The sea ice around Antarctica reached a record high in August of 7.2 million square miles (18.6 million square kilometers) — the greatest extent observed since recordkeeping began in 1979.
But as Antarctic sea ice grows, the sea ice of the Arctic is shrinking dramatically. The Northern ice cap reached a record low of 1.32 million square miles (3.42 million square km) in September 2012, due to warming air and waters.
If the Earth is warming, and both ends of the planet are affected by climate change, why, then, are the two poles showing such different trends?
For one thing, the North Pole and South Pole have fundamentally different geography. Antarctica is a huge icy continent surrounded by a ring of sea ice, whereas the Arctic ice cap floats on the ocean. And unlike Arctic ice, Antarctic sea ice is seasonal — it forms in winter and melts almost completely in summer. Strong circumpolar winds may be compacting and thickening the Antarctic ice. But the Arctic ice is much more vulnerable to ocean warming, and summer storms only speed up the thaw.