This is getting silly. Maybe scary is better. CT’s Northern Hemisphere sea ice area anomaly used to go down to -1.5 Million Km2.

Back in June/July, they had to change the graph and add a white bit to the bottom, to allow for the unusually low numbers, so they stretched thw white bit to -2 Mill.

Then a month or so back, it went to -2.5Mill.

Just last week (thanks for the heads up, Steve), thanks to the fact that the ice still isn’t there, when it should be, even more white was added to the bottom of the graphic, to allow for the new lowest ever anomaly of -2.7 Million Km2.

Here is the ‘tale of the tape‘ as it currently stands. Aw, shucks, the darned needle’s gone and fell right off the bottom again. Below -2.7 Million Km2.

Two obvious things to note here. First, the way the loss of sea ice has fallen below long-term averages this year has caught out the team at CT (who know much more about the subject than amateurs, like me) not once, but four times, in six months. Second, the only increase in white stuff as far as the Arctic sea ice is concerned is the extra white sections being pegged onto the graphs to allow for the ever-increasing anomaly.

There’s a chance for a good old-fashioned spread bet here. How much extra white space should CT add to its anomaly graph this time? Will -3 Mkm2 be the limit of the anomaly between now and next Spring? Anyone care to take a punt at -3 to -3.5 Mill.? I might be tempted to offer odds against a spread of -3.5 to -4 Mill. between now and April, but someone might want to take the spread even further. Is this as far as the anomaly will go this year?

I’d like to know what readers are willing to suggest will be the largest sea ice anomaly of 2007, and the largest anomaly between October 1st, just gone, and April 1st 2008. I’ll publish my forecast in a couple of days time.

Oh: and here, for the sake of completeness, is the NSIDC briefing from October 17th. I’ve emailed to ask what their measurement system shows the anomaly as. The comment below is from that briefing:

The differences from climate norms for the previous century continue to increase, even though the 2007 melt season has ended and the ice has begun its seasonal recovery. As of October 16, the extent was 3.20 million square kilometers (1.23 million square miles) below the long-term average.