Actually the IPCC predicts an increase of precipitation / snow in the Arctic regions, not an increase in sea ice.
Increased precipitation rates are logical since the moisture contents of the air decreases strongly with temperatures. Heavy snowfall below some 20 degrees Celsius (-3F) is rare. It's too cold to snow. So if the temperatures increase from -30 to -20 you could expect more snow.
This is also assumed to be the relation between alleged temperature and snow accumulation in the past as analyzed from the ice cores:
Obviously the sea ice growth is depending on many factors, with probably the most important, the lack of clouds, reducing back IR radiation. You can see that effect under bridges, under which, the water takes the longest to freeze, because the bridge radiates IR radiation back to the water.
What is "confirmed"? One year does not a trend make. Sea ice was relatively low in the Arctic but more extensive in the Antarctic, so what to say about that? Moreover even if predictions are confirmed, it would support a hypothesis but it does not proof it. Especially binary predictions (more or less) are less convincing than daring / counter-intuitive predictions.
Finally, concluding from a successful prediction that a hypothesis is correct is a logical fallacy, known as "affirming the consequent": A then B, B hence A. Or: If it is snowing, the fields are white. Now the fields are white, hence it is snowing.