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Research Shines Some Light On Mysteries of Antarctica
Disappearance of the west Antarctic ice sheet, captured by a NASA researcher in 2005, could raise worldwide sea levels by about 20 feet.
(Courtesy Of Nasa)
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For instance, the research into the Antarctic ice streams and the melted lakes a half-mile and more below their surface found that the ice is moving as fast as two yards a day. "We thought these changes took place over years and decades, but we are seeing large changes over months," said lead author Helen Fricker of the University of California at San Diego's Scripps Institution of Oceanography. Their findings appeared in Friday's edition of the journal Science.
It remains unclear whether the newly found subglacial lakes have anything to do with climate change. They might be caused by underground geothermal heat or by the heat-producing friction of the glaciers' motion. But Fricker and Bindschadler said the presence of the lakes has alerted scientists to the fact that the ice streams are, to some extent, sitting on top of water -- a situation that could allow them to move even faster.
"Water is critical because it's essentially the grease on the wheel," said Bindschadler, whose research was based on first-of-their-kind measurements by NASA satellites.
For Bromwich, the changeability of the Antarctic climate can be seen in effects seemingly caused by the thinning ozone layer, a process set in motion by the release of chlorofluorocarbon (CFC) molecules from man-made aerosols. Even though consumer products containing CFCs were taken off the market almost 20 years ago, they linger in the atmosphere for decades and continue to cause harm.
Bromwich said the Antarctic ozone layer was depleted in 2006 to an extent never seen before.
As the ozone diminishes, he said, warming ultraviolet light from the sun is not absorbed as readily and the atmosphere stays cooler. That in turns leads to longer periods of winter-like conditions, which might offset any warming from greenhouse gases. In addition, he said, the loss of ozone is believed by some researchers to cause the intensifying westerly winds.
Under these hypotheses, a return to more normal ozone levels would allow built-up greenhouse gases to rapidly warm -- and perhaps dramatically change -- the continent.
Bindschadler said the continent remains essentially mysterious. "Every time we think we understand something, we find that conditions are more complicated, more dynamic than we appreciated. Things are changing fast, and probably a whole lot faster than we know."
