Friday, May 25, 2012
Prodigious plumes of planet-warming methane are bubbling from sediments across a broad region of Arctic seafloor previously thought to be sealed by permafrost, new analyses indicate. The resulting increase of methane gas in the atmosphere may accelerate climate warming, scientists say.
Though immense amounts of carbon are known to be trapped in the peatlands of Siberia, a larger, often unrecognized carbon reservoir lies hidden just north of that frigid region. The East Siberian Arctic Shelf — a 2.1-million-square-kilometer patch of Arctic seafloor that was exposed during the most recent ice age, when sea levels were lower — is three times larger than all of today’s land-based Siberian wetlands. When the region was above sea level, tundra vegetation pulled carbon dioxide from the air as plants grew. That organic material, much of which didn’t decompose in the frigid Arctic, accumulated in the soil and is the source of modern methane.