West Antarctica has been warming and melting more quickly than the rest of the continent. Photo by NASA/UPI | License Photo
June 15 (UPI) -- For the last few decades, the effects of global warming have been especially pronounced in West Antarctica.
Now, researchers in South Korea have developed an explanation for why the western half of the icy continent is warming faster than the eastern half.
Their analysis -- published this month in the journal Science Advances -- showed a strong link between the asymmetric warming and divergent temperatures in the Bellingshausen, Antarctic and Amundsen seas.
Scientists used what's called an empirical orthogonal function, a sophisticated math model, to identify different sources of climate variability across Antarctica.
They deployed the model to decipher climate observations recorded from 1958 to 2012, operating under the assumption that the asymmetric warming was caused by natural climate variability.
"The most important natural factor in driving such west warming and east cooling is the warming over the Southern Ocean in the sector of West Antarctica," study co-author Seong-Joong Kim, professor at the Korea Polar Research Institute, told UPI in an email.
The analysis also revealed surface air temperature fluctuation patterns across multiple decades, most likely influenced by climate patterns in the tropics. Researchers hypothesized that warming sea surface temperatures in the Southern Ocean off the coast of West Antarctica have produced a positive feedback with atmospheric conditions over the western half of the continent.
At present, natural climate variability has minimized the impacts of global warming across eastern Antarctica, but according to researchers, as more greenhouse gases are released into the atmosphere, the effects of natural climate variability will be drowned out by the influence of global warming.
"Note that currently marked warming dominantly occurs over west Antarctica, leading to huge disintegration of ice shelves off the Antarctic Peninsula such as Larsen-C collapse or melting of Pine Island Glacier and Thwaite Glacier, etc," Kim said.
"As global warming continues, collapse of ice shelves over east Antarctica will happen because the externally forced warming will take over the naturally fluctuating cooling over east Antarctica," Kim said. "This will definitely contribute to the increase in future sea level, though it is hard to quantify at this stage."
To improve climate prediction models for the region, scientists are currently working to figure out why sea surface temperatures in the western part of the Southern Ocean have been rising more quickly than other areas.
"We still do not know where the warming over the Pacific sector of the Southern Ocean comes from. It could be from the tropics or the Southern Ocean locally," Kim said. "Investigating the origin of the warm ocean anomaly is our future research topic."