Methane doesn't linger in the air for anywhere near as long as the more notorious greenhouse gas carbon dioxide—but it traps heat 25 times more efficiently, and scientists say the recent steep rise in methane emissions is very disturbing. The National Oceanic and Atmospheric Administration says the concentration of methane in the atmosphere rose by 17 parts per billion in 2021, breaking the record set the previous year: a jump of 15.3 parts per billion, the Guardian reports. "This trend of accelerating increase in methane is extremely disturbing," Cornell University methane researcher Robert Howarth tells the AP.
Methane has many sources, including fossil fuels, landfills, and cows, though NASA notes that "contrary to common belief," the cow emissions are mainly from belching, not farting. NOAA atmospheric scientist Lindsay Lan says early signs suggest that some of the recent jump in emissions has a natural cause, with the cyclical La Nina cooling event in the Pacific causing an increase in methane emissions from wetlands, though other researchers say leaks from oil and gas drilling operations are also playing a major role.
Emissions of carbon dioxide, which can remain in the atmosphere for thousands of years, compared to nine for methane, also jumped in 2021, bringing them to the highest level since 4.3 million years ago. "Our data show that global emissions continue to move in the wrong direction at a rapid pace," NOAA Administrator Rick Spinrad said in a statement, per USA Today. "The evidence is consistent, alarming, and undeniable." Climate scientists say that since methane emissions are so powerful but short-lived, they're the best target to reduce to get immediate climate benefits. (Off the coast of Siberia, scientists have found methane bubbles rising from the deep.)