A rare piece of good news about the effects of global warming trickled through the media this weekend, as Dutch researchers announced that Greenland’s massive ice sheet isn’t melting as quickly as some had feared. Researchers used 17 years of satellite data to measure the seasonal changes to the ice sheet, which covers about 80 percent of Greenland’s surface, and found that the episodes of extremely rapid melting that researchers have observed recently are a transient summer phenomenon.
The melting of the Greenland ice sheet figures into the most troubling global warming doomsday scenarios; if the vast stretch of ice melted completely, it would raise global ocean levels by about 23 feet, swamping island nations and coastal communities. The new study dismisses the idea that such a doomsday could come to pass within a few decades. However, other researchers were quick to say that this study doesn’t answer all the questions about how the ice sheet will behave under shifting climatic conditions.
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Last summer, the Arctic was an unusually watery and warm place. Sea ice around the pole shrank to a record low, while air temperatures over Alaska were unusually warm from August to October, hovering about 4 degrees Fahrenheit above average. To understand how the two events were related scientists studied the feedback cycle in which the dark, open water around the pole absorbs more heat than reflective ice, thus causing more atmospheric warming.
In the resulting report, which will be published on Friday in the journal Geophysical Research Letters, researchers say that the phenomenon is powerful enough to cause extra warming more than 900 miles inland. That bodes ill for the Alaskan permafrost which supports roads, towns, and oil rigs and pipelines; if the permafrost thaws, all this infrastructure could be undermined. In addition, the thawing tundra could release methane that’s been frozen for millennia. Since methane is a powerful greenhouse gas, that release could further accelerate global warming.
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A clump of hair that lay frozen in the Greenland tundra for 4,000 years has yielded DNA from the earliest Arctic residents, and offers clues to their origins.
Researchers have long wondered who those rugged settlers were, and where they came from. Were they part of a massive migration that swept through all of North America, or were they a separate tribe that eventually gave rise to Greenland’s present-day Eskimos?
Until now, no ancient human remains had been found in that harsh climate to allow researchers to study the genetics of those “Paleo-Eskimos.” But the new discovery sheds some light on the people, and suggests that neither of the earlier theories is correct; in fact, they were a distinct tribe that journeyed all the way from Siberia to Greenland, but didn’t stick around to populate the frozen north.
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