Rising atmospheric carbon dioxide actually cools part of Antarctica - In a world where most regions are warming because of increasing concentrations of atmospheric carbon dioxide (CO2), central Antarctica has been cooling slightly in recent years.
Greenhouse gases such as CO2
typically trap heat radiated back toward space from the planet’s
surface, but large swaths of the East Antarctic Ice Sheet (the broad
pink mass on the right side of the image) are, on average, actually
colder than the upper layers of the atmosphere for much of the year-the
only place on Earth where that’s true.
When the team looked at the
overall balance between the radiation upward from the surface of the ice
sheet and the radiation both upward and downward from the upper levels
of the atmosphere across all infrared wavelengths over the course of a
year, they found that in
central Antarctica the surface and lower atmosphere, against
expectation, actually lose more energy to space if the air contains
greenhouse gases, the researchers report online and in a forthcoming Geophysical Research Letters. And adding more CO2
to the atmosphere in the short-term triggered even more energy loss
from the surface and lower atmosphere there, the team’s climate
simulations suggest.
The topsy-turvy temperature trend stems, in part,
from the region’s high elevation; much of the surface of the ice sheet
smothering East Antarctica lies above an elevation of 3000 meters, so it
is much colder than it would be at lower altitudes. Moreover, that
region often experiences what meteorologists call a temperature
inversion, where temperatures in the lowest levels of the atmosphere are
cooler than those higher up. For the lower-altitude fringes of the icy
continent, and for the rest of the world (even Siberia and Greenland),
the greenhouse effect still works as expected. Source: Sciencemag
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