A carbon footprint is the total amount of greenhouse gases (including carbon dioxide and methane) that are generated by our actions.

What is a carbon footprint?

Greenhouse gas emissions from human activities strengthen the greenhouse effect, causing climate change. Most is carbon dioxide from burning fossil fuels: coal, oil, and natural gas. The largest emitters include coal in China and large oil and gas companies, many state-owned by OPEC and Russia. Human-caused emissions have increased atmospheric carbon dioxide by about 50% over pre-industrial levels. The growing levels of emissions have varied, but it was consistent among all greenhouse gases. Emissions in the 2010s averaged 56 billion tons a year, higher than ever before.[4]

Electricity generation and transport are major emitters, the largest single source being coal-fired power stations with 20% of GHG. Deforestation and other changes in land use also emit carbon dioxide and methane. The largest source of anthropogenic methane emissions is agriculture, closely followed by gas venting and fugitive emissions from the fossil-fuel industry. The largest agricultural methane source is livestock. Agricultural soils emit nitrous oxide partly due to fertilizers. Similarly, fluorinated gases from refrigerants play an outsized role in total human emissions.

At current emission rates averaging six and a half tonns per person per year, before 2030 temperatures may have increased by 1.5 °C (2.7 °F) over pre-industrial levels, which is the limit for the G7 countries and aspirational limit of the Paris Agreement.[5]

Emissions may be tracked over long time periods, known as historical or cumulative emissions measurements. Cumulative emissions provide some indicators of what is responsible for greenhouse gas atmospheric concentration build-up.