http://www.sciam.com/article.cfm?cha...6783414B7F0000

Launching weather balloons has been a nearly daily habit at some Antarctic
research facilities since 1957. Carrying radiosondes--instruments that
measure atmospheric conditions such as temperature and wind speed--the
balloons travel as high as 12 miles or more. A new analysis of the past 30
years of records from nine research stations, including Amundsen-Scott at
the South Pole, reveals that the air above the entirety of Antarctica has
warmed by as much as 0.70 degree Celsius per decade during the winter
months.

John Turner of the British Antarctic Survey and his colleagues report in
today's issue of Science that this warming trend is consistent across data
from multiple stations run by multiple countries using multiple types of
instruments. Previous studies had shown that Antarctica's surface
temperatures had warmed by roughly 2.5 degrees C over the last half century,
but this study provides the most complete look at atmospheric trends to
date.

"The rapid surface warming of the Antarctic Peninsula and the enhanced
global warming signal over the whole continent shows the complexity of
climate change," Turner says. "Greenhouse gases could be having a bigger
impact in Antarctica than across the rest of the world and we don't
understand why."

This warming has implications for snowfall on the continent as well as the
melting of land-based ice reserves, potentially leading to global sea-level
rise, the researchers warn. Although they cannot ascribe a particular cause
to the warming, they ruled out several other potential explanations,
including heat transfer from other regions (there was no observed change in
wind patterns) and solar radiation changes (the sun is either at or below
the horizon throughout the winter months in question).
And although current computer models fail to predict this warming trend, the
scientists argue that the data is consistent with what would be expected as
a result of increasing greenhouse gases. "Our next step," Turner says, "is
to try to improve the models." --David Biello