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Climate change doubles coastal erosion in Alaska over 5-year period

Coastal erosion along a 64-kilometer (40-mile) stretch of Alaska’s Beaufort Sea doubled between 2002 and 2007, report researchers, who link the development to “declining sea ice extent, increasing summertime sea-surface temperature, rising sea level, and increases in storm power and corresponding wave action.”

“These factors may be leading to a new era in ocean-land interactions that seem to be repositioning and reshaping the Arctic coastline,” write Benjamin Jones, a geologist with the U.S Geological Survey in Anchorage, and colleagues in the journal Geophysical Research Letters.

The researchers warn that though the pattern may not be representative of the overall Arctic, they may forecast the future pattern of coastline erosion in the region, according to the American Geophysical Union.

“This segment of coastline has historically eroded at some of the highest rates in the circum-Arctic, so the changes occurring on this open-ocean coast might not be occurring in other Arctic coastal settings,” said Jones.

“The recent trends toward warming sea-surface temperatures and rising sea-level may act to weaken the permafrost-dominated coastline by helping more quickly thaw ice-rich coastal bluffs and may potentially explain the disproportionate increase in erosion along ice-rich coastal bluffs relative to ice-poor coastal bluffs that we documented in our study,” Jones continued. “Any increases in already rapid rates of coastal retreat will have further ramifications on Arctic landscapes – including losses in freshwater and terrestrial wildlife habitats, in subsistence grounds for local communities, and in disappearing cultural sites, as well as adversely impacting coastal villages and towns. In addition, oil test wells are threatened.”

Average annual erosion rates along the studied segment of the Beaufort Sea have risen from about 6.1 m (20 ft) per year between the mid-1950s and late-1970s, to 8.5 m (28 ft.) per year between the late-1970s and early 2000s, to 14 meters (45 feet) per year during the 2002-2007 period.

Jones, B. M., C. D. Arp, M. T. Jorgenson, K. M., Hinkel, J. A. Schmutz, and P. L. Flint (2009), Increase in the rate and uniformity of coastline erosion in Arctic Alaska, Geophys. Res. Lett., 36, L03503, doi:10.1029/2008GL036205.

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