Posted on | juli 27, 2012 | 1 Comment
The combination of declining Arctic ice and Greenland’s melting ice sheet are part of a troubling trend that cannot be ignored. As of June 2012, Arctic sea ice declined by 1.10 million square miles and as of July a total of 97 percent of Greenland’s ice sheet had melted.
According to satellite images from NASA (see above left), Greenland’s ice sheet is melting at an alarming rate. Before July 2012, the most extensive melting seen by satellites in the past three decades was about 55 percent. Ice core records reveal that we have not seen such pronounced melting of Greenland’s ice sheet since 1889. To make matters worse a 70 square miles (181 square km) iceberg broke off Greenland’s Petermann Glacier.
The speed at which Greenland’s ice sheet is melting is a source of concern as NASA images show that between July 8 and July 12 more than 57 percent of the surface ice had thawed. This event is very rare occurring every on average every 150 years. This would not be so troubling if it were a rare event, however, only four years ago (2007) Arctic ice shrank to similar levels, the smallest size in hundreds of years.
Most of the preceding ice melts of this magnitude occurred 7000 years ago and were attributable to the sun’s tilt on its axis which sent more sunshine to extreme northern latitudes. There is no such solar tilt going on now. Scientists attribute the melting of the Greenland ice sheet to unusually warm weather across the Arctic.
Warmer weather is also melting sea across much of the Arctic but it is most evident in the Bering, Kara, and Beaufort Seas, as well as Hudson and Baffin Bay. National Snow and Ice Data Center said warming has hastened the melting of ice over much of the sea route from Western Europe to the Pacific. The passage eastward from the North Atlantic to the Pacific shows open water which is highly unusual for July. This is all part of an ongoing pattern of rapid spring snow melt over the past six years.
Average Arctic sea ice extent for June was 456,000 square miles below the 1970-2000 average. Total ice loss for June was 1.10 million square miles, the largest June ice loss in the satellite record, continuing the particularly rapid ice loss in May. June, 2010, 2011, and 2012 have had the lowest amount of ice coverage in the satellite record. There appears to be a consistent pattern of declining sea ice coverage.
As predicted by models of global warming, the melting of Greenland’s ice will cause sea levels to rise while the melting of sea ice in the arctic can heat things up in the Northern Hemisphere and cause more extreme weather.
Scientists will not attribute any individual extreme event to global warming, however, if this melting persists, it will become increasingly hard to attribute it to anything but a warming planet.
AUTHOR: Richard Matthews
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