Inupiat Eskimos go ice-hoping on the Chukchi Sea. Photograph: Gilles Mingasson/Getty Images
Tuesday 13 October 2015 06.00 EDT
A policy briefing from the Woods Hole Research Center concludes that the IPCC doesn’t adequately account for a methane warming feedback
Tuesday 13 October 2015 06.00 EDT Last modified on Wednesday 22 February 2017 13.03 EST
While most attention has been given to carbon dioxide, it isn’t the only greenhouse gas that scientists are worried about. Carbon dioxide is the most important human-emitted greenhouse gas, but methane has also increased in the atmosphere and it adds to our concerns.
While methane is not currently as important as carbon dioxide, it has a hidden danger. Molecule for molecule, methane traps more heat than carbon dioxide; approximately 30 times more, depending on the time frame under consideration. However, because methane is present in much smaller concentrations (compared to carbon dioxide), its aggregate effect is less.
But what has scientists focusing on methane is the way it is released into the atmosphere. Unlike carbon dioxide, which is emitted primarily through burning of fossil fuels, methane has a large natural emission component. This natural emission is from warming permafrost in the northern latitudes. Permafrost is permanently frozen ground. Much of the permafrost is undisturbed by bacterial decomposition.
As the Earth warms, and the Arctic warms especially fast, the permafrost melts and soil decomposition accelerates. Consequently, an initial warming leads to more emission, leading to more warming and more emission. It is a vicious cycle and there may be a tipping point where this self-reinforcing cycle takes over.
Recently, a policy briefing from the world-leading Woods Hole Research Center has moved our understanding of this risk further through a clearly-written summary. The briefing cites two recent papers (here and here) that study the so-called permafrost carbon feedback.