Andrew Dessler on Uncertainty
February 13th, 2006Posted by: admin
Guest Post by Andrew Dessler
Ed.- Professor Andrew Dessler, of Texas A&M University’s Department of Atmospheric Sciences, has been a frequent and substantive contributor to discussions here at Prometheus for a while now. On the occasion of the publication of his new book (The Science and Politics of Climate Change, co-authored with Edward Parson, Cambridge University Press, 2006), we thought it might be valuable to ask Andrew to present his views of science and policy in the climate issue to stimulate discussion and debate among our readers, and to give Prometheus readers a little diversity in the perspectives presented here. Andrew introduced his book here. This is part two, on uncertainty. RP
Anyone familiar with the climate change debate is familiar with the “scientific uncertainty” argument, which usually goes something like this:
The response to climate change must be based on sound science, not on speculation or theory. There is too much uncertainty and too much that we do not know about climate change. It would be irresponsible to undertake measures to reduce emissions, which could carry high economic costs, until we know that these are warranted.
Political analyst Frank Luntz suggests that this argument can aid in convincing people to oppose action on climate change, especially when used as part of a broader set of arguments that include economic and standard rhetorical components. The foundation of the argument – that there is uncertainty in present scientific knowledge of climate change – is uncontroversial. But is there so much uncertainty that we should delay action on addressing climate change until we know more? According to this argument, the answer is yes.
To dissect this argument, let’s consider three different arenas of decision making under uncertainty:
(1) Criminal trial: Anyone who’s watched TV knows that a criminal defendant in the US is presumed innocent unless the prosecution succeeds in demonstrating guilt “beyond a reasonable doubt.” In other words, the decision to act (i.e., convict) requires a high standard of proof. The requirement of overwhelming proof is based on a value judgment about the relative severity of the two possible ways a criminal verdict can err — either by convicting an innocent defendant, or by acquitting a guilty one. Society has long judged it worse to convict an innocent defendant than to acquit a guilty one, so the criminal trial has been biased to make that outcome less likely.
The crucial point here is that the standard for conviction is based on a normative judgment about the relative harm of the two possible errors. The worse we judge a particular error to be, the more we try to make it unlikely by biasing the decision-making process against it. In doing so, we willingly accept a heightened risk of making the other type of error, because we judge it to be less bad.
(2) Civil trial: In civil law – private suits by one party against another, in which usually only monetary damages or requirements to change behavior are at stake – society has judged that there is no clear basis to believe one type of error or the other (i.e. errors that favor the plaintiff or the defendant) to be worse. As a result, civil suits are decided without bias, according to “the preponderance of the evidence.”
(3) National defense: In matters of national security, US policy often takes action based on threats that are not just uncertain but unlikely. In other words, even a slight risk of a threat is sufficient to justify action. The reason is that our government judges that the cost of being unprepared to meet a threat that does materialize is much worse than the cost of preparing for a threat that never materializes. This is well articulated by Secretary of State (at the time) Colin Powell when discussing why the USA was pursuing national missile defense: “[T]here is recognition that there is a threat out there . . . And it would be irresponsible for the United States, as a nation with the capability to do something about such a threat, not to do something about [it] . . . you don’t wait until they are pointed at your heart. You start working on it now.” (Remarks at the International Media Center, Budapest, Hungary, May 29, 2001). This can be considered as a strident articulation of the “precautionary principle”.
What do these three examples tell us about climate change? The “uncertainty” argument we presented at the beginning of this post argues that we should wait until we have overwhelming evidence before acting to address climate change, adopting a standard similar to that for a criminal trial. On the other hand, environmentalists often use Powell’s missile defense argument to advocate immediate action on climate change despite uncertainty.
Which standard for action should we adopt? The choice is not scientific; rather, it reflects a judgment about the relative costs of the possible errors. The argument that climate science is too uncertain to merit action would be appropriate if one judged it a worse mistake to limit GHG emissions too much than not to limit them enough — i.e. that the economic losses from too much mitigation were much worse than the costs of unavoided impacts of climate change.
It is our opinion that this is not the case and that, in fact, the reverse situation appears more likely. If uncontrolled climate change and its impacts turn out to lie at or below the bottom of the present projected range, then an aggressive mitigation program would impose substantial unnecessary costs, presently estimated to lie between a few tenths of a percent and several percent of future GDP. But if climate change and impacts lie near or above the top of the present projected range, then not pursuing aggressive mitigation would likely expose the world’s people to much more severe costs and risks, including a possibility of abrupt, catastrophic changes.
Thus, at its heart, the “scientific uncertainty” argument is not about science at all, but about a judgment about whether it is worse to under or overreact to climate change. Further, the argument is worded so as to imply that the “criminal trial” standard should be applied to GHGs — that GHGs are innocent until proven guilty beyond a reasonable doubt. We believe that a strong argument can be made that this standard is inappropriate and that overwhelming evidence is not necessary in order for us to begin taking action on climate change. We have enough evidence now.
February 13th, 2006 at 9:55 am
I appreciate Andrew Dessler’s comments. His examples of three different arenas of decision making uncertainty provide a good framework for the discussion. What is absent from his conclusion, however, is consideration of the second arena, analogous to a civil court, where the decision is made “…without bias, according to “the preponderance of the evidence.”
This is the most obvious arena for AGW decision making, both from a legal and scientific standpoint.
From the legal point of view, AGW is a global, civil trial. There are no accusations of law breaking, just the accusation that one group’s behavior will cause harm to another group. Such disputes are worked out in civil court.
From the scientific perspective, all arguments should be worked out based on the preponderance of the evidence. Any other suggestion is, by definition, unscientific!
Skeptics are often portrayed as demanding conclusive proof that disaster is imminent, but I am sure that most of us would be quite happy with an unbiased weighing of the evidence, coupled with a cost/benefit analysis.
If it can be shown that CO2 is ‘guilty’ of undue warming, then damages must be assessed, offset by benefits from said warming. That means the amount of warming due to CO2 must be quantified (to a reasonable degree). In court, there must be evidence that the ‘defendant’ is actually responsible for the harm, unlike the media, where the defendant (CO2) can be blamed for anything bad that happens.
Mr. Dessler seems to be using the national defense argument to support his call to action against AGW. While it is true that we spend a very large amount of resources trying to prevent the next terrorist attack, we must realize that the decision to do so is very much a political one. A major misstep here could cause irreparable damage to the political party in power at the time. If the response to terrorism was strictly based on the evidence, the cost of protection would be less and a lot more efficient! The same is true for AGW!
Also, terrorism is definitely real and definitely a threat, even if the probabilities for any one individual to suffer from it are small. We all watched those towers come down! We know it is out there. That makes it easier to sell the precautionary measures to the public.
The average Joe has yet to detect any problem with AGW, despite the doom and gloom headlines. In fact, many probably think a little more warming is good idea, especially this time of year.
On top of it all, there is the question of whether the defendant, CO2, could even get a fair trial on this planet. AGW has been so disparaged in the press, it is doubtful that an unbiased judge could be found to hear the case! Certainly a change of venue is in order.
I would argue for Mars. Mr. Dessler would likely choose Venus.
And so it goes!
February 13th, 2006 at 12:12 pm
The comparisons of the potential harm from AGW to criminal, civil, or national defense actions are not particularly apt. Neither the criminal nor civil legal systems deal with wrongs that will not produce measurable harm for decades to come. The comparison to the national defense (Bush doctrine) case neglects the clear fact that AGW will benefit and harm nations unevenly.
The issue of the discounted present value of the potential harms and gains as well as those of the costs of the advocated avoidance actions is completely ignored here. Especially important are the uncertainties of the future harms and gains and the certainty of the present costs.
Given the expected improvements in per capita wealth and technology during the evolution of AGW, the Coase solution to the problem of allocating these social costs is by no means clearly on the side of immediate action by our generation.
February 13th, 2006 at 1:30 pm
On discounting (DF Linton’s comment):
The economics of discounting the future are not simple. Most discounting errors by ignoring the uncertainty of future discount rates.
My colleagues, D Ludwig, SR Carpenter, and WA Brock (a mathematican, ecologist, and economist) discuss this in a recent paper – Uncertainty in Discount Models and Environmental Accounting- in Ecology and society (http://www.ecologyandsociety.org/vol10/iss2/art13/)
From the abstract:
Customarily, economic discounting has been calculated at a constant exponential rate, a practice that weights the present heavily in comparison with the future. Recent analyses of economic data show that the assumption of constant exponential discounting should be modified to take into account large uncertainties in long-term discount rates. A proper treatment of this uncertainty requires that we consider returns over a plausible range of assumptions about future discounting rates. When returns are averaged in this way, the schemes with the most severe discounting have a negligible effect on the average after a long period of time has elapsed. This re-examination of economic uncertainty provides support for policies that prevent or mitigate environmental damage. We examine these effects for three examples: a stylized renewable resource, management of a long-lived species (Atlantic Right Whales), and lake eutrophication.
February 13th, 2006 at 1:49 pm
Jim Clarke-
Here are a few thoughts about your post:
“What is absent from his conclusion, however, is consideration of the second arena, analogous to a civil court, where the decision is made “…without bias, according to “the preponderance of the evidence.”
In our judgment, the costs of too much mitigation are smaller than the costs of unavoided climate change, so we believe the missile-defense analogy is appropriate. However, this is a normative judgment, and I could understand why someone would take a more “proponderance” approach. However, I would argue that the “beyond reasonable doubt” standard is unsupportable given what we know about global warming.
“From the legal point of view, AGW is a global, civil trial. There are no accusations of law breaking, just the accusation that one group’s behavior will cause harm to another group. Such disputes are worked out in civil court.”
I’m not sure what this means. The AGW debate is not occurring in a court of law, but in the international policy arena. In that arena, we can set the standard of proof anywhere we want it. The point of this post is to ask the question where the burden should be set.
“Skeptics are often portrayed as demanding conclusive proof that disaster is imminent, but I am sure that most of us would be quite happy with an unbiased weighing of the evidence, coupled with a cost/benefit analysis.”
The uncertainty argument is one that is commonly made in the mainstream media. While I do not know what would make “most” skeptics happy, there are clearly some that espouse a “criminal trial” standard.
“If it can be shown that CO2 is ‘guilty’ of undue warming, then damages must be assessed, offset by benefits from said warming. That means the amount of warming due to CO2 must be quantified (to a reasonable degree). In court, there must be evidence that the ‘defendant’ is actually responsible for the harm, unlike the media, where the defendant (CO2) can be blamed for anything bad that happens.”
I disagree strenuously. We are building an expensive missile defense system despite the fact that there is no evidence that North Korea or Iran will or even can launch a missile at us. So one can take action even w/o any evidence that a harm has occurred or even will definitely occur. Your argument would similarly reject any action to protect New Orleans from hurricane danger until after the hurricane struck.
“Mr. Dessler seems to be using the national defense argument to support his call to action against AGW. While it is true that we spend a very large amount of resources trying to prevent the next terrorist attack, we must realize that the decision to do so is very much a political one. A major misstep here could cause irreparable damage to the political party in power at the time. If the response to terrorism was strictly based on the evidence, the cost of protection would be less and a lot more efficient! The same is true for AGW!”
I disagree that national defense spending is done simply for political gain. I suspect that policymakers supporting missile defense believe deeply that it’s the right thing to do, not just politically expedient. In fact, the odds of a missile attack during Bush’s tenure is practically nil, and he could get much more mileage taking the $$$ from that program and using it to further cut taxes. But he doesn’t, because of a judgment that building a missile defense system is the right thing to do.
“Also, terrorism is definitely real and definitely a threat, even if the probabilities for any one individual to suffer from it are small. We all watched those towers come down! We know it is out there. That makes it easier to sell the precautionary measures to the public.”
I is my judgment that, over the next century, there’s no reason to believe that terrorism is a worse threat than global warming.
Regards.
February 13th, 2006 at 2:02 pm
D. F. Linton writes:
“The issue of the discounted present value of the potential harms and gains as well as those of the costs of the advocated avoidance actions is completely ignored here. Especially important are the uncertainties of the future harms and gains and the certainty of the present costs.”
I have two responses to this. First, the decision to base a policy on costs and benefits is itself a moral choice. Cost-benefit analyses ignore the rights of future generations to inherit a clean environment, the ignore the costs of low probability catastrophic events delayed far into the future, as well as the possibility of completely unforeseen “climate surprises”, and it provides no guidance about the ethical issues of climate change. While you can argue that we must consider costs and benefits, I can argue that we must also consider what’s the “right” thing to do from an ethical perspective. And that’s just the beginning — as pointed out by Garry Peterson, there are practical issues about discounting, such as agreeing on an appropriate discount rate, or even if exponential discounting is appropriate for costs so far into the future.
Second, we actually have not ignored costs and benefits in this argument. In fact, we explicitly take them into account when we say “If uncontrolled climate change and its impacts turn out to lie at or below the bottom of the present projected range, then an aggressive mitigation program would impose substantial unnecessary costs, presently estimated to lie between a few tenths of a percent and several percent of future GDP. But if climate change and impacts lie near or above the top of the present projected range, then not pursuing aggressive mitigation would likely expose the world’s people to much more severe costs and risks, including a possibility of abrupt, catastrophic changes.”
Regards.
February 13th, 2006 at 3:36 pm
“The choice is not scientific; rather, it reflects a judgment about the relative costs of the possible errors.”
How is this judgement not scientific? Of course, you need some way of comparing diverse environmental and human impacts over long time scales, which will (should) necessarily involve some value judgements. But in your following paragraph, you explicitly tie such a judgement directly to the (scientifically-estimated) climate outcome, rather than any normative judgement on values!
February 13th, 2006 at 4:17 pm
James-
You wrote:
“How is this judgement not scientific?”
For a perhaps simpler example, let’s consider skydiving. Science can tell us that our odds of having a serious accident is, say, 1 in 10,000 (fyi, I just made that number up). You might say, “too risky for me,” while I might say, “I’m willing to accept the risk because I love the rush.” Thus, science gives us information about the decision, but two people can agree completely on the science and disagree on the decision to jump out of a plane.
The situation is similar for climate change. Science can tell us that effects A, B, and C are likely/possible if we do nothing to address climate change. You and I can agree completely on this, but still disagree on what to do about global warming. For example, I might take a Lomborg perspective and say that money is better spent on other problems facing mankind, while you might be very worried about abrupt climate change and therefore support immediate and maximal cessation of GHG emission. Much of the response depends on how risk averse we are (i.e., how strongly we adhere to the precautionary principle), but other values also matter.
One of the things that Roger really emphasizes, and I agree with, is that only in rare circumstances do scientific results dictate policy actions. Rather, it is the combination of science and normative values that determines policy.
Regards.
February 13th, 2006 at 5:58 pm
Andrew Dessler writes, “If uncontrolled climate change and its impacts turn out to lie at or below the bottom of the present projected range, then an aggressive mitigation program would impose substantial unnecessary costs, presently estimated to lie between a few tenths of a percent and several percent of future GDP. But if climate change and impacts lie near or above the top of the present projected range, then not pursuing aggressive mitigation would likely expose the world’s people to much more severe costs and risks, including a possibility of abrupt, catastrophic changes.”
There are two problems with this analysis:
1) He does not say what “the present projected range” is…though presumably the range he has in mind is the farcical “1.4 to 5.8 degrees Celsius” “projected” in the 2001 IPCC TAR.
2) He falsely implies that there is approximately an equal probability that climate change and its impacts will be “at or below the bottom of the present projected range” or “near or above the top of the projected range.” But the simple fact is that there is approximately a 50/50 chance that warming from 1990 to 2100 will be at or below 1.4 degrees Celsius, and much less than a 1 percent chance that warming will be above 5.5 degrees Celsius.
The happy outcome (for him, anyway) of these two problems is that the government intervention he advocates therefore seems reasonable and “balanced.” But given the facts of the matter (i.e. approximately 50/50 chance of warming at or below the IPCC’s lowest “projected” value of 1.4 degrees Celsius) , it is not reasonable and balanced to advocate government intervention for this “problem”…when there are so many other more pressing problems that exist right now. For example: 1) Indoor air pollution in Africa, India, China, and other places in the developing world, including from the burning of “renewable” fuels such as dung and wood, 2) Outdoor particulate pollution in major cities in the developing world, 3) Drinking water pollution, especially by bacteria and viruses, etc.
Also, even the government intervention he advocates–reducing emissions of “greenhouse gases”: 1) ignores black carbon, reductions of which will have immediate health benefits, as well as potentially slowing global warming; 2) ignores the fact that desired outcomes such as reducing damage from future hurricanes could almost certainly be achieved with less cost by methods other than reducing “greenhouse gases,” 3) ignores options such as ocean iron fertilization (let alone more exotic options such as changes in earth’s albedo); and 4) ignores the fact that he is advocating spending money now for “problems” “projected” for the distant future.
P.S. I see that D.F. Linton already addressed that last point. But it’s worth repeating.
February 13th, 2006 at 9:41 pm
Andrew,
It seems like you are addressing the question quite explicitly at least as the product of scientific uncertainty and value judgements. In fact, all your words explicitly speak about the uncertainty of the impacts of climate change, and not about the values you use to balance the different costs.
Eg:
“The argument that climate science is too uncertain to merit action would be appropriate if one judged it a worse mistake to limit GHG emissions too much than not to limit them enough — i.e. that the economic losses from too much mitigation were much worse than the costs of unavoided impacts of climate change.”
I don’t see how you have presented this as anything other than a purely scientific issue – how to minimise total expected cost. You even said “economic costs”, implicitly ruling out less tangible effects.
If the worst impacts were comprehensively ruled out by scientific analyses, would this not change your views?
February 13th, 2006 at 10:52 pm
James-
I’m not 100% sure I understand your question, but I’ll take a stab at answering it.
As a scientist, my scientific views strongly affect the opinions I hold as a citizen. So you’re probably right that I’ve written the post to emphasize the scientific facts rather than values.
If I were an extremely religious person, on the other hand, I might have written something different — e.g., “I agree that your scientific analysis is right, but according to my interpretation of the Bible, lifting people out of poverty is the most important thing we can do, even more important than stopping climate change. So until you prove to me that climate change will be absolutely catastrophic, I don’t support action to stop it.”
This shows how someone with different values can come up with an antithetical viewpoint on the issue, even though they agree with the science. You can disagree with their viewpoint, but I don’t think it can be considered invalid.
Regards.
February 14th, 2006 at 5:49 am
Well, I see your point, but…
It seems to me that you are trying to grab the “rational cost-minimising, moderately risk-averse” position for yourself, and then saying that the science compels a particular course of action given those values.
The problem is, that the sceptics could claim to take exactly the same position, but judge the (“scientifically-evaluated”) costs and risks to balance in a different place. And the same goes for the alarmists…
February 14th, 2006 at 7:07 am
Andrew (and James)-
Various forms of James’ question:
Are you simply saying that for people who share your values about climate impacts and decision making under uncertainty, then scientific information can indeed help show how to balance costs and benefits?
But what about people who don’t share your values — are you saying anything to them at all?
How do you suggest that prescriptive questions relate to normative questions? What is the role of science in a world with people hold vastly different values?
How does your statement of what you (and Parson) value relate to what I should value, or anyone else, in the process of collective decision making?
February 14th, 2006 at 7:21 am
Andrew-
As you suggest, the argument you are presenting has been called by others “the precautionary principle.” But the precautionary principle in only a useful guide to decision making when participants in the deicsion making process share commons views on values and preferences. In a situation of heterogeneous values, like you fnd in the global climate debate, the precautionary principle is useless as a guide to action.
Thie is why it can be invoked by G. Bush to invade Iraq and the EU to limit climate change, and Bush and the EU disagree with the other in each case.
I discussed this emptiness in the following book review:
http://sciencepolicy.colorado.edu/admin/publication_files/resource-20-2002.19.pdf
And Cass Sunstein has a comprehensive critique here:
http://www.cambridge.org/aus/catalogue/catalogue.asp?isbn=0521615127
and here:
http://www.law.upenn.edu/lrev/Issues/vol151/Issue3/Sunstein.pdf
February 14th, 2006 at 7:52 am
Garry,
Thank you for taking the time to respond to my post. I haven’t read the paper you linked to yet, but here are some general comments.
Clearly, there are uncertainties in forecasting the time perferences of future generations. If we could accurately estimate the distribution of these uncertainties, then producing a distribution of present values of AGW gains and harms would be straight-forward. However, given our practical ignorance of the prospective discount rates of our descendants, I’m not at all clear how any argument based on speculation would be convincing to an objective observer.
Andrew,
My thanks to you also for taking the time to respond. It is respectable to say that your ethics requires some action regardless of its cost. However, why would such a statement convince others who do not share your system of ethics?
One can probably make the case that our descendants have just as much of a right to inhert from us the economic fruits of those investments that would not be made in order to address the worst-imaginable AGW scenarios. It is also not at all clear that failure to inherit a world the a mean global temperature and sea-level within such-and-such a range of the current values is identical to the notion of a “clean” environment.
February 14th, 2006 at 8:50 am
Roger,
Your questions are very apt. Here is my answer, even though they weren’t addressed to me:
Science can not preempt the value judgments of individuals. Science can only show us (sometimes clearly, sometimes dimly) the consequences of potential actions.
If Hayek is to be believed, over time, groups holding systems of ethics than routinely result in them bearing costs greater than their benefits will suffer in competition with those who hold more practical belief systems. However, one can easily imagine members of such groups cheerfully accepting their fate comforted by the knowledge that they did the “right thing.”
February 14th, 2006 at 10:29 am
“It is also not at all clear that failure to inherit a world the a mean global temperature and sea-level within such-and-such a range of the current values is identical to the notion of a ‘clean’ environment.”
I’ll accept that outside *some* bounds would constitute failure to provide a “clean” environment. For example, if the average world temperature in 2100 was ~6 degrees Celsius cooler (i.e., comparable to depths of the last ice age), that would be pretty “messy.”
And 10 degrees Celsius warmer (just to pick a number…recognizing that warmer is probably better than cooler) would be pretty sticky.
But I don’t see any clear reason why the temperature should be less than 2 degrees Celsius warmer than the 1880s, as the Europeans seem to want. (It’s especially bizarre that one of their major reasons for this chosen temperature increase is apparently avoiding increases in malaria.(!))
February 14th, 2006 at 1:06 pm
James-
I would make some slight changes to your statement:
It seems to me that you are trying to grab the “rational cost-minimising, moderately risk-averse” position for yourself, and then saying that the science compels a particular course of action given those values.
What I’m saying is that the scientific evidence, combined with my values, leads me to believe that we should begin action immediately to reduce GHGs.
I think it’s important to make clear that science does not compel action by itself — one needs the appropriate values, also.
You wrote:
The problem is, that the sceptics could claim to take exactly the same position, but judge the (“scientifically-evaluated”) costs and risks to balance in a different place. And the same goes for the alarmists…
I agree that people are free to take the same science and combine it with their values to obtain a different judgment about what should be done. So someone else might judge the risks and costs to compel delay rather than immediate action.
Ultimately, the way to sort out different values is by having a public policy debate. The problem is that rarely do people say, “we agree on the science, let’s debate the values.” Rather, arguements about science get conflated with value arguments, which leads to gridlock.
Regards.
February 14th, 2006 at 4:39 pm
Roger-
1) “precautionary principle”. I am not a big fan of the phrase, and we do not refer to it, except in passing, in our book. I did not have it in the original version of the post, as you know, until you suggested I include it … so I will agree with your critique of the phrase and move on.
2) You ask several interesting questions:
“Are you simply saying that for people who share your values about climate impacts and decision making under uncertainty, then scientific information can indeed help show how to balance costs and benefits?”
No, I’m saying that everyone should agree on the science, and then debate what to do about the issue based on the different values people hold. It’s possible for people to agree on the science but disagree on what to do about an issue.
This approach presupposes, of course, that the positive and normative issues can be cleanly separated, which I believe is achievable for issues in WGI. For many issues in WGII and III, separation is not as clean, and therefore some aspects of the science will necessarily enter into the policy debate.
“What is the role of science in a world with people hold vastly different values?”
Science is one input to a policy debate. I would argue that as values diverge, science has less and less of a role to play. If values diverge enough, then agreement is difficult or impossible, even if there is total agreement on the science (e.g., abortion). The flip side is that where values agree totally, then arguments about science completely determine action (e.g., tornado).
“How does your statement of what you (and Parson) value relate to what I should value, or anyone else, in the process of collective decision making?”
The basis for believing that normative claims have right or wrong answers in an absolute sense is weak. Thus, determining which values to adopt must arise from a policy debate. I present you with arguments about why you should adopt my values, and you present me with arguments about why I should adopt yours, and in the end we come up with some mutually agreed position, and the policy then flows from that.
Regards.
February 14th, 2006 at 5:25 pm
Andrew-
Thanks – this is useful.
You write, “I’m saying that everyone should agree on the science.”
Sarewitz explains why everyone can’t be expected to agree on “the science” in his paper titled “Excess of Objectivity.”
http://www.cspo.org/products/articles/excess.objectivity.html
Read the whole thing but here is an excerpt:
“In other words, we are not suffering from a lack of objectivity, but from an excess of it. Science is sufficiently rich, diverse, and Balkanized to provide comfort and support for a range of subjective, political positions on complex issues such as climate change, nuclear waste disposal, acid rain, or endangered species.
This observation, if it is anything close to the mark, suggests that in the political arena, subjectivity and objectivity are not separate and immiscible realms that must always be kept apart, but rather that they are closely related attributes of any highly complex societal problem — opposite sides of the same coin. When an issue is both politically and scientifically contentious, then one’s point of view can usually be supported with an array of legitimate facts that seem no less compelling than the facts assembled by those with a different perspective. In the midst of such controversy, the boundary between facts and values invariably becomes much fuzzier than we often make it out to be. The problem is not one of good science versus bad, or “sound” science versus “junk” science. The problem is that nature can be viewed through many analytical lenses, and the resulting perspectives do not add up to a single, uniform image, but a spectrum that can illuminate a range of subjective positions. “
February 14th, 2006 at 10:20 pm
“I agree that people are free to take the same science and combine it with their values to obtain a different judgment about what should be done.”
What I am arguing, and I think Roger is making a similar point, is that people actually take _different_ science and combine it with essentially the _same_ (claimed) values to generate a different result.
I am sure that in some cases this is not being performed in a scrupulously open and honest manner, ie people (on both sides of the debate) distort their interpretation of the science in order to avoid having to defend values that would not play out well in the public arena. We (almost) all want to be thought of as rational, mildly risk-averse people – indeed some people on both wings probably even think that they are! Nevertheless there is a certainly room for honest disagreement on the science – especially on the important fringe of low probability high cost outcomes, even if we agree on the better-understood mainstream stuff.
February 15th, 2006 at 10:07 am
James-
I certainly agree with you theoretically — there’s no question that disagreement over action can arise from disagreements over science as well as values.
I would disagree, however, that this is occurring in the climate change debate. I cannot think of a single advocate arguing against action on climate change that uses legitimate *scientific* claims as the basis of their argument. The scientific claims of the most vocal critics of science, Inhofe, Singer, Lindzen, Crichton, etc. cannot be considered valid. I challenge you to provide me with an example of an advocate who bases a non-action argument on legitimate science.
As you pointed out, I would argue that these people are using illegitimate scientific arguments as a tactical device to win a political policy debate.
Regards.
February 15th, 2006 at 11:06 am
Andrew-
What do you mean by “inaction”? Business as usual? Defering mitigation? Not ratifying Kyoto? Adaptation only?
Even the Bush Admistration is proposing “action” in the form of research, Asia pacific Partnership, Methane to Markets.
Be specific about what you mean and I’d be happy to suggest people who fit into your category.
February 15th, 2006 at 11:16 am
Roger-
Fair enough. By action I was referring to “mandatory reductions in GHG emissions”.
February 15th, 2006 at 12:15 pm
Andrew:
OK, lets use your general notion of “mandatory reductions in GHG emissions.” (We will undoubtedly have to parse out what this means.)
How about me? As I’ve written many, many times, it is important to reduce greenhouse gas emissions but I don’t think efforts to enact “mandatory greenhouse gas reductions” are politically or practically feasible. We have to tackle this problem indirectly via no regrets energy policies and alternative energy technology investments (in a way far more aggressively proposed by Bush). I would also support a gas tax, a large one, as a way to fund greater investments in R&D and stimulate no regrets options. None of this include mandatory GHG reduuctions. Of course, we also have to dramatically empahsize adapatation more than we have.
Where are my illegitimate scientific arguments?
February 15th, 2006 at 1:24 pm
Roger-
What I asked James was:
“I challenge you to provide me with an example of an advocate who bases a non-action argument on legitimate science.”
You’re not using science as the excuse for inaction. You’re making an argument about what the most effective tactics to take to get to reduced GHGs.
Until a counter example is provided, I stand by my statement that there is not a “single advocate arguing against action on climate change that uses legitimate *scientific* claims as the basis of their argument.”
Regards.
February 15th, 2006 at 3:30 pm
Dessler writes “You’re not using science as the excuse for inaction. You’re making an argument about what the most effective tactics to take to get to reduced GHGs.”
This is a non-sequiter. The question of what actions, if any, would be “effective” is surely a question of science — including the same science that tries to estimate the relationship between carbon dioxide gas levels and global temperatures.
As for value judgments vs. discounted present values, this is a red herring. The issue is human welfare, the obverse side of which is human misery.
I suggest Dessler live in a Third World slum for a couple of years without outside assistance, and then say the choice between poverty and temperature is a value judgment.
Or does he think GW is going to wipe out the human race?
February 15th, 2006 at 3:51 pm
Andrew Dessler writes, “Until a counter example is provided, I stand by my statement that there is not a ’single advocate arguing against action on climate change that uses legitimate *scientific* claims as the basis of their argument.’”
I don’t support any action to reduce GHG emissions. I don’t support any action to reduce GHG emissions because:
1) A preponderance of evidence does not support the conclusion that they cause NET harm now (i.e., that the harm caused by emissions outweighs the benefits of emissions).
2) A preponderance of evidence indicates that methane emissions are already being lowered from their peak emission level, and will continue downward for the forseeable future.
3) A preponderance of evidence suggests that CO2 emissions will peak circa mid-century, or earlier, and will decline by the end of the century to a value that causes atmospheric concentrations to plateau at a value below 560 ppm (i.e., double pre-industrial concentration). This will happen through normal technological evolution…of which the “climate change community” is either ignorant, or is dishonestly ignoring.
4) The resultant temperature increase (approximately 90% probability of lower tropospheric temperature increase from 0 to 2.2 degrees Celsius above current value) will be such that a preponderance of evidence supports either minimal net harm, or even net benefit.
5) Economic science and economic history provides an overwhelming preponderance of evidence that the average (50th percentile) person in the world in 2100 will be far better off than even the richest 10th percentile person in the world today. It is immoral to ask poor people to sacrifice for the benefit of rich people.
6) Simple environmental analysis indicates there are far, far more important environmental problems (e.g. indoor air pollution from burning solid fuels in developing countries, outdoor air pollution in the world’s megacities, microbiological contamination of drinking water) from which obsession with reductions in GHG emissions detract.
7) Many of the anticipated harms that reductions in GHG emissions will allegedly mitigate (e.g., stronger hurricanes, increased malaria) could more cost-effectively be mitigated by other measures. (Reducing malaria by reducing GHG emissions is a particularly laughably uneconomic idea.)
Focusing on reducing GHG emissions ignores other options available now that probably would be less expensive (e.g., iron fertilization of the oceans…not that I support doing that for the purpose of lowering CO2 atmospheric concentrations).
9) Focusing on reducing GHG emissions ignores black carbon and tropospheric ozone, reductions of which would provide immediate health benefits.
Please explain how each of my claims is scientifically illegitimate. Or, more appropriately, simply admit you stand corrected.
February 15th, 2006 at 6:48 pm
Ah yes, the can’t chew gum and walk argument (8,9) appears butressed by a bunch of idle wishes (3,4,5,6,7) and irrelevancies (1).
February 15th, 2006 at 6:49 pm
Luke Lea-
You misunderstand several aspects of the discussion. Let me go through them point-by-point:
You write:
The question of what actions, if any, would be “effective” is surely a question of science — including the same science that tries to estimate the relationship between carbon dioxide gas levels and global temperatures.
Please re-read Roger’s and my post to correctly understand my response. I said that he was describing a political strategy to reduce GHGs, not provding a scientific argument against GHG regulation.
You write:
As for value judgments vs. discounted present values, this is a red herring. The issue is human welfare, the obverse side of which is human misery.
You’ve simply transfored the value judgment issue into how to define “human welfare.” Some people would take the view that human welfare and economic wealth are equivalent, while others would contend we have other moral and ethical responsibilities (e.g., the Evangelicals). Perhaps you agree with the former position, but you should not assume everyone else agrees with you.
You write:
I suggest Dessler live in a Third World slum for a couple of years without outside assistance, and then say the choice between poverty and temperature is a value judgment.
Straw man. Our choice is not between temperature increase and third-world poverty. This is the kind of unrealistic argument that drives gridlock in the debate.
Regards.
February 15th, 2006 at 7:15 pm
Andrew-
If a decision to reduce GHGs is a polictical decision (agreed), a function of normative commitments, in your framework how is it even possible that you can make a “scientific” justification for action? If as you say science provides answers to positive question, how can it than transorm into answers to normative questions?
If science – politics are separate, then how can science justify one action over another?
February 15th, 2006 at 7:16 pm
Mark-
Your post exemplifies the confusion between science and values.
Number 5, for example, is an argument about morality. Science tells us nothing about the moral choices that you describe.
Numbers 7 and 8 take a cost-benefit viewpoint. Such a view is also a moral choice. Cost-benefit analyses ignore the rights of future generations to inherit a clean environment, ignore the costs of low probability catastrophic events delayed far into the future, as well as the possibility of completely unforeseen “climate surprises”, and it provides no guidance about the ethical issues of climate change. While you can argue that we must consider costs and benefits, I can argue that we must also consider what’s the “right” thing to do from an ethical perspective. And there are practical issues, such as whether exponential discounting is appropriate for costs so far in the future.
Number 6 is similarly also a value judgment.
All of these value judgments are not addressable by science, so your challenge for me debunk them is ill posed.
Some of your points are scientific, but they have no merit. I was especially amused by number 3, that CO2 will peak mid-century w/o any policy to reduce GHGs. You say the “preponderance” of evidence supports you, when I think “no evidence” would be more appropriate.
We discussed your number 4 before, so you know I think it’s balderdash. I won’t repeat that discussion here.
I could go on, but I won’t.
Regards.
February 15th, 2006 at 9:29 pm
Roger-
You wrote:
If a decision to reduce GHGs is a polictical decision (agreed), a function of normative commitments, in your framework how is it even possible that you can make a “scientific” justification for action? If as you say science provides answers to positive question, how can it than transorm into answers to normative questions?
Let me completely clear about my justification. As a citizen, I believe that we have a moral obligation to leave the Earth as close as possible to how we found it. As a scientist, I know that the Earth is warming, humans are likely to blame for the recent warming, and that the warming will continue into the foreseeable future as GHGs build up in the atmosphere.
Thus, a combination of my judgments about what is right and my knowledge of science leads to my judgment that the countries of the world should reduce GHG emissions.
While science plays a role in my decision (it answers the questions that are important in my decision), science does not by itself compel action.
Regards.
February 15th, 2006 at 10:10 pm
Andrew- The role of science in an individual’s decision making seems pretty clear. But put you, Fred Singer, James Lovelock, and Bjorn Lomborg in a room together and require that you come up with a consensus plan for climate policy. What is the role of science there?
February 16th, 2006 at 9:55 am
Roger-
This is a difficult question. I’m not sure I know what role science plays when dealing with people (e.g., Singer) who make transparently false scientific arguments.
If I assume the real issue is greatly divergent values — in other words, Singer et al. make false scientific arguments because his values lead him to oppose action on mitigation, and he can most easliy achieve that objective by making false scientific agruments — then I’ll refer you to my comment up above:
Science is one input to a policy debate. I would argue that as values diverge, science has less and less of a role to play. If values diverge enough, then agreement is difficult or impossible, even if there is total agreement on the science (e.g., abortion). The flip side is that where values agree totally, then arguments about science completely determine action (e.g., tornado).
For the group you proposed, it might be that our values are so divergent that no agreement is possible. I don’t know. In that case, science is not doing much. Luckily, I think the values of the general public are becoming more aligned than your proposed motley crew (crüe?), and an agreement is possible.
Regards.
February 17th, 2006 at 7:11 pm
Andrew Dessler wrote “Until a counter example is provided, I stand by my statement that there is not a ’single advocate arguing against action on climate change (which he later clarified as being ‘mandatory reduction of GHG emissions’) that uses legitimate *scientific* claims as the basis of their argument.’”
I responded that I don’t support mandatory reduction of GHG emissions, and provided 9 scientific claims to support my argument.
Andrew Dessler responded…
…oh my! Well, I don’t have time to address all he wrote, so I’ll focus on two items (item numbers 3 and 4 from my nine claims).
I wrote, “3) A preponderance of evidence suggests that CO2 emissions will peak circa mid-century, or earlier, and will decline by the end of the century to a value that causes atmospheric concentrations to plateau at a value below 560 ppm (i.e., double pre-industrial concentration). This will happen through normal technological evolution…”
He responded, “Some of your points are scientific, but they have no merit. I was especially amused by number 3, that CO2 will peak mid-century w/o any policy to reduce GHGs. You say the “preponderance” of evidence supports you, when I think “no evidence” would be more appropriate.”
Good grief. Are you serious that you truly know of “no evidence?!” Are you familiar with the concept of a “Kuznets curve?” If so, do you understand how subsequent Kuznets curves for countries that develop later and later peak at lower and lower incomes, and have smaller and smaller “bump” heights? Also, when I mentioned Jesse Ausubel, it was clear that you had no clue who he even was. Have you even bothered to study his work on “decarbonization” since we last discussed the issue? Finally, have you carefully read the work of Ray Kurzweil? Have you read Arnold Kling’s commentaries on the implications for economic growth of Ray Kurzweil’s work? What about the work of Robin Hanson? (I would ask if you’ve read my own work on the subject, but it’s pretty clear from the tone of essentially all your remarks that you would consider it to contain nothing of value.) Finally, and most astoundingly, are you ****not even aware**** of the existence of the IPCC TAR “B1″ scenario??
I tell you what…on my own weblog, I have made you another Fabulous Free Money Offer. (However, this time I’m going to try to define the terms of the offer more clearly, so that we don’t end up with the situation we had last time, when you demanded payment before you had fulfilled the conditions of the offer.) Please see my weblog for details, but basically, I’m offering you $10 if you can correctly answer two questions, and give me your scientific analysis on the third question. The three questions are:
1) What were the approximate worldwide per-capita industrial CO2 emissions (i.e., from the consumption and flaring of fossil fuels) in 1950, 1955, 1960, 1965, 1970, 1975, 1980, 1985, 1990, 1995, 2000, and 2005?
2) What are the worldwide per-capita CO2 emissions projected in the IPCC TAR for the years 2030, 2050, 2070, and 2100 under the following scenarios: A1F1, IS92a, B2, and B1?
3) What is your scientific opinion of the implications, if any, of the correct answers to those first two questions?
I’m offering you an additional $10 to provide your BEST estimate values for worldwide industrial CO2 emissions (i.e., not including land use changes) every decade from 1990 to 2100, in the form of 5 percent probability, 50 percent probability, and 95 percent probability estimates. (The meaning of the probability numbers is that that’s the probability that the number will be BELOW the value you estimate. Please see my weblog, and ask if you require further explanation.) I want to emphasize that I want your BEST estimates. I don’t know if Texas A&M has an honor system, but before I give you any money, I want you to certify, on your honor, that the estimates are the BEST you can come up with at present.
I wrote, “4) The resultant temperature increase (approximately 90% probability of lower tropospheric temperature increase from 0 to 2.2 degrees Celsius above current value) will be such that a preponderance of evidence supports either minimal net harm, or even net benefit.”
He responded, “We discussed your number 4 before, so you know I think it’s balderdash. I won’t repeat that discussion here.”
Yes, we have indeed discussed this before. But have you ever even considered the possibility that you think my work is “balderdash” because you are in error, rather than I?
I am offering you another $10 (that’s $30, total) if you will provide me your BEST estimates of average temperature changes in the lower troposphere (as measured by satellites) every decade from 1990 to 2100. I also want them in the form of “5 percent probability, 50 percent probability, and 90 percent probability” estimates. Please see my weblog for details.
http://markbahner.typepad.com/random_thoughts/2006/02/fabulous_free_m.html
February 18th, 2006 at 11:27 am
Update and clarification: I have made my fabulous free money offer to Andrew Dessler even more fabulous. (Sometimes it’s good to be single…my wife would kill me for giving away so much free money!
)
See my weblog post:
“I will give an additional $10 (so now we’re up to $40, total) for your CERTIFIED BEST EFFORT predictions of atmospheric methane concentrations every decade from 1990 to 2100. I want them in the same format as your other predictions, i.e., “5% probability, 50% probability, 95% probability”. See my Fabulous Free Money Offer of yesterday for details.
One more thing…an important clarification: I want your predictions to be in the same conditions as mine and the IPCC’s…without government mandates for GHG emission reductions.
Again, if you are at all uncertain about any of the conditions for these fabulous offers of free money, please ask me questions.”
February 22nd, 2006 at 10:11 am
Hmmmm…
I see Andrew Dessler has not yet taken me up on my Fabulous Free Money Offer. Nor has he answered even the most basic of my questions.
For example, he wrote he found my estimates for anthropogenic CO2 emissions “amusing,” because he claimed that there was “no evidence” that anthropogenic emissions of CO2 would peak circa mid-century, as a result of normal technological development.
I responded by asking if he was aware of the IPCC “B1″ scenario? As anyone can see, CO2 emissions under the “B1″ scenario peak circa mid-century:
http://www.grida.no/climate/ipcc_tar/wg1/figts-17.htm
In fact, CO2 emissions ALSO peak circa mid-century under the “A1T” scenario.
So how about it Dr. Dessler? How was your statement anything but a bald-faced lie? Were you truly not aware of either the “B1″ or “A1T” scenarios?
I’m especially interested in your answer to this question, given your comment only one day earlier that, “I’m not sure I know what role science plays when dealing with people (e.g., Singer) who make transparently false scientific arguments.”
How was your statement anything but a “transparently false scientific argument?” Does this mean that you do not know what role science plays in dealing with people like yourself?