25% of World’s Carbon Sink in Arctic Land and Seas, but Climate Warming Could Change That
15.10.2009 - Atmosphere & Space, Land & Geology, Other, Arctic
According to their results published in the journal Ecological Monographs, Dr. David Mcguire of the US Geological Survey and the University of Alaska at Fairbanks and his colleagues show that Arctic lands and oceans are responsible for approximately one quarter of the global carbon net sink. However this trend could be reversed as the climate warms.
Arctic permafrost has functioned as a carbon sink since the end of the last Ice Age. Frozen soil doesn't decompose carbon like active soils do, and cold conditions at the surface slow decomposition. But as the Arctic warms, the rate of surface decomposition will accelerate, turning the Arctic from a carbon sink into a carbon source.
What's more, thawing permafrost could result in a more waterlogged Arctic, which favours the development and activity of methane-producing organisms. Methane is a powerful greenhouse gas. At the moment the Arctic releases 50 million metric tons of methane; however this is currently counterbalanced by it sequestering 400 million metric tons of carbon dioxide. As temperatures rise, increasing methane output has the potential to counteract current greenhouse gas mitigation strategies.
