The troops are getting restive. What wil happen to this year’s sea ice? Rumours abound. Let’s look at some pictures.
Probably the least interesting is this one from NSIDC. But it looks exciting, doesn’t it. Woo-hoo, look, the sea ice now is lower than it was in 2007, that means it will be at minimum, too, doesn’t it? Well no, of course not. Look at this one from AWI:
2006 was well below 2007 at this point, and turned out to be uninteresting. As far as I know, no-one believes in predicting the minimum (which, of course, is the only number anyone gives a toss about) based on previous months. And when I say no-one cares about anything else that isn’t really true; various people have started caring about the ice volume instead, but I’m a bit dubious about how exciting that is.
But for no reason that I can strongly justify, I happen to prefer the IJIS AMSR pix, reproduced below:
Which is similar too, but clearly not identical too, the AWI pic. Which shows the obvious: that retrieval from space isn’t exact.
Anyway, so what? So, it is not too late to join in the great predict-sea-ice-this-year party. My entry this year is “the same as” last year: linear trend since 1979, this time *not* omitting 2007 or 2008. As I recall, last year RMG was kind enough to work out what that came to in real numbers; perhaps he will again. As before, the possibility of a bet only really makes sense if people actually think very differently from me: which would be, either they think that there will be substantial ice growth this year, or some sudden collapse.
So, there you go: usual money on offer, which is to say “unlimited”, in the sense that so far no-one has wanted to take me close to my limit. If you manage to get there I’ll let you know.
I’d also be interested in the other betting pools that are presumably around this year.
* Me declaring victory in 2008
* The 2009 results
* Me wondering, in January, what we might bet on this year and various people making impractical suggestions 🙂
[A couple of updates: firstly, I should mention that Gareth has been pushing the ice volume stuff and I admit that picture does look interesting.
and second, NB says “The ice is looking uncommonly mushy on MODIS” which I think I’d pay attention to, and look at myself, if I had the time. Maybe during tomorrows’s batch of compilations.
And third, the default bet is:
That the september mean ice *extent* be below 4.835; but with a “buffer” where we call it a draw: between 4.735 and 4.935, no one wins. I’m taking the “high” side of this; anyone interested in the “low” side let me know. For my part, 4.835 is arrived at as the 1979-2009 trend extrapolated, minus 0.5 which is the SD. It seems to have become tradiational for people to bet small amounts, which is fair enough if we’re just playing. But this was intended to flush out the “the sea ice is in catastrophic decline” people. OTOH, if there are any “the sea ice will certainly recover this year” people then you can get odds on trend-plus-SD, i.e. ice being above 5.835 if you like (note that those are all spuriously precise but never mind) -W]