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March 15, 2006

Forbidden Fruit: Justifying Energy Policy via Hurricane Mitigation

Posted to Author: Pielke Jr., R. | Climate Change | Disasters | Energy Policy

We’ve on occasion discussed a paper that we did in 2000 on the relative contributions to future damage of changes in intensity of hurricanes (called tropical cyclones worldwide) and changes in societal vulnerability, under the assumptions of the IPCC to 2050. Our paper found that the independent effects of changes in societal vulnerability are larger than the independent effects of changes in storm intensity by a factor of between 22 to 1 and 100 to one. The ratios are far larger the further one goes into the future. This would seems to provide pretty compelling evidence that even if scientists are underestimating the degree to which hurricane intensity will change in the future, energy policies simply are not going to be an effective tool of hurricane policy. Thus we have often recommended keeping separate the issues of greenhouse gas reductions and hurricane policy.

For obvious reasons some people find this argument inconvenient. One response to a talk I gave on this last week was, “if we don’t have the imagery of hurricane damage it is going to make the task of selling greenhouse gas reductions that much harder” (see also the recent discussion at Kevin’s NoSeNada blog, and thanks to Brian S. for motivating this further discussion). Below is some simple math that should make the point inescapable, drawn from the analysis in Pielke et al. 2000 (PDF). Have a look, and play around with the numbers yourself.

A = hurricane damages today = $1

B = increase in hurricane damages in 2050, according to high end of IPCC TAR = 10% increase = $1 * 0.10 = $0.10

C = increase in hurriane damage in 2050, according to low end of IPCC TAR in Pielke/Landsea normalization method = 220% increase = $1 * 2.20 = $2.20

D = combined effect of B and C = $2.20 * 0.10 = $0.22

E = Total increase in costs = B + C + D = $0.10 + $2.20 + $0.22 = $2.52

F = Total costs in 2050 = A + E = $3.52

Of E the part that can be addressed by intentionally modulating the intensity of hurricanes (a dubious proposition, but lets assume) is $0.32 (B + D), and the part that can be addressed by addressing vulnerability is $2.44 (C + D) (note: does not equal E because D is counted twice because it is influenced by both factors).

So if you focus on energy policies as a way to modulate hurricane behavior as a tool of disaster mitigation, and assuming that (a) you can instantaneously reduce GHGs to pre-industrial, and (b) that we are not committed to change already, then you can at best reduce the increase in future damages from $3.52 to $3.20, still representing a 320% increase from today.

But lets be slightly more realistic, how about Kyoto? Assuming that the effects of GHG reductions on hurricane intensity are instantaneous and exactly proportional to emissions concentrations (also dubious assumptions, but lets go with them) under full and successful implementation of Kyoto, including the participation of the US, the reduction in projected damages would be about $0.03. (Assuming: increase 2005-2050 = ~120 ppm, Kyoto’s effects = ~12 ppm, $0.32 * 12/120 = ~$0.03, but substitute numbers as you wish, I just made these up.) Now before people start writing to tell me Kyoto is a first step, please go ahead and substitute second, third, and fourth steps as you wish and see what effects they get. Then get back to the political realities such as Kyoto is not meeting its targets, and the subsequent steps look a long way off (not to mention the incorrect simplifying scientific assumptions above about the close connections of GHG reductions and corresponding reductions in hurricane intensity) .

Again, it is important for me repeat that I support emissions reductions, and I even think Kyoto makes good political sense for the U.S. to be a part of, however, it stretches credulity to think that Kyoto or any emissions reductions policy makes sense as a tool of hurricane (or more generally, disaster) mitigation. The important policy question is not whether or not global warming affects hurricanes, it probably does, but rather, what outcomes can be expected from different policies in response to hurricanes related to the things we care about, like property and life?

Moving on, if you focus on reducing vulnerability as a tool of disaster mitigation, then you can at best reduce the increase in future damages by $2.42 to $1.10, representing an increase of 10% from today. And of course mitigation need not stop at the level of damages we see today, and in principle can cut into that original $1.00 of losses, which proportionately reduces the increase related to changing storm intensity. It seems obvious that achieving the same $0.03 reduction in future losses from the $2.42 expected due to increasing vulnerability would be a much more tractable and cost effective approach to hurricane mitigation than an indirect effort to modulate storm behavior. Put another way, 100% success in implementation of Kyoto is the equivalent of about 1% success in addressing vulnerability. This is a huge difference in both the politics and the practicality.

Note that all of the above are calculated using the most favorable ratio toward emissions reductions of 22 to 1. The other end of the scale is 100 to one, so keep that in mind. Alos keep in mind that this anaysis goes to 2050, if you'd like to extend it to, say, 2085, probably should at least quadruple the vulneability numbers and increase the intensity numbers by a percent or three.

The bottom line: For advocates of emissions reductions, asserting a hurricane-energy policy linkage is tempting, very tempting. But it does not make good policy sense. It is a bad argument, perhaps even an abuse of science or immoral. If scientific accuracy is of concern, then look elsewhere for your justifications.

Posted on March 15, 2006 11:13 AM


In case anyone's still attributing Katrina's damage to New Orleans to "global warming" here's some info to digest:
"relatively weak shear strengths in the clay layer under the inboard toe of the levee allowed the lateral translation of the levee from the floodwall back along a failure plane in the clay layer. The peat layer above the clay did not initiate the failure. This failure mechanism was not anticipated by the design criteria used."

and (buried in the above)
"Flooding in New Orleans from Hurricane Katrina was much worse than models anticipated in part because of nearly 3 ft of subsidence of levees and storm protections in some locations, according an interim report from an expert task force of engineers and scientists released March 10."

and, last but not least (obviously not "official")
"The U.S. Army Corps of Engineers did a full-scale test 20 years ago on a floodwall like one that collapsed here during Hurricane Katrina, with results that predicted its failure, scientists working on an independent study of the failure said Monday."

Posted by: Steve Hemphill at March 15, 2006 12:44 PM

Thanks for knocking down the straw man, Steve. Very helpful, as usual.

Posted by: Andrew Dessler at March 16, 2006 12:55 PM

Looks to me like your figure F is a sum of 2 years, the year 2000 damages and the year 2050 damages. I'm not clear why you'd want to sum those two. I'd think you'd want to either just use the 2050 projection alone, or sum the data from every year between 2000 and 2050. Either way should give global warming as causing 10% of the total damages.

The bottom line of your projection appears to be that Kyoto would reduce hurricane damages by 1% in 2050. So we're probably talking about half-billion to two billion dollars annually in cost reductions (setting aside the moral issue of lives lost). I think that's a decent chunk of change to set against the costs of Kyoto, especially as it would be only one of many benefits for reducing emissions.

Posted by: Brian S. at March 16, 2006 02:26 PM

Brian S.-

A few replies:

1. On F ...

F = total damages in 2050
E = increase from 2005

Total damages is an important number.

2. I'm glad that you accept the analysis.

3. If the benefits of Kyoto for hurricane mitigation are indeed on order $1 billion/year, then this is not going to help advoacacy for Kyoto.

4. Keep in mind the totally unrealistic sceintifc assumptions necessary to get to that ~1B.

5. If you really are interested in saving ~$1B/year in 2050, then shouldn't we be comparing against one another a range of options to achieve that goal? FEMA suggests that mitigation pays off at 4:1 suggesting that $1B in losses can be averted for costs of $250 million. How does Kyoto compare?


Posted by: Roger Pielke, Jr. at March 16, 2006 03:24 PM

Okay, I understand now - C is the change from 2005 to 2050, not the new amount in 2050.

I accept the logic of figures A through F. I have some doubts about whether the hurricane damage estimates are underestimates rather than overestimates, but setting that aside, you have an "income stream" of $1 billion annually for the next century. What's the present value of that stream - something like $25, $30 billion?

Your point 5 sounds kind of like cost-benefit analysis. As to how Kyoto compares on the c-b ratio, I don't know, but the income stream from hurricane mitigation is one part of the benefit package.

The other way I think you should refine your decoupling concept is to argue that hurricane costs of global warming should be assessed on emissions ($5 to $20 billion annually) and then be spent in the most cost-effective way. If the most effective is reducing emissions, then do that. If the most effective is mitigating the myriad impacts of AGW instead, do that instead.

Posted by: Brian S. at March 16, 2006 04:44 PM

There also the question of practicality and, dare I say it, justice! Who is going to pay for mitigation in, say, Bangladesh? Probably not the emitters... try selling that one to Congress LOL. Also, if adaptation involves moving people around then that's fine in theory but doesn't work in practice. Take New Orleans, for example. Planners went right ahead and allowed a whole city to be built in a crazy location. Or Mt Vesuvius. We all know that one day Naples is going to be buried. The cost effective thing to do would be to move everyone out of the danger zone. It isn't going to happen tho.

Also, the cost of adaptation should not be based on the most likely scenario, but rather on the most extreme plausible scenario. What you define as the most extreme plausible scenario is of course highly subjective.

Finally, the cost of mitigation is a tricky one. Several studies show that the cost can be negligible or even negative, if it is acheived by stimulating technological development (which, of course, Kyoto does).

Posted by: Tom Rees at March 17, 2006 09:12 AM

Hurricanes and Global Warming : It's about time that people see Pielke, Gray, Landsea and Mayfield for what they truly are - obsolete liars.

Posted by: Thomas Lee Elifritz at March 17, 2006 12:02 PM

Thomas Lee Elifritz-

We welcome all sorts of substantive discussions on this site. If you have something of substance to say, then let us know. Please do however take the nasty comments elsewhere.


Posted by: Roger Pielke Jr. at March 17, 2006 09:15 PM



Posted by: Dano at March 18, 2006 12:05 PM

You said:

"But lets be slightly more realistic, how about Kyoto? Assuming that the effects of GHG reductions on hurricane intensity are instantaneous and exactly proportional to emissions concentrations (also dubious assumptions, but lets go with them) under full and successful implementation of Kyoto, including the participation of the US, the reduction in projected damages would be about $0.03."

Three cents on the dollar doesn't sound like a lot. However, multiply this by a billion in the case of such a hurricane (i.e. the hurricane causes a billion dollars in damage) and you get 30 million dollars.

Take an average number of storms (6) in a given year, with, say an average of 50 million dollars in damage. There's 300 million dollars in damage, which could bave been roughly 10 million dollars cheaper from which to rebuild.

Try increasing the savings from hurricane damage in the future with every ppm of CO2 that is reduced on a yearly basis. Billions of dollars will be saved! Now that sounds like a lot, eh?

Posted by: Stephen Berg at March 21, 2006 10:16 PM

Over at RealClimate I had a bit of back-and-forth with Ray Pierrehumbert on their recent post about hurricanes. Below are his rambling thoughts on this work. My favorite part is this, "your comparison of the climate-related component of increased hurricane damages to the vulnerability component is irrelevant ..." I don't think I'll have much to say in response.

"Your paper sets up a false dichotomy regarding controlling hurricane damage by vulnerability control vs controlling hurricane damage by GHG reductions. It presupposes that one is faced with a decision between controlling GHG just for the sake of hurricanes, and forgetting about GHG's and spending money on bribing people to live further from the shoreline. (In your 2000 paper, you seem to make this point more broadly; you state explicitly that you think that climate impacts are best addressed through adaptation rather than prevention. I'm not saying that's a defensible position based on your analysis, but that is indeed what you state, begging the question of why you go on to imply that it's worthwhile to control GHG anyway). In reality, the decision is not at all like your false dichotomy. GHG's have many impacts, increased hurricane damages being one among many. So, your comparison of the climate-related component of increased hurricane damages to the vulnerability component is irrelevant, since nobody is talking about controlling GHG's for the sole purpose of reducing hurricane damages. Seen in this light, the public attention to the Emanuel and Webster papers is not at all misplaced. It's part of the whole spectrum of GHG effects that need to go into the assessment of the nature of the threat. To be sure, hurricane damage has high "availability" as a threat, since people can picture it more easily than extinction of some invisible mycorhyzae, but that doesn't make it irrelevant -- it just means that some other threats are under-appreciated. For that matter, it wouldn't take much tweaking of your "high end" climate damage numbers to make the costs look more alarming: what if the damage function turns out to be quadratic rather than linear? What if Emanuel's observations turn out to mean that the effect of SST on hurricane intensity is larger than the theoretical prediction? What if we recognize that under business as usual CO2 won't stop at a doubling, but go on eventually to a quadrupling or worse? None of this says that one should neglect spending on reducing vulnerability, but the clear message I take away from your writing is that people should just calm down and forget all about the effect of AGW on hurricanes. Why wouldn't people care about such a massive sign of human impact on nature? By the way, in your arithmetic example at the above link the damages are all monetized. Could you clarify how loss of life is figured into these numbers? You make a 10% increase in hurricane damage look small compared to the increase in monetary damage due to economic factors, but comparing a 10% increase in lives lost (as an example) with a 100% increase in costs of McMansions on the shoreline floating away on the flood is not necessarily appropriate. --raypierre"

Posted by: Roger Pielke Jr. at March 21, 2006 11:32 PM

Huh. So comment threads, Roger, should have the same writing standards as, say, posts?

Anyway, looks to me like he's pointing out that in one place you argue for a no regrets policy, then you don't. If the only reason to reduce GHGs is vulnerability control, it's a bad idea. If you add up all the other factors, it's a good idea.

If you don't have much to say about that, well, OK then. There go your future papers.



Posted by: Dano at March 22, 2006 09:35 AM

Dano- Right.

While we are at it lets add, say, dealing with bird flu as another justification for implementing GHG reductions.

You might say, "Well shouldn't we care that GHG reductions don't have much effect on bird flu?"

To which I might reply, "If the only reason to reduce GHGs is bird flu control, it's a bad idea. If you add up all the other factors, it's a good idea." By your logic, once GHG reductions make sense, then adding on perhaps scientifically unsupportable justifications doesn't matter.

Of course, this warped logic neglects the issue that if resources are taken away from more effective strategies for dealing with bird flu, then such misjustifications can have a serious impact on valued outcomes.

You certainly must know from being a frequent visitor that I am not talking about whether or not GHG reductions writ large make sense. I've already said that they do. The point here is that there is no basis that I am aware of for thinking that GHG reductions can have a significant impact on future hurricane losses.

Given Ray P.'s non-response to my very direct question, and the various attempts by the (valued) Chorus here at Prometheus to redefine the issue in all sorts of creative ways other than straight on, I'm beginning to believe that there may be a consensus on this point!


Posted by: Roger Pielke, Jr. at March 22, 2006 01:24 PM

It would be nice if contrarians/skeptics would get over the "it costs too much" complaint. They should think of the economic benefits of GHG reductions:

-Greatly increasing automobile fuel efficiency would create thousands of jobs, especially in positions which have been cut back so drastically over the past few years. (John McCain has stated that 800,000 jobs would be created if the US were to adopt the reduction plan in the Kyoto Protocol.)

-Money would stay in the country in which we live (and in our wallets) and not be sent to the Middle East and other trouble spots where problems may exacerbate.

-Reductions in health care spending would follow the reduction of industrial and automotive pollution, due to cleaner air (cutting asthma rates and cancer cases). Also, the frequency and severity of heat waves would likely be reduced, leading to fewer hospital visits from the elderly and people with ailments.

These are only three out of the many benefits of GHG reduction. The economy would not be crippled as the Bush Administration would like us to believe. The economy would flourish as a result of action, rather than inaction.

Posted by: Stephen Berg at March 22, 2006 03:59 PM

Stephen- I largely agree with you, however I will return to the issue of framing, and what I have called here in the past "cart or horse." My sense is that if GHG policies were led with jobs, money, health care, etc., rather than long-term diffuse benefits of GHG emissions, these policies would have a greater chance of being adopted.

see these posts:

Posted by: Roger Pielke, Jr. at March 22, 2006 04:20 PM

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