the world’s population lives in places where air quality exceeds WHO limits. 10

Air quality has deteriorated markedly since 1900. The atmosphere now contains 60 percent more PM2.5 particles, whose adverse health effects are coming under increasing scrutiny. For example, in 2016, a joint UK/Mexico study under Professor Barbara Maher of Lancaster University discovered microscopic particles lodged inside the brains of 37 individuals who had lived in Manchester or Mexico City – both air pollution hotspots. These tiny aerosols are thought to be a possible cause of Alzheimer’s disease. 11

So, whether or not they affect climate change, aerosols are implicated in a wide range of adverse health conditions affecting people around the globe. Air pollution kills 200,000 people a year in the United States alone. These fatalities illustrate the global nature of the emissions problem, since they are caused in part by prevailing winds from Asia that cross the Pacific from China to the U.S. West Coast carrying unhealthy concentrations of man-made sulphates, carbon grit and industrial chemicals. Almost 33 percent of the air over San Francisco and Los Angeles can be traced directly to Asia, and this air contains 75 percent of the black carbon aerosol pollution that reaches the West Coast. 12 13 14

How is Air Pollution Measured?

Authorities measure air quality with the Air Quality Index, or AQI, which uses colors (varying from country to country) to indicate the current state of air pollution. In the United States, for example, the AQI is based on five key pollutants: ground-level ozone, particulate matter, carbon monoxide, sulfur dioxide, and nitrogen dioxide is divided into the following six categories indicating increasing levels of health concern: 15

What Are The Secondary Causes Of Climate Change?

In addition to the above primary causes, there are a number of secondary or indirect influences, known as feedbacks. These climate feedbacks amplify or reduce the effects of the above drivers. A good example of a positive feedback (a booster) is water vapor.

Water Vapor: A feedback not a forcing

As greenhouse gases trap heat in the troposphere the air temperature rises. This warming causes the atmosphere to hold more water in the form of vapor and the air becomes more humid. But water vapor is also a greenhouse gas that absorbs heat, so it boosts the warming effect even further (positive feedback). This causes the atmosphere to hold still more water, and so on, until other processes stop the feedback loop.

The point is, water vapor is not an independent cause of man-made warming, it only amplifies the original driver. This can be confusing at first, so let’s go through the process once again. Greenhouse gases are emitted (this is the climate driver, the forcing). The gases cause a warming effect. As a result, more water evaporates into water vapor and rises into the atmosphere. Because this vapor is itself a greenhouse gas with heat-trapping abilities, it adds to the warming effect of the other gases, sometimes doubling it.

As you can see, there’s no doubt that water vapor has a significant effect, but we must remember two things. First, the water vapor is controlled by temperature, not vice versa. Without the original warming effect, no extra water vapor would have appeared. Second, the amount of water vapor in the air is directly related to temperature. So as soon as the temperature falls, the vapor consenses back into liquid. In other words, water vapor tends to have a very temporary effect compared to (say) carbon dioxide, the main greenhouse gas, which can remain in the atmosphere for thousands of years.

Other feedbacks

Melting ice and snow is another example of positive feedback. Ice reflects sunlight back into space via the albedo effect, so as it melts it leads to greater warming. The polluting of Arctic ice by black ash deposits from runaway wildfires (a 2019 occurrence) leads to a similar effect.

As well as positive feedbacks, there are also negative feedbacks that act as a brake on a particular driver. Rather confusingly, a good example of negative feedback is water vapor – specifically, cloud formation – because clouds reflect sunlight and thus help to cool the Earth.

As you can see from the fact that water vapor can have both warming and cooling effects, fathoming the cause and effect of climate change is not always easy. This is why climate science is so dependent on complex climate models to generate accurate projections.

Regional Weather Systems
Naturally occurring weather cycles – such as the Indian Ocean Dipole (IOD) and the El Niño-Southern Oscillation (ENSO) in the Pacific – play an important role in climate variability in the tropics, delivering droughts, heatwaves, forest fires or floods, depending on sea surface temperatures.

What Are Climate Tipping Points?

Another type of climate accelerator is the tipping point. Scientists have identified a number of climate tipping points – or critical thresholds – that, once crossed, will lead to an unstoppable rise in temperature. For example, once polar ice-melt reaches a certain point, it could trigger an irreversible rise in sea levels, as well as a rise in temperature due to a lowering of the albedo effect, as the ice disappears.

Another tipping point could be the thawing of permafrost in Arctic regions, because it could release huge quantities of methane and carbon dioxide lying below the surface.

Other tipping points may arise following irreparable damage to one of the Earth’s biomes, like the Amazon Rainforest. If this hot and humid forest were to dry out, due to sustained high temperature or continued deforestation, it could turn into savanna and destabilize the entire climate system of southern and central America.

What Are Some of the Effects of Climate Change?

The impacts of climate change on Planet Earth and its climate system are gradually becoming more and more severe and widespread. As well as its direct impact on the human population, climate change is also responsible for a range of indirect effects, such as the loss of biodiversity, which can damage food, water or medical supplies, and destroy the ecological balance. (For the 8 major impacts on human life, see our article: Effects of Global Warming on Humans.)

Ecological Effects

A major impact of global warming is its effect on biodiversity within the animal and plant kingdoms. Climate change causes a growing loss of habitat for a wide range of animals, birds and insects, which can have profound effects on the food web, sometimes with global consequences. Take bees, for example. Bees are important pollinators, pollinating 70 of the 100 types of crops that feed 90 percent of the world. We may lose all the plant species that bees pollinate, as well as all of the animals that eat those plants and so on all the way up the food chain. Bottom line: if bees became extinct the world could struggle to sustain a human population of 7 billion – never mind the expected 11 billion by 2100. Our supermarkets would have half the usual amount of fruit and vegetables. 16

Changes In Weather

We are already seeing exaggerations in weather systems, including more severe cyclones and hurricanes, heavier rainfall, more drought and extremely high temperatures.

These extreme weather events are responsible for an upsurge in wildfires, widespread flooding, and increased air pollution. According to the UN, over 90 percent of the world’s population is exposed to unhealthy levels of toxic air. Severe heatwaves are also affecting crops and reducing soil moisture.

It’s important to understand that the majority of plants and animals inhabit areas with very specific climate conditions, including temperature and rainfall patterns. Any significant change in these climatic conditions is likely to have an existential effect on the flora and fauna of the area.

Changes In The Cryosphere

Some of the most worrying examples of climate change are those affecting the cryosphere – the planet’s store of frozen water. Global warming reduces the amount of ice and snow, which in turn reduces the reflective capacity of the Earth, so less sunlight is reflected back into space and more is absorbed, leading to greater warming. The damage to the Arctic and Antarctica is especially worrying as they play a crucial role in regulating the planet’s climate. Average air temperatures in the Arctic have risen by around 5°C over the past 100 years. The Arctic Ocean is expected to become ice free during the summer before 2050 – a disaster for polar bears.

With climate change melting Arctic ice, the main hunting grounds for polar bears, these cubs face an uncertain future.
Climate change and the loss of their sea habitat is the greatest danger to polar bears. The problem is, polar bears feed on seals that breed at the ice edge. But with the ice thawing earlier in spring, and freezing later in winter, bears have less time to hunt, and have to survive without food for longer. Fewer cubs survive and those that do are smaller. This places polar bears on the list for 10 endangered animals. Image: U.S. Fish and Wildlife Service.

The knock-on effects are being felt throughout the entire northern hemisphere. For example, due to unseasonal high temperatures, 43,000 square kilometres (17,000 sq mi) of Siberia were recently destroyed by forest fires, in what Greenpeace described as an “ecological catastrophe”. 17 According to one study, temperatures in the region are higher now than they have been for 44,000 years, maybe even 120,000 years. 18

Looking south, the Antarctic ice sheet is the biggest single mass of ice on Earth (14 million sq. km). This dazzling expanse of ice plays a critical role in combating warming. First, it reflects a huge amount of sunlight back into space; second, it holds roughly 86 percent of all fresh water on the surface of the planet. Even small-scale melting is likely to have significant effects on global sea level rise. The bad news is, areas of the Antarctic Peninsula are among the fastest-warming places on Earth. 19

Impact Of Climate Change On Oceans

Oceanography is an important contributor to climate science because oceans are important ‘carbon sinks’ as they absorb huge amounts of CO2 from the atmosphere. When mixed with water this CO2 CO2 produces carbonic acid, causing the oceans to become more acidic. This acidification leads to significant damage to coral reefs, and is compounded by ocean warming which leads to coral bleaching. Coral reefs support a quarter of all marine species at some point in their lives, all of whom are adversely affected. Coral reefs also provide livelihoods for more than 500 million people.

The greater the global warming the greater the coral loss. If it rises to 1.5°C coral reefs will decline by a further 70-90 percent within 30 years. If global temperature rises to 2°C almost all coral reefs will disappear. 20 21

Another effect of climate change on the ocean is the loss of mangroves due to ocean warming and marine heatwaves. Mangrove forests (mangals), along with seagrasses and other coastal marine vegetation, store a huge amount of so-called ‘blue carbon‘ in soil under the sea.

Effect On Sea Levels

Climate warming causes a rise in sea levels for two reasons. First, warm seawater expands: second, warming causes ice to melt adding extra water to the oceans. Since 1880, average levels have risen by 8 inches (20 centimeters) and the rate of increase is becoming much more rapid. They are projected to rise by another 1-4 feet by 2100, although the latest projections are warning of even higher sea level rises. 18 When aggravated by other climate change effects, like storm surges and high tides, the rise in sea level could lead to severe floods in many coastal regions. If warming ever reached 4°C, the impact on low-lying cities could be catastrophic.

Damage To Forests

Forests, too, act as carbon sinks, and deforestation caused by wildfires – such as the recent spate of Arctic fires – can undermine the entire biome. Living trees soak up carbon dioxide, but burnt or dying trees discharge their stores of carbon dioxide, stoking the greenhouse effect in the process. Like polar ice melt, deforestation could be a tipping point for irreversible global warming. Each year, roughly 6-12 percent of global forests are lost, destroying countless plants and animal habitats. Some 300 million people live in forests, which are also home to 80 percent of the world’s land-based biodiversity.

Climate Warming Increases Hunger

Extreme weather events associated with climate change increase the incidence and intensity of droughts, floods and storms. This causes damage to crops as well as infrastructure, therefore exacerbating hunger and poverty. Root crops, like potatoes, are especially vulnerable to prolonged rainfall. In addition, any serious rises in sea level will directly impact food supplies and livelihoods in coastal areas and river deltas.

Population Explosion And Calorie Needs

The current world population of 7.7 billion is expected to reach 9.8 billion in 2050 and 11.2 billion in 2100, according to “World Population Prospects: The 2017 Revision” a United Nations report published in 2017. The upward trend in population size is projected to continue, even as fertility levels decline. Experts forecast a 50 percent increase in food demand by 2050. 22 It’s worth noting that consumption of food calories per person worldwide, has increased by about one-third since 1961, and the average person’s consumption of meat and vegetable oils has more than doubled. 23

A Single Benefit Of Climate Change

If frosts disappear and minimum temperatures remain above about 5°C – and both are predicted to happen if Earth warming continues – agricultural scientists are predicting a significant lengthening of the growing season. Increases of about one month are projected for most of the United States, while in Norway, farmers could be growing their crops for up to two months longer. However, the extra yields of a longer season will hardly compensate for the generally adverse effects of global warming.

What Is Being Done About Climate Change?

For more than thirty years world leaders and diplomats have been holding climate talks to try and agree a common approach to our climate problem, using the resources of the United Nations. This is the only way to build a global consensus concerning what actions need to be taken, and by whom. Unfortunately, despite notable successes in (e.g.) reducing acid rain (Montreal Protocol 1987) and Mercury emissions (Minamata Convention 2013), the search for consensus is bedevilled by political point-scoring. Even at this late hour, many leaders refuse to accept that global warming takes precedence over everything else. See, for instance, our article: Emissions Gap: The Latest facts and figures.

At present, efforts to contain the worst effects of global warming are now focused on preventing temperatures from rising more than 2°C. above the pre-industrial average (traditionally, a baseline derived from climate statistics during the period 1850-1900), and ideally no more than 1.5°C.

What Climate Action Has Been Agreed?

International talks on climate action are overseen by the secretariat of the United Nations Framework Convention on Climate Change (UNFCCC), based in Bonn. The UNFCCC itself is the main international treaty on climate change and was adopted at the Earth Summit in Rio de Janeiro in June 1992. Its objective is to “stabilize greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system”.

The treaty sets advisory limits on greenhouse gas emissions for individual states. The UNFCCC has 197 members and enjoys almost universal support. The treaty also allows members to negotiate progress on climate action every year at meetings known as Conferences of the Parties (COP).

In 1997, the Kyoto Protocol to the UNFCCC laid down legally binding obligations for developed countries to reduce their emissions of six greenhouse gases: Carbon dioxide (CO2), Methane (CH4), Nitrous oxide (N2O), Hydrofluorocarbons (HFCs), Perfluorocarbons (PFCs), and Sulphur hexafluoride (SF6). The Kyoto Protocol acknowledges common but differentiated responsibilities and places the obligation to reduce current emissions on developed countries for the understandable reason that they are historically responsible for most of the mess.

In 2010, the United Nations Climate Change Conference (the 16th session of the COP) recommended that future temperature rises should be limited to no more than 2.0 °C (3.6 °F) above the pre-industrial baseline.

The Paris Agreement

In 2015, the Paris Climate Agreement (effectively superceding the Kyoto Protocol) was adopted, which regulates greenhouse gas emission from 2020 onwards. The Paris Agreement lowered the previous temperature target of 2.0°C to 1.5°C. Its stated aim is to create a stronger response to global warming by “holding the increase in the global average temperature to well below 2°C above pre-industrial levels and pursuing efforts to limit the temperature increase to 1.5°C above pre-industrial levels.” For an explanation of ‘pre-industrial levels’, see our article: When did Global Warming Start?

By February 2019, 185 states and the European Union (EU), representing nearly 87 percent of global greenhouse gas emissions, have ratified or accepted the agreement, including the China, India and the United States, whose combined emissions add up to 42 percent of the total.

Unfortunately, as the impasse at the Madrid COP 25 conference in December 2019 showed, things have slipped. The international community cannot seem to agree on certain key aspects of climate action, such as: Who Pays? and whether – and to what extent – developing countries can continue to increase their emissions. It’s hard to escape the conclusion that our climate plan can’t cope with the crisis.

In any event, the ethics of climate change demand that richer countries fund most of the costs of global warming and that poorer, less developed countries be allowed to continue increasing their greenhouse gas emissions to complete their development. At the same time, poorer nations must improve their governance for the system to work.

What is the Intergovernmental Panel on Climate Change?

The Intergovernmental Panel on Climate Change – usually abbreviated to IPCC – is a UN agency set up in 1988 by the World Meteorological Organization (WMO) and the United Nations Environment Programme (UNEP). Its role is to provide objective, scientific advice on climate change, its impacts and risks, and possible responses.

IPCC’S Special Report on Global Warming

  • In 2018, the IPCC published its Special Report on Global Warming of 1.5°C – an authoritative, scientific guide for governmental climate action. The report was prepared by 91 authors from 40 countries and contains more than 6,000 scientific references.
  • According to the report, in order to limit global warming to 1.5°C, worldwide emissions of carbon dioxide (CO2) would need to decline to no more than 45 percent of 2010 levels by 2030, and to net zero by 2050 (climate neutrality). The report acknowledges that creating a sustainable energy system will not be easy and that the targets will necessitate rapid, far-reaching and unprecedented changes in all aspects of society. Furthermore, it stated that even if this stringent target was actually achieved, Earth would still suffer from widespread drought, famine, extinction of animal species, collapse of entire ecosystems, and loss of habitable land, casting over 100 million people into poverty.
  • In 2018, at the United Nations Climate Change Conference in Poland, 15 international bodies (with 50,000 employees and 2 million tons of emissions per year) made a joint commitment to implement climate neutrality across all their operations. Each organization agreed to ascertain their emissions, reduce them as much as possible and offset the remaining balance with carbon credits.
  • Greenhouse gas emissions in the UK will be cut to almost zero by 2050, under the terms of a new government plan to tackle climate change. Britain is the first major nation to declare a “climate emergency” and commit to carbon neutrality by 2050. It has been widely praised by green groups. (In 2018 the Netherlands committed to a 95 percent cut in its emissions by 2050.) 24

What Can I Do To Help Reduce Climate Change?

It’s easy to feel helpless and insignificant in the face of a global climate crisis, especially when most of the heavy lifting has to be done by governments and corporations. But this is precisely when your individual contribution is needed. Because there is still so much climate change denial and scepticism in the halls of government.

Furthermore, the fossil fuel industry makes so much money that its acquiescence in any worldwide campaign to reduce CO2 emissions cannot be taken for granted.

So, what can we do as individuals to help save the world? Answer: SPEAK OUT! Talk to your representatives in parliament, ask them what they are doing to protect us all from the effects of climate change? Talk to your friends, use social media to spread the message that our planet is dying and needs saving. If you have more time, join an environmental action group, like Greenpeace or Friends of the Earth, or join your local Green Party.

We have a climate emergency – now is not the time to stay quiet. Now is the time to mobilize and make a fuss!


  1. IPCC. Fifth Assessment Report (AR5) of the United Nations Intergovernmental Panel on Climate Change (1) []
  2. NASA Goddard Institute for Space Studies. “NOAA data show 2016 warmest year on record, globally.” Jan 18, 2017. []
  3. “Climate Change 2007”, IPCC’s Fourth Assessment Report (AR4). (3) []
  4. Climate Change: Atmospheric Carbon Dioxide.” Rebecca Lindsey, NOAA. September 19, 2019. (4) []
  5. Luthi, D., Le Floch, M., Bereiter, B. et al. High-resolution carbon dioxide concentration record 650,000–800,000 years before present. Nature 453, 379–382 (2008). (5) []
  6. Loulergue, L., Schilt, A., Spahni, R. et al. Orbital and millennial-scale features of atmospheric CH4 over the past 800,000 years. Nature 453, 383–386 (2008). (6) []
  7. Where greenhouse gases come from. EIA. 2019. []
  8. Understanding the Global Warming Potential of Greenhouse Gases. EPA. []
  9. Global Forest Resources Assessment, 2010. []
  10. Air Pollution.” World Health Organization. (11) []
  11. Magnetite pollution nanoparticles in the human brain.” Barbara A. Maher, Imad A. M. Ahmed, Vassil Karloukovski, Donald A. MacLaren, Penelope G. Foulds, David Allsop, David M. A. Mann, Ricardo Torres-Jardon, and Lilian Calderon-Garciduenas. PNAS September 6, 2016. (12) []
  12. Air pollution and early deaths in the United States. Part I: Quantifying the impact of major sectors in 2005.”
    Fabio Caiazzo, Akshay Ashok, Ian A. Waitz, Steve H.L.Yim, Steven R.H.Barrett. (13) []
  13. “Pollution Knows No Borders. Jan 2019. PureEarth. “ (14) []
  14. Air Pollution in China Is Spreading Across the Pacific to the U.S. “Asian pollution climatically modulates mid-latitude cyclones following hierarchical modelling and observational analysis.” Wang, Y., Zhang, R. & Saravanan, R. Nat Commun 5, 3098 (2014). (15) []
  15. Criteria Air Pollutants (EPA). (16) []
  16. BBC Future May 4, 2014. (17) []
  17. Massive wildfires rage on in Russia”, BBC News July 31, 2019. (18) []
  18. Miller, G. H. et al; (2013). “Unprecedented recent summer warmth in Arctic Canada”. Geophysical Research Letters. 40 (21): 5745–5751. (19) [][]
  19. Contribution of Antarctica to past and future sea-level rise.” Robert M. DeConto & David Pollard. Nature. Vol 531, p.591. March 2016. (20) []
  20. IPCC Special Report on Global Warming of 1.5°C (2018) (21) []
  21. Coral Reefs & Climate Change. IUCN. (22) []
  22. How to Sustainably Feed 10 Billion People by 2050.” Janet Ranganathan, Richard Waite, Tim Searchinger, Craig Hanson. World Resources Institute. December 5, 2018. (24) []
  23. IPCC’s Special Report on Climate Change and Land. August 8, 2019. (25) []
  24. “Climate change: UK government to commit to 2050 target”, BBC News, June 12, 2019. (26) []
Share on facebook
Share on twitter
Share on linkedin
Share on whatsapp
Share on email