Where the world's greenhouse gas emissions actually come from
Humanity now releases roughly 50 billion tonnes of greenhouse gases a year, measured in carbon dioxide equivalents. Power plants lead the list, followed by transport, while cows, rice paddies and leaky gas pipelines add a surprising share. A 2017 survey found just 100 companies behind 71% of global emissions.
Carbon dioxide from burning coal, oil and gas is the main driver, accounting for more than half of warming; burning fossil fuels released an estimated 37.4 billion tonnes in 2023, and coal-fired power stations alone produced 20% of greenhouse gases as of 2021. Methane has almost the same short-term punch. Its largest human source is agriculture, above all livestock, with cattle responsible for about 65% of the livestock sector's output, followed closely by venting and leaks from the fossil-fuel industry. Fertilised soils give off nitrous oxide, and refrigerant gases punch above their weight.
Energy as a whole causes around 73% of emissions. Land-use change, chiefly tropical deforestation, adds roughly a quarter. By sector, estimates for 2024 put power at about 27%, transport at 15%, and industrial energy and agriculture at 11% each. Rising electricity demand from artificial intelligence is a growing worry.
The build-up began around 1750 with fossil-fuelled industry and accelerated after about 1950 as population and economies boomed. By 2021, carbon dioxide in the air stood almost 50% above pre-industrial levels. China emits the most, around 10 billion tonnes a year, more than a quarter of the total, while the United States emits more per person. The average person now accounts for 4.9 tonnes annually, more than double the 2.3 tonnes estimated to be compatible with the Paris goal of 1.5 °C, and people in industrialised countries can emit ten times as much as those in developing ones.
There are signs of change. The year 2015 was the first to combine global economic growth with falling carbon emissions, and EU emissions were about 35% below 1990 levels. Cities, often blamed, tend to have lower per-person emissions than their national averages. Treaties also help: the Kigali Amendment of 2016 set out to phase down hydrofluorocarbons.
Source: Greenhouse gas emissions
