You just knew this was coming: IPCC hurricane conclusions

are crap.
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.
Say, anybody seen Al lately? No? Hmmm.....

Thre IPCC's WG1 paper states: "There are also suggestions of increased intense tropical cyclone activity in some other regions where concerns over data quality are greater." Hatton points out the data quality is similar in each area.

The IPCC continues: "It is more likely than not (> 50%) that there has been some human contribution to the increases in hurricane intensity." But, as Hatton points out, that conclusion comes from computer climate models, not from the observational data, which show no increase.

"The IPCC goes on to make statements that would never pass peer review," Hatton told us. A more scientifically useful conclusion would have been to ask why there was a disparity. "This differential behaviour to me is very interesting. If it's due to increased warming in one place, and decreased warming in the other - then that's interesting to me."

Hatton has thirty years of experience of getting scientific papers published, but describes this one, available on his personal website, as "unpublishable".

"It's an open invitation to tell me I'm wrong," he says. He was prompted to look more closely by the Climategate emails, and by his years of experience with computer modelling. All code and data on which policy conclusions are made should be open and freely downloadable, he says - preferably with open tools.

And Hatton has done what a bunch of the Climaquiddick scientists refused to do: made ALL his data & methods available; kind of like what scientists are supposed to do.

Note: at the very end there's this:
Critics point out that an increase in low-intensity storms being recorded is due to better instrumentation. Most are at sea, and thanks to radar and satellites, more are now observed.
Couple of decades back, when the 'global warming' stuff was getting started, there was a lot of "There are more tornadoes than there used to be, and it's because of the heating!" yelling; this was countered by a bunch of meteorologists pointing out that with the combination of newer radar(doppler especially) and more people around to see, a lot of them- especially smaller ones- that weren't spotted before were being reported now. The number of travelling vacuums was about the same, but more of them were actually noted and reported than before.