Tuesday, December 11, 2007

Articles - cnn.com - planet.in.peril

http://www.cnn.com/SPECIALS/2007/planet.in.peril/
http://www.cnn.com/2007/TECH/science/07/11/globalwarming.overview/index.html

Global warming: A natural cycle or human result?

He calls his discovery Warming Island.
Explorer Dennis Schmitt found an island nearly two years ago near Greenland
Many climatologists and scientists say arctic ice melt and other changes in the Earth's climate are the result of an increase in the world's temperature, a trend widely called global warming.

http://topics.cnn.com/topics/global_climate_change
http://www.cnn.com/2007/TECH/science/12/11/arctic.melt.ap/index.html#cnnSTCText
Scientist: 'Arctic is screaming'
  • Story Highlights
  • Record melt seen all over the Arctic in 2007
  • Scientists worry global warming has passed an ominous tipping point
  • What happens in the Arctic has implications for the rest of the world

Greenland's ice sheet melted nearly 19 billion tons more than the previous high mark, and the volume of Arctic sea ice at summer's end was half what it was just four years earlier, according to new NASA satellite data obtained by The Associated Press.

"The Arctic is screaming," said Mark Serreze, senior scientist at the government's snow and ice data center in Boulder, Colorado.

This week, after reviewing his own new data, NASA climate scientist Jay Zwally said: "At this rate, the Arctic Ocean could be nearly ice-free at the end of summer by 2012, much faster than previous predictions."
"The Arctic is often cited as the canary in the coal mine for climate warming," said Zwally, who as a teenager hauled coal. "Now as a sign of climate warming, the canary has died. It is time to start getting out of the coal mines."
White sea ice reflects about 80 percent of the sun's heat off Earth, NASA's Zwally said. When there is no sea ice, about 90 percent of the heat goes into the ocean which then warms everything else up. Warmer oceans then lead to more melting.

n the United States, a weakened Arctic blast moving south to collide with moist air from the Gulf of Mexico can mean less rain and snow in some areas, including the drought-stricken Southeast, said Michael MacCracken, a former federal climate scientist who now heads the nonprofit Climate Institute.

"I don't pay much attention to one year ... but this year the change is so big, particularly in the Arctic sea ice, that you've got to stop and say, 'What is going on here?' You can't look away from what's happening here," said Waleed Abdalati, NASA's chief of cyrospheric sciences.
A record amount of surface ice was lost over Greenland this year, 12 percent more than the previous worst year, 2005, according to data the University of Colorado released Monday.

But temperature measurements 66 feet deep in the frozen soil rose nearly four-tenths of a degree from 2006 to 2007, according to measurements from the University of Alaska. While that may not sound like much, "it's very significant," said University of Alaska professor Vladimir Romanovsky.

According to that pattern, 2007 shouldn't have been a major melt year, but it was, said Konrad Steffen, of the University of Colorado, which gathered the latest data.

Other new data, from a NASA satellite, measures ice volume. NASA geophysicist Scott Luthcke, reviewing it and other Greenland numbers, concluded: "We are quite likely entering a new regime."
NASA scientist James Hansen, the lone-wolf researcher often called the godfather of global warming, on Thursday will tell scientists and others at a meeting of researchers in San Francisco that in some ways Earth has hit one of his so-called tipping points, based on Greenland melt data.

Last year, Cecilia Bitz at the University of Washington and Marika Holland at the National Center for Atmospheric Research in Colorado startled their colleagues when they predicted an Arctic free of sea ice in just a few decades. Both say they are surprised by the dramatic melt of 2007.

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