Sunday, October 28, 2012

Arctic thaw will release 850 billion tonnes carbon, says latest study

Global warming just spun more out of control than thought. As much as 44 billion tons of nitrogen and 850 billion tons of carbon stored in the frozen wastes of Arctic could be released into the environment as the region begins to thaw over the next century, a new study led by the US Geological Survey said. The thawing process has already started with sea-ice levels at their lowest this summer.

What is staggering is the new numbers put out by the USGS. If these are correct, it would mean that carbon quantity in the atmosphere will roughly double. It will greatly enhance the rate at which warming is already taking place and could cause widespread destruction of life and habitat. This is the first time an estimate of the nitrogen trapped in the Arctic permafrost has been released. Scientists had till now been using computer model based climate predictions. The carbon estimate is consistent with previous modeling estimates and gives more credence to other scientific studies with similar carbon estimates.

"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," said USGS Director Marcia McNutt in a media release. "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 the estimates, scientists studied how permafrost-affected soils, known as Gelisols, thaw under various climate scenarios, the USGS said. They found that all Gelisols are not alike: some Gelisols have soil materials that are very peaty, with lots of decaying organic matter that burns easily these will impart newly thawed nitrogen into the ecosystem and atmosphere. Other Gelisols have materials that are very nutrient rich 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 contribute to warming. What was frozen for thousands of years will enter our ecosystems and atmosphere as a new contributor.

"The scientific community researching this phenomena has made these international data available for the upcoming Intergovernmental Panel on Climate Change. 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," said study lead Jennifer Harden, USGS Research Soil Scientist.

Times of India

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