What it means: methane traps far more heat than carbon dioxide but breaks down within about 12 years. To compare the gases, each is converted to the amount of carbon dioxide with the same warming effect over 100 years: one tonne of methane counts as 28 tonnes. Most farming methane comes from cattle and sheep digesting their food, with the rest from manure. Waste is mainly rotting rubbish in landfill sites, plus wastewater treatment. Methane from landfill and coal mining has fallen sharply since 1990 as less waste was buried and deep coal mines closed. Oil, gas and coal supply is now mostly gas leaking from the network of pipes. Land use is mostly from peat bogs. Shown for context.

Source: DESNZ, Final UK greenhouse gas emissions national statistics, 1990 to 2024, table 1.4. Converted using the IPCC's 100-year warming factors (Fifth Assessment Report), as in the official figures.