A heat wave in 2020 revealed a new source of methane emissions from the Arctic that could be “much more dangerous” than previously believed, according to a new German study.
The study, conducted by three geologists, found that a heat wave observed in 2020 unveiled a source of methane emissions “potentially in much higher amounts” from rock formations thawing in the Arctic permafrost.
According to The Washington Post, scientists have long been concerned about “the methane bomb," a potentially disastrous amount of methane released from thawing wetlands in Siberia's permafrost. The methane released from the wetlands is "microbial" and stems from the decay of soil and organic matter.
The methane emissions from the rock formations, however, come from thawing limestone that releases gases from below the permafrost that are “much more dangerous” than what was previously believed.
Permafrost typically traps methane, but as global temperatures rise, the permafrost melts and more of these trapped gases are released into the atmosphere.
Nikolaus Froitzheim, one of the scientists who conducted the study and a professor at the Institute of Geosciences at Germany's University of Bonn, explained that he and two colleagues observed two “conspicuous elongated areas” of limestone in the Taymyr Peninsula around northern Siberia.
“We would have expected elevated methane in areas with wetlands,” Froitzheim said. “But these were not over wetlands but on limestone outcrops. There is very little soil in these. It was really a surprising signal from hard rock, not wetlands.”
Currently, the largest sources of methane that aren't trapped in permafrost come from agriculture and leaks from hydraulic fracturing, according to the paper. But the revelation of a new source of methane is troubling —Froitzheim pointed out that it is unknown how much methane is to be expected from the limestone formations.
“The question is: how much will come, and we don’t really know," Froitzheim said.