(Crossposted from Fishoutofwater’s diary)
“Rapid irreversible melting of one third to two thirds of earth’s permafrost, will add huge amounts of greenhouse gases to the atmosphere, accelerating warming, reports the National Ice and Snow Data Center (NSIDC). Permafrost melt lakes portend the destabilization of the Arctic’s landscapes and ecosystems and emissions of greenhouse gases CO2 and CH4.
The NSIDC model study makes “conservative” assumptions, such as no methane production and no temperature feed backs that accelerate melting. These assumptions make the models tend to underestimate the actual rate of change. The model predicts a peak in melting and CO2 emissions in 100 years, but methane and feedback loops could cause the peak to come sooner. The total quantity of carbon is calculated out to the year 2200.
“The amount of carbon released is equivalent to half the amount of carbon that has been released into the atmosphere since the dawn of the industrial age,” said NSIDC scientist Kevin Schaefer. “That is a lot of carbon.””
Irreversible melting of permafrost is a feedback loop that can be avoided only by rapid reduction in greenhouse gas emissions. Once the melting accelerates the feedback loops may make permanent melting impossible to stop. Moreover, much of the carbon is likely to be released as methane which is produced in wet ground and lakes by bacterial degradation of carbon. Methane is 25 times as strong a greenhouse gas as CO2 over 100 years.