Heads It's Natural Variations, Tails It's Global Warming.

From The Washington Post:
“This modeled Antarctic sea ice decrease in the last three decades is at odds with observations, which show a small yet statistically significant increase in sea ice extent,” says the study, led by Colorado State University atmospheric scientist Elizabeth Barnes.
A recent study by Lorenzo Polvani and Karen Smith of Columbia University says the model-defying sea ice increase may just reflect natural variability.
If the increase in ice is due to natural variability, Zhang says, warming from manmade greenhouse gases should eventually overcome it and cause the ice to begin retreating.