New research suggests the Northern Siberia sea floor is releasing 17 million tons into the atmosphere every year; more than twice as much as was previously estimated.
"It is now on par with the methane being released from the arctic tundra, which is considered to be one of the major sources of methane in the Northern Hemisphere," Natalia Shakhova, one of the paper's lead authors and a scientist at the University of Alaska Fairbanks, said in a news release. "Increased methane releases in this area are a possible new climate-change-driven factor that will strengthen over time."
Methane is a harmful greenhouse gas about 30 times more potent than carbon dioxide. On land the gas is released when organic material that has been frozen melts and decomposes. In the sea it is usually trapped beneath permafrost ice, if that ice thaws the methane is released.
Ocean methane release can be significantly more dramatic than on land.
The researchers have noticed that the ice is melting more rapidly than they would have predicted, this is partially a result of rising temperatures near the floor. Frequent storms in the area have also caused methane to be released into the atmosphere at an alarming rate.
"Results of this study represent a big step forward toward improving our understanding of methane emissions from the East Siberian Arctic Shelf," Shakhova said. "I believe that all other arctic shelf areas are significantly underestimated and should be paid very careful attention to.
The methane-rich East Siberian Arctic Shelf covers over two million square kilometers. This is three times the size of the Siberian wetlands which are believed to be responsible for most of the atmospheric methane release in the Northern Hemisphere. The Siberian wetlands release about eight million tons of methane every year.
The team used a combination of "sonar and visual images of methane bubbles in the water, air and water sampling, seafloor drilling and temperature readings," the make their findings.
"We believe that the release of methane from the Arctic, and in particular this part of the Arctic, could impact the entire globe," Shakhova said. "We are trying to understand the actual contribution of the ESAS to the global methane budget and how that will change over time."
