January 20, 2014 at 12:33 pm #4467
Beneath the Cracking, Melting Ice, the Arctic Methane Monster Continues its Ominous Rumbling http://robertscribbler.wordpress.com/2014/01/14/beneath-the-cracking-melting-ice-the-arctic-methane-monster-continues-its-ominous-rumbles/
Arctic methane catastrophe scenario is based on new empirical observations
Critics of new Nature paper on costs of Arctic warming ignore latest science on permafrost methane at everyone’s peril
“The mechanism which is causing the observed mass of rising methane plumes in the East Siberian Sea is itself unprecedented and hence it is not surprising that various climate scientists, none of them Arctic specialists, failed to spot it. What is actually happening is that the summer sea ice now retreats so far, and for so long each summer, that there is a substantial ice-free season over the Siberian shelf, sufficient for solar irradiance to warm the surface water by a significant amount – up to 7C according to satellite data.
That warming extends the 50 m or so to the seabed because we are dealing with only a polar surface water layer here (over the shelves the Arctic Ocean structure is one-layer rather than three layers) and the surface warming is mixed down by wave-induced mixing because the extensive open water permits large fetches.
So long as some ice persisted on the shelf, the water mass was held to about 0C in summer because any further heat content in the water column was used for melting the ice underside. But once the ice disappears, as it has done, the temperature of the water can rise significantly, and the heat content reaching the seabed can melt the frozen sediments at a rate that was never before possible. The authors who so confidently dismiss the idea of extensive methane release are simply not aware of the new mechanism that is causing it.”
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