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Global Warming and Hurricanes, Problems in Recent Research.--

After my post on ABC's coverage of the threat of global warming, I read through some interesting bits of the evidence on issues I raised. Several commenters pointed me to an interesting blog, Real Climate, which seemed to be a reasonable treatment of issues written by those who generally accept the orthodox view of man-made global warming. [In the comments, Bruce McCullough points me to a blog that disagrees with the prevailing orthodoxy, Climate Audit.]

Real Climate pointed to an interesting scholarly article on the hurricane debate: Curry, Webster, & Holland, "Mixing Politics and Science in Testing the Hypothesis That Greenhouse Warming Is Causing a Global Increase in Hurricane Intensity" in the current Bulletin of the American Meteorological Society (BAMS). Although I found the paper mostly persuasive that there had been a very large increase in category 4 hurricanes since 1970 (with drops or no change in the other categories of hurricanes), I see three problems with the paper.

Starting at 1970. First, the paper dismisses concerns that the choice of 1970 as a starting point may give a misleading account because of the evidence that there was global cooling from 1940 to 1970. They [combine] treat this legitimate concern as [with] a logical fallacy [and attack that fallacy], but they never explain [deal adequately with the implications of] coherently what's fallacious about potentially choosing start or cut-off dates that are unrepresentative of larger trends or that give misleading measurements of the strength of any overall trend. [The authors justify their choice of 1970 because of the pooorer data quality before that date, which is fine, but they do not fully recognize the possible implications of that choice for the generalizability of their results.]

Double Counting 1994 Hurricanes? Second, if the authors actually did what they report having done with their data, then the BAMS paper should never have been published. In two charts showing the main hurricane trends, they report the data in five year periods, except for 1994, which is included in two periods, 1990-94 and the six-year period 1994-99. This may be just a typographical error, but they make this error three times in the paper (in most of the most important charts). And exactly the same error appears in another paper they published in Science in 2005 using related data, so it may well not be a typo. If these are not merely typographical errors, and they did what the article reports that they did (i.e., double counted 1994 hurricanes), then the paper should never have been published. [Just to be crystal clear, if I had to bet, I'd bet that the authors just made repeated typographical errors. And even if the error is substantive, obviously it wouldn't have been intentional.]

False Statements to the Public About Category-5 Hurricanes. Third, although the article ended with a substantial discussion of responsible argumentation over the issue of hurricanes and global warming in the mainstream press, as an apparent model they pointed to their own public commentary:

In our AAAS press release . . ., given the recent devastation associated with Hurricane Katrina, the main public message that we wanted to communicate was

The key inference from our study [in Science released along with the press release] of relevance here is that storms like Katrina should not be regarded as a "once-in-a-lifetime" event in the coming decades, but may become more frequent. This suggests that risk assessment is needed for all coastal cities in the southern and southeastern U.S. . . . The southeastern U.S needs to begin planning to match the increased risk of category-5 hurricanes.

Just to remind people: Katrina was a category-5 hurricane at its peak, but it was a category-3 hurricane when it hit the Gulf Coast, and it was only a category-1 hurricane at New Orleans (95 mph), though it was just below the threshold for a category-2 hurricane. The damage at New Orleans probably occurred, not because it was such an unusual hurricane but because the levees were in appalling condition (whether you fully buy Wizbang's provocative account or not).

But the data presented in the BAMS paper show what looks to be a very small and statistically insignificant rise in category-5 hurricanes from 1970 through 2005 (these data include some Pacific as well as some Atlantic hurricanes). The big increase shown in the BAMS paper is almost a tripling of category-4 hurricanes; other classes of hurricanes seem to show significant drops or no significant changes.

A 2005 Science article co-authored by the same group as the BAMS paper--Webster, Holland, Curry, & Chang, "Changes in Tropical Cyclone Number, Duration, and Intensity in a Warming Environment"--does look at Northern Atlantic hurricanes 1970-2004 separately from Pacific ones, but lumps category-4 and category-5 storms together, showing an increase for the combination, not reporting anything on category-5 hurricanes alone. I went to the data source cited in the 2005 Science paper and this is what I found for 1960-2004 hurricanes (the Science study covered 1970-2004, excluding the first two rows below and the 4 category-5 hurricanes that occurred after the period of their data, in 2005):


Category 5 Hurricanes in the North Atlantic:

1960-64 . . 4
1965-69 . . 2
1970-74 . . 1
1975-79 . . 2
1980-84 . . 1
1985-89 . . 2
1990-94 . . 1
1995-99 . . 1
2000-04 . . 2

As you can see, in the data they claimed to have used in their Science article (as I counted the events), there is absolutely no trend in category-5 hurricanes in the period of their study: 1970-2004. Indeed, the 1990s showed insignificantly fewer hurricanes than either the 1970s or 1980s. Thus, all of the increase in the North Atlantic category 4-5 storms reported in the 2005 Science article must be due to an increase category-4, not category-5 storms.

Neither paper reports any data that would show a statistically significant increase in category-5 storms that would form the scientific basis for their public claim, made along with their release of the 2005 Science article: "The southeastern U.S needs to begin planning to match the increased risk of category-5 hurricanes."

What increased risk?

If they have the data to support that claim, they should make it public. Anyone reading that claim would think that their Science paper showed such a significant increase. But it didn't. Even after I added the 2005 data on category-5 hurricanes, which they did not use because the season wasn't over yet, the quick regressions I ran didn't show any statistically significant increase in category-5 storms.

Did they just fabricate this claim of "increased risk" of category-5 storms?

If they don't have such data—-and it appears that they don't—-then it's irresponsible for a scientist to imply a scientific basis for such a fear-inducing claim released along with a scientific paper. And it's particularly odd that the authors of the 2006 BAMS paper actually discuss and criticize the mainstream press for poor environmental reporting that gives too much weight to critics of the environmental orthodoxy. The authors tell us that their scrupulousness put themselves at a disadvantage in public debate because they restricted themselves to making claims that were supported by peer-reviewed articles and data. Yet their own peer-reviewed data would seem to me to show that they had no scientific basis for saying that "The southeastern U.S needs to begin planning to match the increased risk of category-5 hurricanes."

Bottom line:

1. The new BAMS article shows persuasive evidence of a huge jump in category-4 hurricanes 1970-2004, but declines or flat trends in the numbers of stronger and weaker hurricanes.

2. The BAMS article does not deal adequately with whether its choice of a relative cool period (1970) as a starting time influenced the results.

3. In both their 2005 Science article and their 2006 BAMS article, the authors appear to double count data from 1994, but it may just be the result of repeated typographical errors in both journals.

4. In the BAMS article, the authors criticize others for irresponsible public statements on global warming and praise their own caution, yet the press release they quote asserts an "increased risk" of category-5 hurricanes threatening the southeastern U.S., but neither their own two articles, nor the data they claim to have used, show any such statistically significant trend.

5. If the quality of peer review and editing in this field is only as careful as it seems to be on the BAMS paper, then I think it prudent for educated lay people to continue to be skeptical about the research and public assertions of climate experts, especially those who tell you to just trust them or who insist that they are just relying on what their data show. Wouldn't expert reviewers of the BAMS paper already know that there had been no increase in category-5 hurricanes in the North Atlantic, and thus that the public statements that the authors proudly trumpet were irresponsible? Certainly, this brief foray into the literature leads me to be less confident of the conclusions of climate researchers, no matter how fervently they are asserted.

UPDATE: I emailed Judith Curry, the first author on the BAMS paper, pointing out the double listing of 1994 and requesting her 1970-2005 data by year by basin by hurricane category, which should allow me to resolve some oustanding questions.

There is a lot of back-and-forth discussion in the comments, particularly here, here, and here.

2d UPDATE: Judith Curry responded at RealClimate here and here. I have submitted a response, which has yet to appear there.

Overall, my criticisms seem to be pretty well confirmed. After thanking Judith Curry for her prompt response, I review where the exchange stands.

1. I am happy that you have confirmed the "1994" errors I found in your two papers, and I am also happy that they are typographical, rather than substantive.

2. You justify your choice of 1970 as the starting date for your study. My criticism was not whether the starting date was the best one (it probably was), but rather how choosing a relative minimum as the start date should affect the interpretation and generalizability of your results. I think we have both said our piece on this issue; I doubt that further discussion will resolve things any further.

3. I was pleased that you acknowledged that, as I had pointed out, the data on cat-5 hurricanes shows no significant trend, an observation that was the main focus of my comments (at realClimate.org post #212). On this point, you wrote:

With regard to category 5 storms, there is no point to trying to identify a trend only in the category 5 storms, owing to the small numbers and the uncertainties in classifying storms with the strongest windspeeds.
Of course, statistical significance is determined not only by sample size, but by the strength of any relationship and the variability in the data. From eyeballing your data, it appears that, if the relationship for cat-5 storms worldwide had been as strong as the powerful relationship that you nicely established for cat-4 storms, then the sample size of cat-5 storms was probably large enough to show statistically significant results. So the fact that there is no significant trend in cat-5 storms is due to the absence of a strong relationship in the data, as much or more than to the relatively small sample sizes.

As for my criticizing your assertion of an increase in the risk of cat-5 storms, which you now acknowledge that your data do not show, you wrote:

In terms of our statements in the press release issued in sept 2005, specifically the Q&A from Science, we had NO IDEA that anyone would even pay much attention this, particularly a year later. We never anticipated this paper and subject to become such a big deal. We were as careful as we could be (given our inexperience with press releases and media in general, and specifically were very careful not to overplay the global warming issue). . . .

The key statement of contention was in our Q&A with Science, which was made in response to the following direct question:

Given that increased intensity, what are the possible ramifications for policy-makers, generally? Would your research have any bearing, at least potentially, on decisions regarding the rebuilding of New Orleans and Gulf Coast?

It is not a statement that we made in our Science paper, nor in the news release issued from Georgia Tech. Rather, it was a statement made on a short time fuse at a request from Science, to respond to policy makers and to the catatstrophe [sic] in New Orleans. In hindsight, I don't thing we would change a word that was said. What is said by a scientist in peer reviewed publications in done in a very different context from interacting with the media. Scientists are expected to respond to questions outside of their field that they are ill prepared to deal with, and do not directly follow from their scientific research. This is the so-called value gap between scientists and policy makers that was addressed in the BAMS article.
I did not rummage through your group's responses to the press to unearth something your co-authors said in dealing with the press back in 2005. In your 2006 BAMS article, which I was commenting on, you purported to quote just three sentences from your group's 2005 dealings with the press. These were the sentences that your new 2006 paper chose to emphasize. These were the three sentences that I quoted, taking issue with the last sentence:

"The southeastern U.S. needs to begin planning to manage the increased risk of category 5 hurricanes."

Since, as you now kindly acknowledge, your data show no increased incidence of cat-5 hurricanes--indeed, you argue that "there is no point to trying to identify a trend only in the category 5 storms"--I objected to your group's use of the phrase "the increased risk of category 5 hurricanes."

My criticism thus seems eminently sound, with one strange, but important caveat.

Judith, you write that the passage I criticize was said in response to a question posed by Science about precautions for hurricanes and you quote those questions. But the phrase that I objected to--"the increased risk of category 5 hurricanes" --does not appear in the interview you referenced. Webster referred instead to "the risk of category 5 hurricanes." In the interview, Webster later refers to "this increased risk," but in context he appears to be referring to a range of risks from cat-3 through cat-5 that the public needs to address, so there is nothing objectionable about such a reference.

Judith, can you point me to any place where Webster or anyone in your group actually uttered or wrote the words that you quote in your 2006 BAMS article?

Or did someone (mistakenly) rewrite Webster's answer to add a scientific assertion that is not supported by the data you present (i.e., "the increased risk of category 5 hurricanes")?

You write: "In hindsight, I don't thing [sic] we would change a word that was said." But if you just pointed us to the right source for the text you quoted, it appears that someone (mistakenly) did "change a word that was said"--and changed it to something unwarranted by the scientific data your group presents.

Is there any way to correct the online version of the 2006 BAMS paper so that the charts are labeled correctly and so that you don't make a claim of an "increased risk of category 5 hurricanes" if Webster didn't actually say that in the passage you purport to quote.

Kate1999 (mail):
What's the relevance of the numerb of one type of hurricanes in just one part of one ocean? I don't see how that's a helpful metric at all.
9.1.2006 10:44pm
volokh groupie:
What's the relevance of the numerb of one type of hurricanes in just one part of one ocean? I don't see how that's a helpful metric at all.

The main reason the paper has relevance is because weather is a chaotic non-linear dynamical system. Therefore, while climatologists may talk about global climate statistics (avg. global temperature, albedo, etc), climate will vary on local geographical scales. In fact, while weather will be dependent on climate in adjacent and other geographical regions, it will usually be very different from the weather of an appropriately sized adjacent zone. There are actually some simple 1-dimensional EBM codes (there are probably some available at GISS' site [which is a great group that posts tons of info for the public]) which demonstrate that and What's the relevance of the numerb of one type of hurricanes in just one part of one ocean? I don't see how that's a helpful metric at all.

The main reason the paper has relevance is because weather is a chaotic non-linear dynamical system. Therefore, while climatologists may talk about global climate statistics (avg. global temperature, albedo, etc), climate will vary on local geographical scales. In fact, while weather will be dependent on climate in adjacent and other geographical regions, it will usually be very different from the weather of an appropriately sized adjacent zone. There are actually some simple 1-dimensional EBM codes (there are probably some available at GISS' site [which is a great group that posts tons of info for the public]) which demonstrate that and which you can probably launch either from windows or in the respective webpages. So as a consequence, curry, et al. are justified in such a narrow analysis because the particular regions they're looking at have a characteristic set of climate/weather patterns and a consistent and directioned variability would likely point to more global changes.

also, an interesting bit of news about the upcoming ipcc report news about ipcc report

by the way prof. lindgren--it seems youre getting interested in the subject so if you have some free time you should really give some thought to getting a book called 'a climate modelling primer' by henderson-sellers and mcguffie

its very user friendly and not very long and is incredibly well regarded by many climatologists
9.1.2006 11:02pm
Mary Katherine Day-Petrano (mail):
Obviously, the poster of this thread does not live in Florida, where most of the State's population has some first hand experience with the increasing number and intensity of Hurricanes as well as global warming summers about 10 degrees hotter than just 4 years ago.
9.1.2006 11:05pm
AnonPerson (mail):
They are not discounting the start date of 1970. They are discounting the use of US landfall hurricanes as representative of all hurricanes. So the question is whether or not all hurricanes show the same trendline as US landfalling hurricanes.
9.1.2006 11:06pm
Aaron Bergman (mail):
This is silly. Categories of storms are an arbitrary and huge binning of the data. Category fives, being extremely rare, have crappy statistics. On the other hand, you can infer from an increase in lower categories that there may be a corresponding increase in high categories. I'd try to do a much smaller binning on windspeed. If given years look Poisson-like, say, the the implication above is perfectly legitimate.
9.1.2006 11:06pm
volokh groupie:
sorry about the copying of the paragraph in the last post

here's the link to the book i was mentioning climate modelling primer

most climatologists agree that after a read of this book you'll generally be prepared to tackle any paper in the subject, particularly those regarding some of the models used in climate simulations
9.1.2006 11:06pm
Aaron Bergman (mail):
Also, the hurrican season is generally said to start in June and can run into January very rarely. Thus, it seems perfectly possible that they are saying that one season is 1993-1994 and the next is 1994-1995.
9.1.2006 11:09pm
Bruce McCullough (mail):
Jim,

If you like Real Climate (which is actually run by
a bunch of so-called "climate scientists" who
don't know statistics) you'll love
www.climateaudit.org
whose purpose is to correct the nonsense on realclimate

Anyone who knows the rudiments of multivariate analysis
can easily see that the so-called "hockey stick" graph
is, at best, the result of gross incompetence. (You
can feed a constant series into that algorithm, and
it will produce a hockey stick.)

Regards,

Bruce
9.1.2006 11:41pm
countertop (mail):
Interesting post and Aaron makes an interesting comment. Without knowing how they define the season, we really don't know much about the 1994 statement.

One other thought, and I simply don't have time this week to read this report - but how do they address the increase in funds towards the study of hurricanes and satellite and aeronautic instruments over the last 10 to 15 years which have enabled us to identify many more storms as hurricanes which only a couple of decades ago may have gone unnoticed or been misclassified?

It seems to me that they have to factor in the huge increase in attention to hurricanes and advancements in reporting technology otherwise their data sets are fundamentally flawed and otherwise worthless.
9.1.2006 11:44pm
AnonPerson (mail):
With some understanding about the underlying distributions and mechanisms producing the events, it's not unreasonable to infer the probability of very rare events from the observed probability of the less rare events.

Is it proof? No. But we are not talking about "absolute proof". We are talking about what is prudent.

Suppose you are a golfer. You know that the more of your first strokes stop on the green, the greater your chances of getting a hole in one. On average, however, only 1 out of 1000 shots that stop on the green are a hole-in-one. On average, however, 50 out of 100 shots stop on the green. Now let's suppose you switch to a new club, and after 500 shots you notice that the percentage of shots that stop on the green have gone from 50% to 75%.

Is it reasonable to infer that your chances of getting a hole in one have increased? Probably. Is it proof? No.

Note that I'm not claiming that in this particular case, what they did was reasonable. I'm just saying that claiming an increased probability of cat-5 hurricanes only on the observed increased probability of cat-4 hurricanes is not clearly a mistake.
9.1.2006 11:45pm
countertop (mail):

the poster of this thread does not live in Florida, where most of the State's population has some first hand experience with the increasing number and intensity of Hurricanes as well as global warming summers about 10 degrees hotter than just 4 years ago.


i don't live in Florida either but I do own property there - on the beach - and spend a significant amount of time at another house in Georgia and can't really say I've seen any increase in hurricanes let alone an 10 degree increase in the average temperature. Increased news coverage with the 24 hour cable channels, yes. But not actual increases in hurricanes or anything approaching the temperature change you allege.
9.1.2006 11:47pm
Clint:
Aaron--

That would work as an explanation, except that they didn't do that for any of the other data points. They labelled the "pentads" as: 70/74, 75/79, 80/84, 85/89, 90/94, 94/99, and 00/04.
9.1.2006 11:47pm
James Lindgren (mail):
Arron, They do the years differently for each other 5-year category, and the data they cite to is organized by year. Indeed, the last 1994 hurricane is Nov. 1994 and the first 1995 one is June 1995. Nice try, but they screwed up.

++++++++++++++++++


Kate1999 wrote:


What's the relevance of the numerb of one type of hurricanes in just one part of one ocean? I don't see how that's a helpful metric at all.

OK, so that's a good reason why they shouldn't be able to claim that there is an increased risk of cat-5 hurricanes in the SE U.S.

+++++++++++++
AnonPerson:

Neither their statistical analysis nor mine is based on land-reaching hurricanes. No recent hurricanes have been cat-5 when they landed, so they DEFINITELY are not making that claim.

+++++++++++++

Volokh Groupie,

Thanks.
9.1.2006 11:53pm
Entropy:
To Mary Katherine Day-Petrano:

Where in Florida are summer temps 10 degrees higher in the apst four years? I checked data from several weather stations in Orlando, such as here and saw no significant increase in temperatures. What part of Florida are you talking about? You can get data from weather stations in Florida here.
The data I found was located by clicking on Average Maximum under the Monthly Temperature Listings menu on the sidebar.
9.2.2006 12:14am
frankcross (mail):
Realclimate is good for the orthodox view. Although "orthodox" sounds a little critical, it's no different from the orthodox view of gravity or anything else, and its contributors are listed with their credentials. It's not entirely onesided as a number of aggressive global warming advocates are unhappy with them.

Climateaudit is simply a closed minded denier site, though. For example, its analysis of the Hansen projections used a single year baseline (like Jim has criticized here), rather than the rolling average that is customarily used. It has a singleminded "anti" purpose, which is valuable but not to be trusted without independent checking.
9.2.2006 12:20am
Lev:
Entropy

Maybe her central airconditioning broke 5 years ago, so her house in summer has been 10 deg hotter the past four.

We must agree with her, don't you think, that if more hurricanes hit Florida, then there are more hurricanes everywhere in the world hitting everywhere else?
9.2.2006 12:21am
James Lindgren (mail):
AnonPerson wrote:

With some understanding about the underlying distributions and mechanisms producing the events, it's not unreasonable to infer the probability of very rare events from the observed probability of the less rare events.

Again, nice try, but the author of the paper, Judith Curry argues:


Also, the U.S. landfalling data shows little correlation with total NATL stats, can't really be used to infer anything about AGW or causes of basin or global hurricane/TS stats (this is discussed in BAMS article)

So, your golf analogy is pretty clever, but it doesn't apply to hurricanes in the North Atlantic, according to the author of the article I am criticizing.

Face it, they just scewed up.
9.2.2006 12:25am
James Lindgren (mail):
Frank Cross,

Thanks for the info on Climate Audit. At the moment, I'm trying not to trust anybody too much on these things.

Jim
9.2.2006 12:27am
AnonPerson (mail):
Neither their statistical analysis nor mine is based on land-reaching hurricanes. No recent hurricanes have been cat-5 when they landed, so they DEFINITELY are not making that claim.


Not sure what you mean here. They are not rebutting your statistical analysis of cooling. According to the paper, the criticism is that US landfalling hurricanes have a minima in 1970, therefore, 1970 is a bad start date. They rebutting by saying that the percentage of US landfalling hurricanes is such a small percentage of the total global hurricanes, that it cannot be used to infer the trend for global hurricanes.

In other words, the criticism that they are dismissing as a logical fallacy is not your criticism, but rather a different one. That is why it makes no sense as a rebuttal to your criticism. It is a rebuttal to a different (but perhaps related) one.

So, I'm just trying to say that they did seem to do a reasonable job of rebutting the chosen criticism. Whether or not it was the right criticism to rebut is an entirely different matter. They seem to have mostly ignored your critism.
9.2.2006 12:30am
James Lindgren (mail):
AnonPerson,

Thanks a lot. That makes sense.

Jim
9.2.2006 12:34am
AnonPerson (mail):
With some understanding about the underlying distributions and mechanisms producing the events, it's not unreasonable to infer the probability of very rare events from the observed probability of the less rare events.

Again, nice try, but the author of the paper, Judith Curry argues:

Also, the U.S. landfalling data shows little correlation with total NATL stats, can't really be used to infer anything about AGW or causes of basin or global hurricane/TS stats (this is discussed in BAMS article)


So, your golf analogy is pretty clever, but it doesn't apply to hurricanes in the North Atlantic, according to the author of the article I am criticizing.

Face it, they just scewed up.

Well, no. If they had said, "The number of cat-4 hurricanes in the world has no correlation to the number of cat-5 hurricanes in the world", then it would be clear evidence that they screwed up.

Instead, they are saying that US landfall data is not well correlated to NATL data. This is a lack of spatial correlation, not a lack of correlation across hurricane sizes.
9.2.2006 12:39am
Harry Eagar (mail):
volokh groupie, you have it backwards. Climate is pretty obviously not mathematically chaotic.

It would more accurately be described as antichaotic, since large changes in initial conditions always result in no net change in later conditions.

Climate has been around for a long, long time. If there were any net trend, we wouldn't be here.
9.2.2006 1:03am
orson23 (mail):

frankcross contrasts thusly:

Realclimate is good for the orthodox view.... It's not entirely onesided as a number of aggressive global warming advocates are unhappy with them.

Climateaudit is simply a closed minded denier site....It has a singleminded "anti" purpose, which is valuable but not to be trusted without independent checking.


Except that the Wegman Report - submitted to the U.S. House Energy and Commerce Committee in July, and headed by GMU stats prof and chairman fo the National Academy of Sciences Aplied Stats Section, Edward Wegman - was unable to replicate the realclimate.org icons Mann, Bradley, and Hughes (1998, 1999) Hockey Stick papers, but was able to replicate climateaudit.org's "amatuer" critiques of MBH by McIntyre and McKitrick (2003, 2005). What does THIS say about these respective authorities? Bona fide "climatologists" versus non-climatologists? Mann said of the Wegman Report, it "simply uncritically parrots claims by two Canadians."

Who is engaged in constuctive criticism and who is dodging the effort to establish legitimacy for thie claims? Given that MBH have resisted and remain to yet release all their data for several years, research which was federally funded that makes them obliged to do so - isn't one conclusion obvious?

The Report reads in part:
"The debate over Dr. Mann's principal components methodology [employed by MBH] has been going on for nearly three years. When we got involved, there was no evidence that a single issue was resolved or even nearing resolution. Dr. Mann's RealClimate.org website said that all of the Mr. McIntyre and Dr. McKitrick claims had been 'discredited'. UCAR had issued a news release saying that all their claims were 'unfounded'. Mr. McIntyre replied on the ClimateAudit.org website. The climate science community seemed unable to either refute McIntyre's claims or accept them. The situation was ripe for a third-party review of the types that we and Dr. North's NRC panel have done."

Furthermore, McIntyre updated the summer's news the situation last month in Canada's National Post by noting that "an earlier report in June by a National Academy of Sciences panel chaired by Gerald North of Texas A&M, which also endorsed specific criticisms of Mann's methodology and which concluded that no statistical confidence could be placed in his claims that temperatures in the 1990s exceeded those in the medieval warm period."

Since MBH constitutes the only evidence for Anthropogenic Climate Warming (ACW) not dependent upon recent instrumentation or climate modeling, one would think that good science would had taken care of this problem instead of smearing its investigators and obscurring its resolution. But you put $6.5 billion (just current FY) in front of a trailer park of scientists, and you're likely to get not just whores for ACW, but pimps too.
9.2.2006 1:07am
James Lindgren (mail):
AnonPerson,

I was responding to your golfing analogy, which implied that if you could not observe something rare (a hole in one), you could still observe changes in something that is not rare, such as hitting the green, and make educated guesses about the likelihood of the thing you hadn't yet observed, a hole in one.

I assumed that you were referring to something that rarely happened, a North Atlantic cat-5 hurricane that later hit land in the SE US, causing major damage. But if you were just referring to the number of cat-5 hurricanes worldwide, we have that data. We have a huge increase in cat-4 hurricanes and a trivial and insignificant increase in cat-5 hurricanes.

Our observations suggest that your speculation about increased risk of a cat-5 hurricanes is not true. Certainly, there is no scientific evidence that would justify the claim made by the Curry group as if it were established in their Science article.

Jim
9.2.2006 1:18am
guest:
Jim,

A few comments:

1) I'd bet that the "94-99" error is just a typo. Things like that are very easy to miss for both the author and the referee(s?). If it's not a typo, there's presumably a good explanation and its likely accounted for in the other plots. Those are both much more likely explanations than such a basic and stupid error in the analysis.

2) Katrina was category 3 at landfall, but it had the storm surge of a category 5 hurricane in some places.

3) The press is stupid, and press releases are written only to draw the press to the work. I also think that the statement that category 5 storms is somewhat justified for a press release - given the increased risk of category 4 storms, its reasonable to speculate that the risk of category 5 storms is also higher, even though the number of category 5 storms itself is too insignificant to used as evidence in either direction.

4) The link between hurricane intensity and global warming is interesting and makes intuitive sense. Although some poor grad student may wind up digging through old records to improve data, there will always be problems with comparing the present day to 50 years ago. I don't see the problem with starting at 1970 in a single paper, particularly if the older data is either less accessible or accurate. Choosing 1970 makes sense to me for a single paper.

The authors also compare the number of US hurricanes between 1945-55 and 1995-2005. I think this comparison suggests that they'd like to do what you suggest (look at earlier periods as rigorously as 1970-2005), but are unable or uncomfortable with doing that for some reason.

Other papers have/will look at the older data. The public may find this frustrating, but that's how science often is done. No paper is perfect or complete. The magnitude of the hurricane/global warming link needs substantial work before its proven, but work such as what you linked to is part of the big picture.
9.2.2006 1:23am
Aaron Bergman (mail):
But if you were just referring to the number of cat-5 hurricanes worldwide, we have that data. We have a huge increase in cat-4 hurricanes and a trivial and insignificant increase in cat-5 hurricanes.

Again, this is crappy binning of the data. You should not just look at the trend in a particular bin, especially a bin as far out along the tail as category five. A better thing to do is to fit each year to a distribution and examine the trend in the fit parameters. Assuming you have a good model for the single year distribution, it is perfectly legit to make predictions about the future of category five storms. (Not that I'm saying that this is what they did -- I haven't read the paper.)

Anyways, I really wish that when people found something they did not understand in a paper, they would phrase their response as a question rather than assuming that an entire field of scientific research is full of idiots. Mr. Ockham probably wouldn't like that hypothesis.

(As for the other comments, do we really have to talk about MBH again? The result isn't not the sole bit of evidence for anthropogenic global warming and it has been independently reproduced. Life goes on.)
9.2.2006 1:40am
Andrew MacDonald (mail):
Jim,

I'm not really sure the 1994 thing changes anything. Neither 1993 nor 1994 had anything above a Category 2 storm. Sloppiness, yes. Does it matter? No.
9.2.2006 1:48am
James Lindgren (mail):
Andrew:

Yes, it's probably a typo, but it's made in 2 papers. I did not argue that the error was driving their results, but it may be.

You are looking at the Atlantic data, but their articles look at Pacific data as well. According to Wikipedia, "1994 Pacific hurricane season": "Of note in this season is an unusual spree of very intense storms."


So, does it matter? If it's not a typo, perhaps Yes.
9.2.2006 2:12am
guest:
Orson23: you should spend as much time checking up on the Wegman report, as you checking up on the global warming research by reading the Wegman report. People tend to find what they want to find, and then stop. Ask yourself questions like, "What about a silly cartoon model is wrong (or perhaps simply not well supported), and how does that affect actual scientific interpretations of what is happening?"

You also may want to not selectively choose quotes that support your argument, while ignoring the entirety of the report.
9.2.2006 3:01am
fishbane (mail):
Jim It would more accurately be described as antichaotic, since large changes in initial conditions always result in no net change in later conditions.

Climate has been around for a long, long time. If there were any net trend, we wouldn't be here.


I'm afraid this is profoundly wrong.

Nothing in chaos theory demands that large changes in initial conditions lead to no "net change in later conditions".

What chaos theory describes is usually misinterpreted, but is that nonlinear systems are stable, until they change and find a new equilibrium. Butterflys in China and all are cool, and there is reason to think about that, but unless you're interested and well versed in the topic, there's good reason to try to be, ah, conservative, in your claims about how chaos theory works. One of the key points is that chaotic systems are stable*.

since large changes in initial conditions always result in no net change in later conditions.


Defining your terms might be interesting. Changes in what, exactly?

Beyond that, you're displaying a nonuseful mishmash of math terms and selected research. You clearly don't understand chaos, or dynamic systems*.

I hate to say this, but this is a product of a hack. I think Jim's better than that.

*That's really dumbing things down.
*For the record, people who study them don't, either. I don't. They're complicated, and not understood. But we do know certain things about how they behave in certain contexts.
9.2.2006 3:40am
James Lindgren (mail):
Fishbane,

All of the quotes you attack were not written by me, but rather by Harry Eager.
9.2.2006 4:30am
noahpraetorius (mail):
I remember a glowing article in USA about a hurricane forecaster (forget his name sorry) 2-3 years ago. From the data in the article, I constructed a "moving average" prediction that was superior to the actual predictions made. Conclusion: hurrican prediction is a farce. Reinforced by the breathless predictions for the current season that have been revised downward twice!
9.2.2006 7:57am
noahpraetorius (mail):
USA Today
9.2.2006 7:59am
Joel (mail):
Michael Mann is a fraud, and so is the Hockey Team at RealClimate. To convince me otherwise, explain to me how he somehow forgot to mention that excluding a single series of tree-ring proxies (U.S. bristlecones) his Hockey Stick vanishes, and how he didn't know full well that this was the case, as evidenced by the contents of his CENSCORED directory.

On his math, the Wegman Report destroyed Mann. Period.

I congratulate the Volokh blog for finding the inconsistencies in Curry's paper. Here's another: Her four year binned chart shows a noticable trend. An annual chart has a trend that is barely noticable, with a big spike in 2005. An autocorrelation of the time series shows a periodicity of... four years!
9.2.2006 9:49am
Random3 (mail):
Jim - You Da Man. Great analysis of the BAMS paper.

frankcross - Dude. There is no "unorthodox" view of gravity. It works always and everywhere according to the established equations (a couple of guys known as Ike Newton and Al Einstein figured it out - without any consensus!) Geesh - you make this GW stuff sound like a religion. "Unorthodox?"
9.2.2006 10:47am
AppSocRes (mail):
Chossing 1970 as a starting point is essentially cherry picking. There's pretty general agreement among those who study them that the intensity of hurricanes has periodicity. The period from 1970 to 1994 had a much lower than everage number of annual hurricanes with fewer than usual landfalls. Things began getting interesting again in 1995. If the authors had started their study in say 1940, their data would show a downward trend in hurricanes and hurricane intensity.

I grew up in Boston, Massachusetts and during the 1950s and early 1960s we had a major hurricane pass through my neighborhood about every three-four years. In the next 25 years two hurricanes got that far north and neither caused much damage.
9.2.2006 12:10pm
Mark Field (mail):

There is no "unorthodox" view of gravity. It works always and everywhere according to the established equations


This is not true. See, e.g., this article.
9.2.2006 12:15pm
Steve Darden (www):
Jim, excellent post. I appreciate your effort to work through the science and claims of warming and hurricanes. The best research [that I've found] confirms no meaningful trend in hurricane frequency or intensity.

One superb resource on the public policy of climate change is the University of Colorado's Center for Science and Technology Policy Research at Boulder, CO. — directed by Roger Pielke, Jr. Pielke recently offered some good advice to environmental activists on this issue of hyping a warming-hurricane connection.

A good example of their work is summarized in my post on Pielke's recent testimony before the House Committee on Government Reform: Climate change: policy analysis, mitigation and management. E.g., here's a summary of Roger's eight "take home points":

1. Human-caused climate change is real and requires attention by policy makers to both mitigation and adaptation -- but there is no quick fix; the issue will be with us for decades and longer.

2. Any conceivable emissions reductions policies, even if successful, cannot have a perceptible impact on the climate for many decades.

3. Consequently, costs (whatever they may be) are borne in the near term and benefits related to influencing the climate system are achieved in the distant future.

4. However, many policies that result in a reduction in emissions also provide benefits in the short term unrelated to climate change.

5. Similarly adaptation policies can provide immediate benefits.

6. But climate policy, particularly international climate policy under the Framework Convention on Climate Change, has been structured to keep policy related to long-term climate change distinct from policies related to shorter-term issues of energy policy and adaptation.

7. Following the political organization of international climate change policy, research agendas have emphasized the long-term, meaning that relatively very little attention is paid to developing specific policy options or near-term technologies that might be put into place with both short-term and long-term benefits.

8. The climate debate may have begun to slowly reflect these realities, but the research and development community has not yet focused much attention on developing policy and technological options that might be politically viable, cost effective, and practically feasible.

Run this query for some 64 climate change/science policy posts summarizing Pielke's research at CIRES.
9.2.2006 12:30pm
Average Joe (mail):
The frequency of hurricanes shows strong oscillatory patterns. I found a reasonably clear and readable description of these patterns here.
The link goes to an insurance company site and there is an interesting story behind that. The time period from 1970 to 1994 had a historically below average number of hurrricances. During this time the coast of Florida experienced a surge in development and population growth, so an increase in hurricane intensity or frequency is of great interest and concern to insurance companies, at least if they want to remain financially solvent.

I also found a more technical analysis of hurricane frequency
here
. This paper, which was published in the Journal of Climate, has a much more narrow focus but it does analyze the aforementioned frequency oscillations in detail, including citiations of data sources and statistical time series analysis of the data.

The strong impression that I got from briefly going through these papers is that Jim Lindgren is absolutely correct in his concern over the Curry et al. paper starting the data analysis with 1970. Given the known history of hurricane frequencies, one would expect the number of hurricanes to rise after that quiescent period, global warming or no global warming. Hope that people find the information in these links helpful.
9.2.2006 12:46pm
frankcross (mail):
The Wegman report shows the value of having folks like climateaudit around to check the hockey stick.

But also the limitations. In his congressional testimony, he said that he believed the evidence showed that manmade global warming was in fact occurring. I'm sure the climateaudit crowd that praises him generally will abandon his veracity on this point.
9.2.2006 1:10pm
Charlie (Colorado) (mail):

But also the limitations. In his congressional testimony, he said that he believed the evidence showed that manmade global warming was in fact occurring. I'm sure the climateaudit crowd that praises him generally will abandon his veracity on this point.


Frankcross, you should try reading what climate audit says instead of making things up.
9.2.2006 1:37pm
byomtov (mail):
If the quality of peer review and editing in this field is only as careful as it seems to be on the BAMS paper, then I think it prudent for educated lay people to continue to be skeptical about the research and public assertions of climate experts, especially those who tell you to just trust them or who insist that they are just relying on what their data show.

So someone who publishes primarily in law reviews is criticizing the quality of peer review and editing in another field?
9.2.2006 1:41pm
Harry Eagar (mail):
fishbane, the large change in initial conditions would be the revolutions in the composition in the atmosphere over the eons.

If very, very small changes are alleged to be driving climate today, then it is absurd to claim that very, very large changes would not have also in the past. Obviously, they didn't. Unlike Venus or Mars, Earth'[s climate is not in equilibrium. It is dynamically stable.

I am saying that climate is not mathematically chaotic, so your objection is not only pointless but opposite to my point.

Lorenz himself was becomingly modest about whether even weather is chaotic. See his Danz Lectures.
9.2.2006 2:06pm
guest:
Harry Eagar: google "Snowball Earth".

Average Joe: That Atlantic hurricanes were fewer doesn't mean that the number of hurricanes worldwide were fewer.
9.2.2006 2:24pm
frankcross (mail):
Perhaps you could give me a link, Charlie. I searched climateaudit for Wegman and it seems they are ignoring his testimony about manmade global warming. I found only one-sided comments
9.2.2006 2:42pm
James Lindgren (mail):

byomtov wrote:

So someone who publishes primarily in law reviews is criticizing the quality of peer review and editing in another field?

As a leader of the law reform movement in the early 1990s, I have been one of the chief critics of law review editing (including the lack of peer review), though as I get more exposure to peer review journals, I see a bit more of the advantages of law reviews than I used to see.

I think peer review is generally better, though one error in the BAMS article that I didn't bother to note in my post--the press release that the BAMS article quotes does not match the text quoted from that release in the article--would surely have been caught. I expect that the typo or double counting of 1994 would probably have been flagged as well, though I'm less certain of that.

But mainly, law professors do not usually tell people that anyone who disagrees with their scholarship is like a holocaust denier. The historian Michael Bellesiles tried this when an entire set of records that he claimed to have studied had been destroyed in the 1906 San Francisco earthquake. And he had to resign in disgrace.
9.2.2006 2:44pm
guest:
Both holocaust deniers and global warming skeptics ignore overwhelming evidence. Obviously, the motivations of both are different, and make holocaust deniers far worse. However, I've spent enough time checking both sides, with an open mind, to convince myself that the skeptics are intellectually dishonest.
9.2.2006 3:24pm
Aaron Bergman (mail):
Have you tried e-mailing the authors with your questions rather than immediately accusing them of "screw[ing] up"?

You statement

Yet their own peer-reviewed data would seem to me to show that they had no scientific basis for saying that "The southeastern U.S needs to begin planning to match the increased risk of category-5 hurricanes."

Is just wrong for the reasons I've stated.

For others, the number of hurricanes is a red herring. The question is relative intensity. The claim is that this shows a strong correlation with sea surface temperature.
9.2.2006 3:32pm
guest:
Jim,

Sallie Baliunas and Willie Soon are two astronomers who claim that global warming is not manmade, but caused by solar forcing. Baliunas oftens says things like:


But is it possible that the particular temperature increase observed in the last 100 years is the result of carbon dioxide produced by human activities? The scientific evidence clearly indicates that this is not the case.


Certainly, solar forcing is an interesting topic. So what, exactly, does her research say? Check out Figure 4 here.
Turns out, their own models show that greenhouse forcing is the dominant cause of climate change in the last 50 years. Yet skeptics cling to her public statements, despite that her models don't support her public claims, and despite that they are unable to physically explain the mechanism by which solar activity would produce as much warming as their models suggest (by contrast, the physical mechanism behind greenhouse forcing is very well understood, and physical models explain the amount of warming).

Whenever I've looked into the work of other skeptics, I find the same type of dishonesty.
9.2.2006 3:58pm
BobDoyle (mail):
Great post again Jim and I concur with your admonition to "continue to be skeptical about the research and public assertions of climate experts, especially those who tell you to just trust them or who insist that they are just relying on what their data show." Skepticism is good all the time but especially when you have (1) one side of the scientific debate constantly making assertions about "consensus" when even the slightest research into the topic will demonstrate that there is certainly NOT the consensus claimed, (2) supposedly unbiased researchers employ ad hominum to dismiss their critics while, (3) they often hide the details of their data and methodology so that it is difficult in many cases to try to reproduce their results, (4) there are oodles of government $$s to be garnered to research and solve the "problem," and (5) many of the players reveal a political agenda, then one should be extremely skeptical.

I'll stick with my post yesterday that I think about 99% of this GW "research" and its "conclusions" are driven by politics and green-religion and only about 1% by legitimate scientific inquiry.
9.2.2006 4:50pm
Le Messurier (mail):
Logic is as logic does! If this years hurricane events hold out for the remainder of the season then it will certainly be fair and logical to draw the conclusion that we are entering a period of global cooling. N'est pas? That's unless you want it both ways. Correlating an increase in hurricane intensity and/or frequency to global warming "proves" nothing other than a nebulous statistical relationship, if even that. Give me causal anytime. (And I don't mean causal netted out of imperfect models either.)
9.2.2006 5:45pm
Aaron Bergman (mail):
Logic is as logic does! If this years hurricane events hold out for the remainder of the season then it will certainly be fair and logical to draw the conclusion that we are entering a period of global cooling. N'est pas?

Well, no. First of all, one data point means nothing. Second of all, there have been so few hurricanes this season that, if there aren't many more for the rest of the season, the statistical weight of that data point is very low.
9.2.2006 6:54pm
Harry Eagar (mail):
guest, it's not a snowball now, is it? Earth climate is in dynamic equilibrium, despite changes in atmospheric composition that are many orders of magnitude greater than the measured changes in greenhouse gases.

It is not even certain whether there has been ANY increase in greenhouse gases. There has been an increase in carbon dioxide, but for all you know, it has been overmatched by a decrease in the dominant greenhouse gas, water vapor.
9.2.2006 7:43pm
guest:
Harry Eagar:


since large changes in initial conditions always result in no net change in later conditions....

If very, very small changes are alleged to be driving climate today, then it is absurd to claim that very, very large changes would not have also in the past. Obviously, they didn't. Unlike Venus or Mars, Earth'[s climate is not in equilibrium. It is dynamically stable.


I'm not sure exactly what you are saying, because it's not written clearly. But I think you are promoting a Gaia-type theory, that the Earth always manages to adjust and everything always evens out.

Snowball Earth destroys that idea - it did warm eventually, but for a while Earth would've been a terrible place for any complex organism to fluorish. Earth has been in a rather nice state for a while, but that doesn't mean other states aren't possible - they are, and they have happened.

It is not even certain whether there has been ANY increase in greenhouse gases. There has been an increase in carbon dioxide, but for all you know, it has been overmatched by a decrease in the dominant greenhouse gas, water vapor.

That's just stupid. I'm not going to get drawn into a scientific debate in a lawyer-based forum like this one, but if you are going to question the evidence of "the other side", you may want to actually provide some evidence yourself. But feel free to continue to spew idle lay speculation.
9.2.2006 8:25pm
Le Messurier (mail):
Aaron

Logic is as logic does! If this years hurricane events hold out for the remainder of the season then it will certainly be fair and logical to draw the conclusion that we are entering a period of global cooling. N'est pas?

I should have added a smiley face at the end of that sentence, but I thought "N'est pas" would do it. No, the logic doesn't hold anymore than the logic that a marginal increase in Hurricane intensity is evidence of global warming.
9.2.2006 9:01pm
Aaron Bergman (mail):
I recognized the sarcasm. The problem is in your comparison "the logic doesn't hold anymore than the logic that a marginal increase in Hurricane intensity is evidence of global warming.". You're comparing a long term trend with many data points versus a single data point.

It's always best to be able to demonstrate a direct causal relationship, but you can't always get what you want. Sometimes all you can manage are models and correlations. Can you say that definitely, absolutely global warming is causing more intense hurricanes? Of course not. But you can say that there is evidence for that statement.
9.2.2006 9:07pm
Le Messurier (mail):
But you can say that there is evidence for that statement.

Well, according to the article under discussion not much. Since they are using 1970 as the starting point it is hardly enough time to say "I see a long term trend". We were just beginning to be able to measure hurricane strength in the 70's much less to identify them. Satellites &Hurricane hunter airplanes were just coming into use. IMOP we just don't have enough historical data over A LONG ENOUGH PERIOD to even begin to know if there is a long term trend. 36 years is yesterday in climatoligical trends, and yet we have young scientists trying to guage the future of the Earth with insufficent data. A good way to make a living I guess since they can never be "proven" wrong, so they go on collecting their grant money. Global warming? Probably. Global warming = big hurricanes? Give me a break.
9.2.2006 9:28pm
Steve Bloom:
Below is a response I posted over at Real Climate earlier today. I should add a couple more brief points:

- Webster et al (2005) examined a *global* data set, not just the North Atlantic (which has only 11% of global tropical cyclone activity, BTW). A global analysis going back farther is literally not possible since satellites were needed to get accurate counts in a number of the basins.

- The Curry et al comment that Katrina should be seen as a wake-up call is shared by all hurricane scientists. Even those who believe there will never be a detectable global warming signal in hurricanes agree that the state of existing planning for hurricanes along the vulnerable U.S. coastlines is very poor indeed.

--------------------------

A brief deconstruction of your summary points:

1. The new BAMS article shows persuasive evidence of a huge jump in category-4 hurricanes 1970-2004, but declines or flat trends in the numbers of stronger and weaker hurricanes.

Reply: OK.

2. The BAMS article does not deal adequately with whether its choice of a relative cool period (1970) as a starting time influenced the results.

Reply: The BAMS article shouldn't (and couldn't) have recapitulated the entire contents of it references. Webster et al (2005), which you say you read, addresses the issue thoroughly:

"We deliberately limited this study to the satellite era because of the known biases before this period (28), which means that a comprehensive analysis of longer-period oscillations and trends has not been attempted. There is evidence of a minimum of intense cyclones occurring in the 1970s (11), which could indicate that our observed trend toward more intense cyclones is a reflection of a long-period oscillation. However, the sustained increase over a period of 30 years in the proportion of category 4 and 5 hurricanes indicates that the related oscillation would have to be on a period substantially longer than that observed in previous studies."

3. In both their 2005 Science article and their 2006 BAMS article, the authors appear to double count data from 1994, but it may just be the result of repeated typographical errors in both journals.

Reply: You could have easily confirmed that it was a typo by comparing the graph with the table immediately following it in Webster et al (2005). The total number of 1990-2004 cat 4-5s in the table matches the number shown in the graph for the three five-year periods from 1990-2004.

4. In the BAMS article, the authors criticize others for irresponsible public statements on global warming and praise their own caution, yet the press release they quote asserts an "increased risk" of category-5 hurricanes threatening the southeastern U.S., but neither their own two articles, nor the data they claim to have used, show any such statistically significant trend.

Reply: This amounts to an argument that land use and disaster planners in hurricane-vulnerable areas should plan only for an increase at cat 4s since an increase in cat 5s was not found over the limited period of the study. That would be extremely bad advice. There is no scientific basis for thinking that an increasing storm strength trend would limit itself permanently to cat 4s, and as noted below a good basis for thinking otherwise. As well, bear in mind that extensive areas of the U.S. were vulnerable to cat 4s/5s before this increasing trend was discovered.

Here is the quoted passage in its full context (from a AAAS interview with Peter Webster):

"Q. Given that increased intensity, what are the possible ramifications for policy-makers, generally? Would your research have any bearing, at least potentially, on decisions regarding the rebuilding of New Orleans and Gulf Coast?

"A. The key inference from our study of relevance here is that storms like Katrina should not be regarded as a "once-in-a-lifetime" event in the coming decades, but may become more frequent. This suggests that risk assessment is needed for all coastal cities in the southern and southeastern U.S. for category 5 storms, and for the more northern cities (e.g. New York City) probably for category 3 storms (note the categorical risk for coastal cities at higher latitudes needs to be assessed using typhoon data from the Pacific). The southeastern U.S. needs to begin planning to manage the risk of category 5 hurricanes. There is an additional issue of communicating this increased risk to the public. Past strategies for "weathering the storm" will not work in the face of increased hurricane intensity."

So Webster was not implying that Katrina was a cat 5, but rather was using it as an example of the type of disaster that could occur elsewhere. Note also that the vulnerability of New Orleans to strong hurricanes is not that unusual for a populated area. New York City, Chesapeake Bay and Houston are very vulnerable to similar events where the bulk of the damage results from storm surge. As well, Andrew and the somewhat weaker Rita showed that more ordinary stretches of shoreline can host major disasters.

"Q. More generally, what sort of hurricane activity should the Gulf Coast and the East Coast of the United States expect in the years ahead?

"A. Besides the overall global trend of increasing hurricane intensity, the key issue of concern raised by our study is that the hurricane intensities in the North Atlantic for the last decade have been lower than elsewhere on the globe. It is likely that the differences among the different ocean basins is associated with natural variability. This implies that at some point within the next decade, there is the risk that the intensity of North Atlantic hurricanes could increase rapidly to the global average (with possibly a concurrent decrease in another ocean basin). The variation of Atlantic hurricanes relative to hurricanes in other basins in the context of known cycles of natural variability needs further investigation."

5. If the quality of peer review and editing in this field is only as careful as it seems to be on the BAMS paper, then I think it prudent for educated lay people to continue to be skeptical about the research and public assertions of climate experts, especially those who tell you to just trust them or who insist that they are just relying on what their data show. Wouldn't expert reviewers of the BAMS paper already know that there had been no increase in category-5 hurricanes in the North Atlantic, and thus that the public statements that the authors proudly trumpet were irresponsible? Certainly, this brief foray into the literature leads me to be less confident of the conclusions of climate researchers, no matter how fervently they are asserted.

Reply: I think this is where you started.
9.2.2006 9:28pm
Steve Bloom:
Le Messurier, pay attention to the details. Evidence that you dimiss all of that scientific work without understanding is that you referred to "young scientists." I think if you google the names of the scientists involved you'll find that they are rather senior and respected people in the field. ed.
9.2.2006 9:33pm
Steve Bloom:
Le Messurier, pay attention to the details. Evidence that you dimiss all of that scientific work without understanding is that you referred to "young scientists." I think if you google the names of the scientists involved you'll find that they are rather senior and respected people in the field. ed.
9.2.2006 9:33pm
Steve Bloom:
Le Messurier, pay attention to the details. Evidence that you dimiss all of that scientific work without understanding is that you referred to "young scientists." I think if you google the names of the scientists involved you'll find that they are rather senior and respected people in the field. ed.
9.2.2006 9:33pm
Steve Bloom:
Also google "Rossby Medal" and note that Peter Webster has one.
9.2.2006 9:36pm
Tom952 (mail):
nd it was only a category-1 hurricane at New Orleans (95 mph), though it was just below the threshold for a category-2 hurricane. The damage at New Orleans probably occurred, not because it was such an unusual hurricane but because the levees were in appalling condition

And because the standards of construction were far too low for a coastal community. As a coastal Florida resident who experienced Charlie (Cat 4) and other storms, I learned the importance of construction standards. Homes situated side-by-side, exposed to the same wind and blown debris, suffered either a total loss or mere superficial damage solely due to construction standards. Low-cost details like ring shank nails instead of staples, heavier shingles with six nails per tab, and low cost window coverings make all the difference in the world.

The period of 1970-1990 lulled everyone into forgetting that these storms will occur. The local experience during Charlie demonstrated that the post Andrew state-wide construction standards work during hurricanes, even major ones.
9.2.2006 10:49pm
Joe7 (mail):
Mr. Bloom explains that he and his fellow writers were examining global data. He then states this study is important because of the vulnerability of eastern coastal regions.

However, to determine trends of vulnerability in this region ALL that matters is studying trends for hurricanes that made landfall in that region.
9.3.2006 12:14am
Aaron Bergman (mail):
However, to determine trends of vulnerability in this region ALL that matters is studying trends for hurricanes that made landfall in that region.

Of course not. People use proxies with better statistics all the time.
9.3.2006 12:24am
Lev:
Tom952


low cost window coverings


What would those be?
9.3.2006 12:39am
Lev:
Aaron Bergman

Let me say what I understand you to be saying here. You are saying that the vulnerability of the US East Coast to hurricanes is validly studied by examining the "cyclone" history of China/Phillipines/Japan/Guametc., The Mexican Riviera, the open water Pacific, and Northern Australia?

Much earlier you said:


Also, the hurrican season is generally said to start in June and can run into January very rarely.


The Official US Hurricane Season starts June 1 and ends November 30.
9.3.2006 12:44am
guest:
Steve Bloom - many thanks for the thorough and knowledgeable response to Jim's post. I hope he and the other readers here give the response as much consideration as Jim's initial post (perhaps he should even have it as an update at the top).
9.3.2006 12:50am
Aaron Bergman (mail):
Let me say what I understand you to be saying here. You are saying that the vulnerability of the US East Coast to hurricanes is validly studied by examining the "cyclone" history of China/Phillipines/Japan/Guametc., The Mexican Riviera, the open water Pacific, and Northern Australia?

If you can establish that they're valid proxies, sure. I don't know what's been established in this field -- I'm just commenting that these sweeping prounouncements people have been making aboust statistics are just wrong.

The Official US Hurricane Season starts June 1 and ends November 30.


Yes, and I can think of at least one storm that lasted into January (last year, in fact).
9.3.2006 12:51am
Lev:
The Official Hurricane Season has nothing to do with what calendar year a hurricane occurs in.
9.3.2006 1:15am
Aaron Bergman (mail):
This isn't particularly relevant because it seems like it was a typo, but I didn't say "official", did I?
9.3.2006 1:44am
Lev:
I am often puzzled by what people say in here. You said, with respect to the discussion about the 5 year hurricane accounting periods:


Also, the hurrican season is generally said to start in June and can run into January very rarely.


It seems to me the unofficial Atlantic "season" starts when it starts so far as hurricanes are concerned, as early as April, and ends when it ends. The only relevance of June to that is the official season, ending in November, which presumably encompasses when most hurricanes take place. Whatever the "season" is, is irrelevant to the calendar year for accounting purposes, which seemed to me to be the contrary of what you were saying.

Do you wish to revise and extend your remarks to clarify what you meant?
9.3.2006 2:54am
James Lindgren (mail):
Steve Bloom,

Thanks for coming over here from Real Climate and reposting your response to me here as well as there. My reply here reflects your text as you posted it at Real Climate.

For VC readers who may not have seen it, in response to Bloom's post and mine at Real Climate, Graham Dungworth wrote:

"James' brief? foray into the scientific literature represents the best critique I've ever read within the peer review system!"

Thanks, Graham, for your extravagant praise.

Steve Bloom had a different view. He wrote what he calls "A brief deconstruction" of my summary points.

First, it appears that Steve and I agree on what I view as the main accomplishment of the BAMS paper:

1. The new BAMS article shows persuasive evidence of a huge jump in category-4 hurricanes 1970-2004, but declines or flat trends in the numbers of stronger and weaker hurricanes.

Next, Steve takes issue with my argument about the possible implications of the 1970 starting date.

My second point :

2. The BAMS article does not deal adequately with whether its choice of a relative cool period (1970) as a starting time influenced the results.

Steve's Reply: The BAMS article shouldn't (and couldn't) have recapitulated the entire contents of it references. Webster et al (2005), which you say you read, addresses the issue thoroughly:

"We deliberately limited this study to the satellite era because of the known biases before this period (28), which means that a comprehensive analysis of longer-period oscillations and trends has not been attempted. There is evidence of a minimum of intense cyclones occurring in the 1970s (11), which could indicate that our observed trend toward more intense cyclones is a reflection of a long-period oscillation. However, the sustained increase over a period of 30 years in the proportion of category 4 and 5 hurricanes indicates that the related oscillation would have to be on a period substantially longer than that observed in previous studies."



My Reply: I had read the passage that Steve quotes before I posted, and it seems to confirm my point, since it tends to emphasize what the authors wrote in the BAMS article about a cooling period ending in 1970. I did not accuse the authors of the BAMS paper of bias; I did not say that they should have chosen a different period. I said that "the paper dismisses concerns that the choice of 1970 as a starting point may give a misleading account because of the evidence that there was global cooling from 1940 to 1970," and that they do "not deal adequately [with] whether [their] choice of a relative cool period (1970) as a starting time influenced the results."

The authors admit that 1970 is near a minimum. They argue that the world cooled from 1940 to 1970. So it would seem that Steve has pointed to the precise language to support my prior concern over start or cut-off dates that might be "unrepresentative of larger trends or that give misleading measurements of the strength of any overall trend."

I don't know how extensive Steve's statistical training is, but if it is extensive, then he must recognize the potential problems I raised: using 1970 as a start date may give a misleading picture of the larger trend or it may give a misleading measure of the strength of that trend. These are hardly contentious observations (and do not involve a suggestion that the authors made a mistake in starting at 1970 because of the poor quality of data before 1970). In any event, thanks, Steve, for quoting language from the Science article that so clearly supports my point.

My third point:

3. In both their 2005 Science article and their 2006 BAMS article, the authors appear to double count data from 1994, but it may just be the result of repeated typographical errors in both journals.

Steve's Reply: You could have easily confirmed that it was a typo by comparing the graph with the table immediately following it in Webster et al (2005). The total number of 1990-2004 cat 4-5s in the table matches the number shown in the graph for the three five-year periods from 1990-2004.


My Reply: Steve, are you serious in this argument? The authors' repeated claims that they included 1994 in two different periods (1990-94 and 1994-99) are clearly errors, and there is no way to tell whether they are just typos or something more serious from just looking at the two papers.

First, the graph immediately preceding the table does not have any data labels, so one can't compare and confirm whether the authors double counted 1994 or instead made 4 typos in two different papers (as you are certain they did). All one can do is eyeball the data in the chart, which is not at all clear whether it matches the data table. Indeed, from my eyeballing of the data, I would have estimated more than 270 cat-4 and cat-5 hurricanes 1990-2004 in the chart you point to, not fewer than 270, as the data table you point to shows.

Second, even if the chart were drawn in such a way that one could tell whether it exactly matched the data table (which it most definitely isn't), one still couldn't know whether they double counted 1994 or instead made 4 typos. If the authors mistakenly counted 1994 hurricanes in two of the three groups of years comprising the 1990-2004 period--and summed their three groups to get the total for 1990-2004--then the chart and the table would match exactly and the data would still be wrong because they double counted 1994. You may have some other basis for knowing that the errors are just typos, but the basis that you give would not persuade any sophisticated, fair-minded reader.

My fourth point:

4. In the BAMS article, the authors criticize others for irresponsible public statements on global warming and praise their own caution, yet the press release they quote asserts an "increased risk" of category-5 hurricanes threatening the southeastern U.S., but neither their own two articles, nor the data they claim to have used, show any such statistically significant trend.

Steve's Reply: This amounts to an argument that land use and disaster planners in hurricane-vulnerable areas should plan only for an increase at cat 4s since an increase in cat 5s was not found over the limited period of the study. That would be extremely bad advice. There is no scientific basis for thinking that an increasing storm strength trend would limit itself permanently to cat 4s, and as noted below a good basis for thinking otherwise. As well, bear in mind that extensive areas of the U.S. were vulnerable to cat 4s/5s before this increasing trend was discovered.

Here is the quoted passage in its full context (from a AAAS interview with Peter Webster):

"Q. Given that increased intensity, what are the possible ramifications for policy-makers, generally? Would your research have any bearing, at least potentially, on decisions regarding the rebuilding of New Orleans and Gulf Coast?

"A. The key inference from our study of relevance here is that storms like Katrina should not be regarded as a "once-in-a-lifetime" event in the coming decades, but may become more frequent. This suggests that risk assessment is needed for all coastal cities in the southern and southeastern U.S. for category 5 storms, and for the more northern cities (e.g. New York City) probably for category 3 storms (note the categorical risk for coastal cities at higher latitudes needs to be assessed using typhoon data from the Pacific). The southeastern U.S. needs to begin planning to manage the risk of category 5 hurricanes. There is an additional issue of communicating this increased risk to the public. Past strategies for "weathering the storm" will not work in the face of increased hurricane intensity."

So Webster was not implying that Katrina was a cat 5 [Steve, it was a cat-5 in the ocean, as I noted in my post--JIM], but rather was using it as an example of the type of disaster that could occur elsewhere. Note also that the vulnerability of New Orleans to strong hurricanes is not that unusual for a populated area. New York City, Chesapeake Bay and Houston are very vulnerable to similar events where the bulk of the damage results from storm surge. As well, Andrew and the somewhat weaker Rita showed that more ordinary stretches of shoreline can host major disasters.


My Reply:

Steve, you write: "Here is the quoted passage in its full context."

This is false.


You claim to show the passage that I quoted "in its full context," but you don't include the sentence that I quoted (and criticized), which was taken directly from the 2006 BAMS paper. I quoted ALL of the indented quotation that appeared in the BAMS paper. Here is the exact wording of the BAMS paper that I quoted. (The ellipsis is in the BAMS paper itself; I added the bracketed phrase):

The key inference from our study [in Science released along with the press release] of relevance here is that storms like Katrina should not be regarded as a "once-in-a-lifetime" event in the coming decades, but may become more frequent. This suggests that risk assessment is needed for all coastal cities in the southern and southeastern U.S. . . . The southeastern U.S needs to begin planning to match the increased risk of category-5 hurricanes.

I took issue with the last sentence, pointing out that there was no evidence in either the 2005 Science paper or the 2006 BAMS paper of an "increased risk of category-5 hurricanes." Steve, you claim to present this quoted excerpt in its full context, but you do not include the sentence that I challenged.

You also claim that my comment "amounts to an argument that land use and disaster planners in hurricane-vulnerable areas should plan only for an increase at cat 4s since an increase in cat 5s was not found over the limited period of the study."

I said nothing of the kind.

My goodness, New Orleans was so badly protected that it couldn't withstand a category-1 hurricane, which is what Katrina was when it hit New Orleans. It may have been fortunate that Katrina had been a cat-5 hurricane at some point, because the New Orleans levees may not have been able to withstand the next cat-2 hurricane, which might not have been scary enough to lead to as extensive an evacuation as happened with Katrina. I wasn't at all objecting to the advice, which seems eminently sound; I was objecting to the idea that the authors' data showed a significantly "increased risk of category-5 hurricanes." It doesn't. Remember that in the 2006 BAMS article, the authors claimed that they were only making arguments that were supported by good scientific data. But in the one indented passage that they quoted they made an argument that was not supported by their data, which presumably is the best available.

This brings us to your next argument: "There is no scientific basis for thinking that an increasing storm strength trend would limit itself permanently to cat 4s, and as noted below a good basis for thinking otherwise."

Steve, your speculation is an entirely plausible one (and it occurred to me before I posted)--but it's just that, speculation.

So far the data reported by the authors of the BAMS and Science studies do not show significant support for your view. If a tripling in cat-4 hurricanes does not lead to any significant increase in cat-5 storms, it's hard to imagine what kind of a dramatic increase in cat-4 hurricanes could lead to a significant effect on cat-5 storms. Your belief is a matter of faith, not evidence.

Steve's Reply continues, quoting a 2005 interview of Webster:

"Q. More generally, what sort of hurricane activity should the Gulf Coast and the East Coast of the United States expect in the years ahead?

"A. Besides the overall global trend of increasing hurricane intensity, the key issue of concern raised by our study is that the hurricane intensities in the North Atlantic for the last decade have been lower than elsewhere on the globe. It is likely that the differences among the different ocean basins is associated with natural variability. This implies that at some point within the next decade, there is the risk that the intensity of North Atlantic hurricanes could increase rapidly to the global average (with possibly a concurrent decrease in another ocean basin). The variation of Atlantic hurricanes relative to hurricanes in other basins in the context of known cycles of natural variability needs further investigation."

My Reply:
Steve, since Webster's data shows no statistically significant worldwide increase in cat-5 storms, to the extent that this claim is supported by evidence Webster is arguing that a worldwide increase in cat-4 hurricanes may lead to an increase in cat-4 storms in the North Atlantic. They have no data showing a significant increase in cat-5 storms either worldwide or in the North Atlantic, so this statement that you quote does not bear on my claims at all. It deals with the distribution of cat-4 storms to different basins, not to the risk that cat-4 storms will turn into cat-5 hurricanes. really, you have to be more careful in your argumentation.

Conclusion:
Steve, it would be hard to imagine a less successful "deconstruction" of my comments than yours.

As I said at the beginning, the BAMS article shows very good evidence of a big rise in cat-4 hurricanes in the 1970-2004 period.

Why do you also have to pretend that the limitations and clear errors I point to are not limitations and errors? This is academics. No one is perfect. Everyone makes mistakes; we can all learn from each other if we have an open mind for both the merits and demerits of new research.

James Lindgren
Northwestern University
9.3.2006 5:18am
orson23 (mail):
"How many angels can dance on the head of a pin?" And what does this theological question have to do with our Belief in man-made climate warming? Before addressing ACW and hurricane history, let me respond to two of my critics.

guest wrote: "You also may want to not selectively choose quotes that support your argument, while ignoring the entirety of the report."

Wegman states that that M&M's critique is replicable and valid and that MBH is neither: "While the work of Michael Mann and colleagues presents what appears to be compelling evidence of global temperature change, the criticisms of McIntyre and McKitrick, as well as those of other authors mentioned are indeed valid." "Overall, our committee believes that Mann's assessments that the decade of the 1990s was the hottest decade of the millennium and that 1998 was the hottest year of the millennium cannot be supported by his analysis." Now exactly what did I get wrong?

As for his actual testimony under questioning before Congress, frankcross is correct: Wegman believes ACW is occurring. He is entitled to his opinion, of course - that's not what a statistician's expertise is in, but it is one of my graduate fields at the University of London where my instructors think solar variability may account for as much as half of all recently observed warming. If true, why is it our urgent responsibility to reduce CO2?

During this summer's Congressional Committee testimony, Tom Karl of NCAR endorsed the reliability of GCMs, which purport to demonstrate a challenging degree of planetary warming is imminent (albeit with wide variance between models, and without any ability to resolve albedo fundamentals like cloud distribution), while John Christy noted that the detailed temperature records in California spanning 150 years show no statistically significant warming in the lower state with the greatest longitudinal range. But who is getting most of the federal research funding? Not people at Imperial College London - not data-driven climatologists like Christy. Nor is the famous hurricane prediction expert William Gray at Colorado State University.

Gray specifically blames the politically generated Gold Rush into ACW research during the 1990s for curtailing his obviously more life saving research into understanding the variables of hurricane prediction. Now even he has joined the ACW-skeptics crowd, a field especially populated with senior scientists instead of young bucks striving to "make a name" for themselves, like Michael Mann, leader of the Hockey Team.

Why do I mention all this sociology and division within the scientific ranks? Because mega-billions (yes-we're over $50 billion in the US down this scandalous rat-hole since 1990), are obviously driving the research output in politicized directions - not the science directing the research. This may not bother you, but it does Roger Pielke, Jr, at the University of Colorado at Boulder, an atmospheric scientist and policy researcher who is not unsympathetic to ACW. (Just Google prometheus and Pielke to find his blog.)

Indeed, when the IPCC lied about a leading hurricane experts work, Chris Landsea at NOAA, in an effort to pimp the hurricane data for ACW-"Truth," he quit last year. When Roger Revelle, who Al Gore claims as his scientific mentor, was shown to have harbored doubts about the significance of ACW, Gore sued to silence the publicity. When New Scientist magazine dropped Steven McIntyre as a source in a story about the Hockey Stick debate, all it took was Mann (et al) to convey the lie from Environmental Defense that McIntyre was paid by corporate oil money. It's a rigged and dirty game if you challenge Big Science, funded by government's Black Boot. As Pielke, Jr., blankly observed in April 2005, "If scientific debate equals political debate, then we will find that science has simply become another political battleground, and we will lose much of the positive contributions of science in policy."

Also last year, when the head of the IPCC was reported in Mother Jones to have said: "…we have about a ten-year window to make very, very deep cuts in our carbon fuel use, if, quote, 'humanity is to survive,'" Pielke, Jr., replied: "I am less troubled by the fact that Dr. [Rajendra] Pauchuri made these remarks…than I am about the overall silence about the way that IPCC science has become transformed into issue advocacy among the rank and file in the broader community of IPCC scientists." Our scientific institutions are thus rendered unreliable prostitutes grubbing for political agendas.

Which brings us back to Lindgren's hurricane paper above. Three points follow.

First, as Gray argues, a long running multi-decadal cycle of increased hurricane activity followed by decline is apparent from the historical record; its causes are unknown causes, but it predates human impact. Given this, how much weight ought we give to any "mostly persuasive" scientific paper? Some? A lot? Or uncertain? Given the propensity for Big Science to generate fads, this publishing cycle beginning with last year's work by MIT's Kerry Emanuel in Nature (implying that the Curry, et al paper is a follow-on), I'd say not much.

Second, there is an "angels dancing on the head of pin" quality to any ACW debate that turns on arcana like distinguishing Cat-4 from Cat-5 hurricanes in a data set of varying quality. Why? Because the history of modern instrumentation in data gathering of extreme weather events always shows an up-tick in numbers whenever observational networks improve. Take the best documented example, tornados and radar. Each expansion of instrumentation and every technological leap forward in electronic imaging resulted in a magnitude increase in reported numbers of US tornados. Small and brief ones -- the smallest ever measured was a scant seven feet! - formerly remote or too transient, are now detected and compiled into the historic record. But arbitrarily truncating this data for analytical convenience amounts to scientific malpractice.

Similarly with hurricane records, only with reverse observational consequences. In 1975, only daylight hurricane imagery was available from two satellites parked in geostationary orbit. By contrast, the technology of the 1990s permits round the clock observational data from eight satellites. Today we know that hurricane intensity can vacillate from one Cat to the next and back again in a single day - and that such changes are not uncommon - something unknown in the 1970s, and not yet well-documented until the 1990s. Therefore, given the coincidence of improved data gathering with cyclical change, that some category over a recent three decades span might yield an apparent increase sould not be surprising. In fact, the surprise would be if there were none.

More importantly for grasping global significance, even if hurricane activity in the North Atlantic is up over the past two decades, what are we to make of ACW in light of the fact that it is down in the Pacific basin (as Philip Klotzbach documented in Geophysical Research Letters this spring)?

Finally, consider the sheer arbitrariness of the Saffir-Simpson categories based on maximum sustained winds. Last year's Katrina came ashore as a Cat-3 event, delivering winds to New Orleans that were barely Cat-2, yet with cloud cover and atmospheric pressure (and consequent storm surge) more typical of a Cat-5 hurricane. Thus, the reduction of multidimensional storms to a single number reveals our considerable ignorance about the complex natural phenomenon from which we are supposed to derive a small ACW signal. Honestly, aren't we simply expecting too much significance from too little data? In short, underlying complexities may be obscured by conventions imposed upon continuously variable phenomena.

By contrast, the significance of the Wegman Report for the ACW debate is simple: we are pushed back to a data-driven versus model-idolatry controversy - where the next salient question is: "are these 'idols' worthy of our golden calf-like worship, or not?" - which was the "state of the art" in climatology before 1998 when MBH first appeared.
9.3.2006 8:28am
Michael B (mail):
Nicely focused post, essentially a microcosm of the broader GW debate in addition to being valuable in its own right. Well focused aspects of the debate tend to make it more difficult to employ obscurantist tactics, in that sense they additionally are helpful in gaugeing what is occurring in the broader set of GW debates.
9.3.2006 9:43am
byomtov (mail):
But mainly, law professors do not usually tell people that anyone who disagrees with their scholarship is like a holocaust denier.

Mainly?

What is the relevance of this, except to get in a shot at Bellesiles? Do you really believe that the claim about holocaust deniers is common in articles in peer-reviewed journals? Perhaps you could provide your estimate of how often it is made.
9.3.2006 12:22pm
Ambrose (mail):
Perhaps you should allow Daubert challanges to posts of scientific subjects. Not to exclude posts, but to provide some basis on which to judge the posts.
9.3.2006 1:34pm
BobDoyle (mail):
Such slurs should NEVER appear in ANY peer-reviewed journals. The fact that it could pass the editors and peer-reviewers in this instance implies much about the level of dedication to both real science and politically-motivated pseudo-science within this area of inquiry.
9.3.2006 1:34pm
Harry Eagar (mail):
Steve, I fail to understand your policy point.

The exact same policy advice was being given -- and ignored -- in 1968, when the outlook was for, if anything, cooling.

I know, because I still have a clipping of the story I wrote about Neal Frank's campaign to get governments in the Southeast to take the possibility of seiches seriously. None has, even yet.

Frank was then head of the National Hurricane Center. After Katrina I asked him about intensity changes. He doesn't buy 'em.
9.3.2006 1:43pm
Aaron Bergman (mail):
Do you wish to revise and extend your remarks to clarify what you meant?

No. Read what I said again.

(And then ask yourself why you're focussing on something utterly trivial.)
9.3.2006 1:47pm
James Lindgren (mail):
byomtov,

I know my original post was long, but if you reread it, you will see that the "holocaust denier" statement was made by the experts in the ABC report. I mentioned Bellesiles because he was the only exception I could think of in law or legal history who responded to serious criticism by accusing his critics (not me) of being like holocaust deniers.

It seems odd that you would object both to my use of the word "mainly" to reflect that there are exceptions AND to my identifying the one exception I could think of (Bellesiles).

Jim Lindgren
9.3.2006 2:13pm
guest:
Jim,

what ticks me off about your post is that you assume the minor flaws you see are both very significant and done with some sort of biased agenda in mind. You have "fallacious" crossed out, but not fully deleted - implying that there's some sort of biased reason they chose 1970. There wasn't.

You conflate a typo to being a serious flaw with the paper, instead of just a typo, and seem to ascribe it to researcher's trying to show something in the data that's not there. (and yes, Steve is serious that you can confirm that it's consistent with the chart... I just did.) As others stated, if you are actually concerned this isn't a typo, you should email the first author.

Lacking data with any significance, it's entirely reasonable to speculate that the chance of category 5 hurricanes increases if the chance of category 4 hurricanes also increases.

I repeat that you should post Bloom's rebuttal as an update.
9.3.2006 2:27pm
James Lindgren (mail):

guest wrote:

what ticks me off about your post is that you assume the minor flaws you see are both very significant and done with some sort of biased agenda in mind. You have "fallacious" crossed out, but not fully deleted - implying that there's some sort of biased reason they chose 1970. There wasn't.



I don't think you understand the editing convention I was following. I would much rather have not shown the crossouts and simply deleted the words I crossed out, but I didn't want to be accused of editing my post after posting without showing changes. Those changes were generated by a valid criticism that one of the commenters made above, so I edited the passage to reflect that the paper combines critics' concerns about the 1970 starting date with some logical fallacies attributed to unnamed critics. Then the authors of the paper effectively demolish the critics' fallacies. But they do not adequately deal with the implications of using 1970 as the start date. I just added another brackets to that passage in my original post to try to make it still clearer.

Further, as I commented above:


I did not accuse the authors of the BAMS paper of bias; I did not say that they should have chosen a different period. I said that "the paper dismisses concerns that the choice of 1970 as a starting point may give a misleading account because of the evidence that there was global cooling from 1940 to 1970," and that they do "not deal adequately [with] whether [their] choice of a relative cool period (1970) as a starting time influenced the results."


Guest wrote:


You conflate a typo to being a serious flaw with the paper, instead of just a typo, and seem to ascribe it to researcher's trying to show something in the data that's not there. (and yes, Steve is serious that you can confirm that it's consistent with the chart... I just did.) As others stated, if you are actually concerned this isn't a typo, you should email the first author.


Guest, you keep trying to attribute things to me that I didn't say. I wrote: "IF these are not merely typographical errors, and [the authors] did what the article reports that they did (i.e., double counted 1994 hurricanes), then the paper should never have been published." If they double counted, that's a serious error, even if it is not driving the conclusion. If they didn't double count 1994, then it's just 4 typos in 2 papers. Do I think that either error involves bias? Of course not.

As for confirming the data by looking at the chart without data labels that would permit confirmation, I already dealt with that argument in my response to Steve:


The authors' repeated claims that they included 1994 in two different periods (1990-94 and 1994-99) are clearly errors, and there is no way to tell whether they are just typos or something more serious from just looking at the two papers.

First, the graph immediately preceding the table does not have any data labels, so one can't compare and confirm whether the authors double counted 1994 or instead made 4 typos in two different papers (as you are certain they did). All one can do is eyeball the data in the chart, which is not at all clear whether it matches the data table. Indeed, from my eyeballing of the data, I would have estimated more than 270 cat-4 and cat-5 hurricanes 1990-2004 in the chart you point to, not fewer than 270, as the data table you point to shows.

Second, even if the chart were drawn in such a way that one could tell whether it exactly matched the data table (which it most definitely isn't), one still couldn't know whether they double counted 1994 or instead made 4 typos. If the authors mistakenly counted 1994 hurricanes in two of the three groups of years comprising the 1990-2004 period--and summed their three groups to get the total for 1990-2004--then the chart and the table would match exactly and the data would still be wrong because they double counted 1994. You may have some other basis for knowing that the errors are just typos, but the basis that you give would not persuade any sophisticated, fair-minded reader.


Guest wrote:


Lacking data with any significance, it's entirely reasonable to speculate that the chance of category 5 hurricanes increases if the chance of category 4 hurricanes also increases.

I repeat that you should post Bloom's rebuttal as an update.


Guest, I also said that this "speculation is an entirely plausible one . . .--but it's just that, speculation." I did not say that the speculation was unreasonable, just that the evidence did not support it.

And I pointed out that the authors' own data do not sem to show an increase in cat-5 hurricanes despite a tripling in cat-4 storms:


So far the data reported by the authors of the BAMS and Science studies do not show significant support for your view. If a tripling in cat-4 hurricanes does not lead to any significant increase in cat-5 storms, it's hard to imagine what kind of a dramatic increase in cat-4 hurricanes could lead to a significant effect on cat-5 storms. Your belief is a matter of faith, not evidence.

You must remember that the authors of the paper claim that they limited their public comments to issues that were established by scientific evidence published in peer review journals, not to otherwise reasonable speculations that were not supported by their own data. They may well have such evidence (it is entirely possible that they do); it's just not in either of their two published papers discussing the phenomenon.

As for emailing Judith Curry, I've already done so, and I included a request for her data by basin by year by hurricane category.
9.3.2006 4:31pm
Mike Lorrey (mail) (www):
Of course the pro-GW people are going to cherry pick the data. If you look at hurricane numbers for the whole 20th century, the first half had 50% more cat 4 &5 hurricanes than the latter half, yet they claim most of the warming occured in the latter half. This doesn't jive with the chicken little assertions of GW causing more 'canes.

If you talk to real climatologists, they'll point you at a 100 year cycle of North Atlantic Occcilations and Pacific Decadal Occilations that are primarily dependent upon variations in the solar cycle.

Any stats on storms and climate of less than a century is cherry picking and scientifically meaningless.
9.3.2006 6:21pm
guest:
I don't think you understand the editing convention I was following.

I apologize for misunderstanding your editing technique, and appreciate your honesty in crossing it out. I do think it suggests your own bias in approaching the article.

I wrote: "IF these are not merely typographical errors, and [the authors] did what the article reports that they did (i.e., double counted 1994 hurricanes), then the paper should never have been published."

Even by saying "if" suggests that this is a reasonable possibility. My guess is that it's a typo, and I think this is roughly confirmed with the table. There very well be some reason for it in the data, and that it's accounted for in the analysis. I strongly doubt that it's mistaken analysis, because it would be such a stupid and glaring error. I believe that it's irresponsible to make such accusations without knowing more, and I hope that you post an update after hearing back from Judith Curry.

Lacking data with any significance, it's entirely reasonable to speculate that the chance of category 5 hurricanes increases if the chance of category 4 hurricanes also increases. And I pointed out that the authors' own data do not sem to show an increase in cat-5 hurricanes despite a tripling in cat-4 storms... If a tripling in cat-4 hurricanes does not lead to any significant increase in cat-5 storms

Hold on there... Either the data is significant, or it's not. Your data (NB, only a part of what the author's used) on the North Atlantic is not significant (worldwide hurricanes may be statistically significant). The data you present doesn't show anything regarding category 5 hurricanes. Your second and last sentences implies some significance that is not there - the data doesn't show anything, and should be ignored (with a quick analysis using Poisson statistics (there may be a better way to do it, but it would still be insignificant), I think one say that category 5 hurricanes in the North Atlantic increased by less than a factor of 3.6, with a 95% confidence - much larger than the 1.56 increase in cat. 4 hurricanes in the North Atlantic).

Speculation is not a matter of faith. Speculation in scientific papers is about making reasonable guesses based on physical arguments. Although the speculation is untested by the analysis in a scientific paper, usually a similar or related phenomenon is tested.

I did not accuse the authors of the BAMS paper of bias; I did not say that they should have chosen a different period. I said that "the paper dismisses concerns that the choice of 1970 as a starting point may give a misleading account because of the evidence that there was global cooling from 1940 to 1970," and that they do "not deal adequately [with] whether [their] choice of a relative cool period (1970) as a starting time influenced the results."

I'd hope you realize after Bloom's post that their choice of time period is entirely reasonable based on data quality (i.e., satellite data providing a complete and unbiased data set for a given time period). They do provide an argument for why the post-1970 period is a better test of their hypothesis. Scientists defend their data with such arguments all the time. I agree that it's an issue for the field, but I don't think it's a problem for a single, focused paper - unless the reader (either the media or yourself) want to place more significance to a single paper than is reasonable .
9.3.2006 6:26pm
Harry Eagar (mail):
guest, the ONLY data available or ever to become available on frequency of storms starts around 1970.

You can twist and bend it as much as you want, but the only possible conclusion you can draw from it is that big storms were distributed rather evenly during the past four decades.

We cannot go back and count storms that were not observed before 1970, so whether recent experience shows a new trend is unknowable.

As for big storms in the No. Atlantic, Professor Lindgren's summary shows that, since 1964, there have been either one or two in each 5-year block.

And three in each 10-year block. Now, if you have only 3 events and you halve the bin size, you MUST have a distribution of 2 &1 or 0 &3.

There are no 0 &3 distributions, so what we have is NO CHANGE over 40 years.

The No. Pacific shows about the same.

People who claim that storms are increasing in number or frequency are talking through their hats.
9.3.2006 6:43pm
guest:
guest, the ONLY data available or ever to become available on frequency of storms starts around 1970.

Maybe, maybe not. There will obviously always be quality issues with pre-1970 data, which is why the choice of 1970 makes sense. That was Bloom's point.

You can twist and bend it as much as you want, but the only possible conclusion you can draw from it is that big storms were distributed rather evenly during the past four decades.

Umm... huh? I think the point of the Curry paper is that the category 4-5 storms are not evenly distributed.

And three in each 10-year block. Now, if you have only 3 events and you halve the bin size, you MUST have a distribution of 2 &1 or 0 &3.

There are no 0 &3 distributions, so what we have is NO CHANGE over 40 years.


It's not NO CHANGE... it's no statistically detectable change. Big difference. The data are consistent with either an increase, a decrease, or no change in category 5 storms in the North Atlantic (hence, the term insignificant).

The No. Pacific shows about the same.

I haven't seen the number of Cat. 5 storms in areas other than the North Atlantic, but perhaps I missed a pointer to that data. Please link to this data.
9.3.2006 6:52pm
guest:
Orson23:

Mann responded to the Wegman reporthere (and given that Jim linked to your hysterical post, he should probably link to Mann's response to Wegman's report, as well).

Also, if you are going to level the criticism of bias from money, please dish it out equally - who funds folks like Michaels and Baliunas?
9.3.2006 9:10pm
Harry Eagar (mail):
It isn't a quality of data problem, it's a no data problem.

If you cannot even know how many storms there were, you cannot begin to assess if there has been a change in intensity.

I imagine the No. Pacific data is on the Internet somewhere. I got mine face to face from the guys who count the storms.
9.3.2006 9:30pm
Mark A. York (mail) (www):
As a scientist myself, a fisheries biologist, I took the time to write a novel about global warming following Michael Crichton's misguided lead. Crichton's probelm is he doesn't understand the reality of the problem amd apparently neither do you. Who agrees with me? Realclimate scientists. Did you gather they work for NASA? Hello! Cluetrain on track nine. Meteorologists for weather site Wunderground do also. But what could they know compared to a non climate scientist like Wegman? This is pure shillery. Kerry Emanuel disagrees, and he IS the expert on this. Hurricanes are just one aspect and no one event can be attributed to a global increase in temperature, which is documented and real at one degree celsius and climbing: CO2 380 ppm and climbing. No amount of sleight of hand qualitative data issue can erase reality: more warm water in the equatorial regions is more fuel for the fire.

Never mind ice sheets melting at record rates, permafrost evaporating and villages in the arctic falling into the sea, moved at taxpayer expense. Lets argue about erasing hurricane intenity data. It's fool's errand. I have characters in my book cut from this same cloth. They're denier idiots. The choice is yours? Education or ignorance and denial?
9.3.2006 11:31pm
James Lindgren (mail):
Guest,

The only things in your last few posts that I think I need to respond to are your comments on Cat-5 hurricanes. You wrote (appearing to quote me in the first paragraph you italicized):


Lacking data with any significance, it's entirely reasonable to speculate that the chance of category 5 hurricanes increases if the chance of category 4 hurricanes also increases. And I pointed out that the authors' own data do not sem to show an increase in cat-5 hurricanes despite a tripling in cat-4 storms... If a tripling in cat-4 hurricanes does not lead to any significant increase in cat-5 storms


Hold on there... Either the data is significant, or it's not. Your data (NB, only a part of what the author's used) on the North Atlantic is not significant (worldwide hurricanes may be statistically significant). The data you present doesn't show anything regarding category 5 hurricanes. Your second and last sentences implies some significance that is not there - the data doesn't show anything, and should be ignored . . . .

You are really confused. The first sentence that you italicize and quote as if I wrote it is YOUR SENTENCE. I did not write: "Lacking data with any significance, it's entirely reasonable to speculate that the chance of category 5 hurricanes increases if the chance of category 4 hurricanes also increases."

You wrote that sentence, not me. Don't make up language and then criticize me for what you made up.

And you also wrote this:


I haven't seen the number of Cat. 5 storms in areas other than the North Atlantic, but perhaps I missed a pointer to that data. Please link to this data.


I think you completely misunderstood my argument here, which was based on the charts in the 2006 BAMS article.

Their chart seems to show a slight, but apparently not statistically significant, increase in cat-5 storms from 1970 through 2005 worldwide. This compares to a tripling in cat-4 storms worldwide over the same period.

Accordingly, I wrote about the link between cat-4 and cat-5 hurricanes:

Steve, your speculation is an entirely plausible one (and it occurred to me before I posted)--but it's just that, speculation.

So far the data reported by the authors of the BAMS and Science studies do not show significant support for your view. If a tripling in cat-4 hurricanes [worldwide] does not lead to any significant increase in cat-5 storms [worldwide, as the 2006 BAMS data show], it's hard to imagine what kind of a dramatic increase in cat-4 hurricanes could lead to a significant effect on cat-5 storms.

Last, Guest, I was thrilled to read your argument:


Hold on there... Either the data is significant, or it's not.

EXACTLY! That's what I've been trying to get you to admit!

So you must now agree with me that the BAMS data showing no significant increase in cat-5 hurricanes worldwide means that you have jettisoned the argument that it's OK to treat something as true, despite no significant trend in either the North Atlantic or worldwide data on cat-5 hurricanes.

After all, as you put it, "Either the data is significant, or it's not." It's apparently not, so let's not pretend any longer that it is.

Jim Lindgren
9.3.2006 11:33pm
Mark A. York (mail) (www):
The data are significant. Recalibrating what constitutes a category 4-5 is an ad hoc attempt at rewriting history. It plays into "denierosis" which is terminal in my view and it's a disease only conservatives seem to have.
9.3.2006 11:46pm
Lev:
I would be most interested in a thread that analyzed the recent California legislation intended to reduce carbon dioxide emissions by 25% back to 1990 levels - how exactly they plan to do this and what the consequences are.

If they are successful, does that mean there will be no more Cat 4 or 5 hurricanes.
9.4.2006 12:01am
James Lindgren (mail):

Mark A. York wrote:

The data are significant. Recalibrating what constitutes a category 4-5 is an ad hoc attempt at rewriting history. It plays into "denierosis" which is terminal in my view and it's a disease only conservatives seem to have.


I did NO recalibrations of the 2006 BAMS paper. It shows a huge rise in cat-4 storms, while it appears to show NO significant increase in cat-5 hurricanes, which the authors (not I) separate out from cat-4 hurricanes. As to the North Atlantic hurricanes discussed in the prior 2005 Science paper, I did not "recalibrate" any storms; I simply went to the data source they cited and showed that the North Atlantic data on cat-5 storms matched the authors' worldwide cat-5 data in the BAMS article: NO SIGNIFICANT EFFECT.

I wrote:


1. The new BAMS article shows persuasive evidence of a huge [statistically significant] jump in category-4 hurricanes 1970-2004, but declines or flat trends in the numbers of stronger and weaker hurricanes.

Even Steve Bloom agreed with me on that point, replying simply "OK." You seem to disagree, but you are unable to point to why the BAMS data on cat-5 hurricanes is significant when the BAMS paper seems to show that it's not.

Your being a climate scientist doesn't magically make non-significant data significant. To be at all persuasive, you really have to argue using evidence. Why don't you put aside name-calling and support your strongly worded assertions of significance beyond the big jump in cat-4 storms which is established in the BAMS paper?
9.4.2006 4:58am
guest:
Jim,

Sorry to screw up quotes. I messed up and I apologize for it. Yikes. On the bright side, at least I wasn't turned around to the point of criticizing the second your thoughts, not mine.

My very first post said

...even though the number of category 5 storms itself is too insignificant to used as evidence in either direction.


and I'm pretty sure I haven't said otherwise. If that's what you've been trying to get me to admit, that's just weird (though I imagine you were simply confusing posts - there's a lot of them, so that's pretty understandable). But I think that evens us up for putting words in each other's mouths.

But then you say (and I think this is you this time):

It appears to show NO significant increase in cat-5 hurricanes...

Didn't we just agree that the data were not significant? I think so... yet this statement is phrased such that the reader will interpret that there was no increase. That's not true. The upper limit on the increase is larger than the increase that would be expected from the increase in Cat. 4 hurricanes. The Atlantic data on Cat. 5 hurricanes doesn't say anything significant, so please don't phrase it as if we would've expected to see an increase.

I have said that, lacking significant data, its entirely reasonable to speculate about Cat. 5 storms based on Cat. 4 storms. I also speculate that the worldwide Cat. 5 numbers may be marginally significant, and am interested in seeing them, if Curry happens to respond with their data.
9.4.2006 5:30am
markm (mail):
"guest, the ONLY data available or ever to become available on frequency of storms starts around 1970."

Older data about storms that never made landfall may be too poor to use for comparisons, but every major storm that hit the USA has been recorded in newspaper archives ever since there were cities all along the costs. It might take a lot of extra work to use that data, but it's not nonexistent.

One thing I have seen (I can't remember where) was a graph of major storms that started on or before 1940 - and the peak in the 1940's was as high as any recent year. 1970 was near a minimum. I have no idea how those numbers were measured. In any case, if this is a cyclical phenomenon, and any study that doesn't extend over a full cycle or more will be worthless.
9.4.2006 7:48am
byomtov (mail):
James Lindgren,

You used the word "mainly" in a discussion of the differences between law review articles and peer-reviewed articles in other disciplines:

"But mainly, law professors do not usually tell people that anyone who disagrees with their scholarship is like a holocaust denier.

Suppose I am comparing the merits of X and Y, and declare that, "mainly," X lacks some undesirable feature. I think it is far for the reader to conclude that Y has that feature and that this difference is an important one.

But while your statement about law professors is surely true, it is hardly the case that other scholars frequently make such declarations, so your difference is no difference at all.
9.4.2006 12:04pm
Harry Eagar (mail):
mark, it is well known, at least among people who know anything about hurricanes and other large storms, that until satellite surveillance began, many, many storms were never observed.

In the eastern tropical Pacific, the average number of known storms more than doubled once satellites started observing.

What difference can it possibly make whether a storm came ashore? If you are counting storms, you have to know how many there were.

It is similar to your statement that it is certain that temperature has risen a degree in a century. It is not certain. About two-thirds of the globe was not under observation a hundred years ago, including all the coldest places.

Since we are certain, from current observations, that large regions can differ in sign in secular temperature measurements, it is possible that the temperature rise in the last hundred years was larger than a degree, smaller than a degreee or even, maybe, not a rise at all.
9.4.2006 2:03pm
Eli Rabett (www):
Well, everyone here is going on as if there is only data. Analysis with only data is curve fitting. snark: Analysis with only models is string theory /snark.

But we do have a theoretical framework within which the data can be analyzed. That framework is based on known and verified physics. It predicts much about climate. That model predicts that tropical cyclone intensity should strengthen across the board as sea surface temperatures rise. Since there are very few Cat 5 cyclones, it is not surprising that there has been no significant increase within the parameters of the observed sea surface temperature warming. That is why Steve Bloom was exactly right as to the policy position wrt building codes and preparation. Jim Lindgren is merely trying to parse his way out of an area he should have been much more cautious of wandering in to.

On the other hand, we have the assumption of an Atlantic multi-decadal cycle in hurricane intensity and frequency, but THIS IS CURVE FITTING, and, from the data, how many cycles have been observed? Think about it, how do you fit a cycle if you have not accurately observed many ups and downs. Worse, how does this apply to the Pacific. To give you an idea of the mess this curve fitting gets you into we have the words of Len Pietrafesa, hurricane expert at North Carolina State University:

"There are five fundamental modes of oscillation -- three to five years, 10 to 12 years, about 20 years, about 35 years and 45 to 60 years. The (oscillation) modes superimpose, and we get what we get as a function of the year we are in."

You could fit a cow with that number of Fourier components.
9.4.2006 5:29pm
James Lindgren (mail):
Judith Curry has responded over at RealClimate.org. She reports that the double listing of 1994 is indeed a typo. She also confirms that the data do not show a statistically significant increase in cat-5 storms (so most of my other criticisms, which were based on that fact, also appear to me to be well founded).
9.4.2006 5:31pm
guest:
Judith Curry also notes that the category 5/Gulf coast comment was a response to a question, rather than being in their paper or their press release. That differs substantially from your characterization of that statement.

So all you are left with is that you are correct that a data point that was never claimed to be significant is insignificant, and that more data before 1970 would really be great, except that it doesn't exist. And, oh yeah, the number of weak storms has remained constant, although the paper included exactly the same statement ("The number of category 1 hurricanes has remained approximately constant"), so that's not really a criticism of the paper, is it?

Your brief foray into the scientific literature truly is a brilliant critique. Great job!

What I find really amusing is that, at least in my scientific but lay opinion, there are significant outstanding issues with the hurricane-global warming link that need to be resolved. But by framing the debate as an attack on the integrity of a single, well-focused paper, you completely miss most the real issues.

Please post Judith Curry's comments in a manner that's obvious to those few of us not still reading this thread.
9.4.2006 6:14pm
Aaron Bergman (mail):
She also confirms that the data do not show a statistically significant increase in cat-5 storms (so most of my other criticisms, which were based on that fact, also appear to me to be well founded).

You still don't seem to understand this point. The data for category five storms means nothing. The statistics are too small to say, from that bin alone, whether things are rising or falling or whatever. By taking into account the rest of the data, however, you can much better determine the trend. Doing this precisely involves having a good model for the yearly distribution in intensity, but even without that, for the purposes of answering a policy question one can make a reasonable general inferrence based on the science.

Let's remember where this started. You said, "Did they just fabricate this claim of "increased risk" of category-5 storms?". Will you agree that this is unnecessarily inflammatory? Do you understand the "scientific basis" for the claim now?
9.4.2006 7:38pm
Eli Rabett (www):
Let me get up on another soapbox. The categories of storms are arbitrary and very coarse. A hurricane at the top of the Cat 3 could have winds that were within the measurement error of a Cat 4. It would be much better to have enough data that we could use a finer scale for analysis. However, given that more hurricanes are not a good thing, let us not wish for that.

It is important to realize that even a category 1 storm is pretty destructive. Increased sea surface temperatures from global warming will move more tropical depressions into the tropical storm category, more tropical storms into the hurricane category, more cat 1 to cat 2, etc. Not something to wish for.
9.5.2006 1:24am
Judith Curry (mail):
warning: if you try to link to the urls, delete the spaces in the url address, i could not get past your 60 character limit


Dear Volokh bloggers:

I wandered onto this site via a circuitous route. If you are interested in this work, I refer you to 2 links:
1. The BAMS article itself
http://ams.allenpress.com/ pdfserv/10.1175%2FBAMS-87-8-1025
2. My recent congressional testimony on the same topic
http://reform.house.gov/UploadedFiles/ GT%20-%20Curry%20Testimony.pdf

At the start of my testimony is a brief essay on global warming and skepticism.
Also, section 4 in the BAMS article was mainly trying to point out that we had no greenhouse warming agenda in writing the original science article, but were "pushed" be the media into dealing with this issue. I and my colleagues have done our best to maintain as much integrity in our science as possible, given the craziness of this debate in the media and in the blogosphere. None of us are raving greenhouse warming maniacs with an "agenda"

For interesting discussions of the technical aspects of the paper, i refer you to threads on realclimate and climateaudit
http://www.realclimate.org/index.php/ archives/2006/08/fact-fiction-and-friction/
http://www.climateaudit.org/?p=790

Thanks for your interest in my work

Judy Curry
9.5.2006 12:33pm
James Lindgren (mail):
Judy:

Thanks again for coming over here to respond.

Jim Lindgren
9.5.2006 3:25pm