By BRYAN WALSH Tuesday, Sept. 27, 2011
If you want to witness climate change, just head north — and keep going until you run out of globe. Of course, that's easier said than done; the Arctic is a forbidding, isolated area, short of people and encased in ice much of the year. But those who make their way to places like Barrow, Ala. — the northernmost point of the U.S. — or the icy seas of the Arctic Ocean will witness a part of the planet that is warming and changing faster than anywhere else. While the world as a whole warmed by about 1°F (.55°C) over the entire 20th century, parts of the Arctic have warmed by 4° to 5°F (2.2° to 2.7°C) just since 1950. The physical changes from global warming are visible in the Arctic almost in real time — and they are a warning for those of us who live in more comfortable latitudes. As the polar expert Walt Meier of the National Snow and Ice Data Center (NSIDC) has put it: "What happens in the Arctic doesn't stay in the Arctic."
That's bad news, since not only is the warming threat in the Arctic bad, it's almost certainly intensifying. Earlier this month scientists at the NSIDC announced that Arctic summer sea-ice extent had fallen to its second lowest level since at least 1979, and likely long before that. Just 1.67 million sq. mi. (4.32 million sq km) of the Arctic sea was covered by ice as of mid-September — a little larger than the all-time record low of 1.608 million sq. mi. (4.16 million sq km) set in September 2007. And that may be a lowball figure: a separate group of researchers at the University of Bremen in Germany did their own estimate earlier this month and reported that there was even more melt in 2011 than in 2007.
The differences between the two estimates are academic; the larger point is that the current sea-ice extent is more than 1 million sq. mi. (2.5 million sq km) below the 1979–2000 average. That means the Arctic has lost an area greater than all the U.S. states east of the Mississippi. And what ice remains appears to be getting thinner and weaker as well. "There is plentiful data to suggest that the ice is thinning as well as shrinking in area," Nick Toberg and Till Wagner, polar-ocean physicists from Cambridge University, wrote to me recently in an e-mail from the Greenpeace ship Arctic Sunrise, where they were doing sea-ice fieldwork north of Norway. "It's a downward spiral because after successive seasons of thinner ice, each
gets worse than the one before it."
The question now is what's going to happen to the Arctic as we keep adding carbon emissions to the atmosphere and the climate keeps warming. Some scientists worry that Arctic sea ice may be going from a downward spiral to a "death spiral," one from which there is no escape even if we can manage to reduce carbon emissions. As more ice melts, more dark open water is exposed, which absorbs more heat, accelerating the melting. (White sea ice, by contrast, reflects sunlight, slowing warming.) Until recently, many scientists thought it might take until the end of the century for the North Pole to become completely ice-free during the summer. Now there are estimates that we could see a naked North Pole by 2030 or even earlier. "The melting is happening faster in the real world than it has in the models," says James Overland, an oceanographer for the National Oceanic and Atmospheric Administration.
Read more: http://www.time.com/time/health/article/0,8599,2095114,00.html
Printer-friendly format
Email this thread to a friend
Bookmark this thread
(1000+ posts)
Send PM |
Profile |
Ignore
