Antarctic Sea Ice Expanding While Arctic Ice Melts

A new study led by a Georgia Tech climate scientist has shown that Antarctic sea ice has expanded despite global warming, unlike Arctic sea ice; but this is expected to change as greenhouse gases continue to warm Antarctic waters. 

Jiping Liu, a research scientist and leader of the study from Georgia Tech, is now able to provide an explanation for the Antarctic’s growing sea ice over the past 30 years, even though global warming has claimed much of the Arctic’s sea ice.  

According to climate models and observations of sea-surface temperature and precipitations from 1950 to 2009, ocean warming actually provoked precipitation in the upper atmosphere, which falls as snow in the Antarctic. The top layers of the ocean then becomes less dense because the snow makes these surface layers less salty, thus making them more stable. This prevents density-driven, warmer currents in the deeper part of the ocean from reaching surface waters and from ultimately melting the Antarctic sea ice.

It may seem like a contradiction that warm surface waters are what causes precipitation that is helping create sea ice, yet also causes the melting of sea ice when it rises, but the problem, according to the study, is that oceans are becoming too warm in the Antarctic due to human-caused global warming.

Increased amounts of greenhouse gases causes climate warming, and this warming causes the precipitation in the Antarctic to become rain instead of snow, which melts ice and snow at a much faster pace. The suns rays are then absorbed into the dark ocean as the ice melts, which warms the ocean even more, and eventually leads to the melting of more sea ice. 

Issues associated with melting sea ice is that some animals in the Antarctic rely on it for hunting and survival, and it also could change the way water in the ocean travels around the world, which could interfere with circulation patterns that “provide nutrients for up to three quarters of marine life.”

Walt Meier of the National Snow and Ice Data Center (NSIDC) in Colorado noted that the results of this study are not surprising and the acceleration of melting Antarctic sea ice was previously predicted. He also mentioned that this study disproves the idea that a decline in Arctic ice and expansion of Antarctic ice results in a net zero effect because Arctic ice is “multiyear,” meaning that it persists through the seasons, while Antarctic ice melts and forms every year and isn’t dictated by air temperature as much as it is wind and ocean circulation.

The study was published in Proceedings of the National Academy of Sciences on August 16 of this year.