Wednesday, November 04, 2015

Ice, a Big Moderator of the Earth's Climate, Will Change the Arctic and the Planet When It Leaves

The Cruise ship Sarfaq Ittuk takes a mid-September tour of the Arctic Ocean around Greenland. By September 2050, scientists predict, this stretch of the ocean will be almost ice-free. (Photo Credit: Flickr)  Click to Enlarge.
By midcentury, the Arctic coastline and most of the Arctic Ocean will be devoid of sea ice for an additional 60 days each year, with some regions seeing closer to 100 days more of open water, according to a study released this week in the journal Nature Climate Change.

The shift toward more sea-ice-free days would affect "all aspects of the Arctic environment," the authors wrote, including which areas of the region will be open to commercial shipping and therefore natural resource extraction.  It could also change aspects of the polar ecosystem and affect the livelihoods of those who live in the region.  Arctic sea ice, or frozen ocean water, naturally grows and shrinks with the seasons, but since 1979 -- when scientists gained the ability to use satellite records to track the natural processes of sea ice -- researchers have observed sharp declines in its extent.

Although it's covered in snow most of the year, sea ice is important for moderating the global climate.  It helps cool the polar regions in part because sea ice has a bright surface.  The National Snow and Ice Data Center (NSIDC) estimates that 80 percent of the sunlight that strikes sea ice is reflected back into space.

Using climate simulations generated by the National Center for Atmospheric Research-based Community Earth System Model, the researchers from the University of Colorado, Boulder, focused on four coastal locations within the Arctic to model changes in the number of open water days from 1850 to 2100.  The "business as usual" scenario suggests that between 2040 and 2080, most of the historical sea ice ranges in the Arctic will have shifted completely to a longer season free of sea ice courtesy of a changing climate.

Read more at Ice, a Big Moderator of the Earth's Climate, Will Change the Arctic and the Planet When It Leaves

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