Tuesday, November 30, 2010

Soil microbes define dangerous rates of climate change

Seed Daily: The rate of global warming could lead to a rapid release of carbon from peatlands that would further accelerate global warming. Two recent studies published by the Mathematics Research Institute at the University of Exeter highlight the risk that this 'compost bomb' instability could pose, and calculate the conditions under which it could occur.

…The first paper by Catherine Luke and Professor Peter Cox describes the basic phenomenon. When soil microbes decompose organic matter they release heat - this is why compost heaps are often warmer than the air around them.

The compost bomb instability is a runaway feedback that occurs when the heat is generated by microbes more quickly than it can escape to the atmosphere. This in turn requires that the active decomposing soil layer is thermally-insulated from the atmosphere. Catherine Luke explains: "The compost bomb instability is most likely to occur in drying organic soils covered by an insulating lichen or moss layer".

The second paper led by Dr Sebastian Wieczorek and Professor Peter Ashwin, also of the University of Exeter, proves there is a dangerous rate of global warming beyond which the compost bomb instability occurs. This is in contrast to the general belief that tipping points correspond to dangerous levels of global warming....

Càrn na Ceàrdaich. A flat and boggy summit with views across the peatlands towards Ben More. Shot by Richard Webb, Wikimedia Commons via Geograph UK, under the Creative Commons Attribution-Share Alike 2.0 Generic license

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