It is becoming common knowledge that sea-ice is melting at increasing rates in the Arctic with predictions now suggesting that the region might be ice free in the summer by 2030. The question is, should we really be worried about this, and if so, just how worried should we be? Much of the media attention on the Arctic region is focused on how melting sea ice might alter ocean currents in the north Atlantic, but the real danger lies in what might happen as more and more of the permafrost (permanently frozen soil, water and rock) melts. Locked up in the permafrost are large quantities of carbon (which could be released to the atmosphere as carbon dioxide gas) and, particularly worrying, given its potency as a greenhouse gas, methane. If the permafrost all melts (which apparently could happen within the next 100 years) then the addition of so much carbon dioxide and methane to the atmosphere could lead to an additional increase in global temperatures of 10 degrees Celsius. Put bluntly, that would just about blast humans off the planet. Another key aspect of this issue is that it’s not a tap that can be turned on or off. If temperatures rise enough to melt all of the permafrost then the additional release of greenhouse gases will mean that there’s nothing that can be done to reverse the process. The only hope then is to try to limit the temperature increases that are already in the pipeline to prevent this runaway gas release from occuring. There’s a detailed article on this topic in New Scientist, Issue 2701 [28 March 2009] .
Tim O'Hare 