Study: Arctic Seafloor Methane Releases Double Previous Estimates
The East Siberian Arctic Shelf is a methane-rich area that encompasses more than 2 million square kilometers of seafloor in the Arctic Ocean. It is more than three times as large as the nearby Siberian wetlands, which have been considered the primary Northern Hemisphere source of atmospheric methane. Previous estimates performed for the ESAS suggested that the area was releasing 8 teragrams of methane into the atmosphere yearly.
During field expeditions, the research team used a variety of techniques—including sonar and visual images of methane bubbles in the water, air and water sampling, seafloor drilling and temperature readings—to determine the conditions of the water and permafrost, as well as the amount of methane being released.
Methane is an important factor in global climate change, because it so effectively traps heat. As conditions warm, global research has indicated that more methane is released, which then stands to further warm the planet. Scientists call this phenomenon a positive feedback loop.
“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.”
Shakhova and Semiletov are also affiliated with the Pacific Oceanological Institute at the Russian Academy of Sciences, Far Eastern Branch, as are research team members Anatoly Salyuk, Denis Kosmach and Denis Chernykh. Other members of the research team include Dmitry Nicolsky of the UAF Geophysical Institute; co-lead author Ira Leifer of the Marine Sciences Institute at the University of California, Santa Barbara and Bubbleology Research International; Valentin Sergienko of the Institute of Chemistry at the Russian Academy of Sciences, Far Eastern Branch; Chris Stubbs of the Marine Sciences Institute at the University of California, Santa Barbara; Vladimir Tumskoy of Moscow State University; and Örjan Gustafsson of the Department of Applied Environmental Science and Bolin Centre for Climate Research, Stockholm University.
Posted: November 26, 2013