Polar Opposite Records Set in 2012

In the Arctic and Antarctic, completely opposite records were set, this year. While the Arctic is showing the lowest levels of sea ice in satellite-record history, the Antarctic is actually showing the highest ever recorded levels of sea ice. According to the National Snow and Ice Data Center, the Antarctic is seeing this record new high of ice coverage with 19.44 million square kilometers. Meanwhile, Arctic sea ice reached its minimum this year at 3.61 million square kilometers.

Sea ice is drastically shrinking in one place while seeing great growth in another. What does this say about climate change?

Scientists have known for a long time that climate change would affect Northern Hemisphere before the Southern. This is largely because the two hemispheres have extremely different physical geography. Because Arctic ice is surrounded on all sides by land, it is subject to influences from air and sea-surface temperatures.  Meanwhile, because the Antarctic is surrounded by vast stretches of open ocean, its conditions are more heavily influenced by ocean currents and stronger winds. Furthermore, the hole in the ozone layer over Antarctica also affects the continent’s ice. The ozone hole has made it so the stratosphere absorbs significantly less UV light than it otherwise should. Absorbing less UV light makes the stratosphere in the southern hemisphere much colder and that carries down to the earth’s surface. That affects atmospheric circulation in the Antarctic, further helping the sea ice to grow.

With significantly different conditions governing the climates of the two poles, it's no wonder that they see differences in ice coverage. Scientists project that, in the coming decades, Antarctic sea ice will begin to shrink as the generally increasing planetary temperatures will outweigh the influences of the other factors that affect the amount of sea ice in the Antarctic.