Aargh! Just as the Arctic sea-ice anomaly was settling down to a reassuring ~1.25Mkm2, after the rapid October recovery from it’s record low level, suddenly it has done another triple back-flip and colliwobble. CT’s current number is -1.759 Mkm2 (here’s the graph).

I was just thinking the other day that we might see a mean decline in Winter Season ice area of something in the region of 10%, when this happens. It’s probably a temporary blip. Perhaps.

In case you don’t realise, the difference between a Winter (October-December by CT’s reckoning) seasonal anomaly of, say. 1.5, rather than 1.25 Mkm2, is really quite substantial. Winter anomalies have generally been slight and slow (though still statistically significant), even as Summer sea-ice records are shattering all around us (2005, 2007). Whilst the absolute amount lost is relatively smaller than in Summer, the rate of decline, if the anomaly this Winter were to be around -1.5 on average, is much faster than previously.

Ray Pierrehumbert reports substantially on the Sea Ice bit of the AGU, including on Mark Serreze’s rather bleak observations about rates of change and the implications for sea level estimates. Perhaps we are seeing another example of the ‘state-change’ of conditions which is currently concerning most of the Cryospheric fraternity.

Now, back to that bet… I wonder if Joe is  looking like a better bet than he was a week or two back?