Revealed! NOAA’s Mystery Hurricane Report

September 27th, 2006

Posted by: Roger Pielke, Jr.

Here is in its entirety is the NOAA “report” discussed in Nature yesterday. It is in fact titled a “fact sheet” and looks more like a set of talking points than a consensus report. I do not have the figures being referred to in the text. There is absolutely nothing new or surprising in the fact sheet. Why NOAA or DOC officials would not want this released is beyond me. Have a look.

NOAA Fact Sheet: Atlantic Hurricanes and Climate

What has been Atlantic hurricane activity during the 20th Century?
• Atlantic hurricane seasons since 1995 have been significantly more active, e.g. more hurricanes and more intense hurricanes, that the previous two decades (figure 1)
• Earlier periods, such as from 1945 to 1970 (and perhaps earlier), were apparently as active as the most recent decade.
• The past decade has seen increased U.S. landfalls, however periods of even higher landfalls occurred early in the century (figure 2)
• Strong natural decadal variations, as well as changes in data quality, density, sources, and methodologies for estimating hurricane strengths, lie at the heart of arguments whether or not a global warming contribution to a trend in tropical cyclone intensities can be detected.

How have ocean temperatures varied?
• Over the 20th Century, global ocean temperatures and sea surface temperatures in the main development region (MDR) for hurricanes in the tropical Atlantic, (and Gulf of Mexico) have warmed at similar rates, indicating a role for global warming in these regions. (Figure 3)
• Anomalous MDR, tropical Atlantic temperatures were significantly warmer than the global average from about 1930 to 1970 and after 2000 . This warming is attributed to the Atlantic Multi-decadal Oscillation (AMO)
What factors influence seasonal to multi-decadal hurricane activity
• Hurricanes respond to a variety of environmental factors besides local ocean temperatures.
• The tropical multi-decadal phenomenon and the El Nino/La Nina cycle are important factors in determining the conditions for seasonal to multi-decadal extremes in hurricane activity.
• Research indicates that global warming can also increase hurricane intensities; there is less evidence for impacts on frequency.

How long will the current active period last?
• Scientists disagree as to whether currently a sound basis exists for making projections on how long the current active period will last. The viewpoints are:
o Limited understanding of natural decadal variability, combined with its irregular temporal behavior, preclude definitive statements about how long the active period will last. (NOAA)
o One might expect ongoing high levels of hurricane activity and U.S. landfalls for the next decade and beyond since the previous active period (1945-1970) lasted at least 25 years. (NOAA)
o Because of global warming the active period could persist
Programs of improvements to data sets, diagnostic studies for improved understanding, and systematic numerical experimentation studies will help to reveal the underlying causes for the recent active period and to predict how long the period of increased activity will last. NOAA is actively engaged in each of these activities.

Key Problems NOAA is working on
• Understanding the dynamics of the AMO, its links to the larger-scale tropical climate variability, and developing an ocean monitoring and decadal prediction capability
• Improving the quality and scope of hurricane relevant data sets
• Numerically simulating and ultimately understanding seasonal to decadal hurricane variability
• Understanding whether or not and to what degree anthropogenic forcing is having an influence on hurricanes
• Developing a predictive understanding of global climate variability and trends and the impacts of these on extreme events
• Making improvements to short range hurricane track and intensity forecasts through improved models and development of additional capabilities for hurricanes.

NOAA Resources for Additional Information

• NWS/NCEP/CPC – intraseasonal to multi-season climate forecasts; seasonal hurricane forecasts; diagnostic studies of major climate anomalies; real time monitoring of climate.

• NWS/NCEP/TPC/NHC – issue daily and seasonal (in conjunction with CPC and HRD) operational hurricane forecasts; maintain and update the official Atlantic and Northeast Pacific hurricane databases from which observational climate studies are conducted

• NESDIS/NCDC – official archive for climate data sets; development of global tropical cyclone databases, analysis of historical frequency and strength of Atlantic Basin hurricanes to support engineering design and levee rebuilding in New Orleans, analyses of climate trends, monitoring and historical perspective on current seasons.

• OAR/AOML/HRD & PHoD – physical understanding of hurricane dynamics through use of research aircraft and field studies; improvements to hurricane track and intensity forecasts; monitoring of Atlantic ocean circulations; studies of Atlantic climate

• OAR/GFDL – studies of climate variability and change; development and use of the required climate models; development of models used for operational hurricane forecasts by NOAA and the NAVY; numerical studies of climate impacts on hurricanes and their decadal variability

• OAR/ESRL – diagnostic studies of climate variability and changes; impacts of climate on extreme events.

• NOAA Climate Office – intramural and extramural support for development of a predictive understanding of the climate system, the required observational capabilities, delivery of climate services.

13 Responses to “Revealed! NOAA’s Mystery Hurricane Report”

  1. D. F. Linton Says:

    Perhaps the motives of Nature’s source within NOAA would explain this teapot tempest better than any thing in this document.

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  3. Hayden Says:

    Actually this statement: “Research indicates that global warming can also increase hurricane intensities; there is less evidence for impacts on frequency.” is WAY off NOAAs hurricane talking points.

    They have never admitted to ANY link through their official mouthpieces. In fact, you can still find this statement on NOAA’s website: “NOAA research shows that the tropical multi-decadal signal is causing the increased Atlantic hurricane activity since 1995, and is not related to greenhouse warming.”

    If you follow this story you can find an incredible effort by NOAA public affairs to control all public statements that pertain to this issue. This may seem like a small statement to those that read scientific research and are aware of observed correlations – however CNN/FOXNEWS etc. – where most Americans get their information – is still repeating the official NOAA line as stated above.

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  5. Roger Pielke, Jr. Says:

    Hayden- Thanks but I think that your reference is out of date. NOAA since modifed its earlier statement with this addition:

    “*EDITOR’S NOTE: This consensus in this on-line magazine story represents the views of some NOAA hurricane researchers and forecasters, but does not necessarily represent the views of all NOAA scientists. It was not the intention of this article to discount the presence of a human-induced global warming element or to attempt to claim that such an element is not present. There is a robust, on-going discussion on hurricanes and climate change within NOAA and the scientific community.

    The headline and paragraph could have more clearly stated:

    “Agreement Among Some NOAA Hurricane Researchers and Forecasters”

    There is agreement among a number of NOAA hurricane researchers and forecasters that recent increases in hurricane activity are primarily the result of natural fluctuations in the tropical climate system known as the tropical multi-decadal signal.””

    I do not think that there has been any shortage whatsoever of media coverage of the possibility that global warming may have an effect on hurricanes. This is borne out by opinion poll, for instance:

    If you have data to the contray, do share it.


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  7. Roger Pielke, Jr. Says:

    Housekeeping update;

    I now have multiple copies of the document (thanks to all who have responded!) with different dates. The substance is the same, so I have removed the date from the original post.


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  9. TCO Says:

    I don’t see any dramatic controversy in NOAA management not signing off on particular slanted press releases. The inmates don’t run the asylum. If one of the researchers wants to submit a paper to a journal, let him do that. Management doesn’t have to acqueisce in every random press sheet. Or do so immediately. Or do so without edits.

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  11. Webster Says:


    Here is the issue as I see it. NOAA has allowed papers to be published that have a particular slant: global warming has no or minimal impact on hurricane intensity and frequency. Further, it has made statements that this is the consensus of NOAA scientists. But it has also muzzled scientists with contrary opinions by not allowing the press access to them. Finally, a report from a group of NOAA scientists is not allowed distribution. The draconian aspects of censorship aside (and they are hard for me to put them aside) The issue to me is simple. NOAA is not performing its mandate in providing the probability of meteorological and oceanic events occurring be they of short term (hurricane tracking and intensity forecasts, for example) or longer term (e.g., ENSO forecasts) or the probability that global warming may effect these shorter term probabilities. In other words, NOAA is not performing a scientific due diligence on a problem of possible consequence. Nor are they allowing their scientists to perform a scientific due diligence. From an adaptation perspective alone it would seem to me that information from NOAA on linkages of global warming and hurricanes is critical. Without an assessment of the probabilities of increasing intensity/frequency/location the job of adaptation in hurricane effected regions becomes particularly difficult.

    I believe that there is still a lot of work to be done on the issue of hurricanes/tropical storms and global warming. But I also believe that the evidence is sufficiently strong for probabilities to be assessed. Simply, the public deserves better than the actions of the NOAA administration.

    It is sad to see politics run roughshod over science and service.

    Peter W

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  13. Roger Pielke, Jr. Says:


    Thanks much for weighing in. A few replies and a few questions:

    1. Are you suggesting that NOAA has disallowed publication of certain scientific papers? I haven’t seen or heard anything about this. If so it would be a far more serious issue than the “fact sheet” or press releases.

    2. You assert, “NOAA is not performing its mandate in providing the probability of meteorological and oceanic events occurring be they of short term (hurricane tracking and intensity forecasts, for example) or longer term (e.g., ENSO forecasts) or the probability that global warming may effect these shorter term probabilities.”

    NOAA does provide ENSO forecasts:

    And seasonal hurricane forecasts:

    As an operational agency NOAA product necessarily must go through a process of “technology transfer” — i.e., a proof of concept. Products in this phase are listed “experimental”, e.g., see this list:

    I am aware of no one in the hurricane community — in the US funded by any agency or abroad — who has developed methods for seasonal forecasting that explicitly incorporate global warming. Are you? If the research is not there, nor proof of concept products, how can NOAA operationalize a product? After all seasonal hurricane forecasts were made on an experimental basis for more than a decade before NOAA operationalized them.

    3. You write, “From an adaptation perspective alone it would seem to me that information from NOAA on linkages of global warming and hurricanes is critical. Without an assessment of the probabilities of increasing intensity/frequency/location the job of adaptation in hurricane effected regions becomes particularly difficult.”

    This is simply incorrect based on a wide range of studies of hurricane impacts and the role of predictions in decision making. Improved adaptation can proceed based only on a rough sense of probabilities (we know where hurricanes hit) and a detailed sense of vulnerabilities. We prepare well for earthquakes without precise knowledge of probabilities.

    4. You write, “I also believe that the evidence is sufficiently strong for probabilities to be assessed.”

    Does this mean we can expect future seasonal forecasts to come from your group? ;-)

    Thanks again!

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  15. Rick Piltz Says:

    Hayden’s comment is on the mark. Your reply to him is totally misleading. To set the record straight: The partial disclaimer text on the NOAA magazine article is in a small-font endnote at the end of a long article that remains unchanged to this day, including, in the opening paragraph, the sentence that Hayden quotes. Further, the footnote was added LONG after the magazine article was published and it was added without any announcement. It also was added after the end of the hurricane season, when it was least likely to be picked up. The original piece ran on November 29, 2005, the day before the hurricane season officially ended, deliberately timed when NOAA knew there would be extensive end-of-season news coverage. The undated endnote was added sometime in February 2006. The misleading NOAA article got media coverage, including by Rush Limbaugh, who on December 1 said “NOAA has made it plain there’s no evidence whatsoever global warming has anything to do with any increasing hurricane activity or intensity.” This is the sort of damage the NOAA scientists’ fact sheet might help to stop if the administration wasn’t burying it — and may help explain why they want to keep it buried. Applied Poli. Sci. 101.

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  17. Roger Pielke, Jr. Says:


    Thanks. I accept that you may not like how NOAA has responded to criticism of its handling of the hurricane/climate issue. After this week it is clear to me that they still have a ways to go.

    But as far as “damage,” I seriously doubt that a bigger font on a web page is going to change what Rush Limbaugh says. In fact, you’d be hard pressed to provide evidence of any “damage” done by NOAA’s behavior, except to NOAA itself. But if you have such data, do share it. Rush Limbaugh statements don’t make it.


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  19. Rick Piltz Says:

    My point in mentioning Rush was just to give a vivid example of how NOAA’s misleading communication has served to feed what I refer to as the global warming denial machine.

    And, come on now: I clearly wasn’t arguing for a larger endnote font, but against administration politicals burying a federal climate scientists’ fact sheet that helps to set the record a bit straighter.

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  21. webster Says:

    Re your comments:

    First I acknowledge an error. Of course I know that NOAA provides forecasts of weather and climate. And you know I know that. I was talking of what one might infer about chnages to weather and ENSO forecasts relative to global warming.

    But that is incidental. I am amazed that a person interested/involved in policy is disintersted in probabilities. How can one make rational decisions (all the way from crossing a road to determining whether or not a city should be evacuated ) without considering probabilities. I thought they were the grist of policy. And I thought for once we would agree. Alas, perhaps I don’t understand policy making as it is currently undertaken. Perhaps it is best way to deterimine policy should be made (dare a scientist say such a thing?) and one not practiced enough. Or is it that you like to argue a point, any point for the sake of argument. I think there is a high probability of the latter!

    I guess it doesn’t really matter.

    Peter W

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  23. Roger Pielke, Jr. Says:


    Thanks. The issue of how and when probabilities matter for adaptation is not simple, and involves a range of different perspectives. See for example:

    Dessai,S. and Hulme,M.(2004) Does climate adaptation policy need probabilities? Climate Policy 4 107-128.

    How would NOAA’s operational products look different if they included global warming factors? Can you point to examples of such forecasts being made experimentally?


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  25. James Elsner Says:

    We have been developing the science and technology of hurricane climate since 1993 ( We create probabilistic seasonal models (see Peter’s comments) that can be used operationally. The science on which the models are based appear in leading academic journals. They are used by the reinsurance industry and contain an option to include global warming as a factor. They are ignored at NOAA.