NASA Study Provides Answer to Antarctic Ice Growth Mystery

Over the last few years, the extent of sea ice surrounding the southern continent of Antarctica has been steadily increasing, in sharp contrast to the diminishing ice reserves found at the north of the planet at the Arctic Circle. With ever-increasing temperatures worldwide and escalating fears about climate change, scientists had been at a loss to explain why Antarctic ice was still flourishing.

However, a new study from NASA appears to offer an explanation as to why the ice is increasing. Contrary to previously suggested reasons, the NASA data points to the geographical topography surrounding the continent and the effect this has upon the winds and the water itself.

An intriguing mystery

With the Arctic Ocean entering a new era in terms of ice scarcity, scientists had been dumbfounded by the continued stability of the ice found at the South Pole. The ebb and flow of sea ice in the south has been fairly consistent over the last 50 years, reaching its maximum in September and its lowest point – about 17% less than the highest amount – in February.

Over the last few years, the ice has been steadily increasing. It enjoyed a particularly remarkable year in 2008, showing incredible variation in the extent of ice, while 2012, 2013 and 2014 were all record-breaking years in area coverage. In fact, in that last year, a 1,500-year-old sample of moss was brought back to life after being frozen in the exceptionally thick ice.

Scientists had previously tried to explain away the discrepancy between Arctic and Antarctic sea ice levels through a number of different arguments. Some posited that the hole in the ozone layer over the southern part of the planet was having an unusual effect on winds, thus creating more ice in the process. Others speculated that the melting of the ice shelves contributed freshwater into the sea, thereby reducing salinity and making conditions more conducive to freezing.

Geography and topography the key

However, NASA appear to have put paid to such theories with their latest study, which utilised radar data from the QuikScat satellite to monitor the movements of the ice over the years in relation to the geographical features of the land beneath it.

Since thicker ice reflects radar signals more strongly, NASA could pinpoint the exact whereabouts of these thicker sheets and deduce their age as a result. They noticed that early in the season, a sort of protective shield of ice was being formed around the continent as strong winds pushed it offshore.

In turn, the creation of this shield and its movement away from the continent itself (thanks again to the wind) allowed for water to infiltrate the area in between. Since this water was protected by the shield from the crashing of waves, it became cooler and began to freeze as well, thus enlarging the total amount of ice around the Antarctic. The extent to which the ice shield can expand depends largely on ocean currents, which in turn are dictated by the underwater topography of the ocean floor.

Since these conditions do not exist in the Arctic, it’s unlikely similar phenomena will be observed there. But while its northern counterpart looks to be under threat from global warming, the Antarctic ice should be safe for some time to come.