Arctic melt speeds up in 2007
December 12th, 2007,This past year turned out to be a record-breaker for Arctic warming, according to scientists quoted in an article by Seth Borenstein, Associated Press science writer. The portents are not good and should embolden us to act more aggressively to curb carbon emissions.
Below are some excerpts from the article. Warning: some of the quotes from the scientists are among the most alarming that I’ve seen on the climate change issue.
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, Colo.
Just last year, two top scientists surprised their colleagues by projecting that the Arctic sea ice was melting so rapidly that it could disappear entirely by the summer of 2040.
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.”
So scientists in recent days have been asking themselves these questions: Was the record melt seen all over the Arctic in 2007 a blip amid relentless and steady warming? Or has everything sped up to a new climate cycle that goes beyond the worst case scenarios presented by computer models?
“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.”…
“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. “This is going to be a watershed year.”…
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.”
Melting of sea ice and Greenland’s ice sheets also alarms scientists because they become part of a troubling spiral.
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.
“That feedback is the key to why the models predict that the Arctic warming is going to be faster,” Zwally said. “It’s getting even worse than the models predicted.”
NASA scientist James Hansen, the lone-wolf researcher often called the godfather of global warming, on Thursday was to tell scientists and others at the American Geophysical Union scientific in San Francisco that in some ways Earth has hit one of his so-called tipping points, based on Greenland melt data.
“We have passed that and some other tipping points in the way that I will define them,” Hansen said in an e-mail. “We have not passed a point of no return. We can still roll things back in time - but it is going to require a quick turn in direction.”
See the article for some good specifics on why 2007 was a record year for warming in the Arctic.