I was thus surprised to see the email copied below (which was sent to a bunch of people) from Eric and UCAR Vice President Jack Fellows:

From: “Jack Fellows”
Date: August 5, 2008 7:36:07 PM EDT
To: Bierbaum Rosina , peter backlund , Kelly Redmond , kelly redmond , Brad Udall , david yates , Jonathan Overpeck , kathy hibbard , linda mearns , mary hayden , lawrence buja , tom warner , kathleen miller , philip mote , caitlin simpson , Chester J Koblinsky , lisa goddard , Nolan Doesken , Alan Robock , Mark Abbott , “Mark Z. Jacobson” , dan vimont , Anthony Janetos , greg carbone , “Rudnicki Mark” , Keith Talbert Ingram , brian oneill , Paty Romero Lankao , Liz Moyer , david battisti , urc
Cc: eric barron
Subject: 2008 AGU Fall Session on Climate Adaptation

Eric Barron and I are putting together the AGU session described below. If you have put one of these AGU sessions together, you know that I can’t promise you that it will be an oral session or the day/time it will happen, and you are restricted to no more than 3 first author abstracts for the Fall AGU mtg. That said, we’d love to have you participate in this session. Let me know if you are interested by _17 August _so I can meet an 18 Aug AGU deadline. If you can’t participate but know of a great person, please forward this email on to them. Thanks. This is a large email list, so pls just respond to my email address. Jack

Description: PA03: How Can the Science Community Help Local and Regional Decision Makers Who are Exploring or Implementing Adaptation Options to Climate Change? All weather is local! The same will be true regarding adapting to climate change. This session will examine how local universities and decision makers are working together to adapt to anticipated climate change impacts and explore how these independent activities might be networked together into a “national adaptation network or model”. NOTE: we are primarily interested in people who have really interesting policy research or a project that is partnering with local and regional decision makers to deal with climate adaptation, mitigation, or even geoengineering.

Note that the time stamp of the email is after the brouhaha started about the decision to cut CCB. This appears to be an exercise in damage control — “We really care about adaptation, no really, we do. Look we sponsored a session at AGU!” — since neither Barron or Fellows have even done any work in adaptation (and to my knowledge Fellows is an administrator, not at all a researcher).

Let me try my hand at answering the question that they pose:

How Can the Science Community Help Local and Regional Decision Makers Who are Exploring or Implementing Adaptation Options to Climate Change? . . . This session will examine how local universities and decision makers are working together to adapt to anticipated climate change impacts and explore how these independent activities might be networked together into a “national adaptation network or model”.

First thing, don’t cut a program with a 34-year track record of success in doing exactly this. Are these guys serious that they now want to discuss how to recreate the functions of the NCAR CCB at an AGU session? Seriously?

I’d love to give NCAR/UCAR management the benefit of the doubt and believe that they have a rigorous method for setting priorities and making cuts. But not only is this sort of tone deaf damage control/spin insulting to the actual adaptation research community, but a sign that NCAR/UCAR may have a management problem rather than a budget problem.

Equivocation isn’t a sign of cognitive weakness. Uncertainty is intrinsic to the scientific process, and sometimes you have to have the courage to stand up and say, “Maybe.”

For Achenbach’s efforts he gets called stupid and a tool of the “deniers”. Such complaints are ironic given that Achenbach explains how foolish it is to put too much weight on extreme events in arguments about climate change:

the evidence for man-made climate change is solid enough that it doesn’t need to be bolstered by iffy claims. Rigorous science is the best weapon for persuading the public that this is a real problem that requires bold action. “Weather alarmism” gives ammunition to global-warming deniers. They’re happy to fight on that turf, since they can say that a year with relatively few hurricanes (or a cold snap when you don’t expect it) proves that global warming is a myth. As science writer John Tierney put it in the New York Times earlier this year, weather alarmism “leaves climate politics at the mercy of the weather.”

There’s an ancillary issue here: Global warming threatens to suck all the oxygen out of any discussion of the environment. We wind up giving too little attention to habitat destruction, overfishing, invasive species tagging along with global trade and so on. You don’t need a climate model to detect that big oil spill in the Mississippi. That “dead zone” in the Gulf of Mexico — an oxygen-starved region the size of Massachusetts — isn’t caused by global warming, but by all that fertilizer spread on Midwest cornfields.

Some folks may actually get the notion that the planet will be safe if we all just start driving Priuses. But even if we cured ourselves of our addiction to fossil fuels and stabilized the planet’s climate, we’d still have an environmental crisis on our hands. Our fundamental problem is that — now it’s my chance to sound hysterical — humans are a species out of control. We’ve been hellbent on wrecking our environment pretty much since the day we figured out how to make fire.

This caused that: It would be nice if climate and weather were that simple.

And the U.S. Climate Change Science Program recently issued a report with the following conclusions:

1. Over the long-term U.S. hurricane landfalls have been declining.

2. Nationwide there have been no long-term increases in drought.

3. Despite increases in some measures of precipitation , there have not been corresponding increases in peak streamflows (high flows above 90th percentile).

4. There have been no observed changes in the occurrence of tornadoes or thunderstorms.

5. There have been no long-term increases in strong East Coast winter storms (ECWS), called Nor’easters.

6. There are no long-term trends in either heat waves or cold spells, though there are trends within shorter time periods in the overall record.

In the climate debate, you would have to be pretty foolish to allow any argument to hinge on claims about the attribution of observed extreme events to the emissions of greenhouse gases. But as we’ve noted here on many occasions, for some the climate debate is a morality tale that cannot withstand nuance, even if that nuance is perfectly appropriate given the current state of understandings. But given the public relations value of extreme events in the climate debate, don’t expect Achenbach’s reasoned view to take hold among those calling for action. Like the Bush Administration and Iraqi WMDs, for some folks sometimes the intelligence that you wish existed trumps the facts on the ground.

First, the report adopts an approach to presenting the science more befitting an advocacy group, rather than a interagency science assessment. The report ignores the actual literature on economics and policy, choosing instead to present fluffy exhortations about the urgency of action and reducing emissions. I can get that level of policy discussion from any garden variety NGO, for $2 billion per year over the past 18 years, I would expect a bit more.

The report opens with this language:

The Future is in Our Hands

Human-induced climate change is affecting us now. Its impacts on our economy, security, and quality of life will increase in the decades to come. Beyond the next few decades, when warming is “locked in” to the climate system from human activities to date, the future lies largely in our hands. Will we begin reducing heat-trapping emissions now, thereby reducing future climate disruption and its impacts? Will we alter our planning and development in ways that reduce our vulnerability to the changes that are already on the way? The choices are ours.

Pretty thin stuff. The report speaks of urgency:

Once considered a problem mainly for the future, climate change is now upon us. People are at the heart of this problem: we are causing it, and we are being affected by it. The rapid onset of many aspects of climate change highlights the urgency of confronting this challenge without further delay. The choices that we make now will influence current and future emissions of heat-trapping gases, and can help to reduce future warming.

It is not within the Congressional mandate of the CCSP to tell policymakers when to act or what goals to pursue. The report does have some limited discussion of options, which would be great (and within the mandate) if it were comprehensive and scientifically rigorous. Unfortunately, it is neither.

Despite recognizing that some adaptation will be necessary, and discussing adaptive responses in the text, the report has a strong bias against adaptation in favor of mitigation:

The more we mitigate (reduce emissions), the less climate change we’ll experience and the less severe the impacts will be, and thus, the less adaptation will be required. . . Despite what is widely assumed to be the considerable adaptive capacity of the United States, we have not always succeeded in avoiding significant losses and disruptions, for example, due to extreme weather events. There are many challenges and limits to adaptation. Some adaptations will be very expensive. We will be adapting to a moving target, as future climate will not be stationary but continually changing. And if emissions and thus warming are at the high end of future scenarios, some changes will be so large that adaptation is unlikely to be successful.

A large body of work, some of which I’ve contributed, indicates that adaptation and mitigation are not tradeoffs, but complements. Somehow this literature escaped the thorough review done by the authors of this report.

The report claims to be focused on bringing together the “best available science.” However in the area of my expertise, disasters and climate change, the report is an embarrassment. For example, once again, it uses the economic costs of disasters as evidence of climate change and its impacts, as shown in the following figure from the report.

Then, later in the report it discusses increasing U.S. precipitation under the heading “Floods” and next to a picture of a flooded house (below). However, in the U.S. there has been no increase in streamflow and flood damage has decreased dramatically as a fraction of GDP. Thus the report reflects ignorance on this subject or is willfully misleading. Neither prospect gives one much confidence in a government science report.

In short, in areas where I have expertise, at best the reporting of the science of climate impacts in this report is highly selective. Less generously it is misleading, incorrect, and a poor reflection on the government scientists whose names appear on the title page, many of whom I know and have respect for. The report asks for comments during the next few weeks, and I will submit some reactions, which I’ll also post here.

So why does the report have such an advocacy focus and rely on misleading arguments?

One answer is to have a look to the people chiefly responsible for the editing of the report, and also the section on natural disasters, where one person’s views are reported almost exclusively to any others.

Perhaps it is time to rotate control of U.S. government “science” reports to some new faces?

If you’d just like the bottom line, here it is:

I am happy to report that Nordhaus (2006) and Schmidt et al. (2008) offer strong confirmatory evidence in support of the analysis that we have presented on adjusting U.S. hurricane losses over time. What do these studies say about the debate over hurricanes and climate change? Well, almost nothing (despite the unsuccessful effort by Schmidt et al. to reach for such a connection). There is no long-term trend in the landfall behavior of U.S. hurricanes, so it is only logical that there would also be no long-term trends in normalized damage as a function of storm behavior. Those looking for insight on this debate will need to look elsewhere. If it is to be found, such a linkage will be found in the geophysical data long before it shows up in the damage data, as we asserted at our Hohenkammer workshop.

Please read on if you are interested in the details.

The first paper is by the leading economist William Nordhaus (2006, PDF). His analysis uses the same original loss data but adjusts it for GDP rather than population, wealth, and housing units. His analysis uses our 1998 study which we updated in 2008. Nordhaus claims to have “verified our analysis” but he does leave a loose end (emphasis added):

Our estimates indicate that the time trend in the damage function is positive. For example, the time trend in the OLS full-sample equation found that normalized damages have risen by 2.9 (+0.76) percent per year, indicating increased vulnerability to storms of a given size.

This is contrary to Roger A. Pielke, Jr., “Are There Trends in Hurricane Destruction?” Nature, Vol. 438, December 2005, E11, who reports no statistically significant trend. Similar negative results were found in Roger A. Pielke, Jr. and Christopher W. Landsea, “La Niña, El Niño, and Atlantic Hurricane Damages in the United States,” Bull. Amer. Meteor. Soc., vol. 80, 2027-2033. Additionally, issues of comparability over time are non-trivial, as is discussed in Christopher W. Landsea, “Hurricanes and Global Warming,” Nature, Vol. 438, December 2005, E11-E12. The reasons for the difference in findings have not been resolved.

The reason for the difference in findings should be completely obvious: Nordhaus looks at 1950-2005, and Pielke (2005) and Pielke and Landsea (1998) both begin their analysis in 1900. Pielke (2005, PDF) reports:

For example, take the 86 storms causing at least US$1 billion in normalized damages, which removes a bias caused by small storms resulting in no damage in the early twentieth century (that is, not subjected to normalization). There is an average per-storm loss in 1900–50 for 40 storms (0.78 events per year) of $9.3 billion, and an average per-storm loss in 1951–2004 for 46 storms
(0.85 events per year) of $7.0 billion; this difference is not statistically significant. Adding Hurricane Katrina to this data set, even at the largest loss figures currently suggested, would not change the interpretation of these results.

The following figures illustrate this point quite clearly. The first figure is from Nordhaus:

The second figure is from the data of Pielke et al. 2008 (PDF):

Clearly, the datasets show the same trends. However, our entire dataset shows no trend, as we reported in the paper:

The two normalized data sets reported here show no trends either in the absolute data or under a logarithmic transformation: the variance explained by a best-fit linear trend line=0.0004 and 0.0003, respectively, for PL05, and 0.0014 and 0.00006, respectively, for CL05. The lack of trend in twentieth century normalized hurricane losses is consistent with what one would expect to find given the lack of trends in hurricane frequency or intensity at landfall. This finding should add some confidence that, at least to a first degree, the normalization approach has successfully adjusted for changing societal conditions. Given the lack of trends in hurricanes themselves, any trend observed in the normalized losses would necessarily reflect some bias in the adjustment process, such as failing to recognize changes in adaptive capacity or misspecifying wealth. That we do not have a resulting bias suggests that any factors not included in the normalization methods do not have a resulting net large significance.

So to summarize, Nordhaus (2006) and Pielke et al. (2008) reconcile perfectly.

A second study is just out by Silvio Schmidt et al. (2008, PDF) which applies a modified version of our normalization methodology to hurricane losses found in the Munich Reinsurance global loss dataset. This study finds no significant trend from 1950, using a log transformation of the dataset:

The trend analysis for the period 1950–2005 yields no statistically significant trend in annual adjusted losses. Even if the two extreme years, 2004 and 2005, are omitted from the trend analysis, no trend can be identified in which the explanatory variable time is significant. Thus, no conclusion can be drawn regarding a possible trend in the periods 1950–2005 and 1950–2003.

The paper does identify a statistically significant trend starting in 1971, but the significance disappears when Katrina is removed from the dataset. Once again, the Schmidt et al. analysis is perfectly consistent with our analysis. The following figure shows their log-transformed data from 1950:

And the following graph is the same transformation applied to the data of Pielke et al. (2008).

One notable difference is that the Munich Re dataset apparently has some gaps, as it reports a number of years with zero damage that our dataset shows the presence of damaging storms. From the graph is should be clear that any claim of a trend over the dataset depends upon 2004 and 2005. And even in this case Schmidt et al. were only able to identify a statistically significant trend by starting with 1971 (which they claim as the start of a cold phase, contrary to most studies that use 1970). The following figure from Schmidt et al. shows how close the two analyses actually are (the red curve is Pielke et al. 2008):

The differences between the two analyses are very small, and I would guess, of no particular statistical significance over the time series of the dataset.

So I am happy to report that Nordhaus (2006) and Schmidt et al. (2008) offer strong confirmatory evidence in support of the analysis that we have presented on adjusting U.S. hurricane losses over time.

What do these studies say about the debate over hurricanes and climate change? Well, almost nothing despite efforts by Schmidt et al. to reach for such a connection. There is no long-term trend in the landfall behavior of U.S. hurricanes, so it is only logical that there would also be no long-term trends in normalized damage as a function of storm behavior. Those looking for insight on this debate will need to look elsewhere. If it is to be found, such a linkage will be found in the geophysical data long before it shows up in the damage data, as we asserted at our Hohenkammer workshop.

Ryan Crompton and John McAneney of Macquarie University in Sydney, Australia have an important new paper in the August, 2008 issue of the journal Environmental Science & Policy titled “Normalised Australian insured losses from meteorological hazards: 1967–2006.” (Available to subscribers here). The paper contributes to a growing literature that documents the importance of understanding the integrated effects of societal change and climate change. The paper also underscores the central role that adaptation policies must play in climate policy.

The abstract states:

Since 1967, the Insurance Council of Australia has maintained a database of significant insured losses. Apart from five geological events, all others (156) are the result of meteorological hazards—tropical cyclones, floods, thunderstorms, hailstorms and bushfires. In this study, we normalise the weather-related losses to estimate the insured loss that would be sustained if these events were to recur under year 2006 societal conditions. Conceptually equivalent to the population, inflation and wealth adjustments used in previous studies, we use two surrogate factors to normalise losses—changes in both the number and average nominal value of dwellings over time, where nominal dwelling values exclude land value. An additional factor is included for tropical cyclone losses: this factor adjusts for the
influence of enhanced building standards in tropical cyclone-prone areas that have markedly reduced the vulnerability of construction since the early 1980s.

Once the weather-related insured losses are normalised, they exhibit no obvious trend over time that might be attributed to other factors, including human-induced climate change. Given this result, we echo previous studies in suggesting that practical steps taken to reduce the vulnerability of communities to today’s weather would alleviate the impact under any future climate; the success of improved building standards in reducing tropical cyclone wind-induced losses is evidence that important gains can be made through disaster risk reduction.

The text of the paper includes this discussion:

The collective evidence reviewed above suggests that societal factors – dwelling numbers and values – are the predominant
reasons for increasing insured losses due to natural hazards in
Australia. The impact of human-induced climate change on insured losses is not detectable at this time. This being the case, it seems logical that in addition to efforts undertaken to reduce global greenhouse gas emissions, significant investments be made to reduce society’s vulnerability to current and future climate and the associated variability. Employing both mitigation and adaptation contemporaneously will benefit society now and into the future.

We are aware of few disaster risk reduction policies explicitly developed to help Australian communities adapt to a changing climate, yet disaster risk reduction should be core to climate adaptation policies (Bouwer et al., 2007). . .

An increased threat from bushfires under human-induced climate change is often assumed. Indeed Pitman et al. (2006) and others anticipate an increase in conditions favouring bushfires. However, analyses by McAneney (2005) and Crompton et al. (in press) suggest that the main bushfire menace to building losses will continue to be extreme fires and that the threat to the most at-risk homes on the bushland– urban interface can only be diminished by improved planning regulations that restrict where and how people build with respect to distance from the forest. Disaster risk reduction of this kind would immediately reduce current and future society’s vulnerability to natural hazards.

Please read the whole paper.

You can read the interview here.

First, let me emphasize that the focus of the report is on changes in extremes in the United States, and not on climate changes more generally. Second, my comments below refer to the report’s discussion of observed trends. I do not discuss predictions of the future, which the report also covers. Third, the report relies a great deal on research that I have been involved in and obviously know quite well. Finally, let me emphasize that anthropogenic climate change is real, and deserving of significant attention to both adaptation and mitigation.

The report contains several remarkable conclusions, that somehow did not seem to make it into the official press release.

1. Over the long-term U.S. hurricane landfalls have been declining.

Yes, you read that correctly. From the appendix (p. 132, emphases added):

The final example is a time series of U.S. landfalling hurricanes for 1851-2006 . . . A linear trend was fitted to the full series and also for the following subseries: 1861-2006, 1871-2006, and so on up to 1921-2006. As in preceding examples, the model fitted was ARMA (p,q) with linear trend, with p and q identified by AIC.

For 1871-2006, the optimal model was AR(4), for which the slope was -.00229, standard error .00089, significant at p=.01. For 1881-2006, the optimal model was AR(4), for which the slope was -.00212, standard error .00100, significant at p=.03. For all other cases, the estimated trend was negative, but not statistically significant.

2. Nationwide there have been no long-term increases in drought.

Yes, you read that correctly. From p. 5:

Averaged over the continental U.S. and southern Canada the most severe droughts occurred in the 1930s and there is no indication of an overall trend in the observational record . . .

3. Despite increases in some measures of precipitation (pp. 46-50, pp. 130-131), there have not been corresponding increases in peak streamflows (high flows above 90th percentile).

From p. 53 (emphasis added):

Lins and Slack (1999, 2005) reported no significant changes in high flow above the 90th percentile. On the other hand, Groisman et al. (2001) showed that for the same gauges, period, and territory, there were statistically significant regional average increases in the uppermost fractions of total streamflow. However, these trends became statistically insignificant after Groisman et al. (2004) updated the analysis to include the years 2000 through 2003, all of which happened to be dry years over most of the eastern United States.

4. There have been no observed changes in the occurrence of tornadoes or thunderstorms

From p. 77:

There is no evidence for a change in the severity of tornadoes and severe thunderstorms, and the large changes in the overall number of reports make it impossible to detect if meteorological changes have occurred.

5. There have been no long-term increases in strong East Coast winter storms (ECWS), called Nor’easters.

From p. 68:

They found a general tendency toward weaker systems over the past few decades, based on a marginally significant (at the p=0.1 level) increase in average storm minimum pressure (not shown). However, their analysis found no statistically significant trends in ECWS frequency for all nor’easters identified in their analysis, specifically for those storms that occurred over the northern portion of the domain (>35°N), or those that traversed full coast (Figure 2.22b, c) during the 46-year period of record used in this study.

6. There are no long-term trends in either heat waves or cold spells, though there are trends within shorter time periods in the overall record.

From p. 39:

Analysis of multi-day very extreme heat and cold episodes in the United States were updated from Kunkel et al. (1999a) for the period 1895-2005. The most notable feature of the pattern of the annual number of extreme heat waves (Figure 2.3a) through time is the high frequency in the 1930s compared to the rest of the years in the 1895-2005 period. This was followed by a decrease to a minimum in the 1960s and 1970s and then an increasing trend since then. There is no trend over the entire period, but a highly statistically significant upward trend since 1960. . . Cold waves show a decline in the first half of the 20th century, then a large spike of events during the mid-1980s, then a decline. The last 10 years have seen a lower number of severe cold waves in the United States than in any other 10-year period since record-keeping began in 1895 . . .

From the excerpts above it should be obvious that there is not a pattern of unprecedented weather extremes in recent years or a long-term secular trend in extreme storms or streamflow. Yet the report shows data in at least three places showing that the damage associated with weather extremes has increased dramatically over the long-term. Here is what the report says on p. 12:

. . . the costs of weather-related disasters in the U.S. have been increasing since 1960, as shown in Figure 1.2. For the world as a whole, “weather-related [insured] losses in recent years have been trending upward much faster than population, inflation, or insurance penetration, and faster than non-weather-related events” (Mills, 2005a). Numerous studies indicate that both the climate and the socioeconomic vulnerability to weather and climate extremes are changing (Brooks and Doswell, 2001; Pielke et al., 2008; Downton et al., 2005), although these factors’ relative contributions to observed increases in disaster costs are subject to debate.

What debate? The report offers not a single reference to justify that there is a debate on this subject. In fact, a major international conference that I helped organize along with Peter Hoeppe of Munich Re came to a consensus position among experts as varied as Indur Goklany and Paul Epstein. Further, I have seen no studies that counter the research I have been involved in on trends in hurricane and flood damage in relation to climate and societal change. Not one. That probably explains the lack of citations.

They reference Mills 2005a, but fail to acknowledge my comment published in Science on Mills 2005a (found here in PDF) and yet are able to fit in a reference to Mills 2005b, titled “Response to Pielke” (responding to my comment). How selective. I critiqued Mills 2005a on this blog when it came out, writing some strong things: “shoddy science, bad peer review and a failure of the science community to demand high standards is not the best recipe for helping science to contribute effectively to policy.”

The CCSP report continues:

For example, it is not easy to quantify the extent to which increases in coastal building damage is due to increasing wealth and population growth in vulnerable locations versus an increase in storm intensity. Some authors (e.g., Pielke et al., 2008) divide damage costs by a wealth factor in order to “normalize” the damage costs. However, other factors such as changes in building codes, emergency response, warning systems, etc. also need to be taken into account.

This is an odd editorial evaluation and dismissal of our work (Based on what? Again not a single citation to literature.) In fact, the study that I was lead author on that is referenced (PDF) shows quantitatively that our normalized damage record matches up with the trend in landfall behavior of storms, providing clear evidence that we have indeed appropriately adjusted for the effects of societal change in the historical record of damages.

The CCSP report then offers this interesting claim, again with the apparent intention of dismissing our work:

At this time, there is no universally accepted approach to normalizing damage costs (Guha-Sapir et al., 2004).

The reference used to support this claim can be found here in PDF. Perhaps surprisingly, given how it is used, Guha-Sapir et al. contains absolutely no discussion of normalization methodologies, but instead, a general discussion of damage estimation. It is therefore improperly cited in support of this claim. However, Guha-Sapir et al. 2004 does say the following on p. 53:

Are natural hazards increasing? Probably not significantly. But the number of people vulnerable and affected by disasters is definitely on the increase.

Sound familiar?

In closing, the CCSP report is notable because of what it does not show and what it does not say. It does not show a clear picture of ever increasing extreme events in the United States. And it does not clearly say why damage has been steadily increasing.

Overall, this is not a good showing by the CCSP.

Kevin Vranes and I have just had a paper accepted for publication on historical earthquake losses in the United States.

Vranes, K., and R. A. Pielke, Jr., 2008 (in press). Normalized earthquake damage and fatalities in the United States: 1900 – 2005, Natural Hazards Review. (PDF)

The dataset that we present in the paper will allow for a range of interesting analyses. Here is the abstract:

Damage estimates from 80 United States earthquakes since 1900 are “normalized” to 2005 dollars by adjusting for inflation, increases in wealth and changes in population. A factors accounting for mitigation at 1% and 2% loss reduction per year are also considered. The earthquake damage record is incomplete, perhaps by up to 25% of total events that cause damage, but all of the most damaging
events are accounted for. For events with damage estimates, cumulative normalized losses since 1900 total $453 billion, or $235 billion and $143 billion when 1% and 2% mitigation is factored respectively. The 1906 San Francisco earthquake and fire adjusts to $39 – $328 billion depending on assumptions and mitigation factors used, likely the most costly natural disaster in U.S. history in normalized 2005 values. Since 1900, 13 events would have caused $1B or more in losses had they
occurred in 2005; five events adjust to more than $10 billion in damages. Annual average losses range from $1.3 billion to $5.7 billion with an average across datasets and calculation methods of $2.5 billion, below catastrophe model estimates and estimates of average annual losses from hurricanes. Fatalities are adjusted for population increase and mitigation, with five events causing over 100 fatalities when mitigation is not considered, four (three) events when 1% (2%) mitigation is considered. Fatalities in the 1906 San Francisco event adjusts from 3,000 to over 24,000, or 8,900 (3,300) if 1% (2%) mitigation is considered. Implications for comparisons of normalized results with catastrophe model output and with normalized damage profiles of other hazards are considered.

Sources

Flood damage data: Here (Note no data 1980-82)

GDP data: Here

For further reading:

Pielke, Jr., R.A., M. Downton, J. Z. B. Miller, S. A. Changnon, K. E. Kunkel, and K. Andsager, 2000: Understanding Damaging Floods in Iowa: Climate and Societal Interactions in the Skunk and Raccoon River Basins, Environmental and Societal Impacts Group, National Center for Atmospheric Research, Boulder, CO, August. (PDF)

Pielke, Jr., R. A. and M.W. Downton, 2000. Precipitation and Damaging Floods: Trends in the United States, 1932-97. Journal of Climate, 13(20), 3625-3637. (PDF)

Downton, M. and R. A. Pielke, Jr., 2005. How Accurate are Disaster Loss Data? The Case of U.S. Flood Damage, Natural Hazards, Vol. 35, No. 2, pp. 211-228. (PDF)

I am happy to report that claims of “inconsistent with” do exist. Here is an example from a paper just out by Knutson et al. in Nature Geoscience:

Our results using the ensemble-mean global model projections (Fig. 4) are inconsistent with the notion of large, upward trends in tropical storm and hurricane frequency over the twentieth century, driven by greenhouse warming.

The climate modelers at Real Climate apparently don’t like the phrase “inconsistent with” in the context of models and try to air brush it away when they write of Knutson et al.:

. . .we know that (i) the warming [of the oceans] is likely in large part anthropogenic, and (ii) that the recent increases in TC frequency are related to that warming. It hardly seems a leap of faith to put two-and-two together and conclude that there is likely a relationship between anthropogenic warming and increased Atlantic TC activity.

Knutson et al. respond in the comments that this in fact is not how to interpret their paper, and — kudos to them — take strong, public issue with the weaselly words implying a connection that they don’t show (emphasis added in the below, and I’ve copied the whole comment for the entire context):

Mike [Mann],

Statement (i), that “the warming [of the tropical Atlantic Ocean] is likely in large part anthropogenic.” is reasonable, taking “anthropogenic” to mean “greenhouse gas”, given the work of Santer et al (2006, PNAS), Knutson et al (2006, J. Clim.), and Gillett et al (2008, G.R.L.). To quote from Gillett et al:

…our results indicate that greenhouse gas increases are indeed likely the dominant cause of [tropical Atlantic] warming…

However, statement (ii), that “the recent increases in [Atlantic] TC (tropical cyclone) frequency are related to that warming” is vague – with “related to” allowing an interpretation that includes anything from a negative relationship, to a minor contribution, to local SST warming being the dominant dynamical control on TC frequency increase. Some might interpret “related to” to mean “are dominantly controlled by”, and we think the evidence does not justify such a strong statement. In particular, the results of Knutson et al (2008) do not support such an attribution statement,if one focuses on the greenhouse gas part of the anthropogenic signal. Quoting from page 5 of the paper:

Our results using the ensemble-mean global model projections (Fig. 4) are inconsistent [emphasis added] with the notion of large, upward trends in tropical storm and hurricane frequency over the twentieth century, driven by greenhouse warming

We agree that TC activity and local Atlantic SSTs are correlated but do not view this correlation as implying causation. The alternative, consistent with our results, is that there is a causal nonlocal relationship between Atlantic TC activity and the tropical SST field. The simplest version uses the difference between Atlantic and Tropical-mean SST changes as the predictor (Swanson 2008, Non-locality of Atlantic tropical cyclone intensities, G-cubed, 9, Q04V01). This picture is also consistent with non-local control on wind shear (e.g. Latif et al 2007, G.RL.), atmospheric stability (e.g., Shen et al 2000, J. Clim.) and maximum potential intensity (e.g., Vecchi and Soden, 2007, Nature).

We view the SST change in the tropical Atlantic relative to the rest of the tropics as the key to these questions. Warming in recent decades has been particularly prominent in the northern tropical Atlantic, but such a pattern is not evident in the consensus of simulations of the response to increasing greenhouse gases. So, whether changes in Atlantic SST relative to the rest of the tropics – that according to our hypothesis have resulted in the changes in hurricane activity – were primarily caused by changes in radiative forcing, or whether they were primarily caused by internal climate variability, or (most likely) whether both were involved, is obviously an important issue, but this is not addressed by our paper

Now a word of caution — Knutson et al. 2008 is by no means the last word on hurricanes and global warming, and the issue remains highly contested, and will remain so for a long time. Of course, you heard that (accurate) assessment of the state of this particular area of climate science here a long time ago (PDF

Knutson et al. is notable because it clearly identifies observations “inconsistent with” what the models report which should give us greater confidence in research focused on generating climate predictions. We should have greater confidence because if practically everything observed is claimed to be “consistent with” model predictions, then climate models are pretty useless tools for decision making.