CO₂ emissions

CO₂ emissions are the carbon dioxide released into the atmosphere, mainly by burning fossil fuels like coal, oil, and gas for energy, transport, and industry. CO₂ is the most significant greenhouse gas driving climate change, both because of the sheer volume released and because it stays in the atmosphere for centuries once it's there.

How much CO₂ is released each year

Global fossil fuel CO₂ emissions reached an estimated 38.1 billion tonnes in 2025, a new record high, according to the Global Carbon Budget report published in November 2025. Emissions have kept rising most years for decades, even as individual countries and sectors have started to bring theirs down.

Where it comes from

The largest sources are energy production, transport (cars, trucks, ships, and planes), and heavy industry such as steel and cement. Land-use changes, particularly deforestation, add further CO₂ on top of fossil fuel emissions, since forests that would otherwise absorb CO₂ are lost.