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April 11, 2008

Kudos to Kerry Emanuel

I have always held Kerry Emanuel in high regard, because he calls things like he sees them, but he also listens to others who might not share his views. He is, in short, a great scientist.

So it was not too surprising to see that Kerry's views have evolved on the issue of hurricanes and climate change, as science has progressed. A Houston Chronicle story reports today the following:

One of the most influential scientists behind the theory that global warming has intensified recent hurricane activity says he will reconsider his stand.
The hurricane expert, Kerry Emanuel of the Massachusetts Institute of Technology, this week unveiled a novel technique for predicting hurricane activity. The new work suggests that, even in a dramatically warming world, hurricane frequency and intensity may not substantially rise during the next two centuries.

The research, appearing in the March issue of Bulletin of the American Meteorological Society, is all the more remarkable coming from Emanuel, a highly visible leader in his field and long an ardent proponent of a link between global warming and much stronger hurricanes.

His changing views could influence other scientists.

"The results surprised me," Emanuel said of his work, adding that global warming may still play a role in raising the intensity of hurricanes but what that role is remains far from certain.

I emailed Kerry to ask if the story accurately reflected his views. He replied that it was a bit exaggerated, but basically OK. Those engaged in the political debate over climate change who are skeptical of a link between hurricanes and climate change might try to make some hay from this news report. But here at Prometheus we'd suggest viewing Kerry's evolving view in the much broader context, which we have shared on multiple occasions, namely:

there are good reasons to expect that any conclusive connection between global warming and hurricanes or their impacts will not be made in the near term.

So don't get to excited about the latest paper in hurricane climatology, the field evolves slowly, and the views of of our best scientists evolve with it.

April 08, 2008

Green Car Congress on PWG

Here is a link to an excellent summary and thoughtful discussion of our Nature Commentary (PWG) at Green Car Congress written by Jack Rosebro.

Posted on April 8, 2008 08:44 AM View this article | Comments (0)
Posted to Author: Pielke Jr., R. | Climate Change | Energy Policy | Risk & Uncertainty

April 02, 2008

Commentary in Nature

[Update #4: The guys at Grist Magazine apparently have not yet read our paper, which probably explains why one of their commentators explains that everything we say is right but common wisdom, while another says that everything we say is wrong. At least they have their bases covered. Why don't these guys at Grist actually read the paper before commenting? One wonders.]

[Update #3: Andy Revkin of the NYT provides some comments as well here.]

[Update #2: John Tierney of the NYT times provides excerpts of an extended set of comments that I shared with him here.]

[Update: Here is a short interview I did with Scitizen link.]

Tom Wigley, Chris Green, and I have a Commentary in today's Nature on the technology challenge of stabilization. It has already generated some discussion and this discussion will be the focus of some of my posts over the next weeks.

Meantime, please have a look at this summary that Tom, Chris, and I prepared:

PWG on PWG

The challenge of stabilizing the concentration of carbon dioxide (CO2) in the atmosphere may be much more difficult that currently realized. In a commentary published April 3, 2008 in Nature, Roger Pielke, Jr. (University of Colorado), Tom Wigley (National Center for Atmospheric Research) and Chris Green (McGill University) argue that the magnitude of the technology challenge associated with stabilizing the amount of carbon dioxide in the atmosphere may have been significantly underestimated by the Intergovernmental Panel on Climate Change (IPCC).

The reason for this underestimate lies in the assumptions of decarbonization common to all scenarios of future emissions growth used by the IPCC. These assumptions may be far too optimistic, and if so, will hide from view the magnitude of the technology challenge associated with stabilizing the amount of carbon dioxide in the atmosphere. In this commentary the authors reveal these assumptions, and discuss their significance for policy making.

Indeed, the authors present evidence that the first decade of the 21st century has seen greater emissions of CO2 than projected by IPCC due to rapid economic development, particularly in Asia. In recent years, the world as a whole has begun to re-carbonize, breaking a long-term trend in which carbon dioxide per unit energy was assumed instead to continue to decline indefinitely.

Stabilization of the concentrations of CO2 and other greenhouse gases is the primary objective of the United Nations Framework Convention on Climate Change (UNFCCC), approved by almost all counties, including the USA. Stabilization requires, eventually, reducing the emissions of these gases by large amounts relative to today, a task commonly referred to as "mitigation." For CO2, mitigation requires replacing current and likely future fossil-fuel-based energy systems by carbon neutral energy sources -- that is, sources of energy that are either fossil-fuel free, are accompanied by the capture and storage of CO2, or are otherwise carbon-neutral.

The costs of mitigation are generally estimated by comparing emissions under a baseline scenario where emissions evolve in the absence of climate policies, with a scenario in which the emissions are reduced (via climate policy) to achieve a chosen atmospheric concentration, called a stabilization target. Pielke, Wigley and Green note that the standard baseline scenarios considered for these calculations already include large amounts of carbon-neutral technologies that are assumed to be developed and implemented spontaneously. In the cases the authors consider, 57 to 96% of the cumulative emissions reduction required for CO2 stabilization at around 500 ppm have been assumed by IPCC to occur automatically, meaning that the majority of the emissions reduction needed to stabilize concentrations is assumed to occur automatically..

Rather than starting with assumptions about future spontaneous technological innovations, the authors’ calculations begin with a set of "frozen technology" scenarios as baselines, i.e., emissions scenarios in which energy technologies are assumed to remain at present levels. This contrasts with previous approaches, which use baselines that already include major technology changes, and, consequently, large spontaneous increases in carbon-neutral energy sources. With a "frozen technology" approach, the full scope of the carbon-neutral technology challenge is placed into clear view.

With the full scope of the technology challenge placed into view, the question then arises as to how much of this challenge will occur spontaneously, and how much must be driven by new policies. Pielke and his colleagues suggest that the amount of spontaneous development of carbon-neutral energy sources has been overestimated in previous analyses, diverting attention away from technological innovation, thereby underestimating the need for policy-driven technology development.

The authors conclude by saying "… there is no question whether technological innovation is necessary – it is. The question is, to what degree should policy focus explicitly on motivating such innovation? The IPCC plays a risky game in assuming that the spontaneous advancement of technological innovation will carry most of the burden of achieving future emissions reductions, rather than focusing on those conditions necessary and sufficient for such innovations to occur."

Posted on April 2, 2008 12:56 PM View this article | Comments (8)
Posted to Author: Pielke Jr., R. | Climate Change | Risk & Uncertainty | Technology Policy

March 26, 2008

LA Times on Adaptation

Pielke LA Times.gif

The image above is from a LA Times story by Alan Zarembo and is based on some of our reserach on future hurricane damages under changes in both climate and society. Zarembo provides a perspective on a group of scholars and advocates that I once called "nonskeptical heretics." Nonskeptical because they accept the science presented by the IPCC (as noted by Zarembo), and heretics because they take strong issue with many of the closely held assumptions that have come to frame the debate over climate policies.

Zarembo characterizes one of the most insidious assumptions -- that support for adaptation necessarily means a loss of support for mitigation:

Other scientists say that time is running out to control carbon dioxide emissions and that the call to adapt is providing a potentially dangerous excuse to delay. . . Although most scientists agree that adaptation should play a major role in absorbing the effects of climate change, they say that buying into the heretics' arguments will dig the world into a deeper hole by putting off greenhouse gas reductions until it is too late.

Well, no. It is a strawman to argue that strong support for adaptation means that one cannot also provide strong support for mitigation. A problem arises for mitigation-first proponents when they invoke things like hurricanes, malaria, and drought as justification for mitigation when clearly adaptive responses will be far more effective. Those who persist in linking mitigation to reducing such climate impacts will always find themselves on the wrong side of what research has shown -- namely, climate change is a much smaller factor in such impacts than societal factors (compare the graph above). It is true. Get over it.

The best arguments for mitigation were presented by Zarembo coming from Steve Schneider, who rightly pointed to the uncertain but highly consequential impacts of human-caused climate change:

"You can't adapt to melting the Greenland ice sheet," said Stephen H. Schneider, a climatologist at Stanford University. "You can't adapt to species that have gone extinct."

If advocacy for action on mitigation emphasized these very large scale long-term impacts, rather than disasters, disease, etc., then there would be no need for adaptation and mitigation to be presented as opposing approaches. Consider that none of the people quoted in the Zarembo story who I know (including me) have suggested that adaptation can replace mitigation, particularly for issues like sea level rise and specifies extinction. So the argument that adaptation can't deal with sea level rise over a century or more is somewhat of a strawman as well.

The reality is that whatever the world decides to do on mitigation, we will have no choice but to improve our adaptation to climate. Humans have been improving their adaptation to climate forever and will continue to do so. Since we are going to adapt, we should do it wisely. And this means rejecting bad policy arguments when offered in the way of substitutes for adaptation, like the tired old view that today's disaster losses are somehow a justification for changes to energy policies. Misleading policy arguments and should be pointed out as such, because they hurt both the cause of adaptation, but ironically the cause of mitigation as well.

If mitigation advocates do not like being told that their misleading arguments poorly serve policy debate, well, they should probably try to come up with a more robust set of arguments. Arguing that support for adaptation undercuts support for mitigation is a little like making the argument that support for eating healthy and getting exercise (adapting one's lifestyle) undercuts support for heart surgery research (mitigating the effects of heart disease). Obviously we should seek both adaptation and mitigation in the context of heart disease.

If the case for action on energy policy is so overwhelmingly strong (and again, I think that it is), then there should be no reason to resort to misleading arguments completely detached from the conclusions of a wide range of analyses. Misleading arguments may be politically expedient in the short term, but cannot help the mitigation cause in the long run. And dealing with the emissions of greenhouse gases will take place over the long run. Meantime, we'll adapt.

Posted on March 26, 2008 07:28 AM View this article | Comments (15)
Posted to Author: Pielke Jr., R. | Climate Change | Risk & Uncertainty | Science + Politics

March 15, 2008

Update on Falsifiability of Climate Predictions

UPDATE 2:40PM 3-15-08: Within a few hours of this post, as we might have expected, rather than contributing to the substantive discussion, a climate scientist chooses instead to tell us how stupid we are for even discussing such subjects. We are told that "until the temperature obviously and unambiguously turns up again, this kind of stuff is going to continue." Isn't that what this post says? For the "stuff" read on below.

Regular readers will recall that not long ago I asked the climate community research community to suggest what climate observations might be observed on decadal time scales that might be inconsistent with predictions from models. While Real Climate has decided to take a pass on this question other scientists and interested observers have taken up the challenge, no doubt with interest added by the recent cooling in the primary datasets of global temperature.

A very interesting perspective is provided by Lucia Liljegren, who has several interesting posts on observations versus predictions. The figure above is from her analysis. Her complete analysis can be found here. She has several follow up posts in which she discusses other aspects of the analysis and links to a few other, similar explorations of this issue. She writes:

No matter which major temperature measuring group we examine, or which reasonable criteria for limiting our choices we select, it appears that possible that something not anticipated by the IPCC WG1 happened soon after they published their predictions for this century. That something may be the shift in the Pacific Decadal Oscillation; it may be something else. Statistics cannot tell us.
It may turn out that this something is a relatively infrequent but climatologically important, feature that results in unusually cold weather . Events that happen at a rate of 1% do happen– at a rate of 1%. So, if recent flat trend is the 1% event, then 30 year trend in temperatures will resume.

For what it’s worth: I believe AGW is real, based on physical arguments and longer term trends, I suspect we will discover that GCM’s are currently unable to predict shifts in the PDO. The result is the uncertainty intervals on IPCC projections for the short term trend were much too small.

Of course, the reason for the poor short term predictions may turn out to be something else entirely. It remains to those who make these predictions to try to identify what, if anything, resulted in this mismatch between projections and short term data. Or to stand steadfast and wait for La Nina to break and the weather to begin to warm.

Those wanting to quibble with her analysis would no doubt observe that the uncertainty around IPCC predictions for the short term is undoubtedly larger that then IPCC itself presented. Lucia in fact suggests this in her analysis, making one wonder if uncertainties are indeed larger than presented, why didn't the IPCC say so?

In 2006 my father and I wrote about the possible effects on the climate debate of short-term predictions that do not square with observations:

predictions represent a huge gamble with public and policymaker opinion. If more-or-less steady global warming does not occur as forecast by these models, not only will professional reputations be at risk, but the need to reduce threats to the wide spectrum of serious and legitimate environmental concerns (including the human release of greenhouse gases) will be questioned by some as having been oversold. For better or worse, a failure to accurately predict the changes in the global average surface temperature, global average tropospheric temperature, ocean average heat content change, or Arctic sea ice coverage would raise questions on the reliance of global climate models for accurate prediction on multi-decadal time scales.

In one of the comments in response to that post a climate scientist (and Real Climate blogger) took us to task for raising the issue suggesting that there was no really reason to speculate about such things given that, "I’ve pointed out that in the obs, there is no sign of > 2 yr decreasing trends."

Another climate scientist commented that climate models were completely on target:

Re the possibility that the Earth is acting in a way that the models hadn’t predicted, I must say I’m pretty relaxed about that. Let’s wait a few more years and see, eh?

I have not yet seen rebuttals to Lucia's analysis, or others like it (she points to a few), which are not peer-reviewed analyses, yet certainly of some merit and worth considering. There continues to be good reasons for climate scientists to begin more openly discussing the limitations of short-term climate predictions and the implications for understanding uncertainties. They have these discussions among themselves all of the time. For example, with a view quite similar to my own, Real Climate's Gavin Schimdt suggests that if the full context of a prediction from a climate model is not understood, then:

model results have an aura of exactitude that can be misleading. Reporting those results without the appropriate caveats can then provoke a backlash from those who know better, lending the whole field an aura of unreliability.

None of this discussion means that the basic conclusion that greenhouse gases affect the climate system is wrong, or that action to mitigate emissions do not make sense. What it does mean is that we should be concerned about the overselling of climate predictions and the corresponding risks to public credibility and advocacy built upon these predictions.

Posted on March 15, 2008 06:15 AM View this article | Comments (22)
Posted to Author: Pielke Jr., R. | Climate Change | Prediction and Forecasting | Risk & Uncertainty

February 20, 2008

Cost-Benefit Analysis of the Spy Satellite Shootdown Attempt

t1home.ship.missile.gi.jpg

The Navy is apparently going to try to shoot down that wayward spy satellite sometime in the next 48 hours. The attempt to shoot it down is justified in terms of protecting human life from the risk of harm caused by the satellite's uncontrolled reentry. This post discusses whether or not the shoot down attempt can be justified in cost-benefit terms. I don't think it can, at least in terms of the formal justifications provided by the U.S. government. There must be other factors involved. The costs per expected life saved are about $2-$3 billion dollars! Read on for details.

CNN reports how the U.S. government has justified the shoot down attempt:

Pentagon officials argue the effort is worth the expense because of the slim -- but real -- chance that the satellite's unused fuel, 1,000 pounds of toxic hydrazine, could land in a populated area.
Because the super-secret spy satellite malfunctioned immediately after launch in December 2006, its fuel tank is full, and it would probably survive re-entry and disperse harmful, even potentially deadly fumes over an area the size of two football fields.

Here are the details of a cost-benefit calculation.

In early 2001 I was asked by NASA to organize a workshop to examine the risks and benefits associated with the reentry of the TRMM (Tropical Rainfall Measuring Mission) satellite. NASA faced a choice between using the satellite's remaining fuel to conduct a controlled reentry into the Pacific, or allow the orbiter to continue gathering data on tropical cyclones and other weather and eventually plunge to earth in an uncontrolled manner. What option had the most benefits as compared to the risks?

Our workshop report can be found here. What is relevant for this current discussion is that NASA prepared an analysis of the probability of casualty due to an uncontrolled reentry of TRMM, which is roughly of the same size as the spy satellite. The NASA presentation can be seen here in PDF.

The area affected by the re-enetering TRMM satellite was estimated by NASA to be about 110 square feet. Because the fuel tank was to be empty there was no concern about a toxic cloud of hydrazine, as is apparently the case with the spy satellite which is carrying a full tank of fuel. As the CNN article cited above notes, the concern is that the ruptured fuel tank might affect an area as large as two football fields, or about 115,000 square feet, or about 1050 times larger than the area that was expected to be affected by TRMM.

In the NASA presentation at our TRMM workshop a risk of human casualty associated with an uncontrolled re-entry was calculated to be 1 in 5,000 (please see the PDF for details of the calculation), based on the size of the debris field and the population density of the area under the orbital path. A risk of 1 in 5000 is pretty small, hence in the end NASA decided to let TRMM fall in uncontrolled fashion (which will happen in a few years).

But the much larger potential debris field associated with the spy satellite suggests a risk of casualty -- using the NASA risk estimate for TRMM scaled to the larger debris field -- of about a 1 in 4.8 risk of casualty, or a bit worse than the odds of surviving Russian Roulette.

Now at an estimated cost of $40-$60 million to shoot down the satellite results in an expected cost per casualty avoided of about $190-$290 million (i.e., $40M*4.8 - $60M*4.8). Given that the vast majority of the casualties might be temporary discomfort from inhalation of hydrazine gas this is a very high cost, this is a very high figure (I'd probably inhale a bit of hydrazine gas for $250 million;-). If we consider the cost per life saved, say, by avoiding a direct hit on a person by the satellite, the cost per life saved rises to $2-$3 billion! (That is, 5000*$40M - 5000*$60M.)

In any reasonable calculation of the costs and benefits to human life of the spy satellite reentry, it does not seem justifiable in terms of human safety according to standard measures of the economic value of lives saved (which tend to be measured on the order of $10 million). So there must be other perceived benefits as well -- such as testing the U.S. military's ability to hit a satellite, showing adversaries U.S. military prowess, and simply eliminating uncertainty associated with the satellite's reentry. The odds may be tiny, but if it happens to land on the Russian Embassy in Ecuador, or some other highly inconvenient place, there would certainly be a huge diplomatic crisis.

Being rich sometimes means that you can afford to eliminate uncertainty via decision making, regardless of the cost. But don't be fooled by the justification, it doesn't stand up to scrutiny, which seems fairly typical of the current administration.

Posted on February 20, 2008 01:13 AM View this article | Comments (3)
Posted to Author: Pielke Jr., R. | Risk & Uncertainty | Space Policy

January 07, 2008

Deja Vu All Over Again

The Washington Post had a excellent story yesterday by Marc Kaufman describing NASA’s intentions to increase the flight rate of the Space Shuttle program. This is remarkable, and as good an indication as any that NASA has not yet learned the lessons of its past.

According to the Post:

Although NASA has many new safety procedures in place as a result of the Columbia accident, the schedule has raised fears that the space agency, pressured by budgetary and political considerations, might again find itself tempting fate with the shuttles, which some say were always too high-maintenance for the real world of space flight.

A NASA official is quoted in the story:

"The schedule we've made is very achievable in the big scheme of things. That is, unless we get some unforeseen problems."

The Post has exactly the right follow up to this comment:

The history of the program, however, is filled with such problems -- including a rare and damaging hailstorm at the Kennedy Space Center last year as well as the shedding of foam insulation that led to the destruction of Columbia and its crew in 2003. . . "This pressure feels so familiar," said Alex Roland, a professor at Duke University and a former NASA historian. "It was the same before the Challenger and Columbia disasters: this push to do more with a spaceship that is inherently unpredictable because it is so complex."

John Logsdon, dean of space policy experts and longtime supporter of NASA, recognizes the risks that NASA is taking:

Every time we launch a shuttle, we risk the future of the human space flight program. The sooner we stop flying this risky vehicle, the better it is for the program.

Duke University’s Alex Roland also hit the nail on the head;

Duke professor Roland said that based on the shuttle program's history, he sees virtually no possibility of NASA completing 13 flights by the deadline. He predicted that the agency would ultimately cut some of the launches but still declare the space station completed.
"NASA is filled with can-do people who I really admire, and they will try their best to fulfill the missions they are given," he said. "What I worry about is when this approach comes into conflict with basically impossible demands. Something has to give."

It is instructive to look at the 1987 report of the investigation of the House Science Committee into the 1986 Challenger disaster, which you can find online here in PDF (thanks to Rad Byerly and Ami Nacu-Schmidt). That report contains lessons that apparently have yet to be fully appreciated, even after the loss of Columbia in 2003. Here is an excerpt from the Executive Summary (emphasis added, see also pp. 119-124):

The Committee found that NASA’s drive to achieve a launch schedule of 24 flights per year created pressure throughout the agency that directly contributed to unsafe launch operations. The Committee believes that the pressure to push for an unrealistic number of flights continues to exist in some sectors of NASA and jeopardizes the promotion of a "safety first" attitude throughout the Shuttle program.
The Committee, Congress, and the Administration have played a contributing role in creating this pressure. . . NASA management and the Congress must remember the lessons learned from the Challenger accident and never again set unreasonable goals which stress the system beyond its safe functioning.

One would hope that the House Science Committee has these lessons in mind and is paying close attention to decision making in NASA. It would certainly be appropriate for some greater public oversight of NASA decision making about the Shuttle flight rate and eventual termination. Otherwise, there is a good chance that such oversight will take place after another tragedy and the complete wreckage of the U.S. civilian space program.

For further reading:

Pielke Jr., R. A., 1993: A Reappraisal of the Space Shuttle Program. Space Policy, May, 133-157. (PDF)

Pielke Jr., R.A., and R. Byerly Jr., 1992: The Space Shuttle Program: Performance versus Promise in Space Policy Alternatives, edited by R. Byerly, Westview Press, Boulder, pp. 223-245. (PDF)

Posted on January 7, 2008 12:21 AM View this article | Comments (0)
Posted to Author: Pielke Jr., R. | Risk & Uncertainty | Science Policy: General | Space Policy

December 21, 2007

On the Political Relevance of Scientific Consensus

Senator James Inhofe (R-OK) has released a report in which he has identified some hundreds of scientists who disagree with the IPCC consensus. Yawn. In the comments of Andy Revkin's blog post on the report you can get a sense of why I often claim that arguing about the science of climate change is endlessly entertaining but hardly productive, and confirming Andy's assertion that "A lot of us live in intellectual silos."

In 2005 I had an exchange with Naomi Oreskes in Science on the significance of a scientific consensus in climate politics. Here is what I said then (PDF):

IN HER ESSAY "THE SCIENTIFIC CONSENSUS on climate change" (3 Dec. 2004, p. 1686), N. Oreskes asserts that the consensus reflected in the Intergovernmental Panel on Climate Change (IPCC) appears to reflect, well, a consensus. Although Oreskes found unanimity in the 928 articles with key words "global climate change," we should not be surprised if a broader review were to find conclusions at odds with the IPCC consensus, as "consensus" does not mean uniformity of perspective. In the discussion motivated by Oreskes’ Essay, I have seen one claim made that there are more than 11,000 articles on "climate change" in the ISI database and suggestions that about 10% somehow contradict the IPCC consensus position.
But so what? If that number is 1% or 40%, it does not make any difference whatsoever from the standpoint of policy action. Of course, one has to be careful, because people tend to read into the phrase "policy action" a particular course of action that they themselves advocate. But in the IPCC, one can find statements to use in arguing for or against support of the Kyoto Protocol. The same is true for any other specific course of policy action on climate change. The IPCC maintains that its assessments do not advocate any single course of action.

So in addition to arguing about the science of climate change as a proxy for political debate on climate policy, we now can add arguments about the notion of consensus itself. These proxy debates are both a distraction from progress on climate change and a reflection of the tendency of all involved to politicize climate science.

The actions that we take on climate change should be robust to (i) the diversity of scientific perspectives, and thus also to (ii) the diversity of perspectives of the nature of the consensus. A consensus is a measure of a central tendency and, as such, it necessarily has a distribution of perspectives around that central measure (1). On climate change, almost all of this distribution is well within the bounds of legitimate scientific debate and reflected within the full text of the IPCC reports. Our policies should not be optimized to reflect a single measure of the central tendency or, worse yet, caricatures of that measure, but instead they should be robust enough to accommodate the distribution of perspectives around that
central measure, thus providing a buffer against the possibility that we might learn more in the future (2).

ROGER A. PIELKE JR.
Center for Science and Technology Policy Research,
University of Colorado, UCB 488, Boulder, CO
80309–0488, USA.

References
1 D. Bray,H. von Storch, Bull.Am.Meteorol. Soc. 80, 439 (1999).
2. R. Lempert, M. Schlesinger, Clim. Change 45, 387 (2000).

December 10, 2007

AGU Powerpoint with Steve McIntyre

Here is a link to a PPT file providing an overview of a paper by Steve McIntyre and I titled, "Changes in Spatial Distribution of North Atlantic Tropical Cyclones," which he will be presenting this week at the AGU meeting.

Here are our conclusions:

Spatially descriptive statistics can contribute to analysis of controversial hurricane issues.
There has been no statistically significant increase in cyclone activity in the western Atlantic basin; the entire increase in measured storm and hurricane activity has taken place in the mid-Atlantic;

Lack of trend in landfall and normalized damage reconciles perfectly with lack of trend in western quartile storm and hurricane indices

The eastward shift cannot be attributed merely to earlier detection.

The shift could be technological or climatological or some combination; there is no plausible statistical basis for saying that the shift to the mid-Atlantic is not as important or relevant as the overall increase.

If the trend only occurs in the mid-Atlantic, should policy-makers care?

Comments welcomed.

Posted on December 10, 2007 11:16 AM View this article | Comments (0)
Posted to Author: Pielke Jr., R. | Disasters | Risk & Uncertainty

December 06, 2007

Revisiting The 2006-2010 RMS Hurricane Damage Prediction

In the spring of 2006, a company called Risk Management Solutions (RMS) issued a five year forecast of hurricane activity (for 2006-2010) predicting U.S. insured losses to be 40% higher than average. RMS is an important company because their loss models are used by insurance companies to set rates charged to homeowners, by reinsurance companies to set rates they charge to insurers, by ratings agencies for evaluating risks, and others.

We are now two years into the RMS forecast period and can thus say something preliminary about their forecast based on actual hurricane damage from 2006 and 2007, which was minimal. In short, the forecast doesn't look too good. For 2006 and 2007, the following figure shows average annual insured historical losses (for 2005 and earlier) in blue (based on Pielke et al. 2008, adjusted up by 4% from 2006 to 2007 to account for changing exposure), the RMS prediction of 40% more losses above the average in pink, and the actual losses in red.

RMS Verification.png

The RMS prediction obviously did not improve upon a naive forecast of average losses in either year.

What are the chances for the 5-year forecast yet to verify?

Average U.S. insured losses according to Pielke et al. (2008) are about $5.2 billion per year. Over 5 years this is $26 billion, and 40% higher than this is $36 billion. A $36 billion dollar insured loss is about $72 billion in total damage, and $26 billion insured is about $52 billion. For the RMS forecast to do better than the naive baseline of Pielke et al. (2008) total damage in 2008-2010 will have to be higher than $62 billion ($31 billion insured). That is, losses higher than $62B are closer to the RMS forecast than to the naive baseline.

The NHC official estimate for Katrina is $81 billion. So for the 2006-2010 RMS forecast to verify will require close to another Katrina-like event to occur in the next 3 years, or several large events. This is of course possible, but I doubt that there is a hurricane expert out there willing to put forward a combination of event probability and loss magnitude that will lead to an expected $62 billion total loss over the next 3 years. Consider that a 50% chance of $124 billion in losses results in an expected $62 billion. Is there any scientific basis to expect a 50% chance of $124 billion in losses? Or perhaps a 100% chance of $62 billion in total losses? Anyone wanting to make claims of this sort, please let us know!

From Pielke et al. (2008) the annual chances of a >$10B event (i.e., $5B insured) during 1900-2005 about 25%, and the annual chances of a >$50 billion ($25 billion insured) are just under 5%. There were 7 unique three-year periods with >$62B (>$31B insured) in total losses, or about a 7% chance. So RMS prediction of 40% higher than average losses for 2006-2010 has about a 7% chance of being more accurate than a naive baseline. It could happen, of course, but I wouldn't bet on it without good odds!

So what has RMS done is the face of evidence that its first 5-year forecast was not so accurate? Well, they have declared success and issued another 5-year forecast of 40% higher losses for the period 2008-2012.

Risk Management Solutions (RMS) has confirmed its modeled hurricane activity rates for 2008 to 2012 following an elicitation with a group of the world's leading hurricane researchers. . . . The current activity rates lead to estimates of average annual insured losses that will be 40% higher than those predicted by the long-term mean of hurricane activity for the Gulf Coast, Florida, and the Southeast, and 25-30% higher for the Mid-Atlantic and Northeast coastal regions.

For further reading:

Pielke, R. A., Jr., Gratz, J., Landsea, C. W., Collins, D., Saunders, M. A., and Musulin, R. (2008). "Normalized Hurricane Damages in the United States: 1900-2005." Natural Hazards Review, in press, February. (PDF, prepublication version)

November 20, 2007

So-kalled WiFi research

Last week it was the Journal of Geoclimatic Science and benthic bacteria, this week it's the Australasian Journal of Clinical Environmental Medicine and autism. The Sokal phemonemon is back with a vengeance, though this time it appears to be just plain fakery.

Matt Drudge has is viewers linking to an article that was, for a short stint this afternoon, published on the Computer Weekly website. The article warned of the dangers of WiFi for children. It cited an article by Dr. George Carlo in the Australasian Journal of Clinical Environmental Medicine claiming that WiFi causes heavy metals to be caught in brain cells. Only problem? Journal no existy.

Here's a slightly cynical overview. You can also check out the authors at the
Quackometer.

Posted on November 20, 2007 02:01 PM View this article | Comments (0)
Posted to Author: Hale, B. | Health | Risk & Uncertainty | Testing

May 11, 2007

State of Florida Rejects RMS Cat Model Approach

According to a press release from RMS, Inc. the state of Florida has rejected their risk assessment methodology based on using an expert elicitation to predict hurricane risk for the next five years. Regular readers may recall that we discussed this issue in depth not long ago. Here is an excerpt from the press release:

During the week of April 23, the Professional Team of the Florida Commission on Hurricane Loss Projection Methodology (FCHLPM) visited the RMS offices to assess the v6.0 RMS U.S. Hurricane Model. The model submitted for review incorporates our standard forward-looking estimates of medium-term hurricane activity over the next five years, which reflect the current prolonged period of increased hurricane frequency in the Atlantic basin. This model, released by RMS in May 2006, is already being used by insurance and reinsurance companies to manage the risk of losses from hurricanes in the United States.
Over the past year, RMS has been in discussions with the FCHLPM regarding use of a new method of estimating future hurricane activity over the next five years, drawing upon the expert opinion of the hurricane research community, rather than relying on a simplistic long-term historical average which does not distinguish between periods of higher and lower hurricane frequency. RMS was optimistic that the certification process would accommodate a more robust approach, so it was disappointed that the Professional Team was "unable to verify" that the company had met certain FCHLPM model standards relating to the use of long-term data for landfalling hurricanes since 1900.

As a result of the Professional Team’s decision, RMS has elected this year to submit a revised version of the model that is based on the long-term average, to satisfy the needs of the FCHLPM.

This is of course the exact same issue that we highlighted over at Climate Feedback, where I wrote, "Effective planning depends on knowing what range of possibilities to expect in the immediate and longer-term future. Use too long a record from the past and you may underestimate trends. Use too short a record and you miss out on longer time-scale variability."

In their press release, RMS complains correctly that the state of Florida is now likely to underestimate risk:

The long-term historical average significantly underestimates the level of hurricane hazard along the U.S. coast, and there is a consensus among expert hurricane researchers that we will continue to experience elevated frequency for at least the next 10 years. The current standards make it more difficult for insurers and their policy-holders to understand, manage, and reduce hurricane risk effectively.

In its complaint, RMS is absolutely correct. However, the presence of increased risk does not justify using an untested, unproven, and problematic methodology for assessing risk, even if it seems to give the "right" answer.

The state of Florida would be wise to err in the decision making on the side of recognizing that the long-term record of hurricane landfalls and impacts is likely to dramatically understate their current risk and exposure. From all accounts, the state of Florida appears to be gambling with its hurricane future rather than engaging in robust risk management. For their part, RMS, the rest of the cat model industry, and insurance and reinsurance companies should together carefully consider how best to incorporate rapidly evolving and still-uncertain science into scientifically robust and politically legitimate tools for risk management, and this cannot happen quickly enough.

Posted on May 11, 2007 01:14 PM View this article | Comments (8)
Posted to Author: Pielke Jr., R. | Disasters | Prediction and Forecasting | Risk & Uncertainty

April 01, 2007

Sea Level Rise Consensus Statement and Next Steps

In a paper by Jim Hansen that we discussed last week, he called for a consensus statement to be issued on global warming, West Antarctica and sea level rise, from relevant scientific experts. A group of scientists have beat him to the punch issuing a consensus statement last week:

Polar ice experts from Europe and the United States, meeting to pursue greater scientific consensus over the fate of the world’s largest fresh water reservoir, the West Antarctic Ice Sheet, conclude their three-day meeting at The University of Texas at Austin’s Jackson School of Geosciences with the following statement:

Read the whole thing, but the take home point is that there remain substantial uncertainties, as indicated in the following parts of the consensus statement:

*Satellite observations show that both the grounded ice sheet and the floating ice shelves of the Amundsen Sea Embayment have thinned over the last decades.
*Ongoing thinning in the grounded ice sheet is already contributing to sea-level rise.

*The thinning of the ice has occurred because melting beneath the ice shelves has increased, reducing the friction holding back the grounded ice sheet and causing faster flow.

*Oceanic changes have caused the increased ice-shelf melting. The observed average warming of the global ocean has not yet notably affected the waters reaching the base of the ice shelves. However, recent changes in winds around Antarctica caused by human influence and/or natural variability may be changing ocean currents, moving warmer waters under the ice shelves.

*Our understanding of ice-sheet flow suggests the possibility that too much melting beneath ice shelves will lead to "runaway" thinning of the grounded ice sheet. Current understanding is too limited to know whether, when, or how rapidly this might happen, but discussions at the meeting included the possibility of several feet of sea-level rise over a few centuries from changes in this region.

What is the policy significance of this statement?

1. Decisions about climate change will have to be made is the face of considerable uncertainties as those related to sea level rise will not be reduced anytime soon.

2. There is the "possibility of several feet of sea-level rise over a few centuries from changes in this region." This contrasts strongly with Jim Hansen's assertion that

"Spatial and temporal fluctuations are normal, short-term expectations for Greenland glaciers are different from long-term expectations for West Antarctica. Integration via the gravity satellite measurements puts individual glacier fluctuations in proper perspective. The broader picture gives strong indication that ice sheets will, and are already beginning to, respond in a nonlinear fashion to global warming.There is enough information now, in my opinion, to make it a near certainty that IPCC BAU climate forcing scenarios would lead to disastrous multi-meter sea level rise on the century time scale" (PDF).

Who will eventually be proven correct? I have no idea. Nor do I think that it matters at all from the perspective of policy (compare Naomi Oreskes' views on this subject here) . The significance of this difference in views has more to do with issue of scientific advice than sea level rise itself -- if scientists create an expectation that our decision making should be guided by consensus views of relevant experts, then they should take care when abandoning that approach to scientific advice when less politically convenient.

3. Bottom line: Sea level rose about 20 cm over the past century. The IPCC expects that it may rise from less than that amount to about 60 cm over the next century. RealClimate says they see another 40 cm possible in the IPCC report. And there is a long thin probability tail of higher amounts with low probability and high consequences.

So, What are the Next Steps?

**Mitigation actions can have only a small effect on sea level rise in the short term (e.g., from no impact decades hences to small impacts a century out) and thus respond primarily to the longer term threats of sea level rise more than a century in the future.

**The most (and only) effective responses to sea level rise over the century timescale will be adaptive. So once again we see that mitigation and adaptation respond to fundamentally different aspects of the climate issue. Mitigation and adaptation should occur in parallel.

**Mitigation and adaptation policies to in response to sea level rise have been looked at (notably in the work of Richard Tol, e.g., here), but far more needs to be done (e.g., as argued here in PDF and here in PDF). Sea level rise has, like so many aspects of the climate issue, fallen into the trap of the "prediction game" at the expense of research on the possible consequences of alternative policies in response to that which we already know. The sea level rise issue risks becoming simply a "poster child" for mitigation rather than an issue deserving more attention itself.

So my recommendation is: Rather than arguing over which predictions of the climate future (or which scientists) are correct, we know enough about the general trend in sea level rise and the possibility of a large increase to begin thinking and talking in far more depth about a wide range of possible policy responses, especially adaptation. Such discussions have to go beyond the simplistic use of future sea level rise as a argument to mitigate. Under any scenario of mitigation the adaptation challenge remains essentially the same, and similarly under any adaptation efforts the mitigation challenge does not change. Absolutely no science on the prediction of future sea level rise will alter this basic reality.

Posted on April 1, 2007 04:58 PM View this article | Comments (10)
Posted to Author: Pielke Jr., R. | Climate Change | Risk & Uncertainty

February 27, 2007

Science, Politics, Variability, Change, Learning, Uncertainty

The issue of floodplain management in the city of Boulder reflects in microcosm many of the themes that we discuss on this site. Here is an excerpt from an article in the Daily Camera today:

Boulder's water board approved a flood plan Monday that predicts hundreds more homes and businesses will be inundated in a 100-year flood than previously believed.
But the new flood study predicts the University of Colorado's South Campus property will stay dry in a 100-year flood, worrying residents who don't want to see the former gravel mine developed.

The city's current map places 363 structures in the flood plain. The new study predicts more than three times as many buildings — 1,137 — would take on some level of water in a 100-year flood, which has a 1 percent chance of occurring in any year.

Some issues raised by this circumstance:

1. The climate varies and changes faster than the built environment. Yesterday's "100-year flood" is today's "50-year flood." Any flood policy based on the assumption of long-term stasis in climate is bound to fail.

2. Scientific understandings change faster than the built environment. Policies should be flexible to the possibility that we may learn more in the future, and such learning may result in revisions to our expectations for risks and vulnerabilities. Any policy that is based on an assumption that we know all we are going to is likely to fail.

3. People have different vested interests in particular scientific outcomes. In Boulder, people with different views about development have strong feelings about how the floodplain should be designated, based on how they think that will affect the chances of development. It would be foolish to think that such considerations can be ignored or kept separate from the political process of designating floodplain restrictions.

4. All important decisions are characterized by some degree of uncertainty. An important analytical question is not whether we can remove uncertainty (we can of course by chose to ignore it), but to design decision processes that are robust in the face of uncertainties.

The case study of flood policy in Boulder, Colorado reflects all of these issues.

Posted on February 27, 2007 07:19 AM View this article | Comments (3)
Posted to Author: Pielke Jr., R. | Risk & Uncertainty

February 23, 2007

Catastrophic Visions

The last time that we pointed to an essay by Brad Allenby of ASU it generated much thoughtful discussion. I expect no different from this provocative piece in the latest CSPO Newsletter from ASU titled Dueling Elites and Catastrophic Visions. Here is an excerpt:

. . . consider two of the primary dialogs of our times that, while superficially quite different, are in fact disconcertingly similar in intent and tone. One is the current U.S. Administration’s insistence on a continuing and inescapable threat of ubiquitous and unpredictable terrorism, a campaign which appears designed to create on-going fear and insecurity in the population. (That the cultural animosity underlying increases in anti-US attitudes is to a significant degree a result of Administration choices and policy is either supreme irony or Machiavellian brilliance, depending on who one listens to.) This campaign is characterized by constant reference to worst case scenarios (e.g., nuclear attack on an American city), patterns of government intervention in common activities that reinforce a siege mentality while providing no obvious additional protection against threats (e.g., certain TSA procedures and requirements at airports), few public details regarding actual threats or specific situations, and the implicit message that the current state of affairs will persist for the indefinite future.
The second is the significant acceleration in stories and publicity regarding predictions of planetary disaster as a result of human activities, especially global warming. This challenge is characterized in remarkably similar terms as the terrorist threat: ubiquitous and uncertain with a potential for unexpected disaster, an emphasis on worst case scenarios, and suggestions that extraordinary government intervention is required and justified because all other values pale in comparison to the threat. So, for example, Vice President Gore recently stated that global warming was "infinitely" worse than the Iraq quagmire, while UK environment secretary David Miliband suggests issuing all British adults with annual carbon allowances. Indeed, the UK government has formed a study group to report back on the idea; Nature (442:340) reports that researchers favor such quotas as "a sensible way to extend emissions trading to the personal level." The connection between social engineering and environmental disaster as lever could scarcely be clearer. Similarly, a recent report in Science notes the reluctance of some climate scientists to consider geoengineering solutions to global climate change not because they don’t work, but because they don’t require social engineering (314:401-403). As one European climate scientist complains, "You’re papering over the problem [by even considering geoengineering options] so people can keep inflicting damage on the climate system without having to give up fossil fuels." Whether scientists should arrogate to themselves the responsibility for deciding for everyone that fossil fuels should be given up, as opposed to other alternatives to managing climate change, is apparently not to be subject to dialog.

Posted on February 23, 2007 01:30 AM View this article | Comments (1)
Posted to Author: Pielke Jr., R. | Risk & Uncertainty

February 22, 2007

Where Stern is Right and Wrong

The Christian Science Monitor adds a few interesting details to Nicolas Stern's recent U.S. visit. On mitigation Stern explains why the debate over the science of climate change is in fact irrelevant:

Even if climate change turned out to be the biggest hoax in history, Stern argues, the world will still be better off with all the new technologies it will develop to combat it.

If mitigation can indeed be justified on factors other than climate change, which I think it can, then why not bring these factors more centrally into the debate?

Stern also dismissed two other arguments for inaction: that humans will easily adapt to climate change and that its effects are too far in the future to address now. Putting the burden of dealing with climate change on future generations is "unethical," Stern said.

Once again adaptation is being downplayed as somehow being in opposition to mitigation. Stern may in fact believe that we need to both adapt and mitigate, but that is certainly not what is conveyed here. The Stern Review itself adopted a very narrow view of adaptation as reflecting the costs of failed mitigation. When framed in this narrow way there is no alternative than to characterize adaptation and mitigation as trade-offs, and in today's political climate guess which one loses out?

Posted on February 22, 2007 07:19 AM View this article | Comments (10)
Posted to Author: Pielke Jr., R. | Climate Change | Risk & Uncertainty | Technology Policy

February 21, 2007

Mike Hulme in Nature on UK Media Coverage of the IPCC

Nature published a letter in its current issue on media coverage of the recent IPCC report. The book he refers to is co-edited by our own Lisa Dilling. Here is an excerpt from the letter:

Nature 445, 818 (22 February 2007) | doi:10.1038/445818b; Published online 21 February 2007
Newspaper scare headlines can be counter-productive

Mike Hulme
Tyndall Centre, School of Environmental Sciences, University of East Anglia, Norwich NR4 7TJ, UK

. . . Communicating science to wider, public audiences, however — in this case on matters of important public policy — is an art that requires careful message management and tone setting. It seems that confident and salient science, as presented by the IPCC, may be received by the public in non-productive ways, depending on the intervening media.

With this in mind, I examined the coverage of the IPCC report in the ten main national UK newspapers for Saturday 3 February, the day after the report was released. Only one newspaper failed to run at least one story on the report (one newspaper ran seven stories), but what was most striking was the tone.

The four UK 'quality' newspapers all ran front-page headlines conveying a message of rising anxiety: "Final warning", "Worse than we thought", "New fears on climate raise heat on leaders" and "Only man can stop climate disaster". And all nine newspapers introduced one or more of the adjectives "catastrophic", "shocking", "terrifying" or "devastating" in their various qualifications of climate change. Yet none of these words exist in the report, nor were they used in the scientists' presentations in Paris. Added to the front-page vocabulary of "final", "fears", "worse" and "disaster", they offer an insight into the likely response of the 20 million Britons who read these newspapers.

In contrast, an online search of some leading newspapers in the United States suggests a different media discourse. Thus, on the same day, one finds these headlines: "UN climate panel says warming is man-made", "New tack on global warming", "Warming report builds support for action" and "The basics: ever firmer statements on global warming". This suggests a more neutral representation in the United States of the IPCC's key message, and a tone that facilitates a less loaded or frenzied debate about options for action.

Campaigners, media and some scientists seem to be appealing to fear in order to generate a sense of urgency. If they want to engage the public in responding to climate change, this is unreliable at best and counter-productive at worst. As Susanne Moser and Lisa Dilling point out in Creating a Climate for Change: Communicating Climate Change and Facilitating Social Change (Cambridge Univ. Press, 2007), such appeals often lead to denial, paralysis, apathy or even perverse reactive behaviour.

The journey from producing confident assessments of scientific knowledge to a destination of induced social change is a tortuous one, fraught with dangers and many blind alleys. The challenging policy choices that lie ahead will not be well served by the type of loaded reporting of science seen in the UK media described above.

Posted on February 21, 2007 03:02 PM View this article | Comments (5)
Posted to Author: Pielke Jr., R. | Climate Change | Risk & Uncertainty

February 12, 2007

An Inconvenient Survey

Last Friday I visited Savannah, Georgia to participate in a viewing and discussion of Al Gore’s “An Inconvenient Truth.” This is the second time I have had a chance to participate in such an event, and it was a pleasure to participate in this event (including getting to see a thoughtful talk by Georgia Tech’s peter Webster).. This time I thought I’d collect a bit of data. So like the college professor that I am I gave a pop quiz right after the movie. After watching a documentary on climate change one should have the basic facts down, right? Unfortunately, no. Here is the pop quiz I gave with answers on the other side.

1. The Intergovernmental Panel on Climate Change released its 4th Assessment Report last Friday. It projects a likely global average temperature increase for 2100 of (degrees C):

A. 1.1 to 6.4
B. 1.5 to 4.5
C. 5.0 to 11.5
D. 7.0 to 9.0

2. The Intergovernmental Panel on Climate Change released its 4th Assessment Report last Friday. It projects a (mid-range) global average sea level rise for 2100 of:

A. 16 inches
B. 48 inches
C. 10 feet
D. 70 feet

3. If the Kyoto Protocol is fully implemented, including US participation, the effects on global average temperatures in 2080 would be:

A. Undetectable
B. Reduce the projected increase by 0.5 degrees
C. Reduce the projected increase by 1.0 degrees
D. Reduce the projected increase by 2.0 degrees

4. If the global greenhouse gas emissions magically stopped right now global average temperatures would:

A. Stop increasing immediately
B. Continue increasing for many decades

5. In order to stabilize atmospheric concentrations of carbon dioxide requires that net global emissions be reduced from today’s levels:

A. to 1990 levels
B. by 20%
C. by 50%
D. by 100%

Answers:

1. A
2. A
3. A
4. B
5. D

No one in the audience of about 200 people admitted to getting all 5 correct. Judging by the show of hands very few came close to the correct answers on 1, 2, 3 or 5. Most people did get #4 correct. In fact, on 1, 2, and 3 the overwhelming answers were C and D and 5 it was A and B. And this was a very educated, engaged audience. I would venture that a scientific survey would find that Mr. Gore’s movie is more apt to mislead than bring the viewer to a clear understanding of the center of gravity of scientific opinion on climate change.

Is it alarmist? By effect on its uninformed audience, I'd hypothesize based on this nonscientific data set that it is.

What was most troubling was the comments of a few people in the audience who reacted pretty negatively to my remarks. One person commented (paraphrase):

We are here to talk about the end of the world and you want to talk about hurricanes. It is energy policy only we need to talk about, not disasters.

Of course Mr. Gore’s movie is chock full of references to disasters, most notably Katrina. The amazing thing to me is that about 6 people from Savannah that I spoke to in some depth, including taxi drivers and lawyers, mentioned to me that Savannah is fortunate to be in a hurricane shadow – it can’t be hit. The reality is that it can and will be hit, and hit hard. And to the extent that the focus on climate change distracts from hurricane preparation, when that fateful day occurs, the resulting disaster will inevitably be worse.

And if you don’t think that the focus on climate-change-as-energy-policy distracts from the need to adapt to climate change, consider this amazing admission from a state official in New Mexico, reacting to our recent paper in Nature:

The problem, Pielke said, is that advocates fear efforts to adapt to climate change will blunt calls to reduce greenhouse gas emissions.
That fear has affected New Mexico's ambitious governmental climate change effort.

A report last year from the New Mexico Office of the State Engineer concluded that "adaptation" is critical to coping with climate change and population growth.

But most of the state's climate change effort has focused on cutting greenhouse gas emissions rather than on coping with the collision between a growing population and a changing climate.

Jim Norton, one of the state officials heading up the effort, agrees with Pielke that adaptation is critical. But there was a fear, Norton said, that too much emphasis "could sort of divert attention away from solving the problem of growing greenhouse gas emissions." [emphasis added]

Reducing emissions is a challenge well worth undertaking. But when it becomes such an overwhelming focus that nothing else is allowed, especially adaptation in mal-adapated communities, then a virtue becomes a vice. An Inconvenient Truth mislead because it suggests that we only need do one thing to respond to the threat of climate change. The reality is that we must do many things, among which we must evaluate tradeoffs, costs and benefits, risks and uncertainties. And that is a real inconvenient truth.

Posted on February 12, 2007 02:44 AM View this article | Comments (26)
Posted to Author: Pielke Jr., R. | Climate Change | Risk & Uncertainty

February 07, 2007

Clarifying IPCC AR4 Statements on Sea Level Rise

The statements in the IPCC’s AR4 SPM released last week on sea level rise have led to some confusion and conflict over what exactly they said and how it compares to the 2001 IPCC TAR. The IPCC could have made it easier for all of us by presenting the data in a comparable manner. This post reflects my efforts to make sense of this situation. I hope that experts on the subject will weigh in on my initial thoughts.

I conclude that the IPCC has indeed lowered its top end estimates of sea level rise over the 21st century relative to 1990, in contrast to the conclusions at RealClimate which suggest that this has in fact not occurred. For details, please read on.

First, what did the IPCC 2001 TAR say about sea level? It reported:

For the complete range of AOGCMs and SRES scenarios and including uncertainties in land-ice changes, permafrost changes and sediment deposition, global average sea level is projected to rise by 0.09 to 0.88 m over 1990 to 2100, with a central value of 0.48 m

Some information was not included:

In addition, Warrick et al. included an allowance for ice-dynamical changes in the WAIS. The range we have given does not include such changes. The contribution of the WAIS is potentially important on the longer term, but it is now widely agreed that major loss of grounded ice from the WAIS and consequent accelerated sea-level rise are very unlikely during the 21st century.

and

The range we have given also does not take account of uncertainty in modelling of radiative forcing, the carbon cycle, atmospheric chemistry, or storage of water in the terrestrial environment.

This is quite similar to the just-released IPCC AR4 (PDF) which says:

Models used to date do not include uncertainties in climate-carbon cycle feedback nor do they include the full effects of changes in ice sheet flow, because a basis in published literature is lacking.

The IPCC AR4 does apparently incorporate information from Greenland and Antarctica:

The projections include a contribution due to increased ice flow from Greenland and Antarctica at the rates observed for 1993-2003, but these flow rates could increase or decrease in the future.

It suggests that on the increasing side that:

For example, if this contribution were to grow linearly with global average temperature change, the upper ranges of sea level rise for SRES scenarios shown in Table SPM-3 would increase by 0.1 m to 0.2 m. Larger values cannot be excluded, but understanding of these effects is too limited to assess their likelihood or provide a best estimate or an upper bound for sea level rise.

Over at RealClimate they seem to have added to the confusion by asserting incorrectly:

Note that some media have been comparing apples with pears here: they claimed IPCC has reduced its upper sea level limit from 88 to 59 cm, but the former number from the TAR did include this ice dynamics uncertainty, while the latter from the AR4 does not

As documented above the TAR did not include such uncertainties, writing of its Figure 11.12:

Note that this range does not allow for uncertainty relating to ice-dynamical changes in the West Antarctic ice sheet.

I asked RealClimate about this, and they responded:

The TAR range included mass-balance estimates for the Greenland and Antarctic ice sheets (though did not include dynamical changes - i.e. changes due to changes in ice streams, calving, grounding line movement, etc which were then thought to be small). Recent observations point to the vital importance of such terms in assessing the net mass balance, thus since they are highly uncertain, it was thought more prudent to not include the mass-balance terms this time around. Our statement above should probably state that "the former number from the TAR did include some ice-sheet mass balance uncertainty, while the latter from the AR4 does not"

What RealClimate fails to acknowledge is that because the TAR did not consider dynamical uncertainties, then a similar uncertainty range would have to be added on top of the TAR top end estimate to make it apples-to-apples with the top end uncertainty in the AR4. So in effect they cancel out and are not relevant to this discussion.

Presumably when the IPCC AR4 says "a basis in published literature is lacking" it is indeed prudent not to speculate. I would assume that there is also no basis in the published literature to conclude that sea level rise might stop instantaneously next year, so they didn’t include that either;-)

So what then do we get when comparing the two reports? The following figure shows the TAR and AR4 estimates on the same graph, taken from the TAR with the AR4 values superimposed. The AR4 ranges are delineated using the same color scheme as the TAR, but with rounded ends. The AR4 values are for 2090-2099, which I have presented as 2095. There is, as noted above, some error term on the upper end of the range. But it should be applied to both the TAR and AR4 estimates, so for comparative purposes they basically cancel out.

Thus, I conclude that the top end estimate has indeed come down from the TAR to the AR4, and those making this observation are accurately representing the AR4. Why didn't the IPCC just say so?

Posted on February 7, 2007 03:18 PM View this article | Comments (23)
Posted to Author: Pielke Jr., R. | Climate Change | Risk & Uncertainty

February 01, 2007

Does the Truth Matter?

Here are seven paragraphs from the conclusion to Alan Mazur’s excellent book True Warnings and False Alarms: Evaluating Fears about the Health Risks of Technology, 1948-1971 (Resources for the Future, 2004, pp. 107-109, buy a copy here)-- the concluding subsection is titled "Does the Truth Matter?" .

Mazur distinguishes between a "knowledge model" and a "politics model" for understanding public debates involving science. These distinctions are somewhat (but not entirely) related to the concepts of the "linear model" and "interest group pluralism" that I discuss in my forthcoming book, which is really about how to reconcile the fact that there are elements of both models in the reality of decision making. Neither of Mazur’s models accurately describes how the world works, we need both. Some of the more useful debates and discussions following my testimony his week reflected a paradigm clash between those who view the world through the lens pf the "knowledge model" and those – like me – who accept that the "politics model" also reflects some fundamental realities as well. Here is the excerpt:

In a democracy, the people or their representatives are free to spend public money as they see fit. Interest groups compete to channel funding to their favorite causes. If U.S. society chooses to allot far more money to cleaning up toxic waste sites, which harm few people, than to prevent teenagers from smoking, which creates an enormous health burden, that is our privilege as a nation.
Still, many risk analysts are disturbed when we fail to maximize the number of lives save per dollar of risk remediation. They point out that actions taken by government to avoid the consequences of an alleged hazard are often unrelated to the severity or scientific validity of the hazard (EPA 1982; Breyer 1993; Graham and Wiener 1995; Mazur 1998). The inference is that policy should be better aligned with science, and that irrational or inefficient elements of policymaking should be eliminated (but see Mazur 1995 and Driesen 2001 for limitations on this positions).

Yet public policy does not always flow directly from scientific knowledge. A value-laden subject decision is always involved, one that requires weighing pros and cons, costs and benefits, winners and losers. A wise policy choice for one party with certain interest may not be the wisest choice for a party with different interests. These considerations raise a question: does scientific evaluation of a warning matter at all?

Essentially two models show how science is applied to public policy. The first – call it the "knowledge model" – assumes that scientists can obtain approximately true answers to their research questions with methods that are fairly objective. This knowledge is used to inform public policy. For example, scientists can determine the health risks from exposure to fluoride at levels adequate to prevent cavities. Policy makers then use this finding as one factor in deciding whether to add fluoride to community drinking water. Such decisions cannot follow from facts alone, but facts ought to influence outcomes. If health risk is high, that should help shift the decision against fluoridation; if low, that should encourage fluoridation. The model makes no sense to anyone who denies that science can find correct answers.

The second model – the "politics model" – can be applied whatever one’s view concerning the objectivity of science. Here partisans use scientific findings as political capital to sway policy in the direction they prefer. If such partisans favor fluoridation, they will claim there is little health risk; if they oppose it, they claim a high health risk. I makes no difference if the findings are correct, objective, or honest as long as they are persuasive. The actors bury findings that work against their position, or attack them as invalid or inapplicable. In the politics model, scientific claims are used polemically, just like any other kind of political argumentation (Mazur 1998; Brown 1991).

The politics model has many proponents. Partisans in a particular controversy often see their goal as sufficiently important to justify any interpretation of scientific data that is favorable to their cause. During breaks from writing this final chapter, I am reading John McPhee’s (1971) laudable biography of David Brower, a major environmentalist of the postwar period. McPhee repeatedly describes Brower’s habit of making up “facts” to support his arguments against industrialists and developers. The biographer seems to regard this as an endearing tactic of the "archdruid" in his advocacy for wilderness preservation. Like McPhee, we sympathize with those who fight the good fight, accepting their argumentation when in other contexts it would be vexing.

But the politics model loses its appeal if applied to the entire array of technical controversies affecting policy. Science that is sufficiently malleable to serve any position in one controversy can serve any position in all controversies, and in that event science does not matter at all. The famous parable of “the tragedy of the commons” tells how each shepherd maximized his own herd’s grazing on the village green until no grass remained for anyone (Hardin 1968). In the same way, if each technical expert interprets data for his or her own convenience, with no attempt at objectivity, there will be no experts left with unimpeachable credibility, and we will all suffer for it. [emphasis added]

Posted on February 1, 2007 07:48 AM View this article | Comments (3)
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