Its all pretty vapid: With sharply rising atmospheric greenhouse gas concentrations, the change to a seasonally ice-free Arctic Ocean seems inevitable. Very good, but The only question is how fast we get there. Well its certainly an important question, but the most important point is that they have no answer.
After the resulting record-low ice extent in September, unprecedented in satellite observations, over 70 per cent of the sea ice cover in spring 2008 consisted of young, fairly thin ice — an even more extreme situation than in spring 2007. The eyes of the science community and fascinated citizens worldwide were therefore focused on 2008. Would there be a new record minimum in September of 2008, suggesting the start of a rapid slide, or would there be some recovery? Indeed, its good to remember that a lot of the predictions of a record min for this year were based on the fact that much of this years ice was first year, and so would melt away more easily than last year. It didn’t happen quite like that; there are lots of complex factors. This year there will be a bit more multi-year ice: perhaps the beginning of a recovery? Naturally enough S+S don’t discuss that possibility.
No-one knows if there will be more or less ice next year. Personally I think, on balance, that the 2007 record is unlikely to be broken, and have offered to put my money on it. Or at least some, unspecified amount: I haven’t refused any offers yet, not that I’ve exactly been inundated with takers. I wonder if “Standing on the brink” S+S are willing to put their money where their insinuations are?
I don’t believe the assertions that recent years are good evidence of acceleration; indeed, I think its quite likely that the IPCC model consensus is correct. Somehow the meme that the world is well ahead of these model predictions has become dominant. But 2007 was obviously exceptional; to a less extent 2008 was too. Lets not get too carried away on the basis of one or two years.