Global methane budget

Controlling the amount of methane in the atmosphere is an important way to keep the global average temperature to less than 2°C above pre-industrial levels. Geoscientists have recently estimated the ‘surplus’ emissions of methane caused by human activities since the start of the European industrial revolution

Methane (CH4) is a naturally occurring gas. It can exist in different parts of the environment (for example soils, wetlands). While atmospheric concentrations of methane are significantly lower than those of carbon dioxide (CO2), methane has a larger warming effect. It absorbs solar radiation around 30 times more than does CO2. Its residency time in the atmosphere, though, is much shorter than CO2: around a decade.

Comparisons with ice core data for 1750 suggest that by 2017 atmospheric methane concentrations were around 2.5 times greater. Methane is thus contributing to the observed temperate increase of over 1°C since the pre-industrial era. The United Nations Paris Agreement seeks to keep total atmospheric warming to below 2°C, preferably no more than 1.5. This means that all greenhouse gases — not only CO2 — need to be managed effectively to reduce the risk and potential harm of a ‘hothouse Earth’.