Temperature gap
Monaghan and his team found that while climate models projected temperature increases of 1.4 degrees Fahrenheit (0.75 degrees Celsius) over the past century, temperatures were observed to have risen by only 0.4 F (0.2 C)."This is showing us that, over the past century, most of Antarctica has not undergone the fairly dramatic warming that has affected the rest of the globe," Monaghan said.The gap between prediction and reality seemed to be caused by the models overestimating the amount of water vapor in the Antarctic atmosphere.The cold air over the southernmost continent handles moisture differently than the atmosphere over warmer regions.The models did, however, correctly capture the increases in snowfall over Antarctica in the late 20th century, followed by a decrease in the last decade.One reason that Antarctica hasn't warmed as much as other parts of the globe is the existence of the man-made ozone hole overhead: It alters wind patterns, creating a swirling belt of winds around the landmass that keeps comparatively warm air from seeping in, preserving the continent's frigid temperatures.
One important exception to this rule is the Antarctic Peninsula, which has warmed by several degrees, in part because winds there draw in warmer air from the north.
Mixed verdict
The Intergovernmental Panel on Climate Change has estimated that sea levels could rise by 7 to 23 inches (18 to 59 centimeters) globally this century, in part due to ice melt at both poles and from mountain glaciers.The new study, funded by the National Science Foundation and the U.S. Department of Energy, suggests that warming in Antarctica could offset this amount by about 2 inches (5 centimeters) if the continent warms by 5.4 F (3 C), as warmer air would hold more moisture and generate more snowfall, which contributes to the growth of the ice sheets, locking up any additional water in the these large masses of ice.That would mean a rise of only 5 to 21 inches (13 to 54 centimeters).But these projections are by no means certain-if melt from Antarctic ice sheets outweighed the snowfall that contributes to their growth, sea level rise could be higher."The research clearly shows that you can actually slow down sea-level rise when you increase temperatures over Antarctica because snowfall increases,but warmer temperatures also have the potential to speed up sea-level rise due to enhanced melting along the edges of Antarctica," Monaghan said. "Over the next century, whether the ice sheet grows from increased snowfall or shrinks due to more melt will depend on how much temperatures increase in Antarctica, and potentially on erosion at the ice sheet edge by the warmer ocean and rising sea level."The findings of the study don't call into question model projections for other parts of the globe, Monaghan said."The models are really doing quite a good job at simulating the 20th-century changes over the six inhabited continents," he told LiveScience.
http://www.foxnews.com/story/0,2933,354577,00.html
As in the days of Noah...