Field reports from a catastrophe, continuing

Arctic Ocean, 2008.
From http://commons.wikimedia.org/wiki/File:Arct0279_-_Flickr_-_NOAA_Photo_Library.jpg

A non-random sampling of recent scientific findings on climate change.


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1) New evidence of methane outgassing from the Arctic Ocean, apparently from supersaturated methane in the surface waters being freed by ice breakup. See E.A. Kort, et al, "Atmospheric observations of Arctic Ocean methane emissions up to 82° north, " Nature Geoscience (April 22, 2012). The article is behind a subscription wall, but see this summary in Scientific American. Methane traps far greater quantities of heat in the atmosphere than carbon dioxide, making it a more potent greenhouse gas. It falls out of the atmosphere more quickly. But there is a vast storehouse of it in the Arctic Ocean and permafrost. 


2) Evidence is accumulating of possible methane emissions from the Arctic Ocean floor, as opposed to the supersaturated methane near the surface. Large sea floor methane releases appear to be underway, but whether they are a recent event caused by human activity or a natural phenomenon has not been established. Scientists involved in the research believe an abrupt, massive release of Arctic methane on the order of 50 gigatons is possible in our lifetime. This would represent an approximately 12-fold increase in total atmospheric methane levels, virtually guaranteeing a dramatic escalation of global temperature increase. 


3) New evidence of accelerating melt of the West Antarctic Ice Sheet, driven by warming ocean temperatures resulting from anthropogenic climate change. See H.D. Pritchard et al, "Antarctic ice sheet loss driven by basal melting of ice shelves, " Nature (April 25, 2012). Commentary on the implications from the Center for American Progress. The eventual breakup of the West Antarctic Ice Sheet will commit the planet to a long term sea level rise of about 10 feet. The collapse of the Greenland Ice Sheet, also under stress, will add another 10. 


4) Barring that eventuality, research by NASA indicates that global sea levels are currently on pace to rise about one foot by 2050. See E Rignot, et al., "Acceleration of the contributions of the Greenland and Antarctic ice sheets to sea level rise," Geophysical Research Letters (March 4, 2011). 


5) The U.S. Environmental Protection Agency cites research by the Federal Emergency Management Agency, estimating that a one foot rise in sea level will cause an annual increase in storm damage to U.S. coastal areas of 36-58 percent. 


6) A new suite of multi-model climate projections sees a near certainty that global temperatures will increase by a minimum of one degree Celsius by 2050, with a much higher than anticipated 15% chance that global temperatures by 2050 will rise three degrees Celsius. See I. Held, "Climate science: constraints on the high end," Nature (March 25, 2012). Two degrees Celsius is currently regarded as extremely dangerous, creating high probabilities of widespread ecosystem disruption, extreme weather, ice sheet breakup, food shortages, fresh water depletion, and climate-driven disease outbreaks.