Why did methane emissions increase during the pandemic, even with less human activity?

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#Methane

During the COVID-19 pandemic in 2020, much of the world came to a standstill

With lockdowns, fewer cars on the streets, factories running less and air travel reduced, air pollution has fallen significantly.

Scientists have observed a clear decrease in carbon dioxide emissions and other human-caused pollutants.

This was expected to bring some relief to the climate, but exactly the opposite happened with methane: this greenhouse gas, the second most important after CO”, had a surprising increase in the atmosphere, reaching the highest levels since measurements began in the 1980s.

Now, a detailed study published in the journal Science, carried out by more than 40 scientists from around the world, finally explains this paradox.

They updated the “global methane budget” until 2023, using measurements from NOAA (the American agency that monitors the atmosphere), data from satellites such as GOSAT and various computer models that track how much methane enters and leaves the atmosphere.

The two main reasons for the spike have been identified: About 80% of the increase came from a change in the chemistry of the atmosphere.

Methane is naturally destroyed by a molecule called hydroxyl radical (OH), which acts as an air “cleaner”.

This radical forms mainly when sunlight reacts with pollutants emitted by human activities, such as nitrogen oxides (NOx) from cars, industries and the burning of fuels.

With lockdowns, these pollutants fell drastically, which reduced the production of hydroxyl radicals.

Without so many “cleaners” in the air, the methane that was already there lasted longer and accumulated in greater quantities.

The other part of the increase, about 20%, came from larger natural emissions, especially from humid areas (such as tropical swamps and marshes), inland waters, and rice fields.

This happened because, at the same time, the La Niña climate phenomenon brought more intense rains to tropical regions of Africa and Southeast Asia.

Wetter soils created ideal conditions for methane-producing microbes, releasing more gas into the atmosphere.

Led by researchers including Philippe Ciais from the Climate and Environmental Sciences Laboratory in France, the study shows that although direct human methane emissions fell somewhat in 2020, the indirect effect of cleaning the air and increasing natural sources outweighed this reduction.

With the return of normal activities, the methane destruction process has returned to its usual pace and growth has recently slowed down.

The conclusion reached is that, with the decrease in human activity, oxide gases in the atmosphere, such as nitrogen oxides, have decreased. This decrease has meant that less hydroxyl ions were formed than before, reducing the “cleaning” effect that these hydroxyl ions had on methane, increasing the level of this gas in the atmosphere. Since methane is 40 to 80 times more significant for warming than CO2, the increase in methane contributed to warming. In other words, the decrease in human activity ended up stimulating increased warming in the atmosphere. Paradoxical, but everything indicates that it is a fact.

The work reinforces the need to better monitor the atmosphere with satellites and understand these complex chemical interactions, because surprises like this can arise not only from more emissions, but also from subtle changes in how the air we breathe works.

Published in 02/18/2026 11h23

Portuguese version

Text adapted by AI (Grok) and translated via Google API in the English version. Images from public image libraries or credits in the caption. Information about DOI, author and institution can be found in the body of the article.

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