And the Antarctic-
'Those winds have intensified in recent years because of increased concentrations of greenhouse gases in the atmosphere and the presence of the ozone hole. Both serve to magnify the differences in temperature and atmospheric pressure between Antarctica and the tropics, which speed up winds and cause them to swirl faster and more tightly around the continent, said Sharon Stammerjohn, a leading sea ice researcher at the University of Colorado, Boulder.
But it's not quite as simple as more wind, more ice.
"It makes no sense to talk about a circumpolar average," Stammerjohn said. "There's so much regional variability." '
and
'It's even possible that the current growth spurt is just a short upward wiggle in a larger downward trend. "Thirty years isn't really that long," Stammerjohn said.'
http://www.latimes.com/science/la-sci-antarctic-sea-ice-20140830-story.html#page...So we can't do a circumpolar average because there is too much regional variability. But we can do a global average.
30 years isn't that long, but 20 years is ample time to prove AGW.