The most important source of human-made greenhouse gas emissions is carbon dioxide (CO2). By adding more and more CO2 to the atmosphere, people are amplifying the Earth’s natural greenhouse effect, which causes global temperatures to rise.
Emissions of carbon dioxide occur whenever fossil fuels are burned for energy, and during industrial processes like cement production. Carbon emissions also happen when forests, soil and seas are degraded or burned. This is known as land-use change.
Every year, we add more carbon dioxide to the atmosphere than natural “sinks” such as plant growth and ocean absorption can remove. This means atmospheric concentrations are rising faster than they should be.
The map shows large differences in emissions between countries, which are a big reason why international agreement on reducing carbon emissions is so challenging. The USA is the world’s largest emitter, followed by China and then North America, which includes Canada and Mexico. European countries, including France, Germany and the UK have lower emissions than their neighbors with similar standards of living – a difference that is linked to energy choices.
Emissions by country have changed a lot over time, but recently they’ve been flat. This is because emissions from fossil fuel burning have levelled off, while land-use change has slowed down. To halt the current trends and avoid global warming of more than 1.5°C, we need to phase out fossil fuels as well as make the world more resilient to climate impacts.