Antarctica's high elevations explain the continent's slower rate of warming, new research suggests. Photo by Tarun Luthra/EGU
May 18 (UPI) -- Antarctica continues to warm much more slowly than the Arctic, and scientists have struggled to come up with an explanation for the disparity. A new study, however, suggests the continent's high elevations explain its delayed warming.
"On average, warming for the entire Antarctic continent has been much slower than Arctic warming so far," Marc Salzmann, a researcher at the University of Leipzig's Institute for Meteorology in Germany, said in a news release. "Moreover, climate models suggest that, by the end of this century, Antarctica will have warmed less compared to the Arctic."
In recent decades, the Arctic has warmed considerably more than the rest of the planet. Researchers suggests unique atmospheric dynamics at the poles, as well as the loss of sea ice, explained the region's rising temperatures.
But these explanations didn't fully account for the discrepancy between polar warming rates.
"I wondered why some of the reasons to explain Arctic warming have not yet caused strongly amplified warming in all of Antarctica as well," Salzmann said. "I thought that land height could be a game changer that might help explain why the Arctic has thus far warmed faster than Antarctica."
Unlike the Arctic, which is a polar ice cap, Antarctica is a continent composed of land. Atop its bedrock are thick slabs of ice, boosting its elevation. The continent is also home to tall mountains.
Salzmann ran computer models to see how the continent's climate would respond to a doubling of CO2 concentrations. He repeated the simulation using a "flat-Antarctica" model, decreasing land height by a meter across the entirety of the continent.
As detailed in the journal Earth System Dynamics, the flat-Antarctica world responded to the rise in CO2 levels with more aggressive warming. Flattening the southern continent altered the region's atmospheric dynamics, shifting the way heat is transferred from the equator to the poles.
"Assuming a flat Antarctica allows for more transport of warm air from lower latitudes," Salzmann said. "This is consistent with the existing view that when the altitude of the ice is lowered, it becomes more prone to melting."
Researchers suggest a flatter Antarctica will soon be a reality. As the continent's glaciers melt and thin, it's land heights will decrease. If Salzmann's model is correct, lower land heights will yield additional warming.
