Global Methane Concentration Posts Biggest Increase In 2021
Researchers say satellite data show that the concentration of methane, a greenhouse gas, in the earth's atmosphere hit a record high last year and also posted the largest year-on-year increase since 2010.
Data obtained by the Japanese greenhouse gas observation satellite Ibuki show that the average of global methane concentration in the atmosphere throughout 2021 stood at 1,857 parts per billion.
The figure was up by 17 ppb from the previous year, and the increase was double the previous average annual change.
Methane levels in the earth's atmosphere have been increasing every year since the satellite observation started in 2010.
Methane is thought to have a greenhouse effect about 30 times greater than carbon dioxide. Its sources include microbes in rice paddies and other marshy areas, cow belching and fossil fuel extraction.
Researchers at the National Institute for Environmental Studies analyze data from the Ibuki satellite. One of them, Ito Akihiko, says the main cause of the rise in methane concentration may have been natural variation, as economic activity was sluggish last year amid the coronavirus pandemic.
Ito says it may be necessary to take into consideration that the concentration can rise due to natural variations, when drafting plans to reduce emissions by human activity.