Increased hurricanes to global warming link: blown away

From the “we told you so” department:

Study says global warming not worsening hurricanes

WASHINGTON (AP) — Global warming isn’t to blame for the recent jump in hurricanes in the Atlantic, concludes a study by a prominent federal scientist whose position has shifted on the subject.

Not only that, warmer temperatures will actually reduce the number of hurricanes in the Atlantic and those making landfall, research meteorologist Tom Knutson reported in a study released Sunday.

In the past, Knutson has raised concerns about the effects of climate change on storms. His new paper has the potential to heat up a simmering debate among meteorologists about current and future effects of global warming in the Atlantic.

Ever since Hurricane Katrina in 2005, hurricanes have often been seen as a symbol of global warming’s wrath. Many climate change experts have tied the rise of hurricanes in recent years to global warming and hotter waters that fuel them.

Another group of experts, those who study hurricanes and who are more often skeptical about global warming, say there is no link. They attribute the recent increase to a natural multi-decade cycle.

What makes this study different is Knutson, a meteorologist with the National Oceanic and Atmospheric Administration’s fluid dynamics lab in Princeton, N.J.

He has warned about the harmful effects of climate change and has even complained in the past about being censored by the Bush administration on past studies on the dangers of global warming.

He said his new study, based on a computer model, argues “against the notion that we’ve already seen a really dramatic increase in Atlantic hurricane activity resulting from greenhouse warming.”

The study, published online Sunday in the journal Nature Geoscience, predicts that by the end of the century the number of hurricanes in the Atlantic will fall by 18 percent.

The complete story is here.

This echoes what I reported on April 11th 2008 about Emanuel’s findings as well as what I reported on February 21st 2008 from Roger Pielke Jr. and Chris Landsea at the National Hurricane Center.

Three prominent researchers agree, two have reversed positions. This I think it is safe to declare the “Increased hurricanes to global warming link” as DEAD.


So two questions remain:

1) Will Al Gore issue a retraction or correction to his movie and claims of a GW to hurricane link?

2) Will the American Meteorological Society abandon their draft policy statement which links Hurricane Katrina and climate?

It would be irresponsible for either Gore or AMS not to acknowledge this sea change in the realization that there is no linkage between global warming and increased hurricane frequency.

Dr. Bill Gray must be a happy man today.


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Dr. William Gray has pointed out the absence of a “valid physical theory as to why hurricane frequency or intensity would necessarily be altered significantly” by the projected rise in temperatures.
The model that prompted this article is apparently an attempt to show whether there is any such theory to be found — and it indicates the opposite of the AGW fans’ warnings. I wonder if Gray would agree with a model that shows a decrease in storms after warming.

Frank Ravizza

How about an apology to Bill Gray from Hillary Clinton?


Really! An 18% decrease in 92 years. Can we extrapolate to the end of the millennium. Such precise forecasting, I’m so impressed…not! Just think, all this hard work is being done on the taxpayer’s dollar.


“I think it is safe to declare the “Increased hurricanes to global warming link” as DEAD.”
What I think you mean is that the science behind the idea that there is no link between ‘global warming’ and increased Hurricane intensity is now settled science and is reflective of the ‘consensus science. Henceforth anyone espousing the opposite view shall be named a ‘denier’ and shall be subjected to public ridicule and ad hominem attack 🙂

Joe S

Oh, my!

Pierre Gosselin

Thanks for posting this. This yet another milestone that is bringing the AGW house of cards crumbling down.
According to one German website, the real climate change is now taking place IN THE MEDIA!
Many of the listed links are in English. It’s a respectable compilation.

Pierre Gosselin

Are scientists now beginning to defect the AGW rogue state?
Maybe some experts see more cooling in the pipeline than we do.

Pierre Gosselin

You can almost start to list the defectors:
1. Kerry Emmanuel
2. Mojib Latif
3. and now Tom Knutson
I know…I’m being premature.


RealClimate managed to post on the story already on Sunday.
Maybe a sign of panic over there, judging from their sudden enthusiasm for debunking studies in Nature.


What I believe is hilarious is the fact that now they are saying that “global warming” will reduce the number of storms. Uhm, so I guess at this point it is safe to say that 2008 is going to have a larger number of storms, right?

Mike from Canmore

To answer your 2 questions: No and Almost for suredly N0.


Anthony, this will be retroactively fitted into Mr. Hansens model to prove they actually predicted that AGW would cause a decrease in Hurricane activity. “Oh what a tangled web we weave”…..

Sorry to disagree with you here, Anthony, but this isn’t going to kill it. Environmentalists will never let one of the cornerstones of their argument just disappear without a trace.
They’ll keep whistling like this never happened, schools will keep showing Gore’s sci-fi flick, and the media will continue to reference it as fact.
Inevitably, another study will pop up in the next few months that claims Knutson’s study is wrong. And then they’ll keep right on teaching it as fact to the next generation.
They’re relentless. The study that will refute this one was already funded & probably began as soon as this study was released by the AP over the weekend. They’ll start at the solution they want & work their way backwards. And those who don’t follow this on a daily basis will be none the wiser.

Mike Smith

“How about an apology to Bill Gray from Hillary Clinton?”
And from Judy Curry.

Dave Andrews

On a deeper level both this and Emmanuel’s paper could just be highlighting that no matter how refined you make the models they still can’t tell you much about the real world.


Gore’s sci-fi flick
All the weaknesses of Silent Running, yet none of the strengths . . .


Really! An 18% decrease in 92 years.
Well, you have to consider the fact that they record every storm nowadays and missed somewhere around half in 1900 . . .
Oh what a tangled web we weave
Oh, wherefore art thou, thy distrust, when thrice we practice to adjust?

Vic Sage

On a deeper level both this and Emmanuel’s paper could just be highlighting that no matter how refined you make the models they still can’t tell you much about the real world.
Which is why the models need to be validated. There is a lot of time and money being spent and we have no idea if we are just “grinding smoke.”

David S

I was thinking that the answer to both questions would be; “When hell freezes over.” But then it occurred to me that hell might freeze over. So I guess the answer to both questions would be a simple NO.

Franz DiVinettucci

Al Gore and AGW apostles are trying their best to enact Goebbles’ political philosophy:
“If you tell a lie big enough and keep repeating it, people will eventually come to believe it. The lie can be maintained only for such time as the State can shield the people from the political, economic and/or military consequences of the lie. It thus becomes vitally important for the State to use all of its powers to repress dissent, for the truth is the mortal enemy of the lie, and thus by extension, the truth is the greatest enemy of the State.”-Joseph Goebbels


Well, the tropics (like the globe) has been cooling since 2002. Maybe that was the reason for Katrina.

Robert S

I think it has been speculated that hurricane frequency would decrease for some time now. I believe the IPCC even mentioned it:
“Based on a range of models, it is likely that future tropical cyclones (typhoons and hurricanes) will become more intense, with larger peak wind speeds and more heavy precipitation associated with ongoing increases of tropical SSTs. There is less confidence in projections of a global decrease in numbers of tropical cyclones. The apparent increase in the proportion of very intense storms since 1970 in some regions is much larger than simulated by current models for that period.”
This new study just adds to the evidence that frequency will decrease.
On the intensity front, Emanuel mentioned this:
“A new technique for deriving hurricane climatologies from global data, applied to climate models, indicates that global warming should reduce the global frequency of hurricanes, though their intensity may increase in some locations.”
In other news, an article titled “Are Atlantic Tropical Cyclones Really Increasing in Number, Intensity?” was in the April edition of the Bulletin of the American Meteorological Society. Here are a few quotes pulled out by Craig James over at his blog:
“it is improbable that the number of tropical cyclones has increased since 1966.”… “In addition, the rate at which storms become hurricanes appears to have decreased”. Also, “little evidence is found that mean individual storm intensity has changed, although the variability of intensity has certainly increased. This increase is probably due to changes and improvements of intensity measurements through time..”


They should throw out all climate models and get back to meteorology (+days at best accurate forecasting), except for seasonal temps of course. Because this study is a model, in my view its not credible even if its goes skeptics way. Also artic ice ain’t melting as agw’ers would like, temps are still going down and staying down….(400, 600 and 900 mb)

Russ R.

There are very good reasons why a warmer world would have less storms and less severe storms. The polar regions would warm much more than the tropical regions, meaning there would be less temperature difference between the equator and the poles. This means a shallow temperature gradient, which is the engine that drives the large low pressure systems that turn into large tropical storms. That is what his model is telling him. It is a simple concept, unless you already have your mind made up, and you discard anything that disagrees with your pre-supposion. Could it be some actual science is breaking out, in the AGW theory support network?
I don’t think we will have to worry about it anyway. We might see stronger storms from a cooler climate. I am sure they will find a way to blame that on “climate change”.
It is fun to watch the climate forecasters get in the mud and argue. It reminds me of the three blind men arguing over what an elephant looks like.


Pardon me if I’m wrong, but the biggest hurricane we know of is the Great Red Spot on Jupiter where, if I understand correctly, it’s DAMN COLD.

Let’s assume there is a link.
Ok, we have two alternate worlds with two identical villages, the exception being that Village A has only and income tax and produces greenhouse gasses. Village B has a combination of income tax and greenhouse gas emissions taxes. Village Bs tax system implemented in a way that completely eliminates greenhouse gas emission, but has no effects on its ability to meet the material need of its population; i.e., the villages have the same GDP and population growth rates.
Both populations start with 2000 people.
The population growth rate is 1.3% for both villages.
The GDP growth rate is 4% for both villages.
30% of both populations have IQs sufficient to perform higher level work requiring a college degree, and do so.
Lets say Village A has a .01 chance of a 100 year storm hitting which will kill .05 of the population and destroy .05 of the economy every year. Due to its greenhouse gas emission, Village B has a .011 change of being hit by a 100 year storm. Various engineering projects are available that will reduce deaths and destruction .005. These projects require 100 civil, environmental, or marine engineers to start.
Assuming a hundred year storm absolutely will not happen until at least 100 years from now, which village is at greatest risk from a hundred year storm? Why?

Bill in Vigo

This is a little OT But.
Has any one checked out the United States Climate summary? It seems that they are using the adjusted GISS temps that still show that 1998 is warmer than 1934 by a substantial margin. It is very good grafting but the bias seems to still be there. I am just eye balling with a straight edge but what a mess. It seems a case of making the historical temps cooler so that the modern temps look warmer.
Some one else look and tell me if I am incorrect.
Bill Derryberry

This good news. Hurricanes, at least Atlantic hurricanes offer a dramatic but very filthy climate signal. El Ninos bringing wind shear, African dust that allows the sun to heat air instead of the seas surface, and other factors mask whatever signal may be lurking in the data.
When Kerry Emanuel got a lot of press for his initial claims that global warming would bring stronger storms, it was clear to me he wasn’t paying attention to what isn’t small stuff.
The Real Climate folks do have some good points about the models’ limits, but there was no reason that this or any future paper in the next while or two will settle the issues.
It is a good step towards giving up on using hurricanes as an indicator of warming.
They shouldn’t be in Gore’s movie.
My guess is that Gray won’t put much credence in this paper. He’s such a confirmed empiricist that if he can’t find signal in a few parameters, he’s not going to trust a model that cannot reflect reality. If the models suggest areas where small changes impact hurricane dynamics, then he’d be interested – in checking historical data to see if the same thing happens in real life.
One of the RC comments was that models have trouble simulating the ITCZ (Intra Tropical Convergence Zone). That strikes me as something that ought to be easy, perhaps the exact location is the hard part.
1″ of snow in parts of Vermont today. My high was 58° (more than 10 degrees below average), 23° on top of Mt Washington. Chilly!


Al Gore retract? Are you kidding? He has blamed the Tropical Cyclone that devastated Burma on global warming. The man has no conscience or morals.

Bill in Vigo (18:46:32) :
“Has any one checked out the United States Climate summary? It seems that they are using the adjusted GISS temps that still show that 1998 is warmer than 1934 by a substantial margin.”
Did you see the pulldown menu above the graph? I had it display the annual data and it reported that 1998 ranked 113 (warmest?)
Annual 1998: 54.99 degF   Rank: 113
Annual 1934: 54.93 degF   Rank: 112
Annual 2006: 54.91 degF   Rank: 111
If you type Ctrl-U (or whatever it takes for your browser to display the raw HTML, then you can cut & paste data from the pulldown.

Pierre Gosselin

Ric Werme,
Are you from Vermont?
So am I!


Please, please! Just what on Earth (or off it!) are ‘warmer’ temperatures and ‘colder’ temperatures? And is that big photograph behind Al Gore obtained from a camera behind him on the floor pointing up?


This does not cantradict the IPCC models and is in agrement with their projections….

Pierre Gosselin (23:50:2-) :
“Ric Werme,
Are you from Vermont?
So am I!”
You asked me that a several threads ago, I forget which one. I had the Old man of the Mountain. I’m next door in NH. Mt Washington (which claims to be home to the world’s worst) has had a little snow too. And METAR reports say snow showers, light & steady snow, and for the last ten hours blowing and drifting snow with steady winds around 50-60 knots and temps in the low 20s. What a cool place!
In a more human account, notes “Glaze ice formed consistently 2 or 3 inches an hour, creating an impressive display 3 to 4 feet deep on a pole directly outside the parapet door through the duration of the night. Glaze ice of this degree required going out every hour to deice. This in turn gave me the opportunity to become intimate with the Pitot Pole, the pole which holds our Pitot static-tube anemometer, after a 92 mph gust thrust me into it.”

Michael Searcy

It would be irresponsible for…Gore…not to acknowledge this sea change in the realization that there is no linkage between global warming and increased hurricane frequency.The problem with Gore retracting the claim is that he never made it, at least not in the film. Here’s the transcript of the relevant section.

Of course when the oceans get warmer, that causes stronger storms. We have seen in the last couple of years, a lot of big hurricanes. Hurricanes Jean, Francis and Ivan were among them. In the same year we had that string of big hurricanes; we also set an all time record for tornadoes in the United States. Japan again didn’t get as much attention in our news media, but they set an all time record for typhoons. The previous record was seven. Here are all ten of the ones they had in 2004. The science textbooks that have to be re-written because they say it is impossible to have a hurricane in the South Atlantic. It was the same year that the first one that ever hit Brazil. The summer of 2005 is one for the books….And then of course came Katrina. It is worth remembering that when it hit Florida it was a Category 1, but it killed a lot of people and caused billions of dollars worth of damage. And then, what happened? Before it hit New Orleans, it went over warmer water. As the water temperature increases, the wind velocity increases and the moisture content increases. And you’ll see Hurricane Katrina form over Florida. And then as it comes into the Gulf over warm water it becomes stronger and stronger and stronger. Look at that Hurricane’s eye. And of course the consequences were so horrendous; there are no words to describe it.
How in god’s name could that happen here? There had been warnings that hurricanes would get stronger.

I see specific references to warmer waters leading to stronger hurricanes, but I see no specific claim that global warming leads to more frequent hurricanes.
When the conditions are favorable, the development of more hurricanes may not be surprising such as the Japanese typhoon situation mentioned, but Gore never claims on ongoing trend in increased frequency, once again, at least not in the film.
The crux of his message is summed in the statement, “As the water temperature increases, the wind velocity increases and the moisture content increases,” and this latest study reinforces this conclusion.
While I can appreciate the desire to demonize Gore, manufacturing claims in order to debunk them is a stretch.
Now, if he has made such claims outside of the film, by all means, let him have it.


The Realclimate comments are absolutely hysterical. “I had taken the hurricane slides out of my global warming presentation, but I’m going to put them right back in after reading this. Thanks!”
I have never seen a more sycophantic group than that. Hysterical and sad at the same time.
It has been a bad year for the warmies.


Michael, the almighty IPCC has decalerd it so:
“Frequency: According to the IPCC-AR4, on a global scale, “[t]here is no clear trend in the annual numbers [i.e. frequency] of tropical cyclones.” As discussed above, however, the frequency of tropical storms has increased dramatically in the North Atlantic. Reasons for this increase are currently subject to intense debate among climate scientists. At least two recent peer-reviewed scientific studies indicate a significant statistical link between the increased frequency and global warming, but research to identify a mechanism explaining this link is ongoing.”
I believe this study comprehensively debunks this link.

Doh! I noticed that is switch A and B in the second part of my question. A has a .011 probability of being hit and B has a .01.
Alternately, rather than having no storm hit for 100 years, the probability for village A could simply increase after 100 years. That way the expected cost of a storm can be calculated for every year and a running total can be kept. This will show that for A, the total cost of storms will alway be the same or lower than B.
The reason is Accountants:Engineers. In order to meet the criteria of same GDP growth, Village B must get it’s additional accountant from the pool of risk mitigating engineers.
You can compare the relevant populations in the US here: Accountants:Engineers. You can see that the needed accountant/auditors would be far larger than the risk mitigating engineers (only certain types of engineers are relevant, and still only a small percentage of them).

GR Mead

It just goes to show that the only model worth a damn is located in the gray squishy stuff between the ears of someone who has carefully and critically absorbed a large mass of longitudinal data across a broad range of sources.
William Gray, as a preeminent example …
There is no substitute for actual time spent actually grinding on actual data to finer and finer grits. If an internal pattern exists in the data — that form of polishing will reveal it, and virtually nothing else will — which is what a computer model is — “virtually nothing.”

Gerald Machnee

Michael Searcy – Now go and check the script to see if Gore says the water or air temperatures are increasing due to global warming.

Gerald Machnee

Gore sees fit to note the hurricane off Brazil. Yes, it occurred when the temperatures were BELOW normal. I do not believe the text books say impossible, may rare. One of the reasons for rare reports is the lack of ships.


Some one else look and tell me if I am incorrect.
It checked out okay to me.
Did you use annual temperatures? The default was January, which did show 1998 as much warmer.


No, wait, you are right. I looked at the rankings. NOAA has 1998 as warmest year for US (by a little).
But they don’t give a world graph, at least not anymore (which had 2005 as warmest year).

Nick Stokes

Look again with more care at your quote:
‘According to the IPCC-AR4, on a global scale, “[t]here is no clear trend in the annual numbers [i.e. frequency] of tropical cyclones.”’
The rest is someone else arguing with them. You will have to look a lot harder to find the IPCC asserting that AGW causes more frequent hurricanes. You won’t succeed.

Nick Stokes


This echoes what I reported on April 11th 2008 about Emanuel’s findings as well as what I reported on February 21st 2008 from Roger Pielke Jr. and Chris Landsea at the National Hurricane Center.
Three prominent researchers agree, two have reversed positions.

Not so much. Here’s Emanuel:

MIT hurricane meteorologist Kerry Emanuel, while praising Knutson as a scientist, called his conclusion “demonstrably wrong” based on a computer model that doesn’t look properly at storms.

And here is a report of a debate last week between Emanuel and Chris Landsea. I don’t think Emanuel is as converted as you said he was.
I don’t think you’ll find the IPCC asserting anywhere that hurricanes would increase in frequency. In fact, from the AR4 FAQ 10.1

Some modelling studies have projected a decrease in the number of tropical cyclones globally due to the increased stability of the tropical troposphere in a warmer climate, characterised by fewer weak storms and greater numbers of intense storms. A number of modelling studies have also projected a general tendency for more intense but fewer storms outside the tropics, with a tendency towards more extreme wind events and higher ocean waves in several regions in association with those deepened cyclones.


I remember reading about the chances for increased shearing winds just after Katrina. If forget if it was Landsea or Gray who mentioned it then, but having grown up in Miami the effects of upper-level shear is legendary to old hurricane watchers. Pray for shear….
Gore, fool that he is, cited on NPR two weeks ago the cyclone that hit Burma as some kind of harbinger of more to come (invoking his usual trope of the horrors of AGW), even though the seas in the Indian Ocean have been cooling for some time now.
Here in the USA, we have more and more tropical storms listed in the Atlantic Basin every year because more tropical depressions are being named, small, short-lived disturbances that would never have been named 20 – 30 years ago. The old-timers know this.
It’s like increased tornado detection due to the advent of doplar radar, increased lightning strike detection due to satellite sensing, and increased sunspot detection of “Tiny Tims” due to new satellite technology. Take those with the classic case of formerly suburban weather stations now surrounded by urban heat islands.
As detection technology improves and standards expand we are suffering from standard inflation (ala grade inflation). Rather than applying historical trend adjustments in a good, sensible way, the field instead lacks a consistent standard by which it normalizes data for historical trend analysis.
Without some sense of what the old standards were and how the new detection methods differ, all the trend metrics are going to go up, up, up! The result should be obvious to anyone, that current trend analyses may be completely misleading, in terms of risk assessment and climate modeling.
So when climatologists anticorrelate historical sunspot counts against climate, they are using the worst metric possible. The 10.7 cm flux from ionosphere measurements is a better metric, but it’s historic value is limited where it can be only roughly imputed from Wolf #’s & SSn.
There’s a difference between wisdom, knowledge and information. But when the information itself is apples and oranges, what we have is garbage data.


Nick, I think you may want to review Chis Landsea’s resignation letter found here:
I’ll quote for you:
“Differing conclusions and robust debates are certainly crucial to progress in climate science. However, this case is not an honest scientific discussion conducted at a meeting of climate researchers. Instead, a scientist with an important role in the IPCC represented himself as a Lead Author for the IPCC has used that position to promulgate to the media and general public his own opinion that the busy 2004 hurricane season was caused by global warming, which is in direct opposition to research written in the field and is counter to conclusions in the TAR.”
So you can sell the notion that the IPCC doesn’t claim it, but I’m not buying it…

Nick Stokes

Again you offer a quote which just isn’t saying what you want it to say. Landsea is complaining not about the IPCC but “a scientist”. And why? Because he is saying something “which is in direct opposition to research written in the field and is counter to conclusions in the TAR“.

[…] in time to coincide with recent pronouncements of no link between global warming and hurricane frequency, thus just […]

(Gary G) Otter

‘I don’t think you’ll find the IPCC asserting anywhere that hurricanes would increase in frequency. In fact, from the AR4 FAQ 10.1’ ~ Stokes
Just curious… but why did it take them until the fourth report, over a period of 20 + years, to tell us that ‘some’ computer models agree with what Dr Gray told us ten years ago?