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NatureScience

Canadian Arctic Barrier Islands from Space

The Advanced Land Imager on NASA’s Earth Observing-1 satellite captured this image of a barrier island facing the Beaufort Sea, on the northern edge of Canada’s Northwest Territories on June 23, 2004, before the ice had melted or retreated during the summer thaw.

A new survey has shown that there are 2,149 barrier islands around the world, spanning 20,783 kilometers (12,914 miles) of coastline, but what is surprising to scientists is that 12.7 percent of those barrier islands—a total of 272—surround the Arctic Ocean.

The image shows the beach in the centre of the image – a tan brown running from top right to bottom left – surrounded by ice in the ocean and the back bay.

Despite the surprising amount of barrier islands surrounding the Arctic, they aren’t as impressive as elsewhere. During the colder months of the year, the Arctic barrier islands are protected thanks to the presence of sea ice and permafrost. But once the ice retreats and the permafrost thaws, heavy winds, waves, and freshwater currents reduce the islands in size, making them rounder and smaller than in other environments (barrier islands in the Arctic are half as long (5 kilometers, or 3 miles) as the global average (10 kilometers or 6 miles)).

“The observed increased seasonal melting of permafrost may be adding significantly to Arctic barrier island retreat,” survey authors Matthew Stutz of Meredith College and Orrin Pilkey of Duke University wrote in The Journal of Coastal Research. The overall thawing of Arctic climates, as well as increasing sea level rise, have these islands retreating more rapidly than elsewhere in the world.

Source: NASA Earth Observatory




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