What are the Causes of Climate change?

This climate change is because of human activity

The main causes of climate change are: 

Humanity’s increased use of fossil fuels – such as coal, oil and gas to generate electricity, run cars and other forms of transport, and power manufacturing and industry

Deforestation – because living trees absorb and store carbon dioxide

Increasingly intensive agriculture – which emits greenhouse gases like methane and nitrous oxide.

Today's industrialised countries –have built their economies on buring fossil fuels to provide electricity, transport and to develop industries. Developing countries are now beginning to do the same. 

Climate scientists agree that humanity is responsible for the vast majority of global warming

The Intergovernmental Panel on Climate Change, the United Nations Environment Program’s climate body, has said for over a decade that there is “unequivocal” evidence that the planet is warming and that the temperature increase is “very likely” due to human-made greenhouse gas emissions.

The IPCC does not carry out research itself but bases its assessment on peer reviewed and published scientific/technical literature.

The Panel is made up of 2500+ scientific expert reviewers, 800+ contributing authors, and 450+ lead authors from 130+ countries.

Over 97% of peer reviewed journal articles on climate science agree with the scientific consensus around climate change.

Causes of climate change

Humans are increasingly influencing the climate and the earth's temperature by burning fossil fuels, cutting down forests and farming livestock.

This adds enormous amounts of greenhouse gases to those naturally occurring in the atmosphere, increasing the greenhouse effect and global warming.

Greenhouse gases

The main driver of climate change is the greenhouse effect. Some gases in the Earth's atmosphere act a bit like the glass in a greenhouse, trapping the sun's heat and stopping it from leaking back into space and causing global warming.

Many of these greenhouse gases occur naturally, but human activity is increasing the concentrations of some of them in the atmosphere, in particular:

carbon dioxide (CO2)

methane

nitrous oxide

fluorinated gases

CO2 produced by human activities is the largest contributor to global warming. By 2020, its concentration in the atmosphere had risen to 48% above its pre-industrial level (before 1750).

Other greenhouse gases are emitted by human activity in smaller quantities. Methane is a more powerful greenhouse gas than CO2, but has a shorter atmospheric lifetime. Nitrous oxide, like CO2, is a long-lived greenhouse gas that accumulates in the atmosphere over decades to centuries.

Natural causes, such as changes in solar radiation or volcanic activity are estimated to have contributed less than plus or minus 0.1°C to total warming between 1890 and 2010.

Causes for rising emissions

Burning coal, oil and gas produces carbon dioxide and nitrous oxide.

Cutting down forests (deforestation). Trees help to regulate the climate by absorbing CO2 from the atmosphere. When they are cut down, that beneficial effect is lost and the carbon stored in the trees is released into the atmosphere, adding to the greenhouse effect.

Increasing livestock farming. Cows and sheep produce large amounts of methane when they digest their food.

Fertilisers containing nitrogen produce nitrous oxide emissions.

Fluorinated gases are emitted from equipment and products that use these gases. Such emissions have a very strong warming effect, up to 23 000 times greater than CO2.

Causes of climate change

The evidence is clear: the main cause of climate change is burning fossil fuels such as oil, gas, and coal. When burnt, fossil fuels release carbon dioxide into the air, causing the planet to heat up.

What causes climate change?

The climate on Earth has been changing since it formed 4.5 billion years ago. Until recently, natural factors have been the cause of these changes. Natural influences on the climate include volcanic eruptions, changes in the orbit of the Earth, and shifts in the Earth's crust (known as plate tectonics).

Over the past one million years, the Earth has experienced a series of ice ages, including cooler periods (glacials) and warmer periods (interglacials). Glacial and interglacial periods cycle roughly every 100,000 years, caused by changes in Earth's orbit around the sun. For the past few thousand years, Earth has been in an interglacial period with a constant temperature.

However, since the Industrial Revolution in the 1800s, the global temperature has increased at a much faster rate. By burning fossil fuels and changing how we use the land, human activity has quickly become the leading cause of changes to our climate.

Greenhouse gases and the greenhouse effect

Some gases in the Earth's atmosphere trap heat and stop it escaping into space. We call these 'greenhouse gases'. These gases act as a warming blanket around the Earth, known as the 'greenhouse effect'.

Greenhouse gases come from both human and natural sources. Gases like carbon dioxide, methane, and nitrous oxide naturally occur in the atmosphere. Others, such as chlorofluorocarbons (CFCs), are only produced by human activity.

When short-wave radiation from the sun reaches Earth, most of it passes straight through and hits the surface. The Earth absorbs most of this radiation and gives off longer-wavelength infrared radiation.

The greenhouse gases absorb some of this infrared radiation, instead of it passing straight out into space. The atmosphere then emits radiation in all directions, sending some of it back to the surface, causing the planet to heat up. This process is known as the 'greenhouse effect'.

The greenhouse effect is critical to our survival. In fact, without greenhouse gases, Earth would be about 30 degrees colder than it is today. Without greenhouse gases and their warming effect, we wouldn't be able to survive.

However, since the Industrial Revolution, we've been adding more and more greenhouse gases into the air, trapping even more heat. Instead of keeping Earth at a warm, stable temperature, the greenhouse effect is heating the planet at a much faster rate. We call this the 'enhanced greenhouse effect' and it's the main cause of climate change.

Are humans responsible for climate change?

When looking at all the evidence, there is a large scientific consensus that humans are the leading cause of climate change. In their latest report, the Intergovernmental Panel on Climate Change stated unequivocally that human activity is the cause of global warming.

Natural climate cycles can change the temperature of Earth, but the changes we are seeing are happening at a scale and speed that natural cycles cannot explain. These cycles affect the global temperature for years, or sometimes just months, not the 100 years that we have observed. Meanwhile, longer-term changes like Milankovitch cycles and solar irradiance take thousands and thousands of years.

There are lots of things that affect climate change, but the evidence is irrefutable. Human activity, such as burning fossil fuels and changing how we use the land, is the leading cause of climate change.