Methane is a very important greenhouse gas among all human emissions, accounting for about 1/5 of its greenhouse contribution.
Atmospheric methane concentrations have increased rapidly over the past decade.
In early 2020, despite a human-wide lockdown due to the New Crown outbreak, the rate of increase in atmospheric methane concentrations rose that year
And the rate of increase is the highest level since 1984.
A paper recently published in the journal Nature explains the reasons for the higher growth rate of atmospheric methane concentrations in 2020.
By assessing methane sources and changes in natural atmospheric methane sinks, the researchers analyzed the reasons for the increase in atmospheric methane.
The atmosphere is a natural methane sink.
It allows methane to react with hydroxyl radicals (OH) to produce carbon dioxide and water.
The authors reported that hydroxyl radical concentrations decreased by about 1.6 percent from 2019, mainly due to lower anthropogenic NOx emissions during the new crown blockade.
They also found that methane emissions from human activities and fire initiation decreased by 1.2 and 6.5 trillion grams per year, respectively, while methane emissions from wetlands increased by 6.0 trillion grams per year.
Specifically, the increasingly warm and humid wetlands of the Northern Hemisphere are considered to be the primary source of methane.
These results suggest that methane emissions are more sensitive to warmer and wetter climates and may act as a positive feedback mechanism in the future.
The authors also note that NOx emissions need to be taken into account when considering how to reduce global anthropogenic methane emissions.