Arctic Sea Ice Melting Faster

There's an interesting debate about Arctic sea ice predictions versus observations going around amongst Tamino, Roger Pielke Sr, and Skeptical Science. I don't have anything to add to it, but this graph is mildly interesting and probably not original: it shows the annual difference between the yearly maximum of sea ice extent and the yearly minimum. The difference is increasing as time goes by, which I suppose is just an indication that there is less old ice and more new ice, and new ice, especially first year ice, melts faster.

Here's the annual decline in volume, from PIOMAS: