NASA Finds ‘Amazing’ Levels Of Arctic Methane And CO2

http://thinkprogress.org/climate/2013/06/13/2138531/nasa-finds-amazing-levels-of-arctic-methane-and-co2-asks-is-a-sleeping-climate-giant-stirring-in-the-arctic/

By Joe Romm on Jun 13, 2013

A NASA science team has observed “amazing and potentially troubling” levels of methane and CO2 from the rapidly warming Arctic. Given the staggering amount of carbon trapped in the permafrost — and the fact that methane is a very potent heat-trapping gas — the space agency is now asking: “Is a Sleeping Climate Giant Stirring in the Arctic?”

We’ve known for a while that “permafrost” was a misnomer (see “Thawing permafrost feedback will turn Arctic from carbon sink to source in the 2020s“). The defrosting permamelt will likely add up to 1.5°F to total global warming by 2100.

Two studies from February provide more evidence the process may happen even faster than we thought:

500,000-Year History of Permafrost Reveals Further Warming of 1.5°C Would ‘Thaw Significant Regions’
“Surface exposure to sunlight stimulates CO2 release from permafrost soil carbon in the Arctic”


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Ultimately, the scientists hope their observations will indicate whether an irreversible permafrost tipping point may be near at hand. While scientists don’t yet believe the Arctic has reached that tipping point, no one knows for sure.

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“Permafrost soils are warming even faster than Arctic air temperatures — as much as 2.7 to 4.5 degrees Fahrenheit (1.5 to 2.5 degrees Celsius) in just the past 30 years,” Miller said. “As heat from Earth’s surface penetrates into permafrost, it threatens to mobilize these organic carbon reservoirs and release them into the atmosphere as carbon dioxide and methane, upsetting the Arctic’s carbon balance and greatly exacerbating global warming.”

Recall that NOAA has reported, “In 2012, new record high temperatures at 20 [meters, 65 feet] depth were measured at most permafrost observatories on the North Slope of Alaska and in the Brooks Range, where measurements began in the late 1970s.”

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Over hundreds of millennia, Arctic permafrost soils have accumulated vast stores of organic carbon – an estimated 1,400 to 1,850 petagrams of it (a petagram is 2.2 trillion pounds, or 1 billion metric tons). That’s about half of all the estimated organic carbon stored in Earth’s soils. In comparison, about 350 petagrams of carbon have been emitted from all fossil-fuel combustion and human activities since 1850. Most of this carbon is located in thaw-vulnerable topsoils within 10 feet (3 meters) of the surface.

Second, methane is a very, very potent heat-trapping gas. Whether the permamelt releases CO2 [carbon dioxide] or CH4 [methane] depends critically on the soils and state of the land surfaces, which CARVE aims to characterize:

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Molecule per molecule, methane is 22 times more potent as a greenhouse gas than carbon dioxide on a 100-year timescale, and 105 times more potent on a 20-year timescale. If just one percent of the permafrost carbon released over a short time period is methane, it will have the same greenhouse impact as the 99 percent that is released as carbon dioxide.

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