Starting in 1988, strong winter winds caused lots of thicker older ice to be pushed out into the North Atlantic. This went on for almost a decade and caused the volume of ice to decline by 50%. Thinner ice melts more easily in the summer, and the summer minimums were dropping until 2007.
2007 brought very strong southerly winds all summer and into following winter. That pushed a lot more ice out the Arctic. The amount of multi-year ice has been increasing since 2009.
2012’s melt season started with southerly winds in the Beaufort Sea opening a large hole in the ice. This absorbed a lot of sunlight in June and July, which warmed the water. When a large winter storm struck in Early August, the warm water mixed with the remaining ice and melted out the Beaufort Sea very quickly.
The winter of 2012-2013 saw a sharp turnaround – the ice pushed from the vulnerable east to the safe western side of the Arctic, and was followed by a very cold summer. If this pattern continues for a couple more years, ice will be almost back to “normal” and will stop screaming at Mark Serreze.
What does all this have to do with CO2? Nothing.