An interesting article on the melting permafrost from the BBC. I feel that Professor Vladimir Romanovsky is right saying that the permafrost in Alaska will start to thaw by 2070. The permafrost is permanently frozen soil that does not melt during the summer and that has been frozen for more than 2 years. The melting of the permafrost could have serious consequences.
Worryingly, there is undersea permafrost that contains large amounts of methane is starting to melt, particularly in Siberia. As methane is approximately 20 times more potent than carbon dioxide as a greenhouse gas, the more released from melting permafrost, the more global warming is enhanced. The Arctic sea ice and the Greenland ice sheet melting will be increased along with areas of Antarctica suffering record ice loss.
Figure 1: This image is from the National Snow and Ice Data Centre and shows the average amount of sea ice surrounding the polar regions (source). The sea ice cover in the spring and autumn months (September in the Arctic and March in the Antarctic) is minimal and future summers could lead to ice free poles. It is debated among climate scientists when exactly the Arctic could become ice free.For humans, the Northwest Passage becoming ice free in the future could mean a quicker and more convenient shipping route to the Asian markets. However, a changing climate could mean that melting glaciers that provide drinking water to millions of people could disappear with the melting cryosphere.
Interesting post - in which climate change scenario is the permafrost expected to melt by 2070? Is that something we have committed to or is it a more worst-case-scenario?
ReplyDeleteThanks for posting! The scenario of the permafrost thawing by 2070 is if the temperature rises globally by around 2 degrees C which is expected to happen at the present rate of carbon dioxide and methane release. The worst case scenario could see a more rapid thaw of the permafrost, perhaps by 2050. The release of methane from Siberian lakes is a particular concern as methane is more potent than carbon dioxide and could enhance global warming further and therefore cause a faster melt of the ice sheets and thawing of the permafrost.
DeleteHave you come across the paper by Whiteman et al. 2013 in Nature a couple of years ago. There they proposed that methane release from arctic permafrost could cost up to 60trillion %!! But the paper has also received a lot of criticisms as well...
ReplyDeleteG. Whiteman, C. Hope, and P. Wadhams, "Climate science: Vast costs of Arctic change", Nature, vol. 499, pp. 401-403, 2013. http://dx.doi.org/10.1038/499401a