Arctic Sea Ice Extent in 2011 courtesy of NSIDC
The National Snow and Ice Data Center (NSIDC) recently released the latest figures for Arctic sea ice extent. According to the Center, the average sea ice extent for the month of August 2011 reached the second lowest level since satellite-based observations began in 1979. Mean ice extent for August was 5.52 million square kilometers, about 28 percent below the monthly average for 1979-2000.
The thinning Arctic sea ice has become highly responsive to shifts in weather patterns. During early summer continuous high-pressure systems across the northern Beaufort Sea accelerated ice loss. By the end of July a low-pressure system had moved into the area and colder temperatures prevailed, slowing the ice loss. At the same time, however, strong winds spread out the ice pack resulting in thinner-than-average ice-coverage.
During the second half of August ice melt accelerated yet again as high pressure returned to the Arctic. As a result the ice retreated faster than it did over the same period in the record year of 2007. By August 31, 2011 sea ice extent measured 4.63 million square kilometers, just 100,000 square kilometers above the previous record for the same day set in 2007. With about two weeks left in the melt season, 2011 has already surpassed the second- and third-lowest absolute minima on record from September 2010 and 2008.
Improved resolution of satellite imagery also suggests that 2011 ice extent has been tracking closer to the 2007 record low than earlier measurements suggested. The more sophisticated system used for the latest set of data resolves the ice pack down to 6.1 kilometers compared to the previous resolution of 24.9 kilometers. Hence the system can now detect small but widespread areas of open water that were previously thought to be continuous ice.
The NSIDC did not make any predication about whether the absolute minimum of 2011 could surpass the record low of 2007. Dr. Meier, a research scientist at the NSIDC, explained that “a lot still depends on the weather. If a warm front comes through, there could still be some rapid melting. But at present we think it could be close to or as low as the 2007 record minimum.”
Arctic Ice Extent Sep 05, 2011 courtesy of http://www.iup.uni-bremen.de/seaice/amsr/
The Arctic ice cap plays an essential role in stabilizing the world’s climate. The loss of summer ice directly contributes to climate change since darker open water absorbs more solar energy than white ice floes. Solar energy is stored in the ocean and melting thus continues even when the solar radiation begins to weaken in September. This late during the melt season variables such as wind patterns, ice thickness, and the heat retention of the Arctic Ocean, will ultimately influence whether or not 2011 sets a new record for minimum extent.
The most recent satellite data, released yesterday by the University of Bremen, suggests that ice extent now tracks below that of 2007. According to the Advanced Microwave Scanning Radiometer-Earth Observing System (AMSR-E) data, ice extent for September 5, 2011 set a new record low, surpassing the previous minimum extent for the same day in 2007. It appears that a photo finish will decide whether 2011 sets a new record for minimum ice extent.
The "Melting Vitruvian Man" created by John Quigley © NICK COBBING/AFP/Getty Images
The dramatic decline of the Arctic ice sheet prompted aerial artist John Quigley to reproduce Da Vinci’s famous sketch “Vitruvian Man” – a male figure in two superimposed positions with its arms and legs apart- on the ice sheet some 500 miles from the North Pole. Quigley, who travelled to the Arctic aboard Greenpeace’s icebreaker Arctic Sunrise calls his soccer-field-sized artwork “Melting Vitruvian Man.” It depicts a male figure whose arms and legs are melting into the ocean to highlight the disappearing ice.
