WMO Consensus Statement on Tropical Cyclones and Climate Change

November 30th, 2006

Posted by: Roger Pielke, Jr.

The World Meteorological Organization (WMO) has just released two updated statements on the state of science on tropical cyclones and climate change. The statements have been released today through the Instituto Meteorologico Nacional, San Jose, Costa Rica. Anyone referencing this post or the statements, please do acknowledge them as the source.

We are pleased that the WMO statements are 100% consistent with the views on this subject that we have been sharing over the past few years. In particular, it should now be completely unambiguous that those who are representing hurricane impacts as being related to greenhouse gas emissions, without acknowledging that this is not a widely shared perspective among scientists, are either cherry picking the relevant science or misrepresenting the community consensus. As a matter of policy, those interested in addressing the impacts of tropical cyclones on people and economies necessarily should be focued on adaptive responses. We have obviously made this case for a while, now there is no ambiguity.

Read on for details on the content of the statements.

The summary statement (PDF) is one page and reflects a consensus among all particpants (125 people from 34 countries) at the just-concluded International Workshop on Tropical Cyclones in Costa Rica. The statement describes its authorship as follows:

The global community of tropical cyclone researchers and forecasters as represented at the 6th International Workshop on Tropical Cyclones of the World Meteorological Organization has released a statement on the links between anthropogenic (human-induced) climate change and tropical cyclones, including hurricanes and typhoons.

The ten consensus statements are as follows:

Consensus Statements by International Workshop on Tropical Cyclones-VI (IWTC-VI) Participants

1. Though there is evidence both for and against the existence of a detectable anthropogenic signal in the tropical cyclone climate record to date, no firm conclusion can be made on this point.

2. No individual tropical cyclone can be directly attributed to climate change.

3. The recent increase in societal impact from tropical cyclones has largely been caused by rising concentrations of population and infrastructure in coastal regions.

4. Tropical cyclone wind-speed monitoring has changed dramatically over the last few decades, leading to difficulties in determining accurate trends.

5. There is an observed multi-decadal variability of tropical cyclones in some regions whose causes, whether natural, anthropogenic or a combination, are currently being debated. This variability makes
detecting any long-term trends in tropical cyclone activity difficult.

6. It is likely that some increase in tropical cyclone peak wind-speed and rainfall will occur if the climate continues to warm. Model studies and theory project a 3-5% increase in wind-speed per
degree Celsius increase of tropical sea surface temperatures.

7. There is an inconsistency between the small changes in wind-speed projected by theory and modeling versus large changes reported by some observational studies.

8. Although recent climate model simulations project a decrease or no change in global tropical cyclone numbers in a warmer climate, there is low confidence in this projection. In addition, it is unknown how tropical cyclone tracks or areas of impact will change in the future.

9. Large regional variations exist in methods used to monitor tropical cyclones. Also, most regions have no measurements by instrumented aircraft. These significant limitations will continue to make detection of trends difficult.

10. If the projected rise in sea level due to global warming occurs, then the vulnerability to tropical cyclone storm surge flooding would increase.

In addition the WMO has released a lengthy statement (PDF) co-authored by the WMO Tropical Meteorology Research Programme Committee, with members, John McBride (Australia, Committee Chair); Kerry Emanuel, Thomas Knutson, Chris Landsea, Greg Holland, Hugh Willoughby (USA); Johnny Chan, C-Y Lam (Hong Kong, China); Julian Heming (United Kingdom), Jeff Kepert (Australia).

The Committee’s statement describes its purpose as follows:

This statement was developed, discussed and endorsed at the World Meteorological Organization (WMO) Sixth International Workshop on Tropical Cyclones, San Jose Costa Rica, November 2006. These invitation-only WMO International Tropical Cyclone Workshops are held every four years to bring together researchers and practitioners in the field of tropical cyclone forecasting. The Sixth Workshop was attended by 125 delegates from 34 different countries and regions. The Statement has been requested by WMO leadership and many heads of National Meteorological and Hydrological Services so they can respond to questions from the media, and also to assist in advising their governments on future activities and how to respond to climate change effects.

The statement includes the following conclusions:

On debate surrounding the trends documented in the Emanuel and Webster et al. papers from 2005: “This is still hotly debated area for which we can provide no definitive conclusion.”

On what to expect for the future: “Given the consistency between high resolution global models, regional hurricane models and MPI theories, it is likely that some increase in tropical cyclone intensity will occur if the climate continues to warm.”

On attribution of recent storms and seasons: “The possibility that greenhouse gas induced global warming may have already caused a substantial increase in some tropical cyclone indices has been raised (e.g. Mann and Emanuel, 2006), but no consensus has been reached on this issue.”

On the societal factors driving losses: “Recent decades have seen a continuous increase in economic damage and disruption by tropical cyclones. This has been caused, to a large extent, by increasing coastal populations, by increasing insured values in coastal areas (e.g., Pielke 2005) and, perhaps, a rising sensitivity of modern societies to disruptions of infrastructure. For developing countries large loss of human life will continue as the increasing coastal populations are a result of population growth and social factors that are not easily countered (Zapata-Marti, 2006).”

On the expectations of new knowledge in this area: “Because of the rapid advances being made with this research, the findings in this statement may be soon superceded by new findings. It is recommended that a careful watch on the published literature be maintained.”

Bottom line?

The perspective that we have provided here over the past several years and summarized in two BAMS articles has held up extremely well.

39 Responses to “WMO Consensus Statement on Tropical Cyclones and Climate Change”

  1. Steve Hemphill Says:

    I guess that in combination with this:


    we can expect a 1% increase in wind speeds over the next century (based on the last 7 years increase of 0.015 deg C)?

  2. 2
  3. Jim Clarke Says:


    Your work in this area has been commendable.

    Do you think this WMO announcement will restrain those who wish to equate AGW with recent disasters? Much more importantly, do you believe that it will promote action, resources and policy towards the important issues of adaptation and smarter development?

  4. 3
  5. Roger Pielke, Jr. Says:


    Thanks for the kind words.

    The scientists involved with the WMO statement are to be commended for their leadership. The odds for more effective disaster policies to be implemented is enhanced with solid policy analyses behind them. Hopefully the WMO statement will motivate more responsible statements by advocates on these issues – we shall see.

    Thanks again!

  6. 4
  7. William Connolley Says:

    Steve – if you’re unwise enough to believe in a trend of 0.015 oC per 7 years into the future, then Brian Schmidt will be interested in betting with you.

  8. 5
  9. Mark UK Says:

    Disaster policies are important after all, those who were hit by Rita or Katrina did not care that much about the whole global warming debate on hurricanes etc… They did care that the response was amateuristic and the plans in place were inadequate to deal with the situation.

  10. 6
  11. Jim Clarke Says:

    Mark UK,

    Any plans for a disaster involving a large number of people are going to be inadequate. There is no way to insure 100% compliance to the directives of the plan. Also, it is a disaster! Unpredictable challenges arise in disasters that must be dealt with. Nonetheless, the hurricane plans for those areas were actually pretty good. In New Orleans, the problem was that the local politicians did not follow the plan and a segment of the population was totally unaware of it. It is my opinion that the Mayor of New Orleans should be in jail for gross negligence. Instead he was re-elected. Go figure!

    As far as the response being amateurish…by what standard? It goes without saying that the response to any large disaster ‘could have been better’, but a better response requires more and more resources from the people who ultimately pay for the response. Why are there not enough shelters? Because it costs money to build shelters and there is little incentive to build shelters that may sit idle for decades, waiting for the next disaster. It is also not possible to stage relief efforts in an area about to be hit by a hurricane. All resources must be hundreds of miles away and brought in only after the winds die down. If the entire region is flooded, it takes that much more time to bring in the resources.

    Because of the physical reality of the hurricane disaster, all residents of hurricane prone areas are warned repeatedly to have at least a 3 day supply of food, water and necessities. Since New Orleans is the ‘worst-case-scenario’, that message should have been even louder and clearer.

    Nothing happened to New Orleans that was not anticipated by the plan, but plans are only as good as the people who are supposed to implement them.

    You may think that the Federal response was amateuristic (certainly the media did everything it could to create and bolster that myth), but no other nation on Earth could have done any better! It really was a very remarkable effort considering the logistical problems that had to be overcome in such a short period of time. It was very likely the greatest immediate response effort yet mustered by any government!

    Faulting global warming or the emergency response is really counter productive. The real problem is that these areas are simply not designed or built to withstand these inevitable natural disasters. And while there is room for improvement in both emergency planning and in emergency response, those are mere bandages over the real problem. Disasters will continue to be ever more costly until societies decide to spend a little more up front in building codes and community planning.

    It’s like walking across the 6-lane highway and then demanding that the auto dealers should be sued for making the cars go too fast and demanding the government have an ambulance johnny-on-the-spot every time one of us gets hit. A much better solution would be to build a bridge over the highway, which may take a little more time and effort in the short term, but well worth it in the long run!

  12. 7
  13. Steve Hemphill Says:

    Oh, sorry William.

    Illustrates the variability of the existing situation though, doesn’t it? Wouldn’t you agree that due to that variability vs. the benefits of an increased food supply we might want to do some more research before hamstringing society for the substantial monetary gain of a few carbon brokers?

  14. 8
  15. William Connolley Says:

    Steve – I take it that means you’re backing off. Still, if you think you’re predicting something other that orthodox temperature trends in the future, you can make money betting at http://backseatdriving.blogspot.com/2005_05_01_backseatdriving_archive.html#111700433898143899 (err, if you turn out to be right, of course)

  16. 9
  17. Steve Hemphill Says:

    Actually William, no I am not backing off.

    I notice you did not answer my question either.

    My position has not changed. It is that we don’t know enough about climate feedbacks to restrict CO2 emissions. That’s what the winky meant.

    Since some analyses point to 1998 as the hottest year and some to 2005, I think it’s fair to say that in any event global warming is slowing. In that vein I pointed out further variability. There is no crisis in the immediate future (from global warming anyway) so we have better things to do with our resources, until we actually have a handle on feedbacks. One of those things is further research. There are literally hundreds of thousands of peer reviewed papers (some with no data or algorithm backup) that show anything anyone wants to prove. It’s *all* cherry picking.

    In particular, the concept that increased damages from tropical storms are primarily due to “global warming” is absolutely ludicrous and I don’t understand how anyone who has seen the development in hurricane prone areas over the last few decades could say that. Of course, there are people who just sit in their labs and never get outside – to them it’s plausible.

    It’s all part of the welfare state/lack of personal responsibility we have gotten ourselves into. CO2 is the base of the food chain, but despite the billion or so people on the edge of starvation there are selfish people who want to limit it, therefore food, with:

    1. no reasoning remotely related to reality (e.g. clouds), or

    2. The potential for them to make a lot of money off carbon trading or some other aspect of limiting fossil fuel use.

  18. 10
  19. Jim Clarke Says:


    I agree with most of your observations, but I don’t think the vast majority of those fearing a climate change disaster have any allusions of making a lot of money off the situation. I think the reason this theory has so much traction is more pathological.

    In the 1960’s, it became fashionable to look upon the success of western civilization as a problem. The generation that fostered this idea was the most privileged generation of all time. They did not struggle to survive to adulthood, or to be educated or to be fed. Perhaps it is because they did not earn their well-being that they began to feel a little guilty about it. I really do not know, but there is no doubt that a certain loathing of ‘industrial man’ became imbedded in Western Culture. This is particularly true in the modern environmental movement, which has influenced all of us with a view that humanity is the enemy of an otherwise idyllic natural world.

    As we examine the science concerning climate change, we find many plausible explanations for the real world data, and many value judgments required to build the modeling data. If we start with the assumption that nature is in harmony and that humans disrupt that harmony, then all our judgments will be influenced by that assumption.

    Climate proxies and methods that show little climate change before the industrial revolution will be favored over the much greater numbers that show a more variable climate in the past. Less accurate surface temperature readings of today will be favored over the more accurate satellite data, because the surface data supports the underlying assumption more effectively. If there are 3 or 4 peer reviewed values for the direct forcing of increasing CO2, the larger value will be chosen for the GCMs. If the cosmic ray theory does a better job of explaining observations, it will not be considered viable because it goes against the cultural assumption that humans are screwing up the planet.

    There are literally hundreds of assumptions that go into the AGW theory and in every case, values are arbitrarily chosen that support the underlying cultural assumption. All of these decisions have been thoroughly rationalized, but the pattern is becoming unmistakable obvious. The Stern report is another classic example of this pathological, cultural, self loathing. There is really no other explanation for the mass behavior we are currently observing.

    If it is not reversed, the decline of Western Civilization is inevitable.

  20. 11
  21. gb Says:


    You mention that we know little of climate feedbacks. However, you predict that global warming is slowing. Thus there is a clear feedback according to you that balances the effect of GHG. This reasoning is inconsistent. In fact, if you look in the scientific literature you will find little evidence that the increase of GHG will not lead to climate change.

    The growth of plants is also depending on the availability of water and the temperature. It is not justified to predict that the increase of C02 (and the climate change) will favour food production. In Africa where the eco system is rather fragile it might well have the opposite effect.

  22. 12
  23. Jim Clarke Says:


    No one is denying feedbacks. We just do not know all of them or the exact value of any of them. Also, no one is claiming that changing CO2 concentrations will have no effect on climate. The debate has always been on the magnitude of that effect. Some have argued that the changes due to increasing CO2 will be undiscernable against natural variability, but that is not the same as saying there will be no effect. Steve’s reasoning is quite consistent.

    Research into the effect of higher concentrations of CO2 on plant life, all else being equal, show that it is beneficial for plants, with relative few exceptions. Pointing out a possible (although highly speculative and unsubstantiated) exception does not negate the rule.

    I would also postulate that the phrase ‘fragile ecosystem’ is an environmental buzz phrase that has no objective meaning, but is used to conjur an emotional response.

  24. 13
  25. Mark Bahner Says:

    “It is not justified to predict that the increase of C02 (and the climate change) will favour food production. In Africa where the eco system is rather fragile it might well have the opposite effect.”

    As Jim Clarke points out, it it highly justified to predict that the increase of CO2 (and global warming) will favor food production. It is not a certainty, but it’s very probable.

    “In Africa where the eco system is rather fragile it might well have the opposite effect.”

    It might. However, increases in CO2 are nearly universally beneficial to plants. Also, very little of humanity’s food is grown in Africa. (Unfortunately for Africa, very little economic activity of any kind occurs in Africa.) Therefore, even if there were decreases in Africa, the increases in food from the United States, Canada, and other countries would very probably produce a net increase in humanity’s food supply from increased CO2 concentrations and greater warmth.

  26. 14
  27. Mark Whitney Says:

    Let’s not forget that water use efficiency is enhanced in most C3 plants studied. That means greater drought resistance and the possibility that marginal lands could become productive. Also, heat resitance is enhanced in many species. The implication here is that if the climate is indeed warming,whether anthropogenic in origin or due to natural variability, it seems suicidal to restrict CO2 emmissions.

  28. 15
  29. Sylvain Says:

    This is a link that I believe illustrate what Jim and Steve are saying:

    This study has been published in may but only learned of it today:


    Khilyuk, L.F., and G. V. Chilingar. 2006. On global forces of nature driving the Earth’s climate. Are humans involved? Environmental Geology, 50, 899–910.

    The authors identify and describe the following global forces of nature driving the Earth’s climate: (1) solar radiation as a dominant external energy supplier to the Earth, (2) outgassing as a major supplier of gases to the World Ocean and the atmosphere, and, possibly, (3) microbial activities generating and consuming atmospheric gases at the interface of lithosphere and atmosphere. The writers provide quantitative estimates of the scope and extent of their corresponding effects on the Earth’s climate. Quantitative comparison of the scope and extent of the forces of nature and anthropogenic influences on the Earth’s climate is especially important at the time of broad-scale public debates on current global warming. The writers show that the human-induced climatic changes are negligible.”

    World climate report discussed it lately:


  30. 16
  31. Brian S. Says:

    I just noticed this conversation. Steve, or anyone else willing to bet other people’s lives on the premise that global warming is grossly overstated, I encourage you to bet your money against mine on the same proposition. Links to my bets are above.


  32. 17
  33. Steve Hemphill Says:

    Brian -

    You missed the point (you’re not alone). The point, ultimately, is that the only thing we really know about CO2 is that it’s the base of the food chain. We know next to nothing about quantitative effects of feedbacks. So, your statement about “betting on the lives of other people” would be ludicrous were it not so morbid.

    The answer is no, I am not inclined to bet money on the lives of hundreds of millions (or ultimately billions) of people, like many alarmists are. Sorry to disappoint you.

  34. 18
  35. Brian S. Says:

    Nice rhetorical shift, Steve, but you are betting peoples lives, while not betting your own money.

  36. 19
  37. TokyoTom Says:


    Ever notice how your bloviating about the Chicken Littles so closely parallels the very rhetoric that you decry?

    You say “there is no doubt that a certain loathing of ‘industrial man’ became imbedded in Western Culture. This is particularly true in the modern environmental movement,” and “The Stern report is another classic example of this pathological, cultural, self loathing. There is really no other explanation for the mass behavior we are currently observing. If it is not reversed, the decline of Western Civilization is inevitable.”

    Some of the enviros may not understand the problems that concern them, but that doesn`t mean the problems don`t exist. Climate change is an issue because it relates to unowned, open-access common resources; ocean fisheries are a similary example. Intensive exploitation of these resources lead to negative consequences. These resources are different from other resources in that they are not owned, so people can’t express their preferences through market transactions, and what transaction do occur don’t reflect social costs.

    The aim is to create rules about open-access resources, so we don’t mutually destroy them (or create other undesirable consequences). Solving these problems actually leads to greater wealth, while leaving them fester is an open-ended exploitation of a capital stock.

    I suggest these articles to bone up on this:

    The Commons: Tragedy or Triumph?
    Bruce Yandle




    The “moral” aspect legitimately comes in when one understands that collective management of common resources has traditionally come about not through direct regulation, but through informal rules within a community of users. It’s not illegal for lobstermen to put their pots where they wish, but there’s a strong local moral code against it. That’s why we instinctively have moral posturing over common resources.

  38. 20
  39. Roger Pielke, Jr. Says:

    Tom, Jim, Steve, Brian-

    We welcome your participation here, but please do remember that this is a post about tropical cyclones! Thanks;-)

  40. 21
  41. Sylvain Says:

    Brian S-

    How is determined the pay out of the bet?

    How is it, or will it be determined that someone died because of the Co2 produce by car or power plant or industries and agriculture.

    From my understanding even if we were able to stop all production of human induced Co2 we would still have to face extreme weather events like hurricanes, droughts, etc.

    From what is mention in this post we are speaking of a difference of 3-5% in wind speed for 1°C of warming. At the current trend of around 0.15° C/decades (1.5°C)this means that a 150 mph wind speed hurricane today would have wind between 154-158 mph by 2100. How is it determined that the 4-8 mph wind speed is what killed someone and not the 150 mph?

    “The same goes for heat waves which is said by some to be death caused by GW. This is a list of all the years from which data were found associated to heat wave in France. I translated the comment that were associated to them.


    627 (many people dying of dehydration)
    640 (recorded tropical heat: men and women were dropping dead with no saliva in their mouth)
    850 (famine caused by the heat and resulting drought recorded)
    987 (scorching heat that created a famine for 5 years)
    995 (scorching heat where trees spontaneously started to burn.
    1000,1135,1232,1393,1473,1504,1518,1540,1583,1605,1612,1642,1660,1681,1706,1719 one of the warmest year they ever saw in France
    and so on: Several by century, in average, do they see heat wave comparable to 2003.”

    If it happens before GW how will you determine the winner of the bet. Also do you admit that adaptation is required to fight climate change (human induced or not)?
    How many lives will be save though adaptation compared to mitigation that won’t stop these event from occurring?

  42. 22
  43. Jim Clarke Says:


    Thanks for your comments.

    My ‘bloviating’ however is not about concern for the commons, which of course, is legitimate. My discussion is about how we make decisions and the effects these decisions produce.

    15 years ago, I was having a great deal of difficulty reconciling the ’science’ of global warming with the global reaction to the science. The reaction was much greater than the science could support. I did not understand it until I happened upon an essay that detailed the ‘5-steps to becoming a despot’:

    1. Adopt a noble cause
    2. Exaggerate the threat to that noble cause
    3. Aggressively demonize those who disagree
    4. Claim to have the only solution to the threat
    5. Demand that the population give up wealth, rights or both in order to be saved!

    Consider global warming:

    1. The noble cause is avoiding a climate change catastrophe.
    2. Nearly everything about the threat is exaggerated, which was the subject of my ‘bloviating’. The uncertainties of the science leave us with 100s of unknowns. If an individual assumes that all unknowns in their life will manifest as a worst-case-scenario, they will not only make poor decisions, they will likely be diagnosed as pathologically paranoid. That same behavior is evident in the AGW crisis community.
    3. The demonization of skeptics is so prevalent that it needs no edification here, but I would just like to point out that I would never refer to your arguments as ‘bloviating’, no matter how much I might disagree. Saying someone is ‘bloviating’ is an attempt to demonize them.
    4. When AGW crisis folks talk about a solution, they are talking about restricting CO2 emissions. They may give lip service to a few other things, but world conferences are all about restricting emissions. It is currently viewed as the only real solution.
    5. The calls for sacrifice to prevent the disaster of global warming are never ending!

    The difference between my ‘bloviating’ and that of the ‘Chicken Littles’ is that the 5-steps outlined above are recognizable throughout human history and at all levels of human relations. The 5 steps always result in bad decision making, and, ironically, usually bring sever damage to the ‘noble cause’! If the means are not justified, the desired ‘noble end’ is never reached!

    The 5 steps have been embraced by all despots to achieve power and have led to the deaths of untold millions of innocents. Where ever humans are inflicting misery on each other, you are likely to find the 5-steps in action, from religious conflicts to the banning of DDT.

    Chicken Littles, on the other hand, have never been right!

    To sum up, my ‘bloviating’ is based on the way things are and always have been. The Chicken Little viewpoint is based on that which has never happened! That is an awfully profound difference.

    Constructively speaking, the best policy decisions are made when the problem is considered analytically and not exaggerated, no one is attacked for their opinion, multiple potential solutions are presented and the benefits/costs of all solutions are weighed to determine the best results for the most people.

    I do not see that happening in the AGW debate (except with our gracious host and a few others). Usually, I see the 5 steps in action once again.

    Over the last century, the 5 steps have led humanity to untold misery, suffering and death, while 20th Century climate change…not a big problem. So which should we fear more in the future?

  44. 23
  45. Jim Clarke Says:


    I entered my response before reading your latest post. While I believe my observations apply to the AGW/tropical cyclone debate as much as any other aspect of global warming, they are not specific to that subject.

    I will attempt to stay more on point.

  46. 24
  47. Roger Pielke, Jr. Says:

    Thanks Jim!

  48. 25
  49. Roger Pielke, Jr. Says:

    Can anyone point to any media coverage of this consensus statement on tropical cyclones?

    Is the lack of coverage because the press release was issued in Costa Rica?

    Is it because of the nature of the consensus?

  50. 26
  51. Sylvain Says:

    No mention of it appeared in any french language paper.

    My bet would be on the nature of consensus. I’m expecting to see the name of Kerry Emanuel associated with skeptics soon enough.

  52. 27
  53. Benny Peiser Says:


    To my knowledge, there have been no media reports about the latest WMO consensus statement. I doubt there will be many. The contention that recent hurricane activity is linked to global warming – promoted by a small minority of researchers – is now so deeply entrenched that it is unrealistic to expect unprejudiced reporting on this issue. Illustrious politicians and environmental campaigners have staked their reputation on the hurricanes-global warming linkage. Indeed, most environmental reporters habitually hype the claims of the minority while they conveniently ignore the views of the majority. Which only goes to show that one man’s scientific consensus is another man’s legitimate object of defiance. Go figure.

  54. 28
  55. Jim Clarke Says:


    I think you touched on this several weeks ago. The media only likes yes/no questions. It doesn’t wish to deal with “we still don’t know” answers like the WMO statement.

    Like Benny Peiser, I would prefer to think that there is something more nefarious going on, but it is probably just the binary nature of the media, coupled with a never ending desire for something sensational. The WMO statement just doesn’t appear to be ‘news’ to most in the news business.

  56. 29
  57. Mark Whitney Says:

    This discussion has gone far afield, and I am complicit in it. But Brian offered a comment that makes my reply worthy of inclusion.
    “…you are betting peoples lives, while not betting your own money.”
    This is the sort of statement that usually precedes any promotion of policy, that is government policy. I believe Brian is prepared to bet my money, yours, and that of many others. I believe that alrmists are willing to bet all of our lives on an unproven hypothesis once again contradicted by the available evidence. Roger, your presentation of tropical cyclones and the resulting discussion is just such evidence.
    Thank You

  58. 30
  59. TokyoTom Says:


    Is this statement really accurate: “there is evidence both for and against the existence of a detectable anthropogenic signal in the tropical cyclone climate record to date”?

    Is absence of evidence the same as evidence of absence, or is there really evidence against the existence of a detectable anthropogenic signal in the tropical cyclone climate record?

  60. 31
  61. Roger Pielke, Jr. Says:

    Tom- Thanks. This is a good question. I assume that by “evidence against the existence of a detectable anthropogenic signal” they are referring to recent studies (e.g., Kossin) that indicate that the historical record is not of sufficient quality in some instances to achieve detection. Keep in mind that the statement was written by a committee under strict time pressures, so some bad English might be expected.

  62. 32
  63. Steve Hemphill Says:

    Or, maybe they meant that the increase was part of a natural oscillation, and has been expected by Bill Gray for many years…

  64. 33
  65. Eduardo Ferreyra Says:

    Betting is not the way to prove a scientific theory, although Julian Simon made his point against Ehrlich.

    Given the uncertainties prevailing in most sciences, betting on anything that is uncertain is just an act of faith, not science. A leap into the abyss hoping we have not fogotten our parachute.

  66. 34
  67. TokyoTom Says:

    Benny, you say “most environmental reporters habitually hype the claims of the minority while they conveniently ignore the views of the majority. Which only goes to show that one man’s scientific consensus is another man’s legitimate object of defiance. Go figure.”

    How does this apply in the case of the WMO statements, which indicate a consensus that there will be an “increase in tropical cyclone peak wind-speed and rainfall … if the climate continues to warm” and that “some increase in tropical cyclone intensity will occur if the climate continues to warm”?

    So if environmental reporters are largely conveniently ignoring the views of the majority while habitually hyping the claims of the minority, are you suggesting they will ignore the consensus outlined in the previous paragraph, while hyping those who say there are and will be no human fingerprints on hurricane intensity?

  68. 35
  69. TokyoTom Says:


    Sorry, for my use of “bloviating”; I just wanted to point out the parallel between your own fevered rhetoric and that you were condemning from the enviros.

    The five-step analysis is very interesting, and I think increasingly relevant in today’s world, where growing complexity in the face of limited time and understanding makes us all more susceptible to manipulation – but this does not cut in only one direction. Think, for example, about how the Bush administration sold the invasion of Iraq and the Global War on Terror. Even on climate change, I think it easy to demonstrate that there has been a deliberate effort to manipulate public opinion in favor of “skepticism” and to paint enviros/leftists as the enemy of mankind or as seeking to destroy the US economy.

    What I think much more useful is consideration of environmental problems as either or both problems relating to (1) open-access resources, which no one owns and so consequently near-unanimity of agreement is needed for effective policy, and which agreement has a social, peer-pressure aspect in addition to a legal aspect, and (2) resources controlled by government, which are subject to rent-seeking by interest groups, which frequently engage in PR battles/demonization of the type you describe. Both together are a recipe for inaction.

    On the background of human cognition, we can understand why people frequently take sides, criticize fence-sitters and dismiss the arguments of perceived opponents. Such an easy evil, and on top of the difficulties posed by tragedy of the commons-type problems.

    Roger, forgive me for being off-topic, but I felt a need to get back to Jim, and the discussion is still relevant to our broader issues.

  70. 36
  71. Jim Clarke Says:


    I whole heartily agree that no one side has a monopoly on exaggeration, obfuscation, demonization and manipulation, but that is no reason to excuse it or believe that we can look past it. The two sides do not cancel each other out.

    The question really is which side has the potential to do the most harm if their tactics are affective?

    Let’s take a look at the issue of tropical cyclones and climate change as an example. Suppose a certain group of individuals can convince the public (using a version of the 5 steps) that hurricanes will be much worse in the future due to global warming, and that we must reduce our emissions of CO2 immediately to prevent these costly disasters. If they are correct about hurricanes, the reduction of CO2 emissions will still have a relatively insignificant impact on overall hurricane damage.

    Now suppose another group of individuals can manipulate the population (using a version of the 5 steps) that climate change will have absolutely no effect on tropical cyclones and say we should spend resources on building better buildings and smarter developments? Even if they turn out to be totally wrong about climate change, their recommendation will result in a much more efficient use of limited resources and lead to a better prepared society.

    While using the 5 steps should never be tolerated, it is logical to be more vigilant with those who have the potential to do the most harm.

    I think we agree on a lot, I just don’t think we can begin to address the problems of the commons effectively until we confirm that our policy development is being driven by the facts, and not a cultural movement ginned up by the same 5 steps that generally lead to despotism.

    Prometheus is one of the few sources of information that I have found that is promoting effective policy by being the antithesis of the 5 steps. That doesn’t mean that I always agree with Roger, but he avoids exaggeration, demonization and myopic views of potential solutions, thus providing a good example for the rest of us.

    Nowhere is this more evident than on his presentation of the tropical cyclone/global warming debate.

  72. 37
  73. TokyoTom Says:


    I am not trying to excuse or look past exaggeration, obfuscation, demonization and manipulation, but to understand the reasons for it.

    Climate change is essentially a struggle over the use of open-access resources. Effective regulation was perceived as needed over 30 years ago (take a look at Nordhaus’s papers), but policy has been held up over prisoners’ dilemma bargaining problems (the basic need for unanimity of agreement/compliance) and by rent-seeking within each country. Which group has been most effective – those favoring meaningful action, or those blocking it?

    And as action is delayed and as emissions/concentrations of GHGs increase and thus the degree of inescapable warming, how do you expect those who are frustrated by lack of action to best have their voices heard? Do you really not expect more heated rhetoric? You seem worried a bout a raod to serfdom/despootism, but isn’t what we really have more like a range war?

    Action to form meaningful institutions to regulate open-access resources increases as the perceived costs of inaction grow. That is precisely what is happening with respect to climate change. And instititions are constituted not merely by laws, but by social pressure and other informal measures as well. There is a very strong and informal system in place for enforcing extra-legal “rights” in the New England lobster fishery, that may very much include damage to property, physical threats and harsh words, and a similar phenomenon occurred when ranchers closed the Western ranges to newcomers.

    You are right of course that adaptation makes great sense as a policy, but you forget two big aspects. First, in the developed world, by far most adaptation will occur in the private economy and will not require government action. Second, adaptation in the poor and developing parts of the world is most urgent, and these countries have the least ability to adapt. Given the institutional failures that are the cuase of these nation’s poverty, adaptation will require significant investments by the developed world. Who is going to provide that funding and how will they persuade their citizens to fund it?

    The funding and coordination of that work faces the very same prisoners’ dilemma issues as does the coordination of mitigation on a worldwide level. Those who are fighting mitigation should be fighting FOR adaptation; instead, by doing their best to torpedo coordination on mitigation they are in fact also hindering the likelhood that effective programs will be established to help the developing nations adapt to climate change.

    Is this what you advocate?

  74. 38
  75. Jeff Norman Says:


    Being a skeptic, I note that your original article at the top says the WMO has allegedly released a statement, but you link to the home page of the Instituto Meteorologico Nacional, Costa Rica, which is in Spanish (I guess).

    Additionally you say “the WMO has released a lengthy statement co-authored by the WMO Tropical Meteorology Research Programme Committee” but link to a pdf file on you web site.

    I went to the WMO web page but could find no reference to this “consensus statement”.

    What is going on?

  76. 39
  77. Roger Pielke, Jr. Says:


    There is no hoax, it is indeed real;-)


    As I understand it, the WMO has a press release written but not approved. In any case the consensus statement is written and released.