Melting and erosion of permafrost along Siberia's vast Arctic coastline is releasing huge amounts of CO2, about ten times more than previously estimated, to the atmosphere. The "Ancient Ice Complex" that crops out along the 7000 kilometer long Siberian coastline has melted and eroded more quickly than expected as the climate warmed 2 degrees Celsius faster than models predicted. Measurements combined with computer models calculated that
44 ± 10 teragrams of old carbon is activated annually from Ice Complex permafrost, an order of magnitude more than has been suggested by previous studies.
About two thirds of this carbon becomes atmospheric CO2 and one third is reburied in marine sediment.
The record melting of Arctic sea ice has accelerated erosion along the Arctic coastline as wave heights rise with the increase of open water. Recent intense late summer storms have sent waves of warm water crashing into the permafrost, surely increasing the speed of collapse.
The authors of the study, published in the prestigious journal Nature, warn in their final sentence:
Thermal collapse and erosion of these carbon-rich Pleistocene coastline and seafloor deposits may accelerate with Arctic amplification of climate warming.
With the record minimum of sea ice this summer, that process has begun. This is one of multiple positive feedback loops in the Arctic that is accelerating warming and rapidly destabilizing the climate of the northern hemisphere.
8:11 AM PT: Note that the study reports the carbon is oxidizing to CO2. The shoreline and the shallow Siberian seas contain plentiful oxygen. Methane forms in Siberia when permafrost melts below the water table or at the bottom of ponds formed when permafrost melts. Under those conditions the small amounts of available oxygen are overwhelmed large amounts of carbon. Under wet, low oxygen conditions, bacteria convert carbon to methane.
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The diary I wrote yesterday "The wind Cries Katrina" got just 553 views according to Jotter. People who read it gave it excellent reviews. It's written in a more lyric style than my science blogging. I don't know if I've ever had so many recommends with so few views. You might want to check it out.