The reason why Arctic sea ice summer minimums have been low recently is because there is a lot less thick multi-year ice than there was 20 years ago.
Experts say that this confirms global warming, but it has little to do with it. Most multi-year ice is lost during the winter, not the summer. The ice gets blown by strong winter winds out into the North Atlantic, where it melts. During the winters from 1988-1996, most of the multi-year ice was lost.
People who get hysterical about the location of the ice edge in September, are complete morons.