Study Finds Why Methane Mysteriously Spiked During Covid-19 Pandemic

The world witnessed an unexpected surge in atmospheric methane levels, which is a potent greenhouse gas, in 2020. It was the period when several nations had announced lockdowns because of the Covid-19 pandemic. Lockdowns meant there were fewer cars on the road and planes in the air. Only a few factories were running, leaving the skies a bit clearer. But despite that, atmospheric methane levels surged.

A new international study, published in the journal Science, reveals that this anomaly was largely driven by a decline in hydroxyl radicals (OH), the atmosphere's primary methane-removing agent.

"Our research combined satellite data, ground-based measurements, atmospheric chemistry data and advanced computer models to reconstruct the global methane budget from 2019 to 2023," Philippe Ciais, from France's Laboratory for Climate and Environmental Sciences (LSCE) and lead author of the paper, explained in an article by The European Space Agency (ESA).

"The results point to a powerful and temporary shift in atmospheric chemistry as the main driver of the methane spike."

Also read | Asteroid Heading Towards Moon Could Create "Optical Flash" On Impact, Finds Study

Because of the lockdowns, nitrogen oxide emissions decreased, leading to a 7.5 Tg CH4 yr-1 reduction in methane removal by OH radicals, accounting for 53-83% of the surge.

Wetter conditions in tropical regions, linked to La Nina, boosted methane emissions from wetlands and rice paddies, contributing 47% to the anomaly.

"By providing the most up-to-date global methane budget through 2023, this research clarifies why methane rose so rapidly - and why it has recently slowed," added Philippe Ciais.

The findings highlight the complex link between atmospheric chemistry, climate, and human activity.

Also read | Scientists Plan To Build 150-Meter Wall To Mitigate "Doomsday Glacier" Melting Crisis

"The study underscores the growing importance of satellites - not only for tracking greenhouse gases, but for revealing the subtle chemical processes that govern their fate in the atmosphere. It shows that climate surprises are not always about what we emit, but about how the atmosphere responds," Clement Albergel, ESA's Actionable Climate Information Section Head, said as quoted.