[Reader-list] Frozen CO2, methane a time bomb : World Congress of Soil Scientists

[Nagraj Adve]

It's been an unusually warm summer in different regions of the Arctic; this
is one seriously grave feedback from melting permafrost.
Nagraj


 *Frozen CO2, methane a time bomb: experts *

*August4, 2010*

*AAP *

Massive volumes ofcarbon dioxide and methane frozen in the earth's soils are
a "time-bombticking under our feet", soil scientists say.

The thawing of vastareas of frozen soils and the decay of peatlands under
higher globaltemperatures could release massive volumes of carbon dioxide
and methane intothe atmosphere - potentially doubling the amount of
atmospheric green house gases.

The World Congress of Soil Scientists in Brisbane has been told that frozen
soils and peatlands inthe northern hemisphere are estimated to store up to
50 per cent of the world's  organic soil carbon.

University of  Wisconsin-Madison soil scientist Dr James Bockheim said
global warming threatens to thaw these soils, some of which have been frozen
for thousands of years.

"Atmospheric temperatures have increased by 3 (degrees) C over the past
decades in theArctic and Antarctic regions and this continued warming may
cause carbon stored in the surface permafrost to be released to the
atmosphere as carbondioxide," he said.

The potential release of greenhouse gases from frozen soils is not currently
taken into account in the Intergovernmental Panel on ClimateChange (IPCC)
calculations as it is not known exactly how thawing will impact on
greenhouse gas emissions.

Rising global temperatures will also increase decomposition of old carbon
stored in peatlands, many of which also are underlain by permafrost.

Dr Merritt Turetsky, from the University of Guelph inCanada, is studying
peatlands and describes them as a time-bomb ticking underour feet.

"Peatlandsrepresent only 1-3 per cent of the world's land surface, but play
a major rolein the global carbon cycle," Dr Turetsky said.

"Peatlands have served as a long-term sink of carbon dioxide but today also
represent one of the largest natural sources of methane.

Dr Turetsky saidthat, under climate change, northern regions are also
becoming more vulnerableto large-scale disturbances such as fire.

Fires in remotenorthern regions can burn hundreds of thousands of hectares
over severalmonths, and Dr Turetsky's research has shown that when fires
burn intopeatlands, emissions of carbon and toxic metals such as mercury can
surpassindustrial levels.