Hurricanes and Global Warming with Dr. Gray

[senorpepr]

The recent US landfall of major hurricanes Dennis, Katrina, Rita and Wilma and the four landfalling hurricanes of last year (Charley, Frances, Ivan and Jeanne) have raised questions about the possible role that global warming played in these unusually destructive seasons.

The global warming arguments have been given much attention by many media and blog citations to recent papers claiming to show such a potential linkage (Emanuel, K., 2005: Increasing destructiveness of tropical cyclones over the past 30 years. Nature, 436, 686-688 and; P. Webster, G. Holland, J. Currie and H-C. Chang, 2005: Changes in tropical cyclone number, duration, and intensity in a warming environment. Science, 309, 1844-1846.

The near universal references to the above papers by most of the major US media outlets and blogs since Katrina and Rita made US landfall requires a response from a few of us who study hurricanes. Having been involved with hurricane research and forecasting for nearly 50 years, I feel I have an obligation to offer comments on these papers’ findings which, in my view, are not valid. My reviews of these two papers can be found on my project’s website:

http://tropical.atmos.colostate.edu/Documents/Responses

Cut-down response versions have been sent to Nature and Science.

Observations my colleagues and I have been gathering do not observationally or theoretically support the contention of the above papers. Despite the global warming of the sea surface of about 0.3oC that has taken place over the last 3 decades (particularly the warming of the last decade), the global number of hurricanes and their intensities have not shown increases in recent years except for the last 11 years in the Atlantic where the increase can be tied to the strengthening of the Atlantic Ocean thermohaline circulation (THC) that is not directly related to global temperature rise.

Although the 2004 and 2005 hurricane seasons have had an unusually high number of major hurricane landfall events, the overall Atlantic basin hurricane activity has not been much more active than the other recent hurricane seasons of 1995, 1996, 1998, 1999, and 2003 have been. What has made the 2004-2005 seasons so unusually destructive is the high percent of major hurricanes which moved over the US coastline. These landfall events were not primarily a function of the overall Atlantic basin net major hurricane numbers, but rather to the favorable broad-scale Atlantic upper-air steering currents which were present the last two seasons. It was these favorable Atlantic steering currents which caused so many of the major hurricanes which formed to come ashore. We should not try to read more than this into the last two seasons. This is how nature occasionally works. The probability of seeing another two consecutive US landfall major-hurricane seasons like 2004-2005 is very low.



Bill Gray

[Ivanhater]

The recent US landfall of major hurricanes Dennis, Katrina, Rita and Wilma and the four landfalling hurricanes of last year (Charley, Frances, Ivan and Jeanne) have raised questions about the possible role that global warming played in these unusually destructive seasons.

The global warming arguments have been given much attention by many media and blog citations to recent papers claiming to show such a potential linkage (Emanuel, K., 2005: Increasing destructiveness of tropical cyclones over the past 30 years. Nature, 436, 686-688 and; P. Webster, G. Holland, J. Currie and H-C. Chang, 2005: Changes in tropical cyclone number, duration, and intensity in a warming environment. Science, 309, 1844-1846.

The near universal references to the above papers by most of the major US media outlets and blogs since Katrina and Rita made US landfall requires a response from a few of us who study hurricanes. Having been involved with hurricane research and forecasting for nearly 50 years, I feel I have an obligation to offer comments on these papers’ findings which, in my view, are not valid. My reviews of these two papers can be found on my project’s website:

http://tropical.atmos.colostate.edu/Documents/Responses

Cut-down response versions have been sent to Nature and Science.

Observations my colleagues and I have been gathering do not observationally or theoretically support the contention of the above papers. Despite the global warming of the sea surface of about 0.3oC that has taken place over the last 3 decades (particularly the warming of the last decade), the global number of hurricanes and their intensities have not shown increases in recent years except for the last 11 years in the Atlantic where the increase can be tied to the strengthening of the Atlantic Ocean thermohaline circulation (THC) that is not directly related to global temperature rise.

Although the 2004 and 2005 hurricane seasons have had an unusually high number of major hurricane landfall events, the overall Atlantic basin hurricane activity has not been much more active than the other recent hurricane seasons of 1995, 1996, 1998, 1999, and 2003 have been. What has made the 2004-2005 seasons so unusually destructive is the high percent of major hurricanes which moved over the US coastline. These landfall events were not primarily a function of the overall Atlantic basin net major hurricane numbers, but rather to the favorable broad-scale Atlantic upper-air steering currents which were present the last two seasons. It was these favorable Atlantic steering currents which caused so many of the major hurricanes which formed to come ashore. We should not try to read more than this into the last two seasons. This is how nature occasionally works. The probability of seeing another two consecutive US landfall major-hurricane seasons like 2004-2005 is very low.


Bill Gray

didnt hey say the chances of another 2004 type season for 2005 was very low

[Budro999]

Gray is just stating the obvious with respect to the chances of having another 2 consecutive, high-landfall years. He did say the same thing about 2005 in 2004, but I guess he is playing the percentages. If he says it enough times, it is bound to come true one of these years.

[Anonymous]

I interviewed Dr. Gray this past May, he told me...GLOBAL WARMING IS NOT CREATING MORE HURRICANES. Its the media...this DOOM AND GLOOM.

[Valkhorn]

Either way, it doesn't lessen the fact that we still need to be wary of our environment and not pollute so much.

[HurryKane]

I'm not going to weigh in on the global warming vs. hurricanes, but there was an excellent interview with him in Discover Magazine regarding his stance on global warming, and how he feels he's lost federal grants because of it.

You can read it here:

http://www.discover.com/issues/sep-05/d ... -dialogue/

[x-y-no]

I interviewed Dr. Gray this past May, he told me...GLOBAL WARMING IS NOT CREATING MORE HURRICANES. Its the media...this DOOM AND GLOOM.

Given that his primary argument in the referenced responses to the Emannuel and Webster papers rests on the uncertainty in the earlier portions of the data sets used, I find it very hard to understand how he can say this with any more confidence than one could assert the opposite.

I'm afraid I have to say that Dr. Gray is overreaching with that claim. One simply cannot conclude a negative on the basis of claimed uncertainty. At best one can argue that the issue is indeterminate.

Also, given that SSTs are a significant factor in his own seasonal forecasting methodology (with higher SSTs tending to favor both more and more intense storms), I don't understand how he can categorically state that the observed global increase in SSTs over the last few decades (which he does not dispute) have not had any effect. That's counterintuitive to say the least. Again the strongest conclusion I think one could legitimately reach is that the effect to date is quite possibly smaller than Emannuel and Webster conclude.

[Ivanhater]

well im writing my next paper for english on the connection between global warming and hurricanes, my professor said well its obvious since we dont have cat 1s anymore we only have cat 5s, i had to bite my tongue ...so Dr. greys thoughts should help in the paper

[Anonymous]

I will post a link to my interview with Dr. Gray

[Ivanhater]

I will post a link to my interview with Dr. Gray

cool, ill make sure i cite you in my paper

[sponger]

I think Dr Grey point is sst's are higher because of the active cycle. This is based on most of the warming occuring since 1990.

The major problem with this debate is it has been hijacked by researchers who have a objective, then skew data to fit their agenda. IE research grants...aka money!

We will never get a handle on whats going on as long as this debate is controlled by the media and junk science.

[f5]

the MAIN problem is man getting in the way.Lets face it hurricanes were here long before man

[Recurve]

In interviews, Gray mentions problems with the data sets used by other researchers, but like X-Y said, that doesn't mean you can assert the opposite conclusion, and he seems to be doing so out of some philiosphical opposition to the idea that greenhouse gasses could influence global climate.
No one has proven that global warming is increasing the number or intensity of tropical storms, but certainly no one has proven that it isn't.

[terstorm1012]

I actually read the articles in Nature and found them pretty interesting. I'm not going to dismiss them because an expert says to. I think that'd be unfair to the researchers who obviously spent a lot of work on them just like I'd never dismiss Dr. Gray's work as his work has been amazing. --- and I don't think I could call myself a thinking person if I just did what the expert told me to. They really are interesting articles that give you much to think about and people should read them and discuss them, not just deride them as that awful code term "junk science."

[Anonymous]

Here is the segment of my May 2005 interview with Dr. Gray, in a rather interesting twist, he asks himself the question. I speak for both myself and Zack, when I say we were privileged to be able to interview Dr. Gray. You can hear me laugh right towards the end, because I was happy he shot the Global Warming bid down.

DR. GRAY "GLOBAL WARMING" CLIP::::
http://www.radio.nhcwx.net/zina/index.p ... e83b367618

[mf_dolphin]

I guess one of the biggest arguements to the Global Warming to Hurricane relationship is that there hasn't been an increase in tropical activity globally. While the Atlantic basin activity has increased the past few years there's not been a corresponding increase in activity in other basins.

[dhweather]

I guess one of the biggest arguements to the Global Warming to Hurricane relationship is that there hasn't been an increase in tropical activity globally. While the Atlantic basin activity has increased the past few years there's not been a corresponding increase in activity in other basins.

BINGO!

I can't argue either way - I can say that we have about 100 years of
data, which is nothing in the grand scheme for forecasting trends.
Maybe we really do have cycles every 30-50 years of crazy activity.
I can also say we (mankind) have done some terrible things to mother
earth with pollution.

[ncweatherwizard]

I guess one of the biggest arguements to the Global Warming to Hurricane relationship is that there hasn't been an increase in tropical activity globally. While the Atlantic basin activity has increased the past few years there's not been a corresponding increase in activity in other basins.

Correct. Globally, the number of tropical cyclones that occur on an annual basis is moreorless constant. For instance, just one small example, the Atlantic basin has shown well above normal activity this year; however, the western Pacific basin is below normal to date for tropical activity.

[thermos]

It isn't just the tropical season (which far surpassed past seasons) but the high temperatures that point towards global warming. September was the hottest month ever recorded and there have been countless high temperature records broken in the 1990s and 2000s.

[x-y-no]

I think Dr Grey point is sst's are higher because of the active cycle. This is based on most of the warming occuring since 1990.

The major problem with this debate is it has been hijacked by researchers who have a objective, then skew data to fit their agenda. IE research grants...aka money!

We will never get a handle on whats going on as long as this debate is controlled by the media and junk science.

This is the kind of baseless smear that gets me fighting mad. Do you know Dr. Emmanuel or Dr. Webster or any of their collaborators or any of the dozens of people who participated in peer review of their research? Do you have any basis in fact for lodging such a charge against them or the many other dedicated researchers in this field?

I don't understand why this kind of crap is allowed on this board. It's every bit as offensive as personal attacks on members, IMHO.