Wednesday, October 30, 2013

Warming of Permafrost on Siberian Coast is Greatly Increasing Erosion


This photo illustration shows the erosion of the east-Siberian island Muostakh. The blue line marks ist coastal line in the year 1951, the red line presents its status in the year 2012. In the upper right corner one can see an aerial picture of the island's northern tip, taken in the year 2012. At its narrowest point the island is shrinking more than four meters per year.
The high cliffs of Eastern Siberia – which mainly consist of permafrost – continue to erode at an ever quickening pace. This is the conclusion which scientists of the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research have reached after their evaluation of data and aerial photographs of the coastal regions for the last 40 years. According to the researchers, the reasons for this increasing erosion are rising summer temperatures in the Russian permafrost regions as well the retreat of the Arctic sea ice. This coastal protection recedes more and more on an annual basis. As a result, waves undermine the shores. At the same time, the land surface begins to sink. The small island of Muostakh east of the Lena Delta is especially affected by these changes. Experts fear that it might even disappear altogether should the loss of land continue.

The interconnectedness is clear and unambiguous: The warmer the east Siberian permafrost regions become, the quicker the coast erodes. "If the average temperature rises by 1 degree Celsius in the summer, erosion accelerates by 1.2 meters annually," says AWI geographer Frank Günther, who investigates the causes of the coastal breakdown in Eastern Siberia together with German and Russian colleagues, and who has published his findings in two scientific articles.
link.

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