By Paul Homewood

I got hold of the accounts of a company established in 2007. The name is immaterial.

Their annual profit is charted below:

If the Directors claimed that company profits had “continued to increase”, I suspect they would soon be getting a visit from the Fraud Squad.

Yet this is precisely the same claim made by the Met Office about Arctic sea ice extent.

Now I’ll let you in on my little secret!

These are not the profits of a real company. They are actually numbers calculated from that very same sea ice extent, inverted simply by deducting the extent from 10 million. This effectively flips the numbers, so that low is high, and vice versa.

The figure for 2021, therefore, becomes 4th lowest instead of 4th highest.

The Met Office justify their claim by including data from 1979 to 2007, when ice extent did fall. But as any scientist/statistician knows, the past is no guide to the future. What happened twenty or more years ago is of no relevance to what is happening now.

I am sometimes accused of cherry picking 2007 as a start year, but as my graph clearly shows, you could pick any year since 2007, and the message would be more or less  the same.

Besides, like it or not, sea ice extent since then has been statistically dependent on the extent in 2007.

To explain, sea ice extent is not determined in some random fashion. The extent in any one year tends to strongly influence the next year and more.

In years when there is a lot of thick multi year ice, the following year would tend to retain much of this. Stating the obvious, thick ice does not melt as easily as thin ice.

Conversely, when much of that thick ice has gone, as in 2007/8, the following summer’s extent will tend to be much lower as well.

I have always emphasised that the period since 2007 is far too short to make any meaningful judgements, and I have no idea whether sea ice extent will start falling again, stay the same or increase in years to come.

But what is abundantly clear is that the actual data does not support the claim that “Arctic sea ice decline continues”.


October 2, 2021