Ice thins, big section breaks off Arctic shelf

(Image of thinning ice in Arctic from Flickr and NASA/pingnews)

News Update 1: A 7-square-mile section of the Ward Hunt Shelf, the largest remaining ice shelf in the Arctic, broke off last week. The ice shelf is now just 11% of its previous size. “Once you unleash this process by cracking the ice shelf in multiple spots, of course you’re going to see this continuing,” said Derek Mueller, an expert on the ice shelf who found the first crack in 2002. The shelf began getting thinner in the ‘50s and by the ‘90s had cut its thickness by half. The Arctic coastline also decreased substantially in the past century, from about 3,500 square miles to about 400 square miles. The largest ice break was in 2005. Scientists attribute much of the problem to warming temperatures and summer ice is on track to disappear completely. “They’re breaking away so rapidly that there’s no hope of regeneration,” Mueller told the Toronto Globe and Mail this week. (Sources: Greenwire, AP, The Daily Green, Toronto Globe and Mail.

Melting Arctic ice can signal permafrost thaw and more greenhouse gas emissions

News Update 2: Last summer saw a record Arctic sea ice melt and another record is forecast for this year, according to a new study by the National Center for Atmospheric Research (NCAR). When the sea ice melts, the temperature over land heats up as far as 900 miles away, the study found, and is likely to thaw permafrost in Alaska, Canada and Russia. Permafrost is the long-frozen earth beneath the top layer of ground. When it thaws it releases methane, a greenhouse gas much more potent than CO2. It also can cause the collapse of infrastructure, such as highways, houses, oil rigs and pipelines. Last August-October the temperature over land in the west Arctic was unusually warm, more than 4 degrees Fahrenheit above the average for 1978-2006. Rapid sea ice thaw could lead to rapid permafrost thaw, the scientists said. (Source: Reuters PlanetArk)