Antarctic Ice Shelves are Thinning Rapidly — and the Losses are Accelerating in West Antarctica

Satellite radar data reveal the speed of flow of the Pine Island Glacier in West Antarctica between March 3 and 15, 2015. Pink indicates the fastest flow: about 100 meters (328 feet). Yesterday, I posted a story about the Halley Research Station on Antarctica's Brunt Ice Shelf. I titled it a "Winter Postcard from Antarctica," and it included photos and comments about life at the station from Tom Welsh, the wintertime manager there. Well, I was so busy putting that post together that I missed the big news yesterday about Antarctic ice shelves in general: They are thinning faster than previously thought. This is a big deal because these ice shelves act like dams that impound giant glaciers behind them, slowing their movement to the sea. So as these ice shelves erode, it allows the glaciers to flow more quickly, releasing more ice into the sea and thereby raising sea level. The new findings have been reported widely elsewhere, including this excellent overview by Andrew Freedman at Mashable. So I won't go into them in great detail here. But I thought I'd share a quick summary as well as some imagery that can help explain what's going on. The new research, published on March 26, 2015, in the journal Science, is based on a new high-resolution record of ice shelf thickness based on satellite radar missions of the European Space Agency from 1994 to 2012. The study showed that from 1994 to 2003, total ice shelf volume in Antarctica changed very little. But then it went into rapid decline. There was one exception to this pattern — and it was not a good one: West Antarctic ice shelves lost ice during the entire observation period. And during the most recent decade the erosion of ice there has been accelerating. The image at the top of this post portrays the speed of the Pine Island Glacier in West Antarctica. The pink coloring is indicative of the fastest speeds, and the blue represents stable ice on either side of the glacier. Based on radar data from the Sentinel-1 Mission of the European Space Agency (ESA), the image shows that parts of the Pine Island glacier flowed about 100 meters (328 feet) toward the sea between March 3 and 15 of this year. According to the space agency: