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05 april 2012

Ontdooiende permafrost oorzaak extreme opwarming aarde in het verleden

Nature Bombshell: ‘Past Extreme Warming Events Linked To Massive Carbon Release From Thawing Permafrost’
Door Joe Romm, Climate Progress, 4 april 2012

The lead author [van het artikel in Nature], climate scientist Rob DeConto, explains in a news release:
While the amounts of carbon involved in the ancient soil-thaw scenarios was likely much greater than today, implications of the study appear dire for the long-term future as polar permafrost carbon deposits have begun to thaw due to burning fossil-fuels, DeConto adds. “Similar dynamics are at play today. Global warming is degrading permafrost in the north polar regions, thawing frozen organic matter, which will decay to release CO2 and methane into the atmosphere. This will only exacerbate future warming in a positive feedback loop.”
Later toegevoegd, ter enige relativering:

What Do Methane Deposits In The Antarctic And Arctic Mean For The Climate?
Door Verity Payne, Carbon Brief / Climate Progress, 30 augustus 2012

[...] Despite recent research suggesting that we’ve underestimated Arctic methane sources, there isn’t yet evidence to suggest that these sources are having a significant effect on atmospheric methane.

[...] Important warming feedbacks from methane emissions in the polar regions – particularly to the Arctic – have the potential to occur. But different feedbacks are likely to act over different timescales, and the possibility of sudden and catastrophic methane release may be overstated.

[...] although polar methane hydrate sources will probably become important over the long term, particularly if Arctic warming continues, in the nearer future it looks like wetlands will remain the major determining factor in global methane emissions. 

Of toch weinig grond voor relativering en des te meer voor alarm: 

UN report calls for closer monitoring of the world's permafrost
Door Graham Lloyd, The Australian, 28 november 2012

Melting ‘Permafrost’ Releases Climate-Warming CO2 Even Faster Than We Thought
University of Michigan News Service / Climate Progress, 12 februari 2013

Exposure to sunlight may act as an amplification factor in the conversion of frozen C [carbon] stores to C gases in the atmosphere.

Zie ook m'n blognotities:
Smeltende permafrost vormt tikkende tijdbom
Smeltende permaforst klimaatramp?
Klimaatverandering kan 'compost-bom' ontsteken

Foto door Duvanni Yar: Sergey Zimov, Director of the Northeast Science Station in Cherskii, Russia stands near the base of a massive exposed Yedoma permafrost ice wedge (2001)

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