Heat-trapping methane gas up by record amount
Global atmospheric levels of the potent but short-lived greenhouse gas methane increased a record amount last year, the National Oceanic and Atmospheric Administration said Thursday, worrying scientists because of the large role methane has in climate change.
The preliminary airborne level of methane jumped 17 parts per billion, hitting 1,895.7 parts per billion last year. It’s the second year in a row that methane rose at a record rate with 2020 going up 15.3 ppb over 2019, according to NOAA. Methane levels are now more than double preindustrial levels of 720 parts per billion, said Lindsay Lan, an atmospheric scientist at NOAA and the University of Colorado.
Methane is a big contributor to climate change, leading to about a 0.9 degrees Fahrenheit (0.5 degrees Celsius) increase in temperature since the 19th century, according to the Intergovernmental Panel on Climate Change. Carbon dioxide has caused about 50% more warming than methane.
“This trend of accelerating increase in methane is extremely disturbing,” said Cornell University methane researcher Robert Howarth.
Methane is about 25 times more powerful at trapping heat than carbon dioxide. But it only lasts nine years in the air instead of thousands of years like carbon dioxide, Lan said. Because it doesn’t last in the air long, many nations last year agreed to target methane for quick emission cuts as low hanging fruit in the global efforts to limit future warming to 1.5 or 2 degrees Celsius (2.7 or 3.6 degrees Fahrenheit) since pre-industrial times. The world has already warmed 1.1 to 1.2 degrees Celsius (about 2 to 2.2 degrees
Fahrenheit).
“To limit warming to well-below 2C this century, we need to cut our methane emissions dramatically, and today we are clearly moving in the wrong direction,” climate scientist Zeke Hausfather of Stripe and Berkeley Earth said in an email.
“Cutting methane has strong immediate climate benefits, as it is the only greenhouse gas for which emission reductions can quickly cool the climate (versus slowing or stopping the rate of warming).”
NOAA has been tracking methane levels in the air since 1983.
Lan said early signs point more to natural causes for the methane jump, because of La Niña, the natural and temporary cooling of parts of the Pacific that change weather worldwide, but it’s still early. La Niña tends to make it rain more in some tropical regions and the two years in a row of record increases during La Niña points to methane escaping from wetlands, she said.
Methane is also a natural gas and an increasingly used energy source. Much methane comes out of livestock and humangenerated agriculture, as well as from landfills. Scientists also fear future release of trapped methane under the ocean and in frozen Arctic land, but there’s no indication that’s happening on a large scale.