Christopher Monckton took such exception to an article in The Australian by Michael Steketee, that he has produced a response for the ultraconservative “think tank” SPPI. Monckton reports at WUWT, with his typical level of humility, that he has “skewered” Steketee.

Monckton only skewers two things: himself, and the truth.



Steketee offers a response in which he points out many of Monckton’s misrepresentations. But one that he doesn’t mention, a falsehood of the first magnitude, is Monckton’s point #9. He paraphrases Steketee as saying:



ARCTIC SEA ICE SHRANK TO ITS THIRD-LOWEST AREA IN THE SATELLITE RECORDS, OFFSET ONLY SLIGHTLY BY GROWTH IN ANTARCTIC SEA ICE.



Monckton offers this response:



In fact, the global sea-ice record shows virtually no change throughout the past 30 years, because the quite rapid loss of Arctic sea ice since the satellites were watching has been matched by a near-equally rapid gain of Antarctic sea ice. Indeed, when the summer extent of Arctic sea ice reached its lowest point in the 30-year record in mid-September 2007, just three weeks later the Antarctic sea extent reached a 30-year record high. The record low was widely reported; the corresponding record high was almost entirely unreported.



Is it really true? Let’s look at the data.

Here’s the global sea ice extent anomaly (monthly averages) based on data from the National Snow and Ice Data Center (NSIDC):

In addition to the data, I’ve plotted a linear-regression trend line. The slope gives us an estimate of the overall rate of global sea ice loss during the era of satellite observations. And that estimate (with 2-sigma error range) is: 36 +/- 14 thousand km^2/yr. The decline in global sea ice extent isn’t an artifact of statistical noise, it’s “statistically significant” at the 99.9999% confidence level. Monckton’s claim that “the global sea-ice record shows virtually no change throughout the past 30 years” is completely, utterly, demonstrably false.

Here’s the sea ice extent anomaly (monthly averages) for the northern hemisphere, according to NSIDC:

In addition to the data, I’ve plotted a linear-regression trend line. The slope gives us an estimate of the overall rate of northern hemisphere sea ice loss during the era of satellite observations. And that estimate (with 2-sigma error range) is: 51.5 +/- 8.5 thousand km^2/yr.

Here’s the sea ice extent anomaly (monthly averages) for the southern hemisphere, according to NSIDC:

In addition to the data, I’ve plotted a linear-regression trend line. The slope gives us an estimate of the overall rate of southern hemisphere sea ice gain during the era of satellite observations. And that estimate (with 2-sigma error range) is: 15.5 +/- 9.7 thousand km^2/yr.

Since satellite observations began, the rate of northern hemisphere sea ice loss is 3.3 times as fast as the rate of southern hemisphere sea ice gain. And that difference is statistically significant — way significant — it’s not just an artifact of the noise, it’s for real. Northern sea ice loss is vastly greater than southern sea ice gain. Monckton’s claim that “the quite rapid loss of Arctic sea ice since the satellites were watching has been matched by a near-equally rapid gain of Antarctic sea ice” is completely, utterly, demonstrably false.

The last time I skewered Monckton, he suggested in a comment at RealClimate that my result was only because I had used the Mauna Loa data for atmospheric CO2 rather than the NOAA data he used. It was trivially easy to show that he was wrong about that too. I wonder whether he’ll try that subterfuge again?

Perhaps Monckton shot off his mouth without even bothering to examine the data. Perhaps Monckton isn’t competent to analyze the data. Perhaps Monckton honestly believes that 36 +/- 14 thousand square kilometers per year, a net loss of over a million square kilometers of sea ice, is “virtually no change.” Perhaps he honestly believes that 15.5 is “near-equally” as large as 51.5. Or perhaps …