Earth

Ben Holt: ‘Arctic change faster than people imagined’

Ben Holt: I think there is a sense of urgency. The Arctic is rapidly changing, faster than people might have imagined.

That was research oceanographer Ben Holt at NASA’s Jet Propulsion Laboratory in Pasadena. Earth & Sky asked Holt what’s happening to Arctic ice.

Ben Holt: Well, the two major changes that have been going are the extent of the ice cover and the thickness of the ice. And the extent has been decreasing steadily for the last 15 years with a particular decrease in the summer of 2007.

By the end of the 2007 melt season, Arctic sea ice was 39 percent below the 20-year average.

Ben Holt: And the thicknesses, which have been measured primarily by submarines placed by the U.S. Navy, have shown a general decrease in thickness, particularly in the last two decades.

What’s more, in early 2008, NASA’s Ice, Cloud, and Elevation Satellite revealed that thinner, younger sea ice in the Arctic had jumped from 35 percent in the mid-1980s to 58 percent. Holt said that the thinning and shrinking of Arctic sea ice indicates a warmer Arctic Ocean.

Ben Holt: So the more you’re heating the ocean, the more it will propagate into potentially further ice reductions, eventually leading to strong shifts in the heat balance of the polar oceans and the rest of the global climate.

The study showing that older, thicker Arctic ice is giving way to younger, thinner ice was conducted by James Maslanik and colleagues at University of Colorado, Boulder. That study indicates that the older, thicker ice is effectively melting away the Arctic Ocean’s hedge against complete summer meltdowns, according to Maslanik. These scientists said this thinning is consistent with long-term warming in the Arctic.

Thanks today to NASA, in celebration of the International Polar Year.

Our thanks to:
Benjamin Holt
Research Oceanographer
NASA Jet Propulsion Lab
Pasadena, CA, USA

Posted 
March 9, 2008
 in 
Earth

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