The study you cite is neither predictive nor evidence based. It is a speculative, after the fact explanation: "We used computer-generated simulations to get this research result. I hope that in the future we'll be able to verify this result with real data through a long-term ice thickness measurement campaign." ( http://www.sciencedaily.com/releases/2005/06/050630064726.ht... )

That doesn't mean it's necessarily wrong. But it is not evidence, nor is it conclusive. There is simply no reason to believe Powell's explanation over the explanation I cited in my previous comment. The NASA explanation is based on actual observation rather than computer simulations.

The climate is so complex that you can always come up with an after the fact explanation. The only way to judge science is either a) by the predictions it makes or b) following the chain of deductive reasoning. Predictions are not really possible with climate science in the short term because there are too many variables. So that leaves b). I have not studied the science behind sea ice changes closely. But many of the global climate models have been subjected to egregious tuning: http://www.climateaudit.org/?p=2475

Given what we know about CO2, hard to see how it could be otherwise, but not worth arguing over.

The effect of CO2 on temperature is both a) logarithmic and b) non-cumulative. For models to predict a levels of warming that are actually alarming, the models must include feedback loops. No one knows if these feedback effects are real. They are entirely speculative.