Most of the world's mountain glaciers and small ice caps will disappear or shrivel dramatically by the end of the century, with Alaska glaciers and ice fields shrinking by 25 to 60 percent over the next nine decades, according to new findings published last week in the journal Nature Geoscience. The study -- the most comprehensive ever done on the role of glacier wastage in sea level rise -- has already received extensive news coverage for its global perspective.
But Alaska's portion of the projected meltdown raises questions about the future of regional hydroelectric projects like the proposed multi-billion-dollar Susitna Dam, as well as Anchorage's drinking water source in Eklutna Lake and any other Alaska stream that relies on glacial melt for its summer flow.
If Alaska's climate continues to warm over the next 89 years as projected, summer runoff in glacier-fed basins like Susitna and Eklutna could initially soar by as much as 60 percent above the present during periods when the melt accelerates, said Regina Hock, a University of Alaska Fairbanks geophysicist who produced the study with lead author Valentina Radić, now a post-doctoral fellow at the University of British Columbia.
But after 2100, look out. As the source glaciers and ice fields recede, this annual summer surge could fall away. And eventually, perhaps, stop.
Alaskans hoping to build dams, secure drinking water or ensure future stream-flow for salmon and navigation should be asking: What then?
"Concerning both the Susitna dam and Eklutna Lake or any other hydropower scheme, it is essential to know how much total annual runoff will change," Hock said in an e-mail to Alaska Dispatch. "However, it seems that this has not really 'trickled in' yet in Alaska."
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