Date of prediction: 2009-05-29

Robert Grumbine dares predicting the sea ice extent 4 months into the future:

»I’ve been working out, finally, my thoughts on what the sea ice cover will be like for the Arctic, in September 2009. That for the average for the month, rather than minimum at any time.


The prediction is: 4.92 million km^2, with a standard deviation to it of 0.47 million km^2. 2008 showed 4.67 million km^2, and 2007 showed 4.30 million km^2 for the month’s average. I’m not saying that the sea ice is ‘recovering’.«

(More Grumbine Science: Sea Ice Odds)

I have no idea how hard or easy it is to hit the right interval with such a prediction. Nor do I have the slightest idea how meaningful it is. Simple guessing strategies like predict a slight variation of last year’s value might work well enough for short-term predictions. However, the verified capability of making predictions about a natural system of process implies that the underlying theory is at least not obviously wrong. No matter what he really did to make his estimate, if he is right he might know something that I don’t.

Added 2009-06-23: Some information on the approach taken in making this prediction.

Added 2009-09-20: A preliminary discussion of the bet status.

Added 2009-10-11: Final results.