Arctic Permafrost Holding a Huge Carbon Pool & Potential Climate Threat

Permafrost blanketing the northern hemisphere contains more than twice the amount of carbon in the atmosphere, making it a potentially serious contributor to global climate change depending on how quickly it thaws according a group of nearly two dozen scientists lead by Ted Schuur, an associate professor of ecology at the University of Florida.

The team's research estimate to the rest of the permafrost-covered northern latitudes of Russia, Europe, Greenland and North America. The estimated 1,672 billion metric tons of carbon locked up in the permafrost in the northern latitudes of Russia, Europe, Greenland and North America is more than double the 780 billion tons in the atmosphere today.

When permafrost thaws, bacteria and fungi break down carbon contained in this organic matter much more quickly, releasing it to the atmosphere as carbon dioxide or methane, both greenhouse gases.

Scientists have become increasingly concerned about this natural process as temperatures in the world’s most northern latitudes have warmed. There is widespread consensus that the highest latitudes will warm the fastest, a process already visible in the accelerated thawing of glaciers worldwide.

Schuur said the researchers estimated the carbon contained in permafrost to a depth of three meters, two meters deeper than many earlier estimates. Although permafrost depths vary greatly with location, basing the estimate on three-meter depth “better acknowledges the true size of the permafrost carbon pool,” Schuur said.

The new estimate is important because it mirrors other climate change science suggesting that at a certain tipping point, natural processes could contribute significant amounts of greenhouse gases, supplementing human-influenced, industrial processes that release fossil fuel carbon, Schuur said.

Schuur said the burning of fossil fuels contributes about 8.5 billion tons of carbon dioxide each year. Deforestation of the tropical forests and replacement of the forest with pasture or other agriculture is thought to add about 1.5 billion tons per year. How much permafrost will add will depend on how fast it thaws, but Schuur said his research indicates the figure could approach 1.1 billion tons per year in the future if permafrost continues to thaw.

With the Arctic warming and permafrost thawing, shrubs and trees are likely to grow on ground formerly occupied by tundra – indeed, such a transformation has already been observed in parts of Alaska, where some arctic tundra is becoming shrub land.

Russian scientist, Sergei Zimov, has been studying climate change in Russia's Arctic for 30 years now. He is worried that as this organic matter becomes exposed to the air it will drastically accelerate global warming predictions even beyond some of the most pessimistic forecasts. For thousands of years animal waste, and other organic matter left behind on the Arctic tundra, have been sealed off from the environment by permafrost. Now climate change is melting the permafrost and freeing mass quantities of prehistoric “ooze” from its state of suspended animation.

"This will lead to a type of global warming which will be impossible to stop," he said.

According to Zimov, when the organic matter left behind by mammoths and other wildlife is exposed to the air by the thawing permafrost, microbes that have been dormant for thousands of years will spring back into action. They’ll begin once again to emit carbon dioxide and methane gas as a by-product. Zimov says thought the microbes are tiny, they will start emitting these gases in enormous quantities simply because there will be a lot of them.

"The deposits of organic matter in these soils are so gigantic that they dwarf global oil reserves," Zimov said. U.S. government statistics show mankind emits about 7 billion tons of carbon a year."Permafrost areas hold 500 billion tons of carbon, which can fast turn into greenhouse gases," Zimov added. "If you don't stop emissions of greenhouse gases into the atmosphere ... the Kyoto Protocol (an international pact aimed at reducing greenhouse emissions) will seem like childish prattle."

While some dismiss the 52-year-old as an alarmist crank, his theory is steadily gaining credibility in the scientific community. "There's quite a bit of truth in it," Julian Murton, member of the International Permafrost Association, told Reuters. "The methane and carbon dioxide levels will increase as a result of permafrost degradation."

The research conducted by Schuur's team was conducted as part of the International Polar Year 2008-2009 and sponsored by the National Science Foundation-funded National Center for Ecological Analysis and Synthesis, and the United Nations Educational, Scientific and Cultural Organization in a grant to the Global Carbon Project.

Posted by Jason McManus.

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