Angry Bear: Updates on atmospheric methane and volume measurements of Arctic sea ice

by Dan Crawford (Rdan), Angry Bear blog, February 18, 2013

Here is a link-filled update on the rise of atmospheric methane and a decrease in volume of Arctic sea ice from reader rjs.

Today we’d like to make note of an interesting development in the arctic     during January. Below we have 3 images of methane concentrations above the Arctic Ocean from 3 ten day periods in january (January 1-10, January 11-20, and January 21-31, 2013) from Russian physicist Dr. Leonid Yurganov. The methane concentration scale, with darker reds being the highest, can be viewed by clicking on the image to enlarge it.



Quite obviously, there's been a sudden increase in atmospheric methane in an area of the arctic ocean north of eastern Europe and western Asia. As shown in the post about this at Arctic News, that area where the methane concentrations are highest coincides with the area of the arctic ocean that is still relatively ice-free. 

This dramatic increase in atmospheric methane seems to be similar to an arctic event that we covered a little over a year ago that occurred in November 2011. At that time Russian scientists [Shakhova & Semiletov] had observed vast plumes of methane bubbling to the surface of the arctic ocean off the coast of eastern Siberia [and again, even more pervasive, in late 2012], which they described as "powerful and impressive seeping structures more than 1,000 metres in diameter."

Back then we figured that since that eastern Siberian area was one of the shallowest areas of the arctic, it had warmed enough during a period of unusual atmospheric circulation that fall to thaw the extensive amounts of frozen methane hydrates known to be locked up by high pressure and cold temperatures on the ocean floor, and they were melting and rising to the surface. In this case it appears that a branch of the warm gulf stream current is causing enough warming to destabilize the frozen methane on the ocean floor in the areas between Norway and Svalbard and points east. This is similar to a scenario that was warned about in a study in the journal Nature in October.

What happens next is anyone's guess, but Dr Yurganov's records indicate that higher levels of arctic methane emissions have been increasing over time. (US scientists must now rely on Canadian and European monitoring of greenhouse gas emissions because NOAA’s monitoring of Arctic methane and CO2 was halted last week by budget cuts.) We've pointed out before that atmospheric methane hit a new high of about 1,813 parts per billion (ppb) in 2011, which was at 259% of the pre-industrial level, and that 40% of the increase was coming from natural sources such as this. 

Methane is 25 times as potent a heat-trapping gas as CO2 over a 100-year time horizon, but 72 times as potent over 20 years, and methane's global heat trapping effect is now roughly one-third that of CO2. Further thoughts on the potential impact of large abrupt release of methane in the Arctic are here. Suffice it to say that if all the ancient carbon were to be released from the arctic it would be enough to raise global temperatures 3 C on top of the 4 C temperature rise from human activities predicted by the recent World Bank study…

Our awareness of this comes the same week that the European Space Agency’s CryoSat-2 probe has confirmed the conclusion of the Pan-Arctic Ice Ocean Modeling and Assimilation System (PIOMAS) at the University of Washington’s Polar Science Center that not only is the extent of the Arctic ice receding, but its thickness has diminished considerably as well. The combined result has been a collapse in total arctic ice volume to one-fifth of what was the minimum ice volume as recently as 1980. With the associated warming in the Arctic, we can only expect the frequency and range of such Arctic methane releases to increase, from both the seabed and the permafrost.