Thawing permafrost could lead to massive carbon release

Posted by Kate Taylor

As much as 44 billion tons of nitrogen and 850 billion tons of carbon stored in arctic permafrost could be released into the environment over the next century by the effects of global warming.

This is roughly the amount of carbon stored in the atmosphere today, and its release could have a serious impact onecosystems, the atmosphere, and water resources including rivers and lakes.

"This study quantifies the impact on Earth's two most important chemical cycles, carbon and nitrogen, from thawing of permafrost under future climate warming scenarios," says US Geological Survey director Marcia McNutt.

"While the permafrost of the polar latitudes may seem distant and disconnected from the daily activities of most of us, its potential to alter the planet's habitability when destabilized is very real."

To generate their estimates, the USGS scientists studied how permafrost-affected soils, known as Gelisols, thaw under various climate scenarios. They found that all Gelisols are not alike: some have soil materials that are very peaty, with lots of decaying organic matter that burns easily, and these will impart newly thawed nitrogen into the ecosystem and atmosphere.

Others have materials that are very nutrient rich, and these will impart a lot of nitrogen into the ecosystem. All Gelisols will contribute carbon dioxide and likely some methane into the atmosphere as a result of decomposition once the permafrost thaws. And these gases will themselves contribute to further warming.

"The scientific community researching this phenomena has made these international data available for the upcoming Intergovernmental Panel on Climate Change," says Jennifer Harden, aUSGS Research soil scientist.

"As permafrost receives more attention, we are sharing our data and our insights to guide those models as they portray how the land, atmosphere, and ocean interact."