The UN panel on climate change has yet another challenge to both its process and its findings on a key element of AGW advocacy.  Meteorologist Dr. Les Hatton, who once worked on weather modeling for the British Met Office and now teaches at the University of Kingston, has taken aim at the notion that storms have increased in intensity over the last fifteen years, especially hurricanes.  He pronounces the IPCC claims on the subject as claims that would “never pass peer review” and provides a separate analysis that demonstrates no overall increase in intensity at all:

Hatton has released what he describes as an ‘A-level’ statistical analysis, which tests six IPCC statements against raw data from the National Oceanic and Atmospheric (NOAA) Administration. He’s published all the raw data and invites criticism, but warns he is neither “a warmist nor a denialist”, but a scientist.

Hatton performed a z-test statistical analysis of the period 1999-2009 against 1946-2009 to test the six conclusions. He also ran the data ending with what the IPCC had available in 2007. He found that North Atlantic hurricane activity increased significantly, but the increase was counterbalanced by diminished activity in the East Pacific, where hurricane-strength storms are 50 per cent more prevalent. The West Pacific showed no significant change. Overall, the declines balance the increases.

“When you average the number of storms and their strength, it almost exactly balances.” This isn’t indicative of an increase in atmospheric energy manifesting itself in storms.

Even the North Atlantic increase should be treated with caution, Hatton concludes, since the period contains one anomalous year of unusually high hurricane activity – 2005 – the year Al Gore used the Katrina tragedy to advance the case for the manmade global warming theory.

This is an interesting development, especially after Dr. Phil Jones admitted that the medieval warming period (MWP) may have been global after all.  Earlier, AGW advocates had argued that rebuttals showing the MWP as significantly higher than the “hockey stick” increases were taking a Northern Hemisphere-centric view of weather, and that the Southern Hemisphere may not have experienced that kind of warming.  Jones’ admission was that there was no way to tell whether the Southern Hemisphere warmed or not meant that the only reliable records show the planet significantly warmer than anything we have experienced in the past century, and not just for decades but for several centuries — without carbon dioxide being the culprit.

In this case, it appears that the IPCC ignored readings from below the equator to bolster their claims.  Unlike in the MWP, we have plenty of measurements of storm activity in the Southern Hemisphere for that period.   If Hatton’s calculations are correct, the IPCC either ignored them or discounted them in the calculations.  Either way, the claims on storm intensity are now suspect, as is much of the IPCC’s claims and supposedly scientific process.

Update: Count Gawker’s Nick Denton among the skeptics … er, “sceptics.”