New evidence finds global warming triggers stronger Atlantic hurricanes

Wed, 2007-02-28 10:00Bill Miller
Bill Miller's picture

New evidence finds global warming triggers stronger Atlantic hurricanes

Scientists at University of Wisconsin-Madison and the National Climatic Data Center (NCDC) of the National Oceanic and Atmospheric Administration reported the finding in the journal Geophysical Research Letters.

“The debate is not about scientific methods, but instead centers around the quality of hurricane data,” says lead author James Kossin, a research scientist at UW-Madison's Cooperative Institute for Meteorological Satellite Studies. Kossin and his colleagues had to smooth out the data before exploring interplay between warmer temperatures and hurricane activity, essentially simplifying newer satellite information to align it with older records.

Sea-surface temperatures may be why greenhouse gases are exacting a unique toll on the Atlantic Ocean, says Kossin. Hurricanes need temperatures of around 27 degrees Celsius (81 degrees Fahrenheit) to gather steam. On average, the Atlantic's surface is slightly colder than that but other oceans, such as the Western Pacific, are naturally much warmer.

Previous Comments

Perhaps you should review the actual paper from Geophysical Research Letters where the author, Dr. Kossin, concludes … we were not able to corroborate the presence of upward trends in hurricane intensity over the past two decades in any basin other than the Atlantic. Since the Atlantic basin accounts for less than 15% of global hurricane activity, this result poses a challenge to hypotheses that directly relate globally increasing tropical SST to increases in long-term mean global hurricane intensity. The University of Wisconsin’s press release from which your quote is taken makes statements that are not supported by the actual science paper that it purports to represent.
doesn’t need to read the actual science papers, it knows the “truth” and it knows what information the people (“the ignorant masses”) should be fed. So don’t expect an apology or retraction from Bill the spin meister.
The Desmogblog article does not at all misrepresent the science article. The subject is interesting, though, and gives a taste of the uncertainties in all climate change impacts. The reasons for melting ice and snow are not even clear to everyone. Just think of the field day that those with heals dug in will have as ecosystems change (I can hear them already: species have gone extinct in the past, therefore we can’t possibly be affecting extinction now). Regarding cyclones and hurricanes, it would be unusual if the relationships to temperature were “all or nothing”. This just means it is like every other part of the natural world. Those who are closer to the data and the models tell us that greenhouse gas accounts for some of sea temperature change, but not all, and warmer seas account for a significant portion of the change in hurricanes but not all. Interesting tidbit: B.D. Santera et al., in the Proceedings of the National Academy of Sciences (Sept 12, 2006; “Forced and unforced ocean temperature changes in Atlantic and Pacific tropical cyclogenesis regions”), say

“Current model estimates of internal climate variability cannot explain observed SST [sea surface temperature] increases in either the ACR or the PCR [Atlantic and Pacific tropical cyclogenesis regions]. This conclusion is insensitive to existing uncertainties in model physics and parameterizations, to observational uncertainty, and to the details of the procedure used to compare SST trends in observations and model control runs. It is also reasonably robust to the choice of time period used to estimate historical SST trends. … In both regions, model simulations with external forcing by combined natural and anthropogenic effects are broadly consistent with observed SST increases. The PCM [Parallel Climate Model] experiments suggest that forcing by well mixed greenhouse gases has been the dominant influence on century-timescale SST increases. We also find clear evidence of a volcanic influence on observed SST variability in the ACR and PCR.”

An interesting graph: http://www.pnas.org/cgi/content/full/103/38/13905/F1

Others have noted that the trend in category 4 and 5 hurricanes are significantly related to SST.

Deconvolution of the Factors Contributing to the Increase in Global Hurricane Intensity

Carlos D. Hoyos, Paula A. Agudelo, Peter J. Webster, Judith A. Curry
School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA USA.

Science, March 16, 2006

To better understand the change in global hurricane intensity since 1970, we examine the joint distribution of hurricane intensity with variables identified in the literature as contributing to the intensification of hurricanes. We use a methodology based on information theory, isolating the trend from the shorter term natural modes of variability. Results show that the increasing trend in number of category 4 and 5 hurricanes for the period 1970-2004 is directly linked to the trend in SST; other aspects of the tropical environment, while influencing shorter term variations in hurricane intensity, do not contribute substantially to the observed global trend.

————————————————————–

P.S. The full list of authors of Santera et al. is

B. D. Santer a,b, T. M. L. Wigley c, P. J. Gleckler a, C. Bonfils d, M. F. Wehner e, K. AchutaRao a, T. P. Barnett f, J. S. Boyle a, W. Brüggemann g, M. Fiorino a, N. Gillett h, J. E. Hansen i, P. D. Jones h, S. A. Klein a, G. A. Meehl c, S. C. B. Raper j, R. W. Reynolds k, K. E. Taylor a, and W. M. Washington c


a Program for Climate Model Diagnosis and Intercomparison, Lawrence Livermore National Laboratory, Livermore, CA 94550;
c National Center for Atmospheric Research, Boulder, CO 80307;
d University of California, Merced, CA 95344; eLawrence Berkeley National Laboratory, Berkeley, CA 94720;
f Scripps Institution of Oceanography, La Jolla, CA 92037;
g Institut für Unternehmensforschung, Universität Hamburg, 22765 Hamburg, Germany;
h Climatic Research Unit, University of East Anglia, Norwich NR4 7TJ, United Kingdom;
i National Aeronautics and Space Administration/Goddard Institute for Space Studies, New York, NY 10025;
j Centre for Air Transport and the Environment, Manchester Metropolitan University, Manchester M1 5GD, United Kingdom; and
k National Oceanic and Atmospheric Administration/National Climatic Data Center, Asheville, NC 28801

b To whom correspondence should be addressed. E-mail: santer1@llnl.gov
Funny, funny stuff.

Question: do you folks actually proofread these things and bang them against hard reality before hitting the “Publish” button?

Apparently not.

And note well: the 95% confidence used in that report to assert that we would NOT have a below-normally-active hurricane season is MORE “certain” than the IPCC’s recent assertion, i.e., that “Most [sic] of the observed increase in globally averaged temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations.”

Uh… “Most”??? Is that, like, 50.0001%? If not, why didn’t they just specify? My guess? Because people would laugh.

Give us all a break, m’kay?

The link you provided states

“”NOAA continues to predict a high likelihood (75% chance) of an above-normal 2006 Atlantic hurricane season and a 20% chance of a near-normal season, according to a consensus of scientists at National Oceanic and Atmospheric Administration’s (NOAA) Climate Prediction Center (CPC), National Hurricane Center (NHC), and Hurricane Research Division (HRD). Therefore, 2006 is forecast to be the tenth above-normal season in the last twelve years.””

and

“”The predicted 2006 activity mainly reflects a continuation of conditions associated with the multi-decadal signal, which has favored above-normal Atlantic hurricane seasons since 1995. These conditions include warmer than average sea surface temperatures (SSTs), lower vertical wind shear, reduced sea level pressure, and a more conducive structure of the African easterly jet””

Which is what I took the desmog short note and its associated linked press release of saying more or less. As well you mention a 95% confidence interval though I didnt see anything of the sort in the link you provided. 95% condifence though is the standard statical accepted confidence level for an analysis of any data to be considered scientifically valid. The IPCC report doesnt exactly conduct a stastical analysis of all the different data sets from a large number of papers to arrive at a conclusion about human influence on climate. Its a general notion statement, based on the collection scientific research on the topic not a stastical analysis per say. Thus its more an educated approximation.

If you read the IPCC report you can see specifically how the differnt climate forcing factors have been estimated, error, and degree of understanding included. Only the 2001 report is currently available but…you can find the report here

http://www.grida.no/climate/ipcc_tar/wg1/index.htm

I was lazy and got the wiki site image of the IPCC graph that shows exactly what you believe they dont specify. Also pasted below.

http://en.wikipedia.org/wiki/Image:IPCC_Radiative_Forcings.png

I don’t believe an overall percentage of each forcing is listed though. It does also suggest there is need for greater research in a couple of climate areas as well.

“…you mention a 95% confidence interval though I didnt see anything of the sort in the link you provided.”

Just invert this:

“1. Expected Activity … 5% chance below normal”

which yields a 95% chance that activity will NOT be below normal, according to the computer’s prediction.

These faulty computer models virtually guaranteed at least normal, if not above-normal activity. How utterly wrong that was (for “scientifically valid”). These computer models couldn’t accurately characterize hurricane activity when they were run two months into the season, and we’re supposed to believe computer models can accurately predict infinitely more complicated phenomena based on events that span millenia? Sorry. No.

“…95% condifence though is the standard statical accepted confidence level for an analysis of any data to be considered scientifically valid.”

So by this you mean to say that the IPCC’s statement, which uses “very likely” (90%), is not scientifically valid? I’ve been saying this all along. Thank you.

“Its a general notion statement, based on the collection scientific research on the topic not a stastical analysis per say.”

Right. Yet they somehow managed to find a 90% - very likely - statistical probability that “Most” global warming was anthropogenic. Either you’re mistaken, and they did a statistical analysis or you’re correct and their statement is deliberately misleading. You can pick.

“If you read the IPCC report you can see specifically how the differnt climate forcing factors have been estimated…”

I’ve read it. And nowhere in the report do they assign a mathematical value to the term “Most”, the way they did with the term “very likely”. As such, the statement says nothing scientific about the degree to which humans have contributed to temperature changes. Yet we see that statement presented ad nauseam as “scientific proof” that we need to make drastic energy policy changes to avoid disaster.

Starting to see why thinking people are skeptical yet? ;-)

It’s more than a little ironic that the site dedicated to clearing the “PR pollution” got suckered by a misleading press release into printing a study that flies in the face of their AGW orthodoxy on hurricanes. Let’s see if they treat the issue with integrity.
This hilarious anecdote is flying around the ‘net about the laughable denier, Tim Ball:

You wanna hear a good one about Tim Ball?

According to one of the guys who lives in the same condo building as Ball, there was a decision made that each resident was to pay $5000 to fix a minor leakage problem in the building.

Ball, went around talking to all the residents telling them that the damage wasn’t as bad as people thought and to listen to him because he knew all about building envelopes.

When it came to the vote, Ball convinced enough people that the decision failed and Ball won. The repairs were never done.

Fast forward two years later:

Since the initial damage was never fixed b/c our little “leaking building envelope denier,” Tim Ball, it got way worse and now everyone in the building is facing $100,000 each to repair the damage. I’m not making this up, heard it straight from one his neighbours, who obviously hate Balls’ guts.

If you don’t believe me, ask Ball himself: timothyball@shaw.ca

So how does this relate to global warming. Well, Ball is NOT an expert in climate change, he has not published any research in over ten years. He is also NOT the “first PhD in climatology in Canada,” not even close. Just like the leaking building envelope he fought against taking action on, global warming is only going to get more expensive the longer we wait to take action.

Seriously, read up on this guy before you start using him as a source of expertise on global warming, you are just assisting him in spreading misinformation.
Hi Kevin, I haven’t read the paper yet. News releases seem to be misleading entirely too often. Can you let me know what to look for? I’m confused by your short comment for a couple of reasons. One is, if a new study comes out and it contradicts “AGW orthodoxy”, why wouldn’t someone interested in truth be interested in publishing it?
Wow. We’ve got a lot of skeptics here with….interesting takes on the science. It’s not too surprising that people would get angry that this new paper finds a link between climate change and hurricanes in the Atlantic. There’s been a number of contrarians denying any link, including Cato scholar, Roger Pielke Jr. and Chris Landsea with the National Hurricane Center. So any new report that runs counter to their dogma is threatening.
Oh Dear … I hope I haven’t been branded a skeptic … or a believer either. I’m just some guy trying to sort out fact from fiction … and there seems to be too little of the former and too much of the later. For example: Cato scholar Roger Pielke Jr. Not according to the Cato Institute and not according to Pielke’s bio on his web site. The new report runs counter to Chris Landsea’s dogma Seems unlikely given that the report in question includes the acknowledgement We are grateful to Peter Webster, Chris Landsea, and an anonymous reviewer for their comments on an earlier version of this paper. Why would Landsea be threatened by a paper that he obviously had a hand in preparing? “New paper finds a link …” Actually … it doesn’t. It finds a positive correlation between SST and hurricanes in 15% of the world’s oceans and a zero or negative correlation in the other 85%. The paper is very careful to avoid attributing increased hurricane intensity to SST and it makes no mention of what the possible causes of increased SST might be. The other statements that are swirling around this paper (and this isn’t the only place where discussion is going on) are derived from the press releases. The controversy is centered around whether or not the press releases (two of them) are a fair and accurate summary of what the paper actually says.

…on not being a skeptic or a believer, BCH. I would hope your mission to sort fact from fiction doesn’t automatically confer moral superiority over those who have, for whatever reason, decided to take a stance in this matter. There’s a lot of that going around, too.

As for the study, there seems to be quite a bit of confusion over some very poor choices of wording, some complex calculations of more than one layer of probability, or both. I wish the principal in this study would take more responsibility for the press releases, or at least learn to communicate properly.

I still haven’t read the paper, but realclimate.org has a short posting and the two real scientists they quote indicate that the METHOD is trained using Atlantic data and so it shouldn’t necessarily work for other basins. Chip Knappenberg (to whom they give the first quotation), a fossil fuel funded guy, seems to pay little attention to details.
Ah, I should face the fact that I probably won’t read the paper, either.

Steve, the paper can be downloaded at:

http://www.ssec.wisc.edu/~kossin/articles/Kossin_2006GL028836.pdf

It is interesting to note that four of the other five basins showed a slight increase when using the “best track” data. Only the East Pacific Basin showed a decline.

It would have been interesting to see a plot of SST for these basins. I would suspect that temperature increases in these other basins are much lower than in the Atlantic Basin since they all start off at a higher temperature initially thus GW would not have as much of an effect.

Of course none of this says whether AGW will increase the number of tropical storms, only their intensity.

Not hardly. I don’t even know what “moral superiority” means in a scientific context. I don’t have anything so up-scale as a “mission” … I’m just curious. I agree with your comments about the cited paper. From what I can interpret the paper claims to have produced a consistent dataset for hurricanes in the various oceanic basins where they occur. That is clearly supports a relationship (or lack of one) between SST and hurricanes is doubtful. The press releases seem to contain commentary attributed to the author and, were I to guess, those comments were in response to questions about the potential relationship between AGW and the science paper. Unfortunately, those comments got presented as the content of the paper itself.
Steve, Someone interested in the truth on climate change would be interested in publishing anything relevant and sound on the topic. However, what you will find on this particular website are a number of opinion editorials all of which are dedicated to the conclusion that the AGW debate is settled, anyone who disagrees is a “denier” [a rhetorical device meant to evoke holocaust denial] and that every scientist who disagrees with the ‘consensus’ is being bribed for their effort. In support of this judgement of mine, I’d recommend you simply read the spin the author of this piece put on this study, and then read the conclusion section made in the study by it’s author. See if the op-ed writer’s conclusion matches the study author’s conclusion.
Atlantic basin tropical cyclones account for 17% of the worlds activity. Why is only the Atlantic basin showing an increase (if there really is one at all that’s being caused by AGW)? Maybe because the Atlantic basin is the one that generates TS’s that hit the US. Katrina is still in the news. How long did the US coverage of a Tsunamia that wiped out more than 300,000 people off the face of the earth? It’s not Anthropogenic GW, it’s AmericoCentric GW.

I’m not sure how the scientists would judge it: but last summer CBC said China had an unusually violent typhoon season (they call them typhoons instead of hurricanes). Report on Typhoon Saomai

“At least 110 people were killed after Typhoon Saomai, the most powerful storm to hit China in five decades, slammed into the southeast coast Thursday, resulting in the evacuation of more than 1.3 million people, state media reported…”

So China evacuated 1.3 million people, while the US couldn’t manage to evacuate New Orleans.

RealClimate discussion at this link.

“The big problem with much of the discussions about trends in hurricane activity is that the databases that everyone is working from are known to have significant inhomogeneities due to changes in observing practice and technology over the years…

…However, rather than this study being taken for what it is - a preliminary and useful attempt to make homogeneous a part of the data (1983 to 2005) - it is unfortunately being treated as if it was the definitive last word. We’ve often made the point that single papers are not generally the breakthroughs that are sometimes implied in press releases or commentary sites and this case is a good example of that…”

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