Warming climate may release vast amounts of carbon from long-frozen Arctic soils

Michael Sullivan at the University of Georgia Today: While climatologists are carefully watching carbon dioxide levels in the atmosphere, another group of scientists is exploring a massive storehouse of carbon that has the potential to significantly affect the climate change picture.

University of Georgia Skidaway Institute of Oceanography researcher Aron Stubbins is part of a team investigating how ancient carbon, locked away in Arctic permafrost for thousands of years, is now being transformed into carbon dioxide and released into the atmosphere. The results of the study were published in Geophysical Research Letters.

The Arctic contains a massive amount of carbon in the form of frozen soil—the remnants of plants and animals that died more than 20,000 years ago. Because this organic material was permanently frozen year-round, it did not undergo decomposition by bacteria the way organic material does in a warmer climate. Just like food in a home freezer, it has been locked away from the bacteria that would otherwise cause it to decay and be converted to carbon dioxide.

"However, if you allow your food to defrost, eventually bacteria will eat away at it, causing it to decompose and release carbon dioxide," Stubbins said. "The same thing happens to permafrost when it thaws."

Scientists estimate there is more than 10 times the amount of carbon in the Arctic soil than has been put into the atmosphere by burning fossil fuels since the start of the Industrial Revolution. To look at it another way, scientists estimate there is two and a half times more carbon locked away in the Arctic deep freezer than there is in the atmosphere today. Now, with a warming climate, that deep freezer is beginning to thaw and that long-frozen carbon is beginning to be released into the environment.

"The study we did was to look at what happens to that organic carbon when it is released," Stubbins said. "Does it get converted to carbon dioxide or is it still going to be preserved in some other form?"

..."We found that decomposition converted 60 percent of the carbon in the thawed permafrost to carbon dioxide in two weeks," Stubbins said. "This shows the permafrost carbon is definitely in a form that can be used by the microbes."...

Permafrost thaw ponds in Hudson's Bay, shot by Steve Jurvetson, Wikimedia Commons via Flickr, under the Creative Commons Attribution 2.0 Generic license