Sea ice surrounding Antarctica is at an all-time high, even as overall averages of global temperature continue to climb. NASA reports that ice formation in the continent's southern oceans peaked this year, breaking ice satellite records dating back to the late 1970s.
"We are seeing overall temperatures warming around the globe, so you would expect to see ice loss," said Dr. Walt Meier, a research scientist at the NASA Goddard Space Flight Center. Given the warming trend, he admits that the Antarctic ice uptick is somewhat of a "mystery."
While the Antarctic sea ice has expanded beyond levels that researchers have seen in the past, experts point to overall atmospheric changes, including shifts in pressures and winds, which can drive ice formations.
The National Snow and Ice Data Center reported that as of Sept. 19, for the first time since 1979, Antarctic sea ice extent exceeded 7.72 million square miles. The average maximum extent between 1981 and 2010 was recorded at 7.23 million square miles.
Despite this trend, sea ice as a whole is decreasing on a global scale. Researchers say that just like global warming trends have different outcomes in various parts of the world, not every location with sea ice will experience ice loss.
"When we think about global warming we would expect intuitively that ice should also be declining in the Antarctic region as in the Arctic," NASA's senior research scientist Josefino Comiso explained. "But station and satellite data currently show that the trends in surface temperature are most positive in the Arctic while in the Antarctic region the trends are a mixture of positive and negative trends," he said, adding that cooling and declining sea surface temperatures could also contribute a "more rapid advance at the ice edge."
Snowfall could also be behind the growing ice pattern. NASA explains: "Snow landing on thin ice can actually push the thin ice below the water, which then allows cold ocean water to seep up through the ice and flood the snow - leading to a slushy mixture that freezes in the cold atmosphere and adds to the thickness of the ice."
Though some global warming cynics might see the ice trend as an opportunity to dispute the larger climate trend, the statistics on the Arctic warming indicate otherwise. NASA says that on an annual average basis, Arctic sea ice has decreased at a rate of 4.3 percent each decade since 1979, whereas in the Antarctic, sea ice has increased at a rate of 1.7 percent every 10 years.
Despite the current increase in Antarctic ice cover, scientists say the trend is likely to reverse in the future as global warming heats the planet.