Interesting story Laura. The story below came out last week and touched on the same topic.

http://www.myrtlebeachonline.com/mld/myrtlebeachonline/news/local/16764796.htm

In brief, Chris Landsea (which is a cool name for hurricane studies), science and operations director of the National Hurricane Center in Miami, disputes the widely held belief that GW has caused an increase in hurricane activity. He bases his opinion on statistics and historical data.

He makes quite a few valid points regarding the differences between perception and the actual statistics.

Global warming can effect hurricanes by either increasing the frequency or the strength. One way to determine if the frequency has increased would be to look for hurricanes that have formed unusally early or late in the season. Global warming may cause the ocean to be warmer longer in the season thus increasing the number of events.

As for strength, that will have to be compared to the historical record & we will be limited by the lack of data in earlier periods & the limitations of the inductive correlation agruements.

I fear there still is little accuracy when making predictions about the next Hurricane Season. Although there have been improvements concerning the expected path of the storms, I believe it's difficult to predict the number of storms that may develop between June and November. And that was the case of last year's.

I will have to wait until the full IPCC reports comes out, as Laura said.

Emiliano

If you would have asked me during the 2005 hurricane season, "Do you think global warming has something to do with the intensity of hurricanes?" I may have told you yes from the media shoving hurricane coverage down my throat. Yes hurricanes are horrible acts of mother nature but they are mother nature, and mother nature has a mind of its own. Can we change mother nature? I highly doubt it.

I would be wary of the full IPCC 4AR report when it is finally issued. Politics is driving the IPCC and the method they have adopted is flawed. How can you issue the summary and then fill in the blanks later and be credible.

Also will they rely heavily on computer models to make their claims about any link between AGW and hurricanes. If so then they will not have established a credible link. Computer modelling has been shown to be woefully deficient.

The AGW alarmists were so sure we would see devastating hurricanes last season and it did not happen. What went wrong. Where is the explanation. Why would we believe them in any case. A broken clock is right twice a day - is that what the alarmists are counting on.

Laura,

I don't think the problem of hurricane intensity is as intractable as you imply. Increased sea surface temperatures increase hurricane intensity. This well known fact is used in all hurricane forecasting models with great success. Therefore, to deduce whether hurricane intensity has increased due to human influence, we primarily need to know whether and how sea surface temperatures are impacted by anthropogenic global-warming. This should be a much simpler question to answer.

The issue of hurricane frequency seems a more difficult problem, although there have been some very intriguing discussions of that issue on many of your global-warming blog links.

Does anybody remember that the 2006 Atlantic hurricane season featured a record LOW number of hurricanes and storms? To say that the only factor affecting hurricane frequency is sea-surface-temperature, and that SST is going up because of Global Warming seems ludicrous in light of this. In fact, this article says "between 2003 and 2005, globally averaged temperatures in the upper ocean cooled rather dramatically, effectively erasing 20% of the warming that occurred over the previous 48 years." This article is one of few I could find that would even mention 2006 when talking about this subject.

YOU GO JESSE!!!

The biggest differences between 2005 and 2006 North Atlantic Storm season:

1)High level support necessary for TS development was missing in 2006. TS need a benign verticle wind profile in order for anticylconic outflow to form. Any kind of wind shear or upper level troughing will preclude this. 2005, on the other hand, had a very large area of the Atlantic that was perfect for this.

2)Early forming, albeit weak, El Nino over the Pacific.

3)Poor conditions over West Africa. This is still under study, but normally a hot, dry winter and spring are necessary for the formation of weak surface distrubances over West Africa. These distrubances, once over water, form the necessary confluence in the boundary layer (layer right above the friction level of the earth's surface) to form deep convection. Once the convection organizes itself along the confluence axis, and if the upper level wind profile is favorable, and if it is moving towards areas of warmer water, the axis of confluence will form a shall cyclone.
If there is enough outflow aloft, a tropical distrubance may form. 2005 saw one disturbance after another form off of Africa. 2006 activty was fairly muted.

It's alot more complicated than many people think.

JP, excellent points, too bad the anthropogenic global warmers doing subscribe to that much rational thought.

As for the IPCC's "scientific" paper that will be released after the scare sheet for policymakers, it is in the IPCC rules that it can (and in fact must) be altered to support the summary scare sheet. If we did "science" like that all the time we would still be riding horses.