The New York-based Natural Resources Defense Council (NRDC) says on its web page entitled "Global Warming Puts the Arctic on Thin Ice" that average temperatures in the Arctic region are rising twice as fast as they are elsewhere in the world. Arctic ice is getting thinner, melting, and rupturing. NRDC points to the largest single block of ice in the Arctic, the Ward Hunt Ice Shelf, as an example: it had been around for 3,000 years before it started cracking in 2000. “Within two years it had split all the way through and is now breaking into smaller pieces.”
Global Warming Threatens Polar Bears
Climate changes are having a devastating impact on the Arctic region’s ecosystem, causing a severe population decline among polar bears, for example. The iconic animal has been declared an endangered species by the Manitoba government.
Global warming is causing the region’s ice to melt earlier and form later, leaving the bears with less time to hunt for seals. Some colonies of bears have shown signs of malnutrition, and biologists say there could be a more severe drop in their population within the next few decades. According to Canadian Wildlife Service research scientist Ian Stirling, if the weight-loss trend continues, most females in the population will be below the minimum weight needed to reproduce by 2012.
In September 2007, the U.S. Geological Survey (USGS) predicted that two-thirds of the world’s polar bears will die off by 2050, including the entire population in Alaska, as a result of thinning sea ice. The Geological Survey study, which is summarized by earthdive.com in an article entitled "Most Polar Bears Gone By 2050, Studies Say"further forecast that the bears would be able to survive to the end of the century only in northern Canada and northwestern Greenland. The agency thinks that in the next 50 years polar bears will lose 42 percent of the Arctic range they need to hunt and breed during the summer.
Arctic Sea Ice is Vanishing
The sea ice is disappearing at about the rate of 70,000 km2 a year; that’s an area about the size of Lake Superior. At that rate, USGS scientists predicted in 2007 that the Arctic will be ice-free by 2050, which would affect not only the Inuit and polar bears, but shipping and offshore oil and mineral development as well.
The thaw could become a self-sustaining acceleration: as the ice melts, the ocean draws in more heat from the sun, which then melts the ice even more quickly.
So much ice melted in the summer of 2007 that the Northwest Passage across the top of Canada became the most navigable it had been since monitoring began. The information came from the U.S. National Snow and Ice Data Center (NSIDC) at the University of Colorado in Denver. According to the Center, the Arctic has lost about a third of its ice since satellite measurements started three decades ago. And, the rate of loss has accelerated sharply since 2002.
Small Sea Ice Recovery in 2009
The cool summer of 2009 offered a brief turnaround in the trend line for melting sea ice.
The NSIDC reports (October 6, 2009) that “At the end of the Arctic summer, more ice cover remained this year than during the previous record-setting low years of 2007 and 2008. However, sea ice has not recovered to previous levels.”
The report notes that ice coverage was still 1.68 million km2 (649,000 square miles) below the 1979 to 2000 September average. “Arctic sea ice is now declining at a rate of 11.2 percent per decade, relative to the 1979 to 2000 average.”
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