One of the most common indications that climate change is happening is the melting of Arctic sea ice. September 16th 2012 marked a record low sea ice extent in the Arctic, with an average 3.61 million square kilometers (1.39 million square miles) of sea ice.
In the Antarctic, sea ice extent also achieved a new record – but this time it was a record high.
Indeed, sea-ice extent in the Antarctic achieved a winter maximum of 19.44 million square kilometers (7.51 million square miles) on September 26th. And in a comparison between 1979 to 2012, scientists have found that Antarctic sea ice extent has actually been expanding slightly by 0.9%.
But how does one reconcile these differences of sea-ice extent between the two poles? Wouldn’t global warming suggest that both ice caps should be melting?
First one needs to understand sea ice melt by looking at the unique context between the two poles. Although recent studies suggest that average temperatures in the Antarctic are increasing, strong winds and a cold stratosphere are causing ice extent to increase slightly.
And in reality, it is only a slight increase of about 16,000 square kilometers (6,2000 square miles) per year – or an area the size of Connecticut. Ice melt in the Arctic is much more pronounced, with an average of 91,600 square kilometers (35,400 square miles), a size more comparable to Indiana.
Viewed within this context, it would seem that ice melt in the Arctic far surpasses ice gain in the Antarctic – and that ice melt in the Arctic is most attributable to global warming.
Image: NASA Earth Observatory