I thought Roger was discussing tendency of climate modelers to oversell the accuracy of their own product. At least that’s how I interpret statements like this:

“what are we to make of the overstated claims of predictive accuracy offered by many scientists?”

Thanks for clarifying that you really meant to suggest that Hansen’s tax plan is not a “deck of cards”. But can I make a suggestion? In future, if your intention is to suggest Roger should help Hansen advocate his preferred tax plan, and you want third parties reading comments to understand what you mean, it might be best to include words like “tax plan” in your comment.

Otherwise, few readers are likely to understand what you intend when you write things like this:

“you might consider thinking and commenting more on the public choice aspects of the problem, as Jim Hansen recently has.”

This sort of oblique statement is utterly puzzling because
a) Roger often comments on public choice aspect of the problem, and has written books on the subject and
b) No one would infer that you are suggesting Roger should jump on Hansen’s band wagon and advocate Hansen’s preferred policies for him.
well need help.

My suggestions were that (1) Roger`s admonishment to the bearers of political footballs (scientists) not to get kicked has little chance of being practically useful to scientists, but is a message very easily coopted by those who would like to the current volunteer-only climate policy continue and (2) if he`s interested in seeing meaningful climate change policy adopted (other than solely the default of ad hoc adaptation to ongoing changes), he might recognize that an effective policy will not be a deck of cards but may very well find popular support if it is a per capita tax refund along the lines proposed by Jim Hansen (based on Jim Barnes, Boyce and Biddle, etc.).

Taking a probabilist’s standpoint, what “consistent with” is saying is that if the climate model represents reality then there is a high probability that such and such a weather event will be observed. Expanding out to the AGW issue, the same argument would go, “if the CO2-climate link is correct then global surface temperature and sea level will rise, glaciers will melt, etc etc. And as a bald statement, this is probably unarguable. Why it is misleading (to put it mildly) is that this high probability is then switched to support the reverse logic, i.e. if the globe warms, sea level rises and glaciers melt then AGW is true with the same high level of certainty. This of course is the conventional way round for scientific advancement – what is the probability that the theory is true given the observations.

Those with some probability background will recognise this as sleight of hand. To calculate the Probability of (A given B) from the Probability of (B given A) is the job of Bayes formula and introduces other terms that can degrade the resultant probability to near zero. To spell it out, we want the probability that AGW is true given the globe is warming etc, but what we are starting from is a “consistent with” type statement amounting to one about the high probability that the globe is warming given the AGW theory is true. The other terms in this case are the missing probabilities deriving from other mechanisms that are also consistent with the observations (chaos, the sun) and other observations that are not consistent with the mechanism (warming and glacier melting preceding CO2). These will vastly erode the initial high probability.

This is a well known problem and goes under the name of “The Prosecutor’s Fallacy” in legal circles – the probability of the defendant being seen near the scene of the crime if he was guilty being conflated with the probability that the defendant was guilty if he was seen near the scene of the crime. It also rears its head in medical screening for diseases that are rare in the population at large where even quite a modest rate of false positives can render useless a test that seems excellent in the lab (exhibiting few false negatives).

So labelling the “consistent with” approach as merely “empty of meaning” doesn’t do justice to it’s pernicious consequences in actual usage.

Taking a probabilist’s standpoint, what “consistent with” is saying is that if the climate model represents reality then there is a high probability that such and such a weather event will be observed. Expanding out to the AGW issue, the same argument would go, “if the CO2-climate link is correct then global surface temperature and sea level will rise, glaciers will melt, etc etc. And as a bald statement, this is probably unarguable. Why it is misleading (to put it mildly) is that this high probability is then switched to support the reverse logic, i.e. if the globe warms, sea level rises and glaciers melt then AGW is true with the same high level of certainty. This of course is the conventional way round for scientific advancement – what is the probability that the theory is true given the observations.

Those with some probability background will recognise this as sleight of hand. To calculate the Probability of (A given B) from the Probability of (B given A) is the job of Bayes formula and introduces other terms that can degrade the resultant probability to near zero. To spell it out, we want the probability that AGW is true given the globe is warming etc, but what we are starting from is a “consistent with” type statement amounting to one about the high probability that the globe is warming given the AGW theory is true. The other terms in this case are the missing probabilities deriving from other mechanisms that are also consistent with the observations (chaos, the sun) and other observations that are not consistent with the mechanism (warming and glacier melting preceding CO2). These will vastly erode the initial high probability.

This is a well known problem and goes under the name of “The Prosecutor’s Fallacy” in legal circles – the probability of the defendant being seen near the scene of the crime if he was guilty being conflated with the probability that the defendant was guilty if he was seen near the scene of the crime. It also rears its head in medical screening for diseases that are rare in the population at large where even quite a modest rate of false positives can render useless a test that seems excellent in the lab (exhibiting few false negatives).

So labelling the “consistent with” approach as merely “empty of meaning” doesn’t do justice to it’s pernicious consequences in actual usage.

Does this translate to:
Roger, what you say is accurate. But please imitate Jim Hansen: don’t say these true things, but talk about something else instead.

Perhaps they don’t realize yet that we’ve all heard the over-hyped message until we are sick of it. Some believe it, some have heard it all before with the last false apocalypse. Many say they believe it just to sound PC but they never do anything anyway (sometimes they buy a Prius). Some think that if it’s the end of the world let’s live a little, and others think that if scientists are so clever then they must be clever enough to save us. Whatever their stance few people will ever do anything unless the alternative will save them money. So scientists shouldn’t feel so much angst about it. Be honest, you people – it really doesn’t matter, but you might feel better about yourself!

At the end of the day the politicians have to deal with the reality that to change our society’s energy structure is not easy. Yes it is possible but it has to be done right. In any event it would be nice if they could actually trust what the scientists say and at the moment they can’t. Kevin Rudd’s election and immediate about-turn tells us he knew all along that the case was over-stated and that drastic and sudden cuts in CO2 mean real pain. When you are landed with the task of creating change but faced with tight monetary restraints and serious loss of income if you do change, then you can’t avoid reality.

Obama would act just the same as Rudd except that he has even less money to work with because Bush has borrowed so much. Clinton faced this problem too after the overspending Reagan-Bush era. I don’t envy the guy that takes over this mess.

The not-so-hidden dynamics of climate change policy in the US is that any change from the current status quo (GHG emissions are free, and voluntary changes are encouraged) is essentially a political decision that would disadvantage a large class of powerful and well-connected economic interests, while those who would benefit from changes are spread throughout the economy and are not as concentrated or as well connected. In such classic struggles over spoils, “truth” is inevitably a football to be fought over in order to influence raw political calculation.

Blaming scientists for the distortions of science that results from the struggle over the political allocation of resources is thus rather perverse – as it completely ignores the real interests who are engaged in the contest. It’s like blaming the football for being kicked (or when Lucy yanks it away from Charlie Brown).

The answer, of course, lies in clarifying whose interests are at stake and exploring possible accommodations.

In this regard, you might consider the irony of your own op-ed: though you argue FOR climate action because of serious warning bells provided by scientists, the headline bills you as warning of “overheated” claims (as opposed to the “overstated claims of predictive accuracy”) and as implying that climate scientists who “advocate for action” generally cannot be trusted, as they “are overselling the predictive capabilities of climate models”. Of course even if NO scientists waved any warning flags (“advocated action”) at all, or oversold the predictibility of models, they would still be accused, one way or another, of a lack of evenhandedness, accuracy etc.

Thus, even while some of your criticisms are accurate, they may easily end up coopted by one of the parties at interest. If you’d like to see progress on climate policy, you might consider thinking and commenting more on the public choice aspects of the problem, as Jim Hansen recently has.

Regards,

Tom

1. Apologies for attributing the quote to you. You might consider a more clear byline in your guest posts, as it was unclear that someone other than you wrote that post.

You write, “the statistically anomalous extreme weather we are now experiencing is precisely what is expected under climate change theory” — fair enough?

2. For plenty of examples of scientists overselling climate predictions, just search Prometheus for “consistent with” — here is a link to get you started:

http://sciencepolicy.colorado.edu/prometheus/archives/climate_change/001416the_consistentwith_.html

Another example might be your association of the recent Midwest floods with greenhouse gas emissions, or perhaps that Minnesota bridge collapse or any other things that you have speculated as being consistent with expected impacts of greenhouse gas emissions.

Should scientists be held to the same standards as “global warming deniers”? Sure. Why not?

Your op-ed smear of climate scientists and climate science is beyond the pale.

First off, though, you falsely attribute a quote to me that is in fact from Bill Becker. “. . . the natural disasters underway today are consistent with the predicted consequences of global warming . . .” Next time, check your facts before trying to call me out on your blog.

Your op-ed sub-head is: “Scientists advocating for action are overselling the predictive capabilities of climate models.”

The entire IPCC is advocating action. So you are accusing the entire climate science community of a lack of integrity. Unbelievable.

And for some reason you don’t want scientists to tell people that the statistically anomalous extreme weather we are now experiencing is precisely what is expected under climate change theory. So that means precisely what? You are saying climate scientists can’t talk about changes in the climate predicted by climate change theory? Unbelievable.

You seem to be trying to enforce some bizarre form of scientific political correctness that isn’t even correct. Incredible.

Sea levels are rising FASTER than the IPCC predicted, as numerous peer-reviewed studies have showed. Arctic sea ice loss is faster, Greenland and Antarctic mass loss is faster, the subtropics are expanding faster, etc.

“So what, I am told, if action on climate change is based on some exaggerations and false claims to certainty, isn’t the end goal important enough to justify bending the truth just a bit? After all, those opposed to action often show no hesitation toward exaggeration and hyperbole.”

This is McCarthyesque smearing. Claiming an equivalence between global warming deniers and the legitimate climate scientists including the IPCC and the National Academies and the scientists who sign the Bali declaration.

Either post on your blog a dozen specific names of serious scientists who are making such exaggerations and false claims — with specific examples from the IPCC and the National Academies and the Bali Declaration
http://www.ccrc.unsw.edu.au/news/2007/Bali.html/
or withdraw this slander.

You keep saying we need to take action, but more and more that appears to be cover for essay after essay calling into question the integrity of climate scientists and the climate science. You provide aid and comfort to the delayers, but still refuse to explain what specific policies you would implement now to stabilize at 450 ppm (or even to avoid 1000 ppm).

If you walk like a delayer and talk like a delayer, you may, just in fact, be one.

Some sort of action to reduce CO2, methane and other GHG emissions is advisable.

The questions is of course: Which actions, and how to implement them.

It seems to me that recently, I am reading more activist blogs dare to state the “N” word: Nuclear. Yes, we need wind, solar, conservation etc. But, the perpetual reluctance to embrace nuclear energy has been a stumbling block pitting those who want to ensure the level of economic growth made possible by large power plants, against those who seem to imagine some nirvana where we all live comfortably and somehow happily hand digging pits in which to install the heat exchanger for the solar powered heat pump we use to replace our furnaces.

So, yes, we need to take action. But we also need to keep option like nuclear energy open.