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Posted at 11:00 AM ET, 02/23/2010

Hurricane study unites formerly divided experts

By Andrew Freedman

* Dreary week: Full Forecast | On the edge of major snow: SLCB *

Lately it seems like climate science is being portrayed by the media and politicians as a rapidly fracturing field -- with a state of knowledge that is getting less and less certain with each passing day. Thus, it's refreshing to be able to present a concrete and newsworthy example of how distorted that view really is.

NASA satellite image of Tropical cyclone Gelane in the Indian Ocean on Feb. 19.

A new study from some of the top researchers on the question of how climate change may affect hurricanes, several of whom have publicly sparred with each other in the past, published a study in Nature Geoscience this week that provides a consensus view of the state of scientific knowledge of how tropical cyclones may change in a warming world.

Their conclusions: Tropical cyclones are likely (greater than 66 percent confidence) to have stronger wind speeds and drop more rainfall due to climate change, and there is a 50 percent chance or greater that some ocean basins would see a large jump in the frequency of the most intense storms. However, the overall global number of tropical cyclones is likely to decrease or stay about the same as it is now.

Or to put it more simply, future storms are likely to be fewer in number, but stronger and wetter.

Tracks of simulated Atlantic Category 4 and 5 hurricanes for the present climate and for a warmer climate condition projected for the late 21st century. Source: Bender et al. 2010.

The study found that projections of globally averaged tropical cyclone intensity show increases of two to 11 percent by 2100. These numbers may vary significantly from region to region, though. For example, National Oceanic and Atmospheric Administration (NOAA) researchers using computer modeling recently found that the frequency of strongest hurricanes (Category 4 and 5 storms) could increase by 80 percent in the western Atlantic by 2100, even though the total number of tropical cyclones would decrease during the same period.

The new study refines the findings of the U.N. Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report of 2007, which put more weight on what, at the time, were new studies that showed the existence of detectable trends in storm intensity, particularly in the North Atlantic.

Given advances in scientific understanding and computer modeling since the IPCC report was prepared, the new study found that uncertainties in tropical cyclone observations are too large to conclude that there has already been a detectable increase in storm intensity, although they noted that several studies have found such trends in some areas.

"... considering available observational studies, and after accounting for potential errors arising from past changes in observing capabilities, it remains uncertain whether past changes in tropical cyclone frequency have exceeded the variability expected through natural causes," the study states.

The conclusion that future storms are likely to be more intense has important implications for coastal residents, since the combination of increased coastal development, rising sea levels and stronger storms is likely to result in increased damages from future hurricanes.

"The future characteristics of intense tropical cyclones (Category 3-5) deserve particular attention, as these storms historically have accounted for an estimated 85 percent of US hurricane damage, despite representing only 24 percent of US land-falling tropical cyclones," the researchers warn.

By providing a useful and newsworthy snapshot of where research on the hurricanes-climate change debate stands, the authors of the study have provided an example of how climate scientists can help communicate key findings to the public. Perhaps others in the climate research community can follow this example.

The authors of the study include Thomas Knutson of NOAA's Geophysical Fluid Dynamics Laboratory, Kerry Emanuel of MIT, Chris Landsea of NOAA's National Hurricane Center, Greg Holland of the National Center for Atmospheric research, and six other experts. Landsea and Emanuel, in particular, have had significant scientific disagreements in the past regarding the role of human activities in changing tropical cyclone behavior.

The views expressed here are the author's alone and do not represent any position of the Washington Post, its news staff or the Capital Weather Gang.

By Andrew Freedman  | February 23, 2010; 11:00 AM ET
Categories:  Climate Change, Freedman, News & Notes, Science  
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Posted by: oriolesfan23 | February 23, 2010 11:14 AM | Report abuse

A couple of climate issues here:

First, as I pointed out in today's earlier post, the lowest extratropical pressures this winter are in the Southern Hemisphere which is currently experiencing summer. isn't this a bit unusual since it is the "winter" hemisphere which should normally experience the most intense extratropical weather...normally in the Aleutian and Icelandic gyres? This winter the "big" gyres seem to be persisting south of Australia and near the Falkland Islands during their summer season.

Secondly, during seasons having a large number of tropical cyclones, the "extra" named cyclones seem to be early and late in the season. How does this correlate with the global warming projections?

Posted by: Bombo47jea | February 23, 2010 12:06 PM | Report abuse

Bombo47jea: a lengthening of the tropical cyclone season would be somewhat consistent with climate change projections, given warmer sea surface temperatures that could allow storms to spin up earlier than they used to, as well as later in the season. But I have not seen studies that show this is occurring, and it would be complicated by various atmospheric factors such as changes in atmospheric wind shear. So the short answer is a question mark.

Posted by: Andrew-CapitalWeatherGang | February 23, 2010 1:14 PM | Report abuse

Remember back after Katrina, how we were going to have lots of powerful storms hitting us from all sides?
Been a mighty quiet few years....

If there is climate change:
1) Did we cause it?
2) If so, can we actually undo it?
3) If so, can we undo it without turning into cavemen or killing 4 billion people?

Will emerging markets just ignore it anyway? They sure weren't in some hurry to sign on to the Copenhangen thing.

The poor or average people are tired of being lied to and manipulated by limousine riding liberals who, now that they enjoy their own comforts, wish to keep others from living ejoyable lives.

Mr Al Gore would help things himself if he stopped riding jets all over to give stupid talks, and maybe lived in a normal sized house.

Posted by: Hembo | February 23, 2010 1:54 PM | Report abuse

"The poor or average people are tired of being lied to and manipulated by limousine riding liberals who, now that they enjoy their own comforts, wish to keep others from living ejoyable lives."

A pretty ironic complaint, given that all projections show that it is the poor peoples of the world - in Africa (drought), south Asia and island nations (flooding and increased disease) - who are and will be feeling the biggest brunt due to climate change the earliest. In fact, those people are already getting hit. The World Health Organization published a study in Nature showing that climate change is already contributing to 150K deaths a year.

If you live in the U.S., you are by definition among the "rich people" (whether you listen to Rush Limbaugh, Rachel Maddow or neither makes zero difference in that determination). "People" here is used in its only real definition: members of the species homo sapiens.

Posted by: B2O2 | February 23, 2010 2:11 PM | Report abuse

Yes, Orioles Fan, I also love the 12z GFS. This is interesting because it seems to me the NAM has been doing better with the big storms this winter. So I'm really eager to see the next set of NAM runs, to see if the trend is our friend.

Re: those cheeky limo-riding liberals and global warming - ah, nevermind...whatever.

Posted by: curtmccormick | February 23, 2010 2:14 PM | Report abuse

so are weather events climate or not?

Posted by: dummypants | February 23, 2010 2:26 PM | Report abuse

Thanks for the story. It is refreshing to read about science without all of the name-calling and blog-based rhetoric.

I am wondering how quickly insurance companies will raise rates to these coastal developments and if they might actually discourage future growth in target areas like New Orleans and Florida.

Posted by: ender3rd | February 23, 2010 2:29 PM | Report abuse

ender3rd: Thanks. You raise an interesting point about insurance. Some insurance companies have already pulled out of Florida in the wake of the 04/05 hurricane seasons and future projections. That does not necessarily have to do with climate change, however, but rather is more related to the fact that damages keep going up because of explosive coastal development during the past several decades.

Posted by: Andrew-CapitalWeatherGang | February 23, 2010 2:52 PM | Report abuse

Returning to an earlier topic, I'm all for shuffling out the Capital Weather Gang logo on a seasonal basis. It would spruce this place up a bit to see 4 different graphics. Especially in light of the all of the snow this winter!!

Posted by: MarylanDChris | February 23, 2010 3:11 PM | Report abuse

Hey I just noticed a winter storm warning is now posted as close as Howard County. Looks to me like the trend IS our friend with this. Could be a sneaky storm.

Posted by: curtmccormick | February 23, 2010 4:07 PM | Report abuse

Regarding insurance in Florida, it's a complete mess owing not only to what Andrew mentioned (explosive/expensive growth), but also to the state government there. The State of Florida imposed a number of restrictions on insurance companies with the aim of keeping rates artificially low. This worked, which was much to the delight of developers who wanted to build without the high cost of insurance. Of course as time went on, the insurance companies began losing money and started pulling out. Florida responded by making their own insurance company (Citizen's Insurance) and imposing more regulations. At the end of the day, you now have a number of coastal communities that should have never been built in the first place and which can no longer afford insurance except through Florida (which is contributing to a deteriorating fiscal outlook for that State).

In any case, thank you Andrew for the summary of the study and sharing it with us. I'm a big fan of studies like this since it (1) brought together intelligent people who happen to disagree on one issue, and (2) it provides a no-nonsense assessment of what may happen. If this particular study also leads to less development in coastal communities, I'm even more of a big fan of it! Not that I'm against development; I'm just against it in areas like the Gulf Coast where development leads to greater danger for both humans and wildlife.

Posted by: nlcaldwell | February 23, 2010 6:28 PM | Report abuse

Did their study find that man was to blame for global warming?

Mr. Q.

Posted by: Mr_Q | February 23, 2010 7:00 PM | Report abuse

Another interesting development in "climate change".

Climate scientists withdraw journal claims of rising sea levels

Mr. Q.

Posted by: Mr_Q | February 23, 2010 7:10 PM | Report abuse

Your column is titled, "Hurricane study unites formerly divided experts".

And the last sentence of your column is, "Landsea and Emanuel, in particular, have had significant scientific disagreements in the past regarding the role of human activities in changing tropical cyclone behavior."

I hope your readers do not mistakenly infer from your column and that last sentence that Landsea and Emanuel now agree on "the role of human activities in changing tropical cyclone behavior". That isn't what the study said.

You should issue a correction to clarify that extremely important point.

Mr. Q.

Posted by: Mr_Q | February 23, 2010 7:16 PM | Report abuse

Here is another "climate change" development that your readers might be interested in.

Arctic sea ice loss of 2007 due to a change in Arctic wind patterns, which pushed Arctic ice further south into warmer waters where it melted.

Arctic sea ice loss due to wind says NASA and JPL

Mr. Q.

Posted by: Mr_Q | February 23, 2010 7:39 PM | Report abuse

Here is another "climate change" development.

An IPCC lead author, Mojib Latif, while discussing the "misrepresentation of the science of disasters and climate change" described the transgression as FRAUD. The exact same term that I have used. :)

When someone engages in fraud, and they financially benefit (via grants and publicity), can we not accurately call that a scam?

Mr. Q.

Posted by: Mr_Q | February 23, 2010 7:46 PM | Report abuse


Let me say first I have not thoroughly read through the two papers you cite, the first in Nature Geo and the second in Science. There is clearly much overlap in the two papers, but I'm not sure to what extent they are independent.

The figure of the modeled tracks with and without warming is in the Science paper. As you know, I'm skeptical of modeling studies predicated on down-scaling global climate models.

I note that Kerry Emanuel is not a co-author of the Science article, and he is quoted as saying of the Science paper, "So, I see some movement toward consensus here" - not a very strong statement (in my opinion) of actually reaching a consensus.

Please clarify, in context of the cited results not being shared by other groups, for example I believe the Hadley Center (relates to uncertainties in differences in rate of warming waters in tropics relative to subtropics)

Posted by: SteveT-CapitalWeatherGang | February 23, 2010 8:31 PM | Report abuse

@CWG, this is not exactly in regard to this specific topic, but I thought that since we are once again discussing AGW, that some might find this interesting:

Btw, I'm kind of unsure about linking to another related blog on here, because I have a lot of respect for "The Gang", and I don't want to detract any of the conversation from here, to there. Nonetheless, this is a great little debate between Joe Bastardi and Bill Nye (Representing both sides of the AGW argument). Maybe you can even feature it on here too.

Posted by: TheAnalyst | February 23, 2010 11:28 PM | Report abuse

Steve, I'm not sure what you're asking me to clarify. Please clarify your request for clarification ;)

My story is about the Nature Geoscience paper, which brings together a large group of Hurricane experts who have been on opposing sides of the so-called "debate" regarding hurricanes and climate change. The Science paper is mentioned because it shares some of the authors, is recent, and lends support to some of the findings regarding particular regions having greater variability compared to others. The two papers are separate efforts. The Science paper was one modeling study. The Geoscience paper is a summary of current knowledge, which brings together a more diverse group of researchers.

I think the Nature Geoscience article details quite well some of the difficulties of modeling tropical cyclones using downscaling methods, and the advances that have been made using various methods. I encourage you to read it closely, and also to check out Knutson's page at GFDL, which has a lot of good background info:

Posted by: Andrew-CapitalWeatherGang | February 23, 2010 11:40 PM | Report abuse

Wow, Andrew and Steve going at it. This is turning out to be something else lol jk :-p

Posted by: TheAnalyst | February 24, 2010 12:00 AM | Report abuse

How about this snippet from the study; ". . . we cannot at this time conclusively identify anthropogenic signals in past tropical cyclone data."

More here.

Mr. Q.

Posted by: Mr_Q | February 24, 2010 1:02 AM | Report abuse

Hello Andrew:

A question about methodological assumptions:

How many hurricane seasons in which these predictions were NOT borne out would it take to elicit a retraction (okay, I'm not that naive) or a formal public modification of the studies?


Posted by: miglefitz | February 24, 2010 5:05 AM | Report abuse

I have studied U.S. hurricane history and, in fact, wrote a book, "Hurricanes and the Middle Atlantic States". Since the mid-1990s, the number of North Atlantic basin tropical cyclones has risen, although part of the rise is due to improved observation technology. One of the most worrisome trends is explosive short-term development, which seems to be occuring more frequently. The peak intensity may be brief, but the flare-ups seem almost as if lighter fluid was thrown on a fire.

Posted by: ricschwartz | February 24, 2010 10:09 AM | Report abuse

I warned you years ago that the predictable biggest losers in this scam would be scientists and the media. You can't push a lie that hard without predictable consequences when the lie is found out.

--begin quote--
Today the word "banker" is a pejorative term. Local managers are anonymous persons held in low regard. City of London magnates are suspect figures. Bankers are associated with unrestrained greed, recklessness and professional incompetence. It would be hard to think of another group that has fallen so fast and so far in public esteem.

The same thing is now happening with scientists. Since the days of Sir Humphry Davy and Charles Darwin, scientists in Britain have been held in the highest regard. Lord Kelvin and Sir Alexander Fleming were treated as secular saints. Nobel Prize winners were honored like prophets in ancient Israel.

Now, as the theory of man-made global warming unravels, scientists are suddenly and devastatingly revealed as fallible, mendacious, self-seeking, criminally secretive, furtively trying to hide their errors, debasing the system of peer review of scientific papers and conspiring to conceal the truth from once highly respected professional publications. The image of the scientist who puts the pursuit of truth before anything else has been shattered and replaced by a man on the make or a quasi-religious enthusiast who wants to prove his case at any cost. Science is becoming the tool of campaigning warfare, in which truth is the first casualty.
--end quote--

Source of the above quote - Forbes

Just wait until this unravels more and the public gets really clued in. Watch and see what happens to public opinion of media.

And like I said years ago, this will be very, very, very bad for the country.

Mr. Q.

Posted by: Mr_Q | February 25, 2010 11:23 PM | Report abuse

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