Antarctica: A Greenhouse Gas Hotspot?

New study suggests that huge amounts of the greenhouse gas methane could be hiding underneath the ice of Antarctica.

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Richard I'Anson

Snow-covered Antarctic mountains at sunset

With brutal blizzards, dry air, and some of the coldest temperatures on earth, the Antarctic is inhospitable to the best of us. But not, apparently, to the 21,000 billion metric tons of organic carbon that could be producing up to four billion metric tons of methane – a potent greenhouse gas – beneath the continent.

In a new study, scientists have discovered that sedimentary basins beneath the Antarctic Ice Sheet contain huge quantities of organic carbon that work in concert with microbes to produce methane. The microbes metabolize the organic carbon to carbon dioxide and methane gas. Coupled with the lack of oxygen under ice sheets, these conditions are “the perfect ingredients for methanogenesis,” University of Bristol professor of glaciology Jemma Wadham said. Their findings were published in the August 30 issue of Nature.

“It is easy to forget that before 35 million years ago, when the current period of Antarctic glaciations started, this continent was teeming with life,” University of California-Santa Cruz earth and planetary sciences professor Slawek Tulaczyk said in a statement. Sedimentary basins in the Antarctic may have contained over ten times more organic carbon than parts of the Arctic, according to the study. “Our modeling shows that over millions of years, microbes may have turned this old organic carbon into methane.”

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The researchers used an established numerical model to simulate how much methane might accumulate below the sea floor. The model demonstrated that most of the organic carbon eventually turns into methane hydrate – an ice-like solid structure in which water molecules surround methane – because of the Antarctic’s low temperature, high pressure conditions. The rest becomes free methane gas. Because the methane hydrate inventories are likely to be located at shallow depths, ice-sheet melting could cause the gas to come out of hiding and enter the atmosphere, the scientists said. They noted, however, that this is still speculation – there’s a lot of uncertainty left about how much methane could be lurking down there. For the moment, the study simply raises questions about the possibility.

“It’s always difficult to talk about risk, especially risk that has to do with natural processes,” Tulaczyk said.

Wadham noted that their findings might even have a positive spin to them if the Antarctic methane hydrate could one day become another energy source. Natural gas is, after all, mostly made up of methane. But that’s far off until there is an economically viable way to get that methane out – the lack of an airport or harbor and any other infrastructure with which to do this undercuts the possibility for now, not to mention the Antarctic Treaty’s prohibition of mineral mining on the continent. For now, the spotlight is on how, for all its remoteness, Antarctica may be a far larger player in the climate game than we’ve appreciated in the past, and one we’d be smart not to ignore.

Tara Thean is a contributor at TIME. Find her on Twitter at @tarathean. You can also continue the discussion on TIME’s Facebook page and on Twitter at @TIME.

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4 comments
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larry
larry

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..::"CURRENT" methane release is already at 0.5 Mt per year.[15]

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Shakhova et al. (2008) estimate that not less than 1,400 Gt of carbon is presently locked up as methane and methane hydrates under the Arctic submarine permafrost, and is subject to puncturing by open taliks.

They conclude that "release of up to 50 Gt of predicted amount of hydrate storage [is] highly possible for ABRUPT release AT ANY TIME".

That would increase the methane content of the planet's atmosphere by a factor of TWELVE,[16][17] equivalent in greenhouse effect to a DOUBLING in the CURRENT level of CO2

http://en.wikipedia.org/wiki/C...

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..::"Ocean Acidification is now irreversible... at least on timescales of at least... TENS of THOUSANDS of years... 

Even with stabilisation of atmospheric CO2 at 450 ppm, Ocean Acidification will have profound impacts (death and extinction) on many marine systems. 

LARGE and rapid reductions of global CO2 emissions are needed globally by at LEAST 50% by 2050.

Analysis of past events in Earth's geologic history suggests that chemical recovery (normal pH for LIFE in the Ocean) will take TENS of THOUSANDS of years - while the recovery of ecosystem function and biological diversity (LIFE AS WE KNOW IT) can take much longer. (MILLIONS OF YEARS) 

http://interacademies.net/1087...

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..:: "Every day, 70 MILLION TONS of CO2 are released into Earth's atmosphere. ( remaining in the atmosphere for thousands of years ) 

..:: "Every day, 20 MILLION TONS of that CO2 are absorbed into the OCEANS, thereby increasing the overall ACIDITY of the OCEANS. By 2100, Ocean acidity will increase another 150 to 200 hundred percent. This is a dramatic change in the acidity of the oceans. And it has a serious impact on our ocean ecosystems; in particular, it has an impact on any species of calcifying organism that produces a calcium carbonate SHELL. -

http://www.ClimateWatch.NOAA.g...

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..:: "These are changes that are occurring far too fast for the oceans to correct naturally, said Dr Richard Feely with the US National Oceanic and Atmospheric Administration (NOAA)..:: "Fifty-five million years ago when we had an event like this (and that took over 10,000 years to occur), it took the oceans over 125,000 years to recover, just to get the chemistry back to normal," he told BBC News...:: "It took two to 10 million years for the organisms to re-evolve, to get back into a normal situation...:: "So what we do over the next 100 years will have implications for ocean ecosystems from tens of thousands to millions of years. That's the implication of what we're doing to the oceans right now."

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http://www.bbc.co.uk/news/scie...

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http://ecodelmar.org/phytoplan...

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Jürgen Hubert
Jürgen Hubert

This _is_ going to be a problem in the long run, but the methane release will likely happen over the course of centuries, not decades, and thus not an immediate problem.

Still, this shows once again why reversing course as early as possible is important, and why "adaption" is a lousy strategy - if we do nothing to stem our CO2 emissions, the situation will get much, much worse...