Permafrost Loss Greater Threat Than Deforestation

Pierre Bezukhov writes "Emissions from thawing permafrost may contribute more to global warming than deforestation this century, according to commentary in the journal Nature. Arctic warming of 7.5 degrees Celsius (13.5 degrees Fahrenheit) this century may unlock the equivalent of 380 billion tons of carbon dioxide as soils thaw, allowing carbon to escape as CO2 and methane, University of Florida and University of Alaska biologists wrote today in Nature. Two degrees of warming would release a third of that, they said. The Arctic is an important harbinger of climate change because the United Nations calculates it's warming at almost twice the average rate for the planet. The study adds to pressure on United Nations climate treaty negotiators from more than 190 countries attending two weeks of talks in Durban, South Africa that began Nov. 28."

Comments

Re:Clathrate gun hypothesis

[khallow]

The simple rebuttal is why hasn't the "clathrate gun" gone off some time in the past 650,000 years? From the link:

The ice core data also shows that CO2 and methane levels have been remarkably stable in Antarctica--varying between 300 ppm and 180 ppm--over that entire period and that shifts in levels of these gases took at least 800 years, compared to the roughly 100 years in which humans have increased atmospheric CO2 levels to their present high. "We have added another piece of information showing that the timescales on which humans have changed the composition of the atmosphere are extremely short compared to the natural time cycles of the climate system," says Thomas Stocker of the University of Bern in Switzerland, who led the research.

There have been several shifts from glacial to interglacial climates during that time. My view is that if massive methane releases were a threat now, then we would have seen something similar during one of these times.