September 19, 2009

Arctic Ice Caps Shrink To Third Smallest In 30 Years

This summer's melt of Arctic sea ice might not have been quite as bad as the past two years, but satellite images reveal that it has now had the third biggest melt in 30 years, according to U.S. government scientists.

The announcement was made on Thursday by the National Snow and Ice Data Center, which reported that the Arctic sea ice pack had reached its yearly minimum just last Saturday. It will not begin to grow again until fall begins.

As of last Saturday, the sea ice only covered approximately 2 million square miles of ocean. In 2007, during the biggest melt in 30 years, the ice only covered 1.6 million square miles, while in the following year the ice covered 1.8 million square miles.

The Boulder, Colorado based center's glaciologists  said that the ice cap probably did not shrink quite as much this year as the two before because the summer was not as hot, and the winds were blowing in different directions.

However, a smaller decline does not mean a recovery, Walter Meier, a research scientist at the center, was sure to point out.

The size of the Arctic sea ice pack drastically dwindled since 1979, especially during the summer months, the center said.

This summer, the low point was 620,000 square miles less than the past 30-year average ice pack size, the NSIDC said.

The size of the Arctic ice cap has increased approximately 14 times over the past 31 years, but the decline of sea ice has definitely been the trend, which directly corresponds to a rise in temperature over the same period, Meier said.

According to Meier, it is better to look at the long-term trend than just year to year.

The record ice loss of 2007 occurred during an unusual Arctic summer, full of destructive events. There were strong winds and high temperatures, which resulted in tragic losses from an already weakened ice pack, said Meier.

About 50 percent of the ice pack this summer is only one year old, which makes it weaker and thinner than older, more established ice. In previous years, older ice would have comprised roughly 75 percent of the ice pack.

"That's a really dramatic change," Meier said.

Arctic sea ice plays a key role in moderating warmer temperatures elsewhere. Experts believe global warming is the cause for greater melting of sea ice and are concerned that there will come a time when no sea ice will survive the summer.

Mead Treadwell, of the U.S. Arctic Research Commission, said that he flew hundreds of miles across  the Beaufort Sea on a Coast Guard flight this week without ever seeing any multi-year ice.

"It's a significant difference for anyone who has been watching this ocean for some time," he said.

Image Courtesy USGS


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