Global Warming? So What is Causing Record Amounts of Sea Ice in the Antarctic?
Good question. Interesting answer via Climate.gov:
Multiple studies have indicated that climate is warming over much of Antarctica. How does that jive with record high winter sea ice extent? The combination of warming near the surface and cooling in the Antarctic stratosphere due to the ozone hole has strengthened circumpolar winds in the Southern Hemisphere. Around many parts of the continent, these stronger winds push ice away from the coast, expanding the sea ice extent.
Polar scientist Ted Scambos of the National Snow and Ice Data Center described the situation in a press release in October 2012:Antarctica’s changes—in winter, in the sea ice—are due more to wind than to warmth, because the warming does not take much of the sea ice area above the freezing point during winter. Instead, the winds that blow around the continent, the “westerlies,” have gotten stronger in response to a stubbornly cold continent, and the warming ocean and land to the north.