On October 7, the National Snow and Ice Data Center (NSIDC) announced that Antarctic sea ice had reached a record five-day extent of 7.76 million square miles on September 22, 2014. This maximum extent is 595,000 square miles over the 1981-2010 average extent and broke the records consecutively set in 2012 and 2013. This record was expected as it follows a trend of irregularly high winter ice extents around the Antarctic. Scientists at NSIDC and at the National Aeronautics and Space Administration (NASA) have been conducting research in order to understand this phenomenon.
Ted Scambos, a senior scientist with NSIDC, told Climate Central that he believes there are two possible explanations for why Antarctic sea ice is growing. “The two main contenders are shifting winds around the Antarctic continent, which could be smearing the sea ice out over a larger area, and a pool of fresher water around the continent resulting from the melting of continental glaciers,” he said. While winds change season to season, the melting of freshwater continental glaciers, which provides a stable environment for sea ice to rapidly grow, is likely the result of climate change. Scambos explained that if melting land-bound ice is the main cause, then “this trend is not going to go away very easily.”
While growing sea ice in the Antarctic may seem to contradict the theory of global warming, researchers say otherwise. Claire Parkinson, a senior scientist at NASA’s Goddard Space Flight Center, said, “the planet as a whole is doing what was expected in terms of warming. Sea ice as a whole is decreasing as expected, but just like global warming, not every location with sea ice will have a downward trend in ice extent.” She went on to say, “It’s really not surprising to people that work in the climate field that not every location on the face of the Earth is acting as expected—it would be amazing if everything did . . . the Antarctic sea ice is one of those areas where things have not gone entirely as expected. So it’s natural for scientists to ask, ‘Okay this isn’t what we expected; now how can we explain it?’”
Walt Meier, a research scientist at NASA’s Goddard Center, offered other possible reasons for this year’s high sea ice extent in the Antarctic. “The winds play a big role,” Meier said, although not exclusively, as “that element alone is probably not the reason for this year’s extent.” In an article published by NASA, Meier suggests that low pressure systems occurring over the Amundsen Sea could be intensifying local weather and changing wind patterns. This affects water circulation patterns, which could be bringing cooler water to the surface around land and enabling the growth of sea ice. Another possible reason he suggests is increased snowfall in the region. When snowfall builds up on sea ice it weighs the ice down and forces it to submerge, causing the snow to get wet and eventually freeze. This process makes the ice thicker and less prone to melting.
While Antarctic sea ice extent has grown, it is dwarfed by the 13 percent yearly loss in Arctic sea ice, which melted to its sixth lowest daily extent this year on September 17. The level of sea ice extent plays a role in keeping the Arctic region cool by reflecting sunlight, and also helps regulate global climate. Regarding the low in Arctic sea ice extent, NSIDC Director Mark Serreze said, “Twenty years ago, having ice extent this low would have astounded us. Now it is expected.” The ten lowest September sea ice extents in the Arctic since the advent of satellite imagery have taken place in the last 10 years. Walt Meier explained that the difference between the Arctic and the Antarctic sea ice extents is partially due to their different locations, as the Arctic has land mass nearby whereas the Antarctic is isolated in the middle of an ocean. “Part of it is just the geography and geometry. With no northern barrier around the whole perimeter of the ice [in Antarctica], the ice can easily expand if conditions are favorable,” Meier said.
As science and technology improve, so does our understanding of how our natural environment works. Ted Scambos said, “What we’re learning is, we have more to learn.” NASA researchers commented, “The new Antarctic sea ice record reflects the diversity and complexity of Earth’s environments.”
Authors: Brendan Ingargiola and Angelo Bardales