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5 December 2013 11:26 am ,
Vol. 342 ,
An animal rights group known as the Nonhuman Rights Project filed lawsuits in three New York courts this week in an...
Researchers have been hot on the trail of the elusive Denisovans, a type of ancient human known only by their DNA and...
Thousands of scientists in the Russian Academy of Sciences (RAS) are about to lose their jobs as a result of the...
Dyslexia, a learning disability that hinders reading, hasn't been associated with deficits in vision, hearing, or...
Exotic, elusive, and dangerous, snakes have fascinated humankind for millennia. They can be hard to find, yet their...
Researchers have sequenced and analyzed the first two snake genomes, which represent two evolutionary extremes. The...
Snake venoms are remarkably complex mixtures that can stun or kill prey within minutes. But more and more researchers...
At age 30, Dutch biologist Freek Vonk has built up a respectable career as a snake scientist. But in his home country,...
- 5 December 2013 11:26 am , Vol. 342 , #6163
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Dwindling Days for Arctic Ice
7 September 2007 (All day)
If computer models are correct, by 2050 Arctic sea ice will shrink during late summer by more than twice as much as it does now. The results of a new study by researchers at the National Oceanic and Atmospheric Administration (NOAA) add weight to speculation that a northern sea route will open up from Europe to Asia for the first time in recorded history.
The Arctic ice cap remains one of the most variable features of our planet. For many millennia, the frozen areas of the Northern Hemisphere have advanced and retreated while a similar but smaller variation occurs on a seasonal basis. Now, between ice ages and in the midst of an upward trend in average temperatures, the Arctic Ocean's ice is showing signs of unprecedented summer shrinkage. That development could be a boon to international ship commerce but a potentially serious threat to the ecosystems that have emerged within polar environments. Furthermore, the transformation of the reflective white ice into heat-absorbing seawater could further accelerate the warming of the planet.
To carry out their study, oceanographer James Overland of NOAA's Pacific Marine Environmental Laboratory and meteorologist Muyin Wang of the agency's Joint Institute for the Study of the Atmosphere and Ocean at the University of Washington, both in Seattle, selected 11 climate models that closely predicted actual amounts of Arctic ice area from 1979 to 1999. Then they directed the computer programs to look ahead to 2050. The result, the team reports in the 8 September issue of Geophysical Research Letters, is that summer Arctic sea ice area could shrink by more than 40% and open waters off Alaska, Canada, and Russia that historically have remained icebound. That compares with about 18% summer shrinkage, on average, from 1979 to 1999. The models also project less ice formation during the winter in the Bering and Barents seas and in the Sea of Okhotsk, although not in Canada's Baffin Bay.
The 40% figure could be conservative, says ice scientist Waleed Abdalati of NASA's Goddard Space Flight Center in Greenbelt, Maryland, "as even the best models have historically underestimated the current rate of ice decline." But one thing is clear, he says: "The dramatic losses we are seeing in Arctic ice cover are not expected to slow down." Research scientist Jianli Chen of the University of Texas, Austin, thinks that the planet will experience a "snowball effect." Shrinking sea ice will increase the ocean's heat absorption, he says, which will in turn "further increase the melting of sea ice and contribute to global warming."