Uncertainty, risk, and (in)action

by Judith Curry

“So when you take uncertainty into account, it actually leads to the decision that we should take action more quickly.”

I first spotted the statement in the Discover Magazine interview with myself and Michael Mann .  I thought it had to be a typo or misquote (note, Mann said this, not me :))

In discussing the Discover Magazine article over at Collide-a-Scape (I don’t recall which thread), I quickly found out that this was no typo or misquote.  I was informed that this was statement came from a recent highly touted paper by Martin Weitzman entitled “On modeling and interpreting the economics of catastrophic climate change.”   Abstract below:

Abstract. With climate change as prototype example, this paper analyzes the implications of structural uncertainty for the economics of low-probability high-impact catastrophes. Even when updated by fnite Bayesian learning, uncertain structural parameters induce a critical ìtail fatteningî of posterior-predictive distributions, Such fattened tails have strong implications for situations, like climate change, where a catastrophe is theoretically possible because prior knowledge cannot place su¢ ciently narrow bounds on overall damages. The core problem is learning extreme-impact tail probabilities from finite data. Fat-tailed structural uncertainty, along with great unsureness about  high-temperature damages, can outweigh discounting in climate-change economics.

I was familiar with that paper, and didn’t recall that particular conclusion.  I was then pointed to a NYTimes Magazine article by Paul Krugman entitled “Building a Green Economy.

Now, despite the high credibility of climate modelers, there is still tremendous uncertainty in their long-term forecasts. But as we will see shortly, uncertainty makes the case for action stronger, not weaker. So climate change demands action. Is a cap-and-trade program along the lines of the model used to reduce sulfur dioxide the right way to go?

Then near the end of the article (page 8):

Finally and most important is the matter of uncertainty. We’re uncertain about the magnitude of climate change, which is inevitable, because we’re talking about reaching levels of carbon dioxide in the atmosphere not seen in millions of years. The recent doubling of many modelers’ predictions for 2100 is itself an illustration of the scope of that uncertainty; who knows what revisions may occur in the years ahead. Beyond that, nobody really knows how much damage would result from temperature rises of the kind now considered likely.

You might think that this uncertainty weakens the case for action, but it actually strengthens it. As Harvard’s Martin Weitzman has argued in several influential papers, if there is a significant chance of utter catastrophe, that chance — rather than what is most likely to happen — should dominate cost-benefit calculations. And utter catastrophe does look like a realistic possibility, even if it is not the most likely outcome.

Weitzman argues — and I agree — that this risk of catastrophe, rather than the details of cost-benefit calculations, makes the most powerful case for strong climate policy. Current projections of global warming in the absence of action are just too close to the kinds of numbers associated with doomsday scenarios. It would be irresponsible — it’s tempting to say criminally irresponsible — not to step back from what could all too easily turn out to be the edge of a cliff.

So there it is, from Nobel laureate Paul Krugman.  Joe Romm has “translated” all this for us in several posts.   Here is a quote from Krugman on this, in response to the book “Superfreakonomics” (note I haven’t read the book).  As Krugman explains:

Yikes. I read Weitzman’s paper, and have corresponded with him on the subject — and it’s making exactly the opposite of the point they’re implying it makes. Weitzman’s argument is that uncertainty about the extent of global warming makes the case for drastic action stronger, not weaker.

Ok, so Krugman is apparently accurately representing what Weitzman meant. I guess my poor little brain had a difficult time letting that Nobel-level economics pass through its filter when I read Weitzman’s paper.

So, lets think about some of the  perhaps unintended implications of this statement.  Two implications that jump immediately into my mind are:

1.  The accusations made against the “merchants of doubt” is that they are talking about uncertainty so as to delay action.  So, now are we to infer that that the merchants of doubt are now climate policy action’s “best friends”?

2.  Consider a potential asteroid strike:  far greater economic impact and also far greater uncertainty than climate change.  So the implication of this is that we should be focusing more on the potential asteroid strike than the potential catastrophic climate change?

Neither Romm nor Krugman discuss these points :)

Insights from Jonathan Gilligan

Over at Collide-a-Scape, Professor Jonathan Gilligan has a very insightful post entitled “Why U.S. Climate Policy is Radioactive”.  This post addresses uncertainty and risk, and compares the climate change issue to policy issues surrounding nuclear waste disposal in Yucca Mountain.  The whole thread including comments is well worth reading.  Some excerpts from the main post:

As Daniel Sarewitz pointed out years ago, in both climate politics and nuclear waste politics, policymakers have tended to “scientize” the issue by acting as though greater scientific certainty would solve problems that were fundamentally political. No advances in earth science, hydrology, materials science, or engineering will do much to reduce our uncertainties about how spent nuclear fuel will behave underground over the course of tens or hundreds of millennia. Neither do I think it likely that advances in climate science will give us great certainty about exactly how bad global warming will be over the coming centuries.

So what are the lessons [from Yucca Mountain that are relevant to climate change]? . . . In both cases, connecting policy action to scientific certainty was likely a bad tactical mistake. In both cases, there is substantial uncertainty about the things we most care about and in fact, in the case of climate change, Martin Weitzman’s Dismal Theorem concludes that calculations of the expected economic cost of climate change are dominated by the mathematical details of the low-probability/catastrophic-consequence tail of the probability distribution. (Weitzman’s theorem is controversial, but the controversy is over the mathematical form he chooses for the tail of the probability distribution.)

I actually found Gilligan’s comments in the discussion part of the thread to be the most relevant to the topic at hand on this thread:

For normally distributed risks, the probability falls off fast enough in the tails that you can ignore the really low-probability/high-consequence events.
But when the tails of the distribution are fat (i.e., when they fall off a lot more slowly than exp(-x^2), and especially if they fall off only polynomially) then the expected cost of the risk is dominated by the extreme of the low-probablity/high-risk tail.  First, uncertainty about climate sensitivity is fundamentally asymmetric, both because of the mathematical form of the feedback function and also because there’s more data to constrain the low-sensitivity side of the distribution. Second, there’s also a lot of uncertainty about the economic damage function for a given temperature change. These combine to give good reason to believe that not only is our uncertainty about the cost of climate change is very asymmetrically distributed, but that uncertainties about enormously catastrophic damage have fat tails, possibly fat enough to dominate any calculation of expected value.
This is similar to the argument Benoit Mandelbrot and Nassim Taleb made about Mandelbrot’s observation that fluctuations in markets for shares, futures, and commodities are not normally distributed but have fat tails: this means that standard risk-management practices (e.g., stress-testing portfolios) will fail to account properly for extremely unlikely events.
My argument is that even if there is probably no cliff, there is still enough chance of a cliff that it’s foolish to wander around blindly. . .  It all comes down to the mathematical shape of the probability distribution of our ignorance.  Or, as Dirty Harry said more succinctly, “Do you feel lucky?”

A comment from Sashka:

“Do you feel lucky?” is a false dilemma. We have a continuum of options along the mitigation-adaptation axis. There is geoengineering option. So, the short answer is “I feel smart.” The idea to describe our differences in terms of risk preferences is not without merit. Except in this case it’s very hard to define the risk.

A comment from Gilligan:

Something I would like to emphasize in the argument between Bart V. and myself on one side vs. Sashka and kdk33 on the other: There is no right or wrong here. We’re arguing more about our comfort or discomfort with uncertain risks than about science. Bart and I are more precautionary and tend to put more credence in fat tails; Sashka and kdk are more comfortable with uncertainty and more dismissive of the fat tail hypothesis.
 
The shape of the probability distribution for extreme catastrophes is not something that can be empirically verified with any great precision, so there is room for reasonable people to disagree both on the shape of the curve that represents our ignorance and on the proper policy response to it.

Nullius in Verba says:

The Precautionary Principle in the absence of quantified risks is equivalent to Pascal’s Wager. It means that the decision is determined entirely by the scariness of the hypotheses being offered rather than the strength of the evidence. Usually a false dilemma is being offered – two scenarios, one scary, one not, when there are many more scenarios possible (and more likely).
A better approach to uncertain risks is to develop more flexible resources ready to jump the right way when more information becomes available. Be an adaptable generalist. Creating economic prosperity for the poor would therefore seem to be the priority, as it is applicable to many different problems and scenarios, rather than only one.

The analogy is fairly straightforward. The Precautionary Principle as commonly applied to climate change says that even if you’re not fully convinced that it will definitely happen, if you accept that it might happen, the costs are so high (e.g. Ted Turner’s cannibal scenario) that it’s still the only rational choice to act to prevent it. Pascal’s Wager applied to the Christian afterlife mythology says that even if you’re not fully convinced that it will definitely happen, the costs (eternal torment versus eternal bliss) are so high that the only rational choice is to believe.  The distinctive features of the argument are that it offers only two alternatives with the putative costs embedded the hypothesis, and the conclusion arises from the hypothesised costs alone, not the evidence.

Deconstructing Friedman’s conclusion about Weitzman’s argument

So, back to the original statement:

“So when you take uncertainty into account, it actually leads to the decision that we should take action more quickly.”

Lets deconstruct the apparent  argument behind this to try to understand this apparent paradox.

Argument A1:

  1. Under the precautionary principle, a minimum threshold of plausibility or certainty is required before acting.
  2. If the assumed PDF is something like a bell shaped normal distribution, possibly skewed but with a thin tail, the probability of the possible catastrophe lies below some minimum threshold that would trigger action.
  3. A broader PDF with a fatter tail, motivated by greater uncertainty, would imbue the possible catastrophe with a greater probability of occurrence that is above the minimum threshold that triggers action.
  4. Thus:  Increased uncertainty provides a greater probability of occurrence of the catastrophe, strengthening the case for action under the precautionary principle
Ok, so what is wrong with this argument?  The problem lies in the assumption that our knowledge of the risks is quantified, which assumes that we have sufficient certainty to formulate a PDF for future climate outcomes plus the associated economic impacts.  Economists have become too accustomed to dealing with Knightian risk.  This quote from Knight as per the Wikipedia:
.
“Uncertainty must be taken in a sense radically distinct from the familiar notion of Risk, from which it has never been properly separated…. The essential fact is that ‘risk’ means in some cases a quantity susceptible of measurement, while at other times it is something distinctly not of this character; and there are far-reaching and crucial differences in the bearings of the phenomena depending on which of the two is really present and operating…. It will appear that a measurable uncertainty, or ‘risk’ proper, as we shall use the term, is so far different from an unmeasurable one that it is not in effect an uncertainty at all.”
.
Nassim Taleb writes in The Black Swan:
.
In real life you do not know the odds; you need to discover them, and the sources of uncertainty are not defined. Economists, who do not consider what was found by noneconomists worthwhile, draw an artificial distinction between Knightian risk (which you can compute) and Knightian uncertainty (which you cannot compute), after one Frank Knight, who rediscovered the notion of unknown uncertainty and did a lot of thinking but perhaps never took risks, or perhaps lived in the vicinity of a casino. Had he taken financial or economic risk he would have realized that these “computable” risks are largely absent from real life! They are laboratory contraptions.
.
So, Knightian risk is characterized by having a well defined PDF, e.g. the “odds” are known, such as playing at the Roulette table.   With varying levels of uncertainty, knowledge about the shape of the pdf may be vague or entirely absent.  Weitzman is assuming that the shape of the PDF for future climate outcomes is a fat tailed distribution, with uncertainty surrounding the characteristics of the fat tail.
.
I have argued previously that the uncertainty surrounding future climates is best characterized by scenario uncertainty, in the sense of modal logic whereby individual model simulations should be regarded as a modal statement of possibility:
.
•  From the uncertainty monster thread) is described as: Scenario uncertainty implies that it is not possible to formulate the probability of occurrence of one particular outcome. A scenario is a plausible but unverifiable description of how the system and/or its driving forces may develop in the future.  Hence the use of scenarios is associated with greater uncertainty (more ignorance) than statistical uncertainty.  Scenarios may be regarded as a range of discrete possibilities, often with no a priori allocation of likelihood.
.
•  From the precautionary principle threadModal logic extends propositional logic to include the classification of propositions according to whether they are contingently true or false, possible, impossible, or necessary.  Betz argues for the logical necessity of considering future climate scenarios as modal statements of possibilities.
.
From the thread on what can we learn from climate models:  a broad discussion of climate model imperfections
.
From the thread on probabilistic(?) estimates of climate sensitivity:  Insufficiently large initial condition ensembles combined with model parameter and structural uncertainty preclude forming a pdf from climate model simulations that has much meaning in terms of establish a mean value or confidence intervals.
Now consider an alternate argument starting from different premises:

Argument A2:

  1. Under a robust decision making framework, the plausible worst-case scenario (catastrophe) is included in the decision making process without letting it completely dominate the decision making.
  2. The catastrophe scenario is one scenario in a possibility distribution of scenarios.
  3. The weight of the catastrophic scenario in the decision making framework increases with the likelihood of occurrence of the catastrophic scenario.
  4. Thus:  Decreased uncertainty regarding the likelihood of the catastrophic scenario increases its weight in the decision making process.

Starting from two different decision frameworks (precautionary principle versus robust decision making) and assumptions about the nature of the uncertainty  (PDF versus possibility distribution) results in opposite conclusions regarding whether uncertainty weakens or strengthens the case for action. Argument A1 finds that Krugmann’s statement is true if you accept the premise that future climate change can be represented by a PDF.  Using a possibility distribution rather than a PDF (Argument A2) leads to a more reasonable conclusion regarding the role of uncertainty in the decision making process.

Conclusions

Depending on your decision analytic framework and what you assume about ignorance and uncertainty, you can come to either conclusion: uncertainty increases the need to act, or uncertainty decreases the need to act.   My argument is that the level of uncertainty is too great for a pdf of climate outcomes to be useful in the context of the precautionary principle.

I would very much appreciate your take on the arguments presented at the end of this post, I am considering including this in the revisions to my uncertainty monster paper.

Moderation note:  this is a technical thread, comments will be moderated for relevance.  To discuss specific scientific uncertainties like cloud feedback or whatever, do so on other technical threads.   To discuss the politics associated with climate decision making, go to another thread.



321 responses to “Uncertainty, risk, and (in)action

  1. Joe Lalonde

    Uncertainty weakens the case drastically as now people question the science of the people who are pushing the “science is settled” issue.

  2. Monte Carlo analysis, or at least consideration of Monte Carlo analysis, tells us a lot about uncertainty. If Monte Carlo analysis were done on the climate models, I am sure that what we would see is pretty much equal probability for any outcome – ie flat kurtosis. That arises because the probability distributions on the key inputs to the models have to be so wide, given the lack of real knowledge about so many of them.

    Surely, if that is the case, then there is no basis for taking any action, other than trying to figure out what is happening more accurately, so that the basis for action is better defined.

    Why is it that model builders seem to be so unfamiliar with Monte Carlo analysis and what it has to say about uncertainty?

    • Climate modelers do a poor man’s version of Monte Carlo analysis. Each model does an ensemble of simulations, varying initial conditions and model parameters, but owing to computer time maybe 10 simulations are run for any one model. Then multiple models are combined (with multiple simulations each) to form an ensemble of opportunity that is not simple to interpret. In any event, the size of the ensemble falls orders of magnitude short of what is needed to fully explore model uncertainty.

      • I may be wrong but I don’t think any of the models input probability distributions for the initial conditions and key parameters. Note too that there is no real basis for taking the distribution of modeling results to be a probability distribution. That assumes the models are perfect.

        In any case it appears that the fat tail derives from the asymmetry of the probability distribution. That is the models say (for CO2 doubling) that warming of less than one degree is highly highly unlikely and cooling is impossible, even thought the peak is around 2 degrees. They also show significant probabilities for very large warming values and that is the fat tail. As Gilligan explains, the key question is just how fast the probabilities fall off, or what is the form of the fat tail? This is of course unknown, even if we believe the models, which skeptics in general do not.

        What is not explained, and seems mysterious, is how this “overcomes” the discount rate? Normally the discount rate makes any cost or benefit beyond several decades out insignificant. Maybe it just makes the cost overwhelmingly large.

        But none of this is important unless one believes the models, which I do not. I think those high end warmings are merely artifacts of runaway positive feedbacks, in the models, not in reality. Policy is interested in what may happen in reality, where the probability distribution is probably symmetric, given the real possibility of a new ice age, something the models cannot see.

      • They run the model multiple times, varying initial conditions and/or parameters. High sensitivity values are also derived from observations (including time paleo).
        I think the issue of the shape of the fat tail is a red herring; the uncertainty is so great that we don’t really know much about the shape of the distribution at all; we can maybe bound sensitivity between 0 and 10C with some confidence, but Weitzman is even talking about 1% possibility of 20C sensitivity. IMO we should be treating this situation as scenario uncertainty and not statistical uncertainty.

      • If by sensitivity you are talking about what might happen in the real world by the time CO2 doubles then it is more like -10 to +10C, not 0 to +10C (if you insist on +10). One must always keep in mind that the models do not include the possibility of large natural variation.

        The policy issue is not what the sensitivity is absent many other factors, which is what the models are modeling. The policy issue is what the sensitivity is in the real world, which has lots of other factors which we do not understand. But I think the realistic possibilities are -2 to + 2C and the likely range is -1 to +1, from today. In any case it is symmetric about zero, reflecting the fact that the influence of increasing CO2 in the real world is unproven. To assume asymmetry is to assume AGW, which we don’t want to do.

      • I may be wrong, but a negative value is pretty much impossible because sensitivity is defined as a climate response to CO2. 1 with some unanticipated feedback should make 0.75 ish a realistic minimum and I tend to agree with Annan that 4 is a realistic maximum. With tails, 0 to 5 for a doubling.

        -1 to +1 is pretty tight, how do come by that?

      • Climate response to CO2 may be cooling. If radiation of surface heat to space is increased by CO2, then that’s the result.

        The positive sensitivities are built-in to the models, not outcomes.

      • Dr Curry,

        A couple of questions:
        1 Has the world ever been significantly colder than today?
        2 Using temperature as the parameter under test; are any of the models capable of generating a prediction of a world significantly colder than now?
        3 If the answer to 2 is no, then the models are unrealistic and, therefore, invalid. (Especially for policy making).
        4 If the answer to 2 is yes, then which model parameter(s) predominate to cause the cooling?
        5 If the answer to 4 were to be, say, the sun or the oceans, what policies would mankind need to put in place to mitigate against a cooling world?
        6 Assuming the model outputs are reliable over extended periods, if mankind’s greenhouse gas contribution were to be eliminated from the model inputs what would the world’s temperature profile be predicted to look like over the next (say) 1,000 years?
        7 And finally, if the models are not reliable over extended periods then over what period are they reliable and why do they collapse?

    • Such irrational calls to action – “So when you take uncertainty into account, it actually leads to the decision that we should take action more quickly” – are standard propaganda techniques used to manipulate and control people.

      E.g., extending the Patriot Act yesterday for four additional years:

      a.) President Obama: “It’s an important tool for us to continue dealing with an ongoing terrorist threat.”

      b.) Senator Ron Wyden: “while there are numerous interpretations of how the Patriot Act works, the official government interpretation of the law remains classified.

      http://www.msnbc.msn.com/id/43180202/ns/us_news-security/

      The official government interpretation of the Patriot Act is as available to the public as is scientific evidence of CO2-induced global warming.

      Government science has become a propaganda tool of politicians.

      With kind regards,
      Oliver K. Manuel
      Former NASA Principal
      Investigator for Apollo

  3. Rob Schneider

    Consideration of uncertainty always enables one to open eyes about the possible outcomes arising from “certain” actions. Actions are always irrevocable.

  4. one is left wondering why a Nobel Prize Laureate would make such a naive mistake .

    And wouldn’t it be funny to answer the door finding a preacher telling the end of the world is nigh, with quotes from Paul Krugman…

  5. It seems to me the flaw in these arguments is that if predictions of disaster become more certain, we should act, and if they become less certain we should also act. The discussion then moves from investigating what will be the most likely outcome to investigating the probabilities of the least likely outcomes. We will be arguing about the thickness of the tail. Will it ever be possible to conclude such an argument? The tail is by definition an outlying scenario so will always be to some degree a matter of opinion.

  6. Nullius in Verba

    You can get much the same sort of issue arising, even without Knightian uncertainty. Consider the St Petersberg paradox:- is the fair price for playing the game really infinite?

  7. Jim Macdonald

    One should also take into account the speed of the imagined catastrophy, global warming vs an asteroid strike. With assumed global warming, it is slow enough to allow counter measures and adaptation to take place. Not so with an asteroid strike or a nuclear war. Also, what if we prepare for global warming and instead, wind up with the next ice age, which may be equally likely?

  8. AGW proponents and skeptics use th term uncertainty to mean two different things. This is a classic case of talking past. Skeptical uncertainty is not about the range of model outputs. The models are unacceptable so it does not matter how fat their tails are.

    • David,

      There seem to be parallels to the Wall Street risk models which crashed so spectacularly. Incredibly sophisticated architecture constructed to the sky atop a foundation of foolish assumptions. Arguing the details of the architecture on the 98th floor seems pointless if the foundation isn’t solid.

  9. Doesn’t Naseem Taleb argue that speculating or using thin tail probabilities is essentially a useless exercise because their relative uncertainty when combined with vulnerability can lead to a very wide range of possible impacts.

    Also, this paper by Oreskes et al (2011) I think is highly relevant. Adaptation to Global Warming : Do Climate Models Tell Us What We Need to Know ? Philosophy, 77(5), 1012-1028.

    Concluding paragraph:

    “At present, it is highly misleading to claim that adaptation will be easier
    or more cost effective then emissions control. Since we do not know what adaptations will be required, we cannot say whether they will be harder or easier—more expensive or less—than emissions control. Whatever im- provements in regional predictive capacity may come about in the future, the lack of current predictive capacity on the relevant scale is a strong argument for why we must both control greenhouse gas emissions and adapt.”

  10. Let me test the logic: knowing absolutely nothing is infinite uncertainty, I guess. But we can’t do anything about it if we know nothing. The highest priority then, would be things we almost nothing about but would be extremely catastrophic. Inklings and loose speculation would qualify. For example: “One prominent scientist theorized that the changes caused by simply observing dark energy could cause it to collapse, taking the universe with it.” http://www.cracked.com/article_16583_the-5-scientific-experiments-most-likely-to-end-world.html

    Greater uncertainty, I suppose, and more catastrophic outcome than asteroid impact or any of the other scenarios that have been discussed.

  11. The precautionary principle seems to be valid in at least some situations. E.g., I am demolishing a building. If I am highly certain that it is unoccupied, I can proceed to set off the charges. However, if uncertainty on this point is increased, I need to precautionarily take preventative actions like searching the building for occupants or cancelling the demolition to avoid the risk of a catastrophe (murder, in this case).

    Even in Dr. Curry’s example of an asteroid strike, we are currently taking some actions, as considerable money is spent on tracking asteroids. Right now there is little uncertainty (no large asteroids have a significant chance of hitting the earth in the near future, and geological records show tens of millions of years between major strikes). If the uncertainty increases (e.g., a large asteroid’s orbit is perturbed so that it has a 20% chance of striking the earth), I would certainly want us to dramatically increase the actions we are taking as a result of this increased uncertainty.

    Why wouldn’t action on climate change be a valid application of the precautionary principle?

    • Nullius in Verba

      The question there is whether you have quantified risks. You talk about how certain you are or are not as to whether the building is occupied, based on evidence like having searched it. If you can quantify or at least set bounds on probabilities as well as costs, then it is no longer Pascal’s Wager but a case of ordinary decision theory.

      An application of the PP in the sense I meant it would say that you can never blow up any building because you can never be absolutely certain that it is empty, and the price of a life is infinite.

      • Agreed that you need some idea of whether there is significant risk. I think that is what Krugman et al were saying. If the uncertainty is very low (e.g., we are virtually certain that the building is unoccupied), then precautionary action is not warranted. However, if the uncertainty is high, it is warranted.

        Given that many (not all) highly regarded climatologists regard the “catastrophic” case as the most likely case and that much of the research literature, including the IPCC report devotes substantial space to quantifying the uncertainties, I tend to conclude that the current state of knowledge regards the risk of catastrophic climate change as significant and that the precautionary principle applies.

        I think a stronger argument against action would be whether there is effective action we can take. However, that is the subject of the topic before this (“the futility of carbon reduction”) and not what I believe we are supposed to be discussing here.

    • Rob Starkey

      “Why wouldn’t action on climate change be a valid application of the precautionary principle?”

      A reasonable question- Here is imo reasonable answer(s).

      1. There is no action that an individual nation can take that will be able to prevent worldwide CO2 to continue rising for decades. In fact quite the opposite is true. It appears that in spite of any actions by the US or the EU that increases in emissions over the next 30 years in countries currently with very low levels of emissions but high populations will overwhelm the likely reductions by the US/EU. It is unreasonable to believe that currently very poor countries will not be increasing their CO2 emissions as their populations DEMAND access to electricity and transportation at affordable costs. It is highly unreasonable to assume that currently “wealthier countries” will subsidize poorer countries energy development to the extent necessary to preclude this as their economic situation will not allow it.

      2. There is no credible evidence that a somewhat warmer world is actually worse for humanity over the long term.

      3. The cost to reduce emissions in currently “developed countries” is very high when one considers the “return on investment” (what those reductions will actually accomplish in term of potential temperature rise avoidance). Since the expense of making CO2 reductions are funded by individual countries, it is really necessary to be able to understand the impact of higher CO2 on the climate of individual nations (and their taxpaying citizens) but this is not possible today with any reasonable accuracy.

      • Rob,
        Your point 1 and 3 are significant arguments against carbon reduction (although not dispositive IMO). As in my post above, I think the real question we should be looking at is whether there is any effective action we can take, is the real question we should be looking at. There is good but nascent research going on about policy decisions around climate. For example, preliminary studies of carbon tax at the Center for Robust Decision Making on Climate and Energy Policy at Argonne National Labs’ Computation Institute suggest that production moving offshore as a result of a carbon tax in one country can be mitigated, but that the overall impact of carbon taxes in developed countries on global CO2 is minimal, which definitely begs the question of why have one at all. I think there are still compelling reasons why increasing the price of carbon could be the right thing, but opposing opinions are more than reasonable.

        Your point 2 strikes me as wishful thinking. One of four volumes of the IPCC report is devoted entirely to the impacts of a warmer climate on the earth and society, much of which appears catastrophic. There is much other research on this as well (e.g., Brooks’ paper on extinction drivers) and common sense that a very high percentage of Earth’s population and infrastructure are tied to assumptions about stability of climate and sea level. Even slight transient changes in environmental conditions (dust bowl during the thirties, localized droughts, flooding of the Mississippi) have caused significant disruptions. I hope I am wrong and you are right that significant changes in climate can be taken in stride but just hoping that massive amounts of published and peer-reviewed research on this topic is wrong strikes me as wishful thinking.

      • The disastrous impact of a warming world…. We’re told that the global temperature increased over the last century. And yet, in that same period there was an unprecedented explosion in the global population. How can these two observations lead to a conclusion that a warming world will lead to disaster?

      • Rob Starkey

        mps

        The IPCC report points out numerous potential concerns, but when you look at the actual data supporting these conclusions I find they fall into general categories:
        1. The conclusions are based upon climate models that have subsequently been demonstrated to be inaccurate. The conclusions based upon these models do not have credibility when they predict specific harms to areas.

        2. The potential harms described can be most efficiently managed by the construction of infrastructure. This infrastructure can be easily constructed over the timeframes in question and generally would be required to be constructed/rebuilt over the timescales in question in any case. This means that the building of this “climate resistant infrastructure would not be particularly large additional cost to humanity over the timescales involved.
        3. The conclusions are pure conjecture and supposition and without much scientific merit

        I would very much like someone to point out a concern that does not fit into these categories.

      • mps,

        For a trial lawyer, heaven on earth would be to have a trial where an opponent had cited the IPCC as quality science. The fun in cross-examination would be off the charts. I remember a story years ago of a famous case (one of the Hiss trials perhaps) where a distinguished doctor testified as an expert witness and the other attorney on cross established that he didn’t know what he was talking about. The lawyer was having so much fun, he kept the doctor on the stand for an entire day making him look more and more foolish.

        The IPCC reports would be worth many years of fun and games. Especially if the scientists themselves were forced to testify after discovery.

    • Demolishing a building isn’t an example of the precautionary principle, because it’s possible and relatively easy to search the building and be sure, or as sure as is humanly possible.

      Once you’ve gone down a checklist and checked all the boxes, doing it a second time isn’t being safer, it’s obsessive-compulsive disorder.

    • al in kansas

      There is an assumption that seems to be generally made in invoking the precautionary principle that the benefits greatly exceed the cost. This cost benefit assumption needs to be acknowledged. The ratio between cost an benefit is also very uncertain and subject to a great deal of disagreement as well in the case of AGW.

    • Precautionary Principle in a real-life situation

      Man enters emergency room with chest pain and feeling nausea.

      All symptoms point to a heart attack from a blocked coronary artery.

      Yet the patient really suffers from a rarer thoracic aortic aneurism that is dissected and starting to leak (John Ritter’s disease)

      So in keeping with the “precautionary principle” he is given a blood thinner.

      Oops!

      • I got an email today from a guy who was diagnosed with prostate cancer 5 years ago, and treated with radiation and chemo, to no result. They kept insisting that he was metastatic and only a few months to live because of his high PSA bloodwork numbers.

        Today he learned that he never had cancer. The PSA numbers were due to a chronic infection. As a consequence of his treatment, he now has severe osteoporosis, and will need over a year of physical therapy to be able to walk normally.

        The precautionary principle is a response to ignorance, but actually knowing the facts is always better. And sometimes getting a second opinion (i.e. skepticism and due diligence) is better than running off with the PP, and jumping into a remedial project that only makes things worse.

      • The “skeptic” mindset, a real-life example:

        Man gets a diagnosis of cancer from an internist and an oncologist consulting.

        Doesn’t want to believe it, so he goes to nine other oncologists, who predict he will likely survive cancer free with therapy, or die in three months (one estimate) to eight years (another estimate.)

        Man decides the doctors are so uncertain about the cancer — is it fatal months or years? — that he refuses all treatment.

      • But the CO2 thing is more like we don’t know we have cancer but the UN Doctor is telling us we have from three months to eight years to live anyway. Well, the UN Doctor think we could have cancer, but don’t actually have any test results that indicate it.

      • Your resentment of the United Nations has no bearing on the discussion.

        A partial list of the national science organizations that have issued statements warning the public about climate change runs to pages. 97% of actively publishing scientists have confirmed the “diagnosis.”

        The massive amount of independent lines of physical proof of AGW is the equivalent of a giant tumor visible on CT — palpable on exam — status post biopsy with malignancy confirmed by the pathologist.

        But in politics or in medicine, denial is a powerful force.

        If only your wishful thinking but only your own future at risk.

      • Your resentment of the United Nations has no bearing on the discussion.

        Of course it does. Deal with it.

        The UN/UNFCCC/IPCC are the root of the entire discussion because they’ve skewed the entire issue away from real science and into politics. Until you recognize that, you don’t have a clue about what the debate is about.

      • Interesting Robert. When 97% of the published scientists agree on the diagnosis, prognosis and treatment, then we got something. A large percentage of the “deniers” only question the prognosis and treatment regiment.

      • Doctor : I put together a computer model of your body and it says you have cancer. I recommend radiation therapy immediately.
        Patient: But Doctor, aren’t you going to run any tests?
        Doctor: Well, we don’t have any tests for the kind of cancer my computer model says you have. Let me turn on this radiation machine for you.
        Patient: Turn that thing off! So you are relying only on the computer model? Won’t that radiation hurt me if I don’t have cancer?
        Doctor: I assure you the computer model is correct. I wrote the program myself using advanced statistical techniques and a branch of complex analysis not even yet known to mathematicians. It HAS to be right!
        Patient: Where does you computer model say the cancer is?
        Doctor: Well, it can’t pinpoint the cancer, so we’ll just irradiate your entire body.
        Patient: I want a second opinion.
        Doctor: Eric, come here a minute. Eric is my programmer. Eric, does the computer model not say this man has cancer.
        Eric: Well … if you damp the mitochondrial subroutine, it is 85% certain he does.
        Doctor: See, I told you so!
        Patient: I’m outta here!

      • “Doctor : I put together a computer model of your body and it says you have cancer.”

        And close behind the paranoia about the UN, we have the twin “skeptic” fallacies: “computer models are bad!” and “all the direct observations of the physical world confirming climate change never happened — disregard those thousands and thousands of studies, I decree that all the evidence comes from computer models!”

        You’re really giving us a “denier’s greatest hits” collection tonight, aren’t you? Let me refer you to Skeptical Science; they busted these myths long ago.

      • Yes, thousands. Could you name a few specifics?

      • Computer models are bad. If you have 500 computer models 1 might be right. No one knows which one though.

      • Robert – Do you believe we will experience another ice age? When do you believe that will happen?

      • We? No. The earth? Certainly. Our descendants? Hopefully.

      • Why would you hope for an ice age for our descendants?

      • It appears to me there is eventually going to be one. I think human beings will be able to adapt, so I hope they’re still around to do it.

      • I wonder if the “mitigation” brigade will think they can mitigate that?

      • Maybe this will occur to them:

      • Aaah – the old idea that painting the Arctic black would prevent the next ice age? That is just SO 60ish :-)

      • And close behind the paranoia about the UN, we have the twin “skeptic” fallacies: “computer models are bad!” and “all the direct observations of the physical world confirming climate change never happened — disregard those thousands and thousands of studies, I decree that all the evidence comes from computer models!”

        Wrong – it’s not that computer models are “bad” – it’s that they’re 1) incomplete, 2) fail to have the predictive power that’s claimed for them, 3) model outputs are not “evidence” but only representations of what would be evidence IF the climate were programmed to match the models, 4) unvalidated and therefore unreliable.

        Wrong again – all the direct observations of the physical world confirming climate change never happened
        What direct observations? Specifically. Temp records? Have you actually read TonyB’s entire article? Did you understand it? Do you understand what’s come out of the surfacestations.org site? Obviously not or you wouldn’t make that statement.

        How about satellite data? How does that factor into all those thousands and thousands of studies? How many climate scientists use those? Spencer, Lindzen and a few others, but a lot of them prefer to use model outputs for their studies.

        So why don’t you tell me what specific direct observations you think are so valuable? Which ones actually class as real indicators of “dangerous global warming” that would require re-ordering the world’s priorities, economies and lifestyles?

        Finally, skepticalscience.com has a problem. Every time I go there I find errors – major errors. So I don’t go there any more. And if that’s your source, then you have a problem. Because if they’ve “busted” any myths, it’s by pure luck, not because they’re such a good source. Actually a better name for thee site would be “pseudoscience.com”

      • I don’t need paranoia in order to distrust an entity that wants to put Syria on its Human Rights council. What is it a about “slimy” that you don’t understand?

      • Rob Starkey

        Robert– Computer models are great when the work. When they provide inaccurate results they are of no value. Today’s GCM’s are not accurate to any reasonable degree. There is not a model that can predict (with reasonable accuracy) what the temperature or the rainfall will be more than a few days into the future.

    • Tom Scharf

      Asteroids are one thing, but long term comets are another. Since these can come screaming in from way out there far beyond the asteroid belt with very long orbit times, we have some chance of having short notice before a collision with a comet which has not been seen before (days, weeks, months).

      Much less frequent than asteroids, but their quantity and risk are less certain. One NASA study suggested the risk of killer asteroids and killer comets to be about equal.

      Too few, too far away, too hard to find, too difficult to quantify.

      So we ignore this threat and instead have stress fits over sea levels rising one inch every decade.

    • Tom Scharf

      Let me use climate science logic with asteroids:

      Didn’t you know 1,000 people die every year on average due to asteroid collisions!!! This is what the consensus science tells us, don’t deny the obvious.

      Errrrr…..it is estimated once every million years an asteroid large enough to kill a billion people will strike the earth, now just do the math…

      A fairly large asteroid of 400m is due to pass within one moon distance of the earth on Nov 8th this year. This will be the largest near miss scheduled until 2028.

      NASA has a pretty good site with the data.

      http://neo.jpl.nasa.gov/index.html

  12. I am quite uncertain when the Yellowstone volcano will erupt but I am sure it will.

    Lets evacuate the north western US.

    • Exactly.

      • Most climate scientists seem to be certain Greenland will experience nonlinear melting, but they do not have a clue when it will start, or for how long it will last, etc. This is why, I think, projections of nonlinear melting are not allowed in the IPCC reports.

        Where is there a request for an evacuation?

        Exactly? I don’t think so.

      • JCH, Bruce is using a form of a proof that the general statement is not true by taking a concrete example of the abstract statement: “So when you take uncertainty into account, it actually leads to the decision that we should take action more quickly.”

        It’s similar to WLOG for mathematics.

      • Rob Starkey

        JCH

        LOL- “most climate scientists feel”

        So you managed to reach this conclusion how and when?

        Do you believe the percentage is the same now as in say 2007?

      • 2007? Possibly more now. In 2007 there were predictions multi-year ice would be recovered by 2011. Where are they now?

      • Rob Starkey

        At least you haveto admit you have no reliable information to demonstrate your claim that the majority of “climate scientists” agree with your position

      • I have no “position” on nonlinear melting. I’m a layperson, and I’ve never been to Greenland. I’ve read a lot articles scientists have written about Greenland, and have collected their blog posts. That nonlinear melting is not included in the IPCC projections of SLR is commonly indicated. Do you know otherwise?

      • JCH –
        In 2007 and 2008 and 2009 there were predictions that multi-year ice would be gone by 2013. Do you believe that?

      • Well ….

        One way to read the following article is that climate change will destroy nuclear reactors on the coast (and they need to be their for cooling water). Therefore nuclear power is not an answer to man made global warming.

        “Nuclear power is often touted as a solution to climate change, but Fukushima serves as a warning that far from solving the climate problem, nuclear power may be highly vulnerable to it.”

        http://www.newscientist.com/article/mg21028138.200-the-climate-change-threat-to-nuclear-power.html?DCMP=OTC-rss&nsref=online-news

        I love the circular logic … CO2 causes the planet to warm causing sea level to rise and more storms on coasts … therefore do not build nuclear power plants … which would save the planet from the CO2 generated by non-nuclear power plants.

      • That’s not true, 1) because most coastal nuke plants have cooling towers, and 2) climate-driven sea level rise isn’t of the 30-meter magnitude that did Fukushima in, and even if it were, there’s time to adapt.

        But go on…

      • This is bloody incredible:

        Heat waves are another serious concern, for two reasons. One, the colder the cooling water entering a reactor, the more efficient the production of electricity. And two, once the cooling water has passed through the system it is often discharged back where it came from in a much warmer state.

        The heat’s just going to keep building up, right? :roll:

        Is there any rubbish the Newscientist won’t publish?

      • This is even sillier

        “”Part of the problem is that science says that by 2100, we’ll experience anywhere from 1.5 to 6 feet of sea level rise,” said the study’s lead author, Austin Becker, a graduate student at Stanford. “That’s a huge range.”

        “The problem on a global scale, he said, is that ports may start scrambling all at once to adapt their structures to changing environmental conditions. “It could potentially exceed our capacity for construction worldwide,” he added.”

        http://www.eurekalert.org/pub_releases/2011-05/su-sna051611.php

        Ok … lets say port managers who deal with 15 foot tides (the nearest port to me) or even higher tides can’t deal with a 1.5 foot rise. For argments, lets say they are really, really stupid. And don’t notice a 1.5 foot or even a 6 foot rise in seal level until 2090 or so ….

        Oh I can’t continue. The scenario is too stupid to worry about.

      • Not to mention the 100 year window in which to do the construction.

        These are our best and brightest at Stanford…

      • God help us if these are the engineers of the future.

  13. I wonder if Krugman and chums ever considered applying the Precautionary Principle to itself? In the AGW case, the imaginable consequences of meaningful limitation – or elimination – of fossil fuels are negative, large and highly likely. Applying the Principle to that scenario would urge some rethinking, surely. Or thinking at all, perhaps.

  14. Norm Kalmanovitch

    The one certainty about climate over the past 31 years is that there has been no enhanced greenhouse effect from GHG emissions as claimed by the IPCC
    Since 1979 satellite measurements of outgoing longwave radiation have not shown any decreasi in OLR from the increased insulation ascroibed to the enhanced greenhouse effect resulting from the increase in GHG emissions.
    Instead there is only an increase in OLR in direct response to the overall increase in global temperatute since 1979 (including the cooling that started in 2002)
    This is incontovertable proof that it is changes to incoming energy and not changes to outgoing energy via the enhanced greenhouse effect that has any measurable effect on global temperature
    (Check OLR data on http://www.climate4you.com)

  15. Judith,
    The opposite conclusion concerning the influence of increased uncertainty in the two alternatives is due to hidden assumptions.

    In the first case the central part of the PDF of damage size is assumed to be fixed. Thus increasing uncertainty rises the tail and increases the likelihood of catastrophic outcome. This way of thinking is well known, and behind the standard conclusions.

    In the second case you introduce hidden assumptions of your own. Essentially you equate increased certainty with increased reason to take the catastrophe scenario seriously, but I cannot see the logic behind this assumption. Equally well the increased certainty could act to make the scenario much less likely, as it does in the first case. Whatever the logic is, the outcome is clearly due to a specific additional assumption introduced by you.

  16. Weitzman’s argument, particularly as applied to climate change, is grounded in a theory divorced from practical experience. The gigantic economic changes sought by CO2 reductionists are simply a form of social engineering. In practice social engineering has a very bad track record. (Think school busing to desegregate and Prohibition.). Additionally, the world changes too fast (mainly due to technology) for steps taken now to have their desired effect 50 or 100 years into the future. Examples of attempted long-term planning that were obvious failures are the Vietnam War (based on the fear of future dominoes falling in the future) and China’s Great Leap Forward.

    Finally, it is almost certain that with a rapidly increasing acquisition of technological knowledge, the actual risk is not what is claimed. It is almost certain that in 100 years, CO2 will be a trivial issue that will be easily solved by geoengineering. In the area of resource scarcity, Julian Simon has been repeatedly proved correct (and repeatedly ignored) in his assertions that human ingenuity outpaces resource scarcity. In the same manner, human ingenuity will be easily able to ameliorate the effects of CO2 if it becomes necessary 50 to 100 years into the future.

    JD

  17. 1. These arguments are wrongly attributed. They go back to Bernouilli’s work in the 18th century. The current thinking is based on the works of von Neumann, Arrow, Pratt and Raiffa in the 1940s-60s.

    2. Uncertainty per se does not increase or decrease the desired level of intervention. Asymmetric uncertainty does. Note that asymmetries may be in the probability distribution function as well as in the evaluation of the impact. For instance, when given a choice between (a) no reward and (b) 50% chance of a million dollar gain and 50% chance of million dollar loss, most people would opt for (a) even though the expected gain in (b) is zero too.

    3. The uncertainty about climate change is asymmetric. In the left tail, climate will not change much and nobody will get hurt. In the right tail, climate will change a lot and there are serious impacts. Therefore, the nature of the uncertainty about climate change is such that it is rational to err on the alarmist side.

    4. There is uncertainty about the costs of emission reduction too, with some saying that it will cost nothing and others that the economy will be ruined. However, modest emission reduction will quickly reduce these uncertainties.

    5. If the probability density function is not known, then you can postulate a probability density function for the probability density function. Weitzman uses that to argue that climate change violates Raiffa’s axioms on rational decisions under uncertainty — that is, cost-benefit analysis is inapplicable. Weitzman does not show what to do instead, so there are no political implications from his research.

    • “However, modest emission reduction will quickly reduce these uncertainties.”

      If life were a James Bond movie, the villain would be Chinese and he would hatch a diabolical plot to scare the western world into destroying its manufacturing base by making energy really expensive and to burden it with so many stupid regulations that 10s of millions of jobs would be exported to China where they would burn vast quantities of coal and produce so much CO2 that whatever western nations did it would never come close to reducing emissions at all.

      Oh … wait …

    • Hi Richard,

      IMHO, your comments are very lucid and I think it would be fun to recast a couple of them to show they focus on only half of the issue. Exchange the words climate and economy in your comments.

      For example, let me recast your paragraph 3 as an economic argument instead of a climate one.

      3. The uncertainty about the resulting economic change is asymmetric. In the left tail, the economy will not change much and nobody will get hurt. In the right tail, the economy will change a lot and there are serious impacts. Therefore, the nature of the uncertainty about economic change is such that it is rational to err on the “alarmist” side. (In this case, the “alarmist” is the person who fears economic catastrophe.)

      And also recast paragraph 4.

      4. There is uncertainty about the climate consequences of economic change too, with some saying that it will “cost” (the climate) nothing and others that the climate will be ruined. However, modest economic increases will quickly reduce these uncertainties.

      I think this recasting shows the precautionary principle is not applicable to the climate change policy debate. The climate and the economy seem othogonal, in the sense that the value of one cannot be shown to fix the other.

      • @George
        You forget that there are two other asymmetries. First, our understanding of climate change and its impacts grows slowly. Our understanding of emission reduction and its impacts grows fast. Second, if we find ourselves in the bad tail of the impact of climate policy, we can stop policy. If we find ourselves in the bad tail of the impact of climate change, there is little we can do.

        The uncertainties about the costs of emission reduction are therefore less important that the uncertainties about climate change.

      • Bad Andrew

        “if we find ourselves in the bad tail of the impact of climate policy, we can stop policy”

        My suspicions that this is a non-serious discussion is now confirmed. ;)

        Andrew

      • Bad Andrew

        In other words, Richard Tol is advocating a climate policy, but doesn’t know whether it will be good or bad.

        Andrew

      • Our understanding of emission reduction and its impacts grows fast.

        Where does that come from?

      • @ChE
        Our understanding of emission reduction and its impacts grows fast because (a) there is a major research program underway and (b) this is now being fed with observations from those countries that have emission reduction policies.

        Norway, for instance, has had a carbon tax since 1991.

      • Richard,

        It’s interesting to see you defending the power of precautionary principle so strongly. The point you made on the differing rates of learning is essential. Still the problem remains that choosing, what to do is left largely to intuition, as our capability of comparing costs to benefits are lacking, and also the questions of ethical nature that affect discounting are largely open.

        My own view is that the largest obstacle for reasonable cost/benefit comparison is the inability do describe and value future alternatives taking into account all choices of future decision makers in the spirit of dynamic programming. Whatever we decide now, will affect future decisions. Locking to some path is a possibility, but more often errors made now are canceled by later decisions making the damage temporary and marginal.

        The loss in delaying mitigation may be even overcompensated by the more effective solutions selected later. It’s easy to imagine many situations where the immediate and later actions are alternatives, while there are also situations where the add. The former situation may result from stronger future economy or from investment in research rather than in implementation of existing immature technology.

      • maksimovich

        qwerty

    • Richard, thanks for your comments. Re #5, when you get to the point of talking about a pdf for the pdf in the context of decision making, the whole thing has broken down. That is why I think imprecise probability measures (e.g. possibility distribution) and evidence theory work better in this kind of situation. That way you can define an explicit plausible worst case scenario, and get away from things like a 1% chance of sensitivity > 20C, for which there is no evidence.

      • I’m not convinced that the imprecise probability measures help at all. The are just one additional level of uncertainty on top of the first one. It’s true that uncertainties based on lack of knowledge are not the same as those based on well defined random distributions, but that expressing that by the second level doesn’t solve anything. Equally valid – or invalid – results can be obtained by modifying the PDF’s.

        The fact that we don’t have good guidelines for doing the modification is an indicator of the real problem, but as I started, the alternative approaches don’t really provide additional understanding. There is always also the risk that we lose real understanding through their use.

    • Richard, the asymmetry you postulate in 3 is tantamount to accepting AGW. Absent AGW cooling is as likely as wasming. The case is symmetric, given present knowledge.

      • @David
        Natural variability is low in interglacials. Natural warming or cooling is therefore small compared to anthropogenic warming.

      • Richard, you seem to have missed my point. We don’t yet know that there is, or ever will be, any anthro warming. You are assuming that there is, which is to say you are assuming AGW is true. That is my only point.

        As I understand it we have reason to believe that natural variability can reach 2 degrees C or so during interglacials.

      • @David
        It is sufficient to assume that there is a non-zero probability of AGW.

      • Richard, not if you also assume there is a non-zero probability of the interglacial ending. The symmetry remains.

      • In fact as I understand probability theory any event that is logically possible has a non-zero probability. This makes the concept singularly unhelpful.

      • @David
        The common wisdom used to be that the enhanced greenhouse effect is too weak to counter a new ice age. In that case, a new ice age is a sunk risk, that is, irrelevant for decisions on greenhouse gas emission reduction.

        It may be that the common wisdom has changed since I last checked (20 years ago). If carbon dioxide emissions can prevent a new ice age, then we should keep a fossil reserve and burn it if the new ice age sets in. This would in fact be an additional reason to reduce fossil fuel use now.

      • Common wisdom, whatever that might mean, is irrelevant. Nor does it exist in a debate. Once again you are merely citing AGW, so my point stands.

      • @David
        Note that common wisdom did not feature in the logic.

    • re: Richard Tol 5/28 10:56

      “3. The uncertainty about climate change is asymmetric. In the left tail, climate will not change much and nobody will get hurt. In the right tail, climate will change a lot and there are serious impacts. Therefore, the nature of the uncertainty about climate change is such that it is rational to err on the alarmist side.”

      Statistics deals with calculable probabilities. CAGW deals with uncalculable probabilities- note, not “incalculable” as unable to be calculated, but “uncalculable” as in not calculable because there is nothing to calculate a probabllity from. What is needed is a statistics of “speculation”. How do we deal with unbounded speculation about what “might” happen? Does a speculative “fat tail” have any meaning at all?

      When we are dealing with uncalculable speculations it is rational to err on the side of getting more data(if it is a data driven problem), or develop different approach(as in organizing a political campaign drive) for an idea driven problem.

      The real answer to me appears to be that when the results are unknowable the best actions to take are ones which increase the adaptability of the human race to meet whatever change comes(R. Pielke Jr.’s favorite idea).. The best means to this end is improving the overall standard of living of the folks at the bottom, near the edge. “One crop away from starvation” to quote Jared Diamond.

      One of the ways to do this is alternative energy systems that actually increase the available energy, as opposed to rearranging the deck chairs on the Titanic(ethanol, solar power, windmills, biofuels, etc none of which will realistically increase the amount of available useable energy). I find it absolutely appalling that the the Chinese are planning on testing thorium reactors when the US developed and ran a LFTR reactor for 30 years. Where are the plans to put that technology into use both here and abroad.

      • When we are dealing with uncalculable risks, we have no fixed rule to guide, what to do. We must just try to be as wise as we can, and the conclusion can equally well go both ways.

        When uncalculable risks have any plausibility of being possible and severe, best effort should be taken to gain better understanding on the uncalculable likelihood and decision then based on that understanding even when it’s not really calculated. In making the decisions the worst outcomes should always be given more weight than more positive alternatives.

        We cannot hide behind our lack of knowledge. If the risk is real and potentially severe it must be taken into account how ever difficult that is. At the same time it’s true that we cannot react to every imaginary fear. That’s the dilemma of decision making.

      • In the case of AGW, and specifically fossil fuel burning, we have the advantage at the early stages of significant calculable harms, which fully justify fairly aggressive action.

        This paper, for example, estimates the health costs of fossil fuel burning at around $50 per ton of CO2 released:

        “Implications of incorporating air-quality co-benefits into climate change policymaking”

        http://www.iop.org/EJ/article/1748-9326/5/1/014007/erl10_1_014007.pdf

      • In other words, they want to piggyback their favorite cause on the cost of CAGW mitigation.

      • “we found a range of estimates for the air quality co-benefits of climate change mitigation of
        $2-196/tCO2″

        2$ is possible. I doubt the higher figures.

  18. With a low but real probability of catastrophic consequences you should be adaptive or you paint yourself into a corner. Taking drastic action to possibly avoid an uncertain risk can expose you to a variety of outcomes perceived to be less damaging, but combined may result in equal or greater damage.

    Turner’s Cannibalistic scenario “may” be possible, but history has proven that human nature can produce unsavory responses to hardship. Greg Craven and others seem to forget that oppressive laws and economic ruin brings out the nasty side of humanity. Whether the vanquished are consumed after being dispatched is a minor point.

  19. “I guess my poor little brain had a difficult time letting that Nobel-level economics pass through its filter when I read Weitzman’s paper.”

    Correct, even though it’s not particularly hard to read and understand his work on this issue. In the context of permit pricing/emissions cuts, Weitzman argues that risk related to irreversible outcomes and cataclysmic effects is unsuited to traditional economic cost-benefit analysis. Many economic models ignore this risk (even though many social analyses have not). As I have repeatedly explained to you – and frankly you seem incapable of grasping it – the argument is that the risk of catastrophe and risks related to what we don’t do are the more compelling aspects of assessing uncertainty, all things considered (including the most current science). Krugman gets Weitzman right.

    “now are we to infer that that the merchants of doubt are now climate policy action’s “best friends”

    No, you are to infer the opposite. Obviously.

    “Consider a potential asteroid strike: far greater economic impact and also far greater uncertainty than climate change”

    Try Posner (2004), Sunstein (2007), and Parson (2007) for discussion of the portfolio of risks, including this one, as recommended to you in Weitzman (2009) –which you claim to have read. Weitzman goes to some length to explain to you why the asteroid and other similar potential scenarios are not analogous smoking guns, and that it doesn’t lessen the need to reckon with climate change.

    “Neither Romm nor Krugman discuss these points”

    They don’t need to. They have actually read and accurately understood Weitzman and many other sources of information.

    • Rob Starkey

      Martha “religious like” belief that increased CO2 is harmful and the “anger” she displays when others do not support her positions is fascinating. In this post her basic point is that others should accept the belief of an economist who says that in spite of his suggestion making no economic sense, we should follow it because his “unsubstantiated fears” are high.

      To me, Martha’s unsubstantiated fears are not a valid reason to take stupid actions.

      • “the “anger” she displays when others do not support her positions”

        That’s an interesting assertion, because your comment seems angry, and hers seems calm and controlled.

  20. Just wanted to point out that this is a philosophical/political discussion (which is all good) and it has little relevance to the advancement of any climate science.

    Andrew

    • The reality is that we wouldn’t be having this “scientific” discussion if policy wasn’t the driver. This is, in fact, about policy. Every last bit of it. Always was.

    • Casual online discussions dominated by the scientifically and mathematically illiterate are not going to advance science. Science advances by doing science, which involves getting out of the house and collecting data.

      The time of non-scientists is better spent in philosophical and political discussion. You are more likely to make a useful contribution in that area.

      • Robert, I agree with you. I am amazed at how unscientific the Climate Preachers are who believe Co2 is the only reason climate changes. Those people are dumber than a sack of hammers.

  21. I think that paleo and model estimates converge on sensitivities near 3 C per doubling. It is hard to make a highly sensitive model that would represent the paleo or recent climate record. climateprediction.net has done Monte Carlo model experiments to explore uncertainties in aspects of climate models. My understanding of their results so far is that it is difficult to get extreme sensitivity (10 C per doubling) with justifiable parameters. Paleo evidence is equally strong that high CO2 in the past did not lead to temperatures consistent with extreme sensitivity, e.g. work by Alley and others say it points to 2.8 C per doubling from evidence of the last few hundred million years. However Kiehl (2011, Science) finds that sensitivities could be up to 7 or 8 C per doubling from paleo evidence of 35 million years ago when the CO2 levels were last near 1000 ppm (which we would approach by 2100 with business-as-usual scenarios).
    I would conclude that the broad probability distribution would include 2-8 C per doubling, falling off rapidly outside that, as constrained by models and paleo science. We should note that these are equilibrium sensitivities and the actual warming would not immediately respond to CO2, but may take decades to centuries to reach the equilibrium values. So, a prediction for 2100 would be more constrained, perhaps 1.5-6 C.

    • Good analysis. I would add two things:

      1. Given the response of carbon sinks to data, we have to wonder to what extent 1.5-6C of warming will result in significantly more non-anthropogenic emissions which could increase warming.

      2. We always stop at 2100, by convention. What about 2150 or 2200?

    • The Eemian, without any significant human contribution to CO2, ended up being 5-6C warmer than it is now. Co2 followed temperature.

      So … what caused the temperature to go up in the Eemian?

      And why isn’t the same mechanism a valid explanation for the natural variations in Holocene climate?

      http://www.ferdinand-engelbeen.be/klimaat/eemian.html

      • “The Eemian, without any significant human contribution to CO2, ended up being 5-6C warmer than it is now.”

        Which argues for an extremely high climate sensitivity.

        “So … what caused the temperature to go up in the Eemian?

        And why isn’t the same mechanism a valid explanation for the natural variations in Holocene climate?”

        Why don’t you do some reading and come back and tell us the answer to these (very basic) climate science questions?

        I do not understand why some people think that their own ignorance is somehow an indictment of science.

        I recommend Skeptical Science and Science of Doom for your research.

      • You don’t know the answer? You claim to know everything …

        The IPCC seems doesn’t know the answer either.

        Maybe both of you should find out.

        They don’t mention CO2 as a climate driver:

        http://www.ipcc.ch/ipccreports/tar/wg1/075.htm

  22. There are many types of uncertainties. Some of them support immediate decisions, some postponing decisions. One of the most common theoretical concepts linked to uncertainties is real options. A real option is the maintained opportunity to choose later, when more information is available. Real options may be formed by postponing decisions as far as possible – or up to the point where closing (executing) the option becomes the better alternative.

    Additional real options can be created by activities that add to the later range of alternatives. Thus inducing research on potentially useful alternatives creates real options at the cost of the research.

    So far everything supports postponing major decisions and making immediate decisions mainly to widen the scope of alternatives. Another useful decision would be to increase research on the consequences of various alternatives to add to our future capability of making wise choices.

    There is, however, also the possibility that our knowledge will improve slowly, while the postponement of actions will increase the ultimate damage more than we gain from the advantages of the postponement, i.e. the utility weighted expected damage will grow faster than the value of additional knowledge. This would lead to the conclusion of Weitzman and many others.

    But we are not yet over. The uncertainties do not apply only to the damage of climate change, but they apply also to every action that is made to mitigate the climate change. These uncertainties are crucial, because we don’t really know, how to counteract climate change efficiently through decisions that can be made in real world. We know too little on the consequences of national and international decisions. We don’t really know, what the Kyoto protocol, and the decisions based on that in EU, Japan, Canada, and other participating countries has really brought to us.

    – Are the CO2 emissions significantly lower, because of the Kyoto protocol?
    – Has EU climate policy affected negatively the economy of EU?
    – Have the Kyoto mechanisms led to any valuable outcomes in developing countries?
    – Has the Kyoto Protocol improved our readiness for further actions more than would have been reached without?

    Is the model of the Kyoto Protocol a realistic basis for a wider agreement, or should it be abandoned at replaced by some other approach?

    The above questions are policy uncertainties, but we have also technological and resource uncertainties on the future of various forms of renewable energy:

    – How should land use be developed, and what is then the right role of biofuels?

    – How fast will solar energy technologies develop and when it’s in common interest to speed up deployment of solar power and in what form?

    A related issue is the question of availability of fossil fuels:

    – How fast are we running short of oil supplies?
    – What is the future of natural gas including shale gas?
    – How should coal be used?

    The future of nuclear energy is one more open issue, and so are all questions on reducing energy consumption by technical solutions and changes in lifestyle.

    The multitude of these issues tells that we do not have just one choice (to act or to postpone) but a huge number of issues to decide. The idea that putting a price on carbon is an efficient way of leading to a good path, may be difficult to justify, but what are the alternatives, if the decision is to act promptly?

    • Pekka, thanks for this post

    • Bad Andrew

      “if the decision is to act promptly”

      Then it’s obvious that the cart has been put before the horse.

      PP, if a decision to act promptly introduces confusion, then it’s a destructive decision, and should be rejected. This is pretty elementary.

      Andrew

      • Bad Andrew

        So my questions become “on what specific information was the decision to act promptly made? Who made it and when? and whom does the decision apply to?”

        Or is this not a serious discussion, which I suspect it’s not.

        Andrew

  23. So when you take uncertainty into account, it actually leads to the decision that we should take action more quickly

    There is no uncertainty in the global warming data.

    Before mid-20th century, before wide spread use of fossil fuels, the global warming rate was 0.15 deg C per decade.
    http://bit.ly/eUXTX2

    Since then, as shown in the above graph, the above global warming rate was not exceeded. As long as the pre mid-20th century global warming rate is not exceeded, there is no evidence for man made global warming.

    It is sad to read the euphemises: “climate change” for global warming & “action” for callously increasing cost of energy; therefore, callously increasing cost of living.

  24. Haste makes waste

    A massive flu epidemic is also a possibility but remaining calm is probably just as good or better advice than taking action ‘quicker’. If the actions you take are uncertain or bad then you don’t really achieve much.

    It reminds me of this part (which is often misquoted) in Alice:
    The Cat only grinned when it saw Alice. It looked good- natured, she thought: still it had VERY long claws and a great many teeth, so she felt that it ought to be treated with respect.

    `Cheshire Puss,’ she began, rather timidly, as she did not at all know whether it would like the name: however, it only grinned a little wider. `Come, it’s pleased so far,’ thought Alice, and she went on. `Would you tell me, please, which way I ought to go from here?’

    `That depends a good deal on where you want to get to,’ said the Cat.

    `I don’t much care where–‘ said Alice.

    `Then it doesn’t matter which way you go,’ said the Cat.

    `–so long as I get SOMEWHERE,’ Alice added as an explanation.

    `Oh, you’re sure to do that,’ said the Cat, `if you only walk long enough.’

    Alice felt that this could not be denied, so she tried another question. `What sort of people live about here?’

    `In THAT direction,’ the Cat said, waving its right paw round, `lives a Hatter: and in THAT direction,’ waving the other paw, `lives a March Hare. Visit either you like: they’re both mad.’

    `But I don’t want to go among mad people,’ Alice remarked.

    `Oh, you can’t help that,’ said the Cat: `we’re all mad here. I’m mad. You’re mad.’

    `How do you know I’m mad?’ said Alice.

    `You must be,’ said the Cat, `or you wouldn’t have come here.’

    Alice didn’t think that proved it at all; however, she went on `And how do you know that you’re mad?’

    `To begin with,’ said the Cat, `a dog’s not mad. You grant that?’

    `I suppose so,’ said Alice.

    `Well, then,’ the Cat went on, `you see, a dog growls when it’s angry, and wags its tail when it’s pleased. Now I growl when I’m pleased, and wag my tail when I’m angry. Therefore I’m mad.’

    `I call it purring, not growling,’ said Alice.

    `Call it what you like,’ said the Cat.

  25. Dr. Curry and All: I admire the depth of thoughtful exploration here — much good stuff, more than I would have expected.

    However, what strikes me most about the Mann quote argument is the relentless determination of the climate change orthodox to reach a predetermined conclusion by any means necessary.

    • William Norton

      Huxley, great observation – especially this part:
      “However, what strikes me most …climate change orthodox to reach a predetermined conclusion by any means necessary.”

      For climate scientists to do otherwise would result in a catastrophic loss of grant money. How can anyone objectively assess risk if one outcome leads to a serious loss of livelihood? Isn’t there a moral hazard here?

  26. I don’t know how to comment on the substance of this post, by the terms set forth by our hostess. It is impossible to discuss anything Paul Krugman writes without discussing politics because everything he writes is political. The precautionary principle in this context is as well a purely political/polemical tool, dressed up as science.

    “The science is settled” so we have to control the economy.

    vs.

    “The science is so uncertain” that we have to control the economy.

    If you try to analyze these contradictory arguments using logic, you will fail. If you analyze them from the political aspect of – “we want to control the economy, what arguments can we use to do so,” they make a lot more sense.

    But given the ground rules, I will demur and leave it to the scientists to apply complex analytical tools to mine this rather mundane example of progressive propaganda for its deeper scientific insights.

  27. In a world where there is only one potential catastrophe waiting in the wings, the Precautionary Principle makes some sense, and most discussion about the PP and the Mann quote seems to precede with that assumption implicit.

    But in the real world where we face multiple uncertain catastrophes: nuclear war, asteroid strikes, pandemics, earthquakes, peak oil, economic collapse, etc., as well as climate change, how do we respond?

    This is where the Mann quote falls apart entirely. If we decide to act even more quickly on account of uncertainty, then we will be rushing around in even more directions to prevent catastrophes, our efforts will be ineffectual, and likely we will burn out and collapse.

  28. Krugman et al leave out from their worst case analysis a crucial factor – what is the worst that could happen if anthropogenic climate influences are mitigated or removed.

    The unstated assumption seems to be that we will go to some sort of climate nirvana – Gaia returning the earth to perfect bliss. Anyone with the least familiarity with climate history, especially since the beginning of the Pleistocene knows this is not the case.

    Climate in a glacial age is highly variable. Even during the Holocene there have been major climate catastrophes, such as the desertification of the Sahara and much of the Middle East. There have recently been a couple of papers suggesting that, but for anthropogenic inputs (mostly China and Europe deforestation, not industrialization) we would now be heading towards a new glacial maximum – a far worst fate than the worst suggested impacts from warming.

    With or without anthropogenic CO2, climate is highly variable. The climate cassandras are willfully dishonest in focussing on the uncertainty of a high CO2 world while ignoring the uncertainties that would exist if we followed their prescriptions.

  29. ferd berple

    Most of us have a much greater risk of being killed in an automobile accident today than almost any other cause. No insurance policy in the world can prevent you from dying in an accident. The only way to avoid being killed is to avoid driving. However, for many of us, driving is necessary for our economic survival. So our choice is economic survival versus physical survival.

    This is very much the situation being posed by AGW. Do we risk economic survival against physical survival. The Precautionary Principle says that we should choose physical survival even if it means economic ruin. Common sense tells us otherwise.

    They reality of life is that economic ruin is in many ways more severe than an automobile accident. At least if you die in an accident your troubles are over. In the case of economic ruin, your troubles are just beginning.

    • 1) Why do you feel the capitalist model is so frail as to collapse into ruins with the trivial stress of a tax on carbon emissions?

      2) What is the evidence for this catastrophic future you find so alarming?

      • I think there is more historical evidence of a chance of economic collapse leading to wars than there is if the temperature goes up 1-2C.

        By the way, where I live, it goes up 50C each year and down 50C.

        I’ve adapted.

      • You didn’t answer the question. Again, why do you think capitalism is so frail as to to collapse into ruins with the trivial stress of a tax on carbon emissions?

        Is there a better system out there, if you have so little confidence in the free market? Are you an advocate of Soviet-style central planning?

      • It doesn’t have to collapse into ruins to have a profound effect on the lives of hundreds of millions of people.

        Even current gas prices are tough on families, and you want to make the prices much, much higher.

        A “trivial carbon tax” will not be high enough to make people change, because buying a Prius is not possible when they can’t afford the payments on their current car. A non-trivial carbon tax will cause brutal economic consequences.

        “For every $10 the typical household earns before taxes, almost a full dollar now goes toward gas, a 40 percent bigger bite than normal.

        Households spent an average of $369 on gas last month. In April 2009, they spent just $201. Families now spend more filling up than they spend on cars, clothes or recreation. Last year, they spent less on gasoline than each of those things.”

        http://news.yahoo.com/s/ap/20110527/ap_on_bi_ge/us_gasoline_summer_squeeze

        I suspect Robert, you are some sort of malthusian sadist who wants to punish the carbon sinners.

        And since the carbon tax will most likely just move jobs from the idiot nations that put one in place to the non-idiot nations like China and India … the amount of CO2 emitted will go up.

        Sadism is what you want. A carbon tax is your whip.

      • “Even current gas prices are tough on families, and you want to make the prices much, much higher.”

        Many European countries pay $8-$9 a gallon for gas, and have significantly less poverty and homeless and a bigger middle class.

        If you are concerned about the impact on working families, you can institute a revenue-neutral tax reform that gives the carbon tax money back as a household dividend. Easy fix.

        Still not seeing the collapse of civilization anywhere on the horizon.

        “Sadism is what you want. A carbon tax is your whip.”

        I’m not interested in your sexual fantasies; let’s try to keep the discussion on topic and PG-13.

      • The only revenue neutral carbon tax is no carbon tax.

        “Many European countries pay $8-$9 a gallon for gas, and have significantly less poverty and homeless and a bigger middle class.”

        Tell that to Portugal, Ireland, Greece and Spain and the countries who are about to join them.

        “With southern Europe struggling under public debt, inflation and scant growth, Spain has broken a European record for unemployment. More than one in five Spaniards are out of work, posing a threat to quick recovery for southern Europe’s biggest economy, and the region as a whole.

        More than one in five working-age Spaniards are unemployed – more than in any other country in Europe. Spain’s jobless rate has hit a 15-year high, nearly double the figure in neighboring Portugal.

        But many Spaniards do not believe that number is accurate. Retiree Luis Cases says that in his hometown of Valencia, it feels like 95 percent of people are out of work.”

        Spain … the poster boy of green job killing sadistic policies.

      • Because the “trivial tax” is just the camel getting his nose in the tent. If you study history anyway, that’s the way it always works out.

  30. Why do we assume that the risks are normally distributed?

    • Weitzman assumes a fat tail distribution, I am saying we don’t know what the distribution looks like, and that we can probably bound it on the upper end (Wietzman’s 20C climate sensitivity is beyond anything anyone is talking about).

      • Dr Curry, if you look at Weitzman’s paper, he is using climate sensitivity is a slightly different way than climatologists use it: he is talking about the ultimate effect of anthropomorphic emissions. So while no one thinks a doubling of CO2 will cause a 20C temperature rise, if an anthropomorphic doubling triggered further releases of CO2 and methane from natural sinks, Weitzman treats all of their warming as a consequence of the original doubling. It’s not climate sensitivity in a literal sense, but it gets at what Weitzman is interested in: the consequences of human actions.

      • I also didn’t understand Gilligan’s argument. When he said that there was uncertainly in both temperature and consequences, that seems to be arguing in favor of a skinny tail (the product of both uncertainties). Then he started arguing as if a fat tail was demonstrated.

        As far as 20C CS goes, at what point does the fact that we haven’t seen anything faintly approaching those high numbers falsify them? If they are going to argue that the vast bulk of the warming is “in the pipeline”, it seems like the probably of that being 20 or 30 or 40 is just as high, because all the extra heat is wound up in some spring somewhere ready to let loose at some unknown point in the future. You have to believe that in order to believe anything above 3 or 4, in which case, what’s the difference between storing 26 gazillions joules and 53 gazillion joules? The real point is that you’ve postulated this completely undescribed energy storage system which has an almost perfect deadtime response – it all goes in one end, and comes out all at once at some unknown point in the future.

        If that’s the case, anything’s possible. And there’s the problem; when anything is possible, nothing can be acted upon.

      • “When he said that there was uncertainly in both temperature and consequences, that seems to be arguing in favor of a skinny tail (the product of both uncertainties)”

        This again is a confusion between the concepts of “uncertain” and “improbable.”

        The distinction between temperature uncertainty and consequence uncertainty is simple, crucial, and often misunderstood by those that cite Weitzman.

        In one sentence: there are uncertainties both in how much warming for a given forcing and how much damage that warming will do; people examining temperature uncertainty tend to make simplifying assumptions like +2C is safe, +4C is expensive, and +6C is catastrophic, but it is also possible that +2C will be expensive and +3C will be catastrophic. So there is important uncertainty there, as well.

      • No, he was uncertain about:

        1) what the climate sensitivity is, and
        2) what the certainty is that a given temperature increase will cause a particular laundry list of negative consequences.

        These are both uncertainties. They affect the probability. but since both have to be true in order for something bad to happen, the probabilities have to be multiplied to determine the odds of something bad happening. The more uncertainty, the skinnier the tail.

        Unless you want to assume that all that you don’t know can kill you, in which case you’re already dead.

      • “These are both uncertainties. They affect the probability.”

        No, they do not. Uncertainty does not affect probability. If it did, burying your head in the sand would actually prevent bad things from happening.

      • Burying your head in the sand can stop you from doing stupid things.

        For example, attempts to limit CO2 in the west have actually shifted jobs AND CO2 production from coal to China.

        If the west had done nothing, less CO2 would have been produced.

  31. Argument A2 seems to assume several things which do not, at first blush, make sense:

    *That there is a special kind of uncertainty that applies to catastrophic consequences of AGW. In fact, uncertainty applies to benign scenarios just as much as catastrophic ones.

    *That uncertainty has a relationship to probability: cost/benefit analysis should be weighted for probability, but uncertain (difficult to calculate probability or imagine risk) is not at all the same as improbable; if it were, burying one’s head in the sand would be a sound risk-management strategy, as dangers would become less pressing the less information we had about them.

    There is no equivalence between “uncertainty regarding the likelihood” and “likelihood.” Thus, no “Thus.”

    Dr. Curry’s reasoning might be made to work in the special case of an extremely high probability of catastrophe. In such a case, the more we know, the greater weight we place on the scenario, and the less we know, the less likely we are to give the scenario its due. But of course it is hard to justify inaction on that basis.

  32. I’m probably too simple, but in my classic view of cost vs. benefit risk analysis, if one possible risk is utter (total) catastrophe the cost approaches infinity so mitigation is demanded even it its probability is zero. Which, of course, makes the entire process specious and moot.

    • Yeah, I don’t know why they don’t argue that alternative energy will help with energy security(which is a more provable threat) more and that as an added benefit that it might help avoid a possible catastrophe rather than the other way around.

      • Because there are carbonaceous ways to deal with energy security in the short to medium term, such as natural gas.

  33. The analogy is fairly straightforward. The Precautionary Principle as commonly applied to climate change says that even if you’re not fully convinced that it will definitely happen, if you accept that it might happen, the costs are so high (e.g. Ted Turner’s cannibal scenario) that it’s still the only rational choice to act to prevent it. Pascal’s Wager applied to the Christian afterlife mythology says that even if you’re not fully convinced that it will definitely happen, the costs (eternal torment versus eternal bliss) are so high that the only rational choice is to believe. The distinctive features of the argument are that it offers only two alternatives with the putative costs embedded the hypothesis, and the conclusion arises from the hypothesised costs alone, not the evidence.

    Here’s the problem with Pascal’s Wager:

    (Punchline at about 2:25)

  34. May I call ‘time-out’?

    All (any?) of the above (with a few exceptions) talk about the ‘Precautionary Principle’ or “Pascal’s Wager”. Surely, the latter requires and the former implies zero (or very small) cost to make each strategy optimal. Any ‘warmist’ solution I’ve seen or heard of is (extremely!) costly in money and societal terms.
    Well?

    • But the PP neither requires nor implies ANY cost, but forces us to put a value on human life, and implies that some lives are more valuable (and thus worth preserving) than others. This is not stated, but is the end-game of the PP where it applies to climate change from a political perspective. The current state of the DDT vs. Malaria fiasco shows this quite clearly as well. Did anyone “legislating” against DDT tally up the lives to be lost from it’s non-use? Would they risk their political careers on a full public disclosure of the bare facts? I doubt it. (Of course, I’m not in favor of eradicating eagles or any other creature, but I think we now know the quantities and localities for effective yet minimally dangerous useage.)

      • I shan’t (would never) argue about the value of a human life, but don’t all ‘warmist’ solutions involve enormous loss thereof? I’ve just been reading about a reduction from 9.3+ billion to 1 billion – ‘warmist’. German, but who’s prejudiced?
        DDT only proves my point. Precaution – ban it (it might affect raptors (not proven at that point – at least if use changed). Cost – millions dead (pick a number).

      • Cost of ban = zero (for those who banned DDT – Western nations). Consequence – we agree on that. Q.E.D.

      • I’m quite certain the 70+ billion spent on aid to Africa each year may not have been as necessary if 10s of millions didn’t catch malaria/yellow fever/dengue/etc each year.

        It puts a bit of a strain on the medical system … and other things.

        “Malaria in selected Southern African countries could cost as much as US$1,000 million, or 4% of GDP … ”

        http://www.malaria.org/tren.html

    • Nullius in Verba

      That’s a good question.

      In the usual application of the PP to CC, the cost if it turns out that there is no significant climate change is usually ignored, not mentioned, or assumed to be trivial in comparison – in much the same way that Pascal omitted to mention the costs of all the time wasted praying and studying the Bible.

      “Let us weigh the gain and loss in wagering that God is. Consider these two cases: if you win you win everything, if you lose, you lose nothing. Wager, then it is without hesitation.”

      A few, like Stern or Lomborg, do try to quantify costs (and usually don’t call it the PP). But for most users I’ve seen, the costs if CC is true are invariably catastrophic, and the costs if it is not are assumed to be a minor reduction in rampant consumerism and corporate profits (which frankly most of the arguers seem to regard as a plus as well) that won’t cause any significant harm. Not all cases of its use are the same, though.

      • > Pascal omitted to mention the costs of all the time wasted praying and studying the Bible.

        A simple reason would be that these are no such costs implied.

  35. Svend ferdinandsen

    Like you concider the risk of a catastrophic warming, you should also concider the risks that the actions don’t work.
    And of cause the risk that the actions do more harm than what they should prevent.
    You could also start making up the possibilities that increased temperature will do good. At least Greenland will benefit from an increased temperature.

    • Strictly speaking, no actions are being proposed. What is being proposed is that we do less of something (pumping massive amounts of greenhouse gases into the atmosphere) not that we undertake any positive actions.

      • Is today ‘opposite’ day or something? are you implying instead of his quote
        “So when you take uncertainty into account, it actually leads to the decision that we should take action more quickly.”
        he actually meant “So when you take uncertainty into account, it actually leads to the decision that we should take NO action more quickly.”

      • You mean you propose to pump less of an already small amount of CO2 (compared to natural sources).

        Why not just plow under all crops and return the farmland to native vegetation or forests?

        Land use is a huge component of the small percentage of Co2 produced by man.

        Ban concrete.

        Ban airlines.

        Maybe YOU could lead the way. Eat only wild food. Bulldoze your home and return the land to natural ground cover. Walk instead of drive or fly.

        Let us know how that turns out in 10 years.

      • This sounds an awful lot like the gist of the lawsuit by the state attorneys general over healthcare. When is inaction action? When is action inaction? When is up down?

  36. The elephant in the room is the HUGE fat tail on the likelihood of consequences of large-scale mitigation — on the left-hand “disastrous impoverishment for no good reason” side. The odds there would round to unity at one significant digit (which is about as accurate as the uncertainty estimates allow). While the odds of a successful mitigation round to zero, even with 2 or 3 significant digits.

  37. Very little uncertainty if one takes a decadal view. Forget about controlling the climate, Earth will do its ‘thing’ regardless.
    Correlation factor of R^2 of ~ 0.85 is hardly a coincidence.
    http://www.vukcevic.talktalk.net/HmL.htm

  38. The operating presumption on the alarmist side is that this CO2 problem, to the extent one exists, can be solved. Moreover that we can, and should be making profound changes ”in all spheres and at all scales in order to stop and reverse global environmental change” …according to a recent statement by a gaggle of over-wrought and probably feverish Nobel Laureates .

    What we’re talking about here a fundamental across the board change in the way we live our lives… a revolution in other words….to avert some catastrophe that is according to all current evidence, highly unlikely. Absurdly unlikely.

    This is just plain wacky. Way, way wacky.

    • I’d take them more seriously if they were willing to hold their everybody-must-sacrifice symposia in cyberspace instead of some resort on some beach somewhere.

  39. John from CA

    Action without thought is what we’re getting from the UNFCCC. I ran across this video last week and thought it made some excellent economic points though in a generally biased way.

    About 15 minutes in length but (IMO) worth the time:

    • John from CA

      The “In-action” part of this debate is fascinating.

      Let’s throw out CO2 from the equation for the moment as a by-product of the real problem and reframe the debate around what if anything can be implemented to save the taxpayer some money and improve the human condition.

      Solar, Wind, and perhaps even geo-thermal are not mature technologies and lack ROEI and return on investment at this point. Yet, the US grid is extremely inefficient and based on very old ideas.

      – The idea that power needs to be On all the time in the off chance you may be home and decide to turn something On is absurd.
      – The idea that water heaters need to heat water all day long is wasteful.
      – The instant On feature for household media equipment is wasteful.
      – The idea of decentralizing power generation seems logical.
      – The idea of point of use power generation may have merits.
      – The idea of evaluating power usage in a more holistic way is logical. Example, can the initial power used to pressurize and distribute water in a municipal water system be converted to energy sufficient to heat water at the point of use? Probably not at the current pressure but could a portion of it be used to help reduce the load for heating — seems logical.

      The question is what action. It seems logical to conclude, taxing the general masses to implement junk solutions is the most wasteful action.

      If viable solutions were presented, there simply isn’t a need for the climate science debate. Isn’t the real problem inefficiency, lack of holistic engineering, and lack of viable solutions to implement?

      • Actually, they problem with wind is that it is mature. There are some small stepwise refinements to be made in going to a DC/inverter type of power collection system, but the mechanical/aerodynamic portion is as developed as it’s going to get. That’s why windmills all look the same.

        Solar might become more efficient an/or cheaper by the square meter in the future, but wind is now what it’s always going to be. With better electrical apparatus, you might squeeze another 10% out, but you’re not getting more than that.

        Practical storage might change the economics somewhat, but I wouldn’t put my quatloos on it. It’s got other inherent invincible problems that make it a loser today and 200 years from now.

      • And yes, power does need to be on all the time. Maybe North Korea would be more to your liking?

      • John from CA

        Yes, unless its generated at the point of use, electric power does need to be available given the current design of the grid and consumption. But, there’s no question the grid and consumption are inefficient/wasteful.

        The question is what action. Taxing the general masses to implement junk solutions is absurd. IMO, it would be logical to turn the Climate debate away from climate fortune telling and focus instead on the true cause of the problems associated with power generation and consumption. AGW is a by-product of the process and not the true cause of the problem.

      • John from CA

        Its just one of many opportunities but it makes a lot more sense than Windmill farms.

        Tankless Hot Water Heaters
        up to $300 Federal Tax Credit
        source: http://www.noritz.com/

        “Tankless water heaters tax credits exist because they are much more efficient and environmentally friendly than tank-type water heaters. There are many energy tax credits, promotions, and rebates available to support tankless technology.  Please check here regularly to see if there are any extra money saving incentives available to you.”

        Up to $500 additional local rebate in my area from the power companies beyond the Federal Tax Credit and the units appear to be manufactured in the USA.

        Personally, I’d like to see smaller units incorporated in laundry and dishwasher appliances to make it even more efficient — zero heat loss from pipes and the ability to eliminate a secondary pipe run for hot water.

      • Elegant design.
        However — conservation is nice, but surplus is better.
        Lpp.com may provide the latter within a very few years.

  40. Euphemisms

    “Man Made Global Warming”=> “Climate Change”
    “Natural Global Warming”=>”Climate Change”
    “Man Made Global Cooling”=>”Climate Change”
    “Natural Global Cooling”=>”Climate Change”
    “Natural Disasters”=>”Climate Change”
    “Man Made Disasters”=>”Climate Change”

    “ACTION”=>”Callously Increasing Cost of Living”

  41. The left leaning scientific community has used its keen intellect to conclude that we are all doomed from climate warming because that rascal mankind is filling the air with CO2. Meanwhile, hundreds of millions on the planet suffer and die for want of a basic commodity. The lethal problem lies with energy, not global warming.

    Rather than spend billions of dollars on the intellectual pursuit of what amounts to determining the number of angels-dancing-on-the-head-of-a-pin, we should be concentrating on the wise use of energy, with the operative drivers being efficiency and cost effectiveness.

    Consider this simple exercise. If energy is wisely used, greenhouse gas emissions will always be reduced. The reverse, however, is not true.

  42. It seems time should enter into the analysis. An asteroid strike will happen rather quickly. We would have possibly weeks?, days? to prepare? A flu pandemic would happen relatively quickly. Even if the CAGW crowd is right, it would still take many decades for the “catastrophe” to play out. Wouldn’t that allow for the possibility of new, effective energy sources to be discovered or developed? Wouldn’t it allow for new mitigation technologies to be discovered or developed? Wouldn’t it allow for adaptation by, for example, population movement? It seems to me time isn’t considered appropriately. (It also seems to me a carbon tax wouldn’t do squat to mitigate the “catastrophe,” even it they are right. I have to conclude they really just want our money.)

  43. First, the most recent, 30-year long, global warming rate is identical to the previous one, before mid-20th century, before widespread use of fossil fuels.
    http://bit.ly/eUXTX2

    Second, the current decadal global temperature trend is flat.
    http://bit.ly/dEFb9d

    Please, where is the evidence for use of fossil fuels causing global warming?

  44. ‘Most of the studies and debates on potential climate change have focused on the ongoing buildup of industrial greenhouse gases in the atmosphere and a gradual increase in global temperatures. But recent and rapidly advancing evidence demonstrates that Earth’s climate repeatedly has shifted dramatically and in time spans as short as a decade. And abrupt climate change may be more likely in the future.’ http://www.whoi.edu/page.do?pid=7123

    Catastrophic climate change at some point is the future seems certain rather than problematic. Equally, there seems little doubt that we are changing the energy dynamics of chaotic Earth systems in ways that add to the potential for abrupt climate change. There would seem to be other risks as well in pushing carbon dioxide to concentrations not seen for 10 to 15 million years – and going higher. Without a doubt we are changing plant physiology globally. To argue that this is good for us or – at least – not harmful seems to me to be an argument from ignorance.

    But the other side of the risk equation is cost. If the cost is minimal or there are multiple benefits there is no point in not doing these things. Reducing black carbon and tropospheric ozone, conserving and restoring ecosystems and agricultural soils, limiting population by ensuring that everyone has access to safe water, sanitation, health and education and increasing R&D into energy systems – are simply some of the ways of making cost effective changes.

    The critical global problem is increasing food and energy supplies by 3% a year for the rest of the century. Doing this while decarbonising production would seem to be an optimal solution.

    • But isn’t the coming catastrophic climate change the end of this interglacial?

      Isn’t that inevitable?

      If there is any chance Co2 will keep the earth warm enough to avoid 5 billion people starving to death don’t we have a responsibility to the children to burn as much fossil fuel as possible?

    • Chief,
      “limiting population”? Rather drastic solution :) Though that may be part of the fat tail on the mitigation side.

      • Limiting population growth through effects that have been seen in the real world. Health, development, education for women and girls especially. No great mystery or conspiracy to genocide – but if we can shave a billion off peak population it reduces the food and energy targets.

      • Much better for climate sadists to enact some brutal economy destroying carbon tax that will (among hundreds of horrible other effects) cause the price of fertilizer to go up making food even more expensive (especially after the biofuel cruelty).

        You and Robert seem to get a tingle up your legs at the prospect of destroying peoples lives just so the Chinese can pump as much coal smoke and co2 into the atmosphere as they want to …

      • You assume that if the Earth’s resources are shared by fewer people that per capita consumption would not rise. I suspect that there is no historical evidence to suport such an assumption.

      • I am assuming that food and energy production need to increase by 3% a year for the rest of the century. Did I not say that explicitly about 50 times.

        There is some other fool who cannot see past his some sort of disgusting tingle up his leg. Far too much information Sunshine – yet paradoxically not nearly enough.

        ‘But the other side of the risk equation is cost. If the cost is minimal or there are multiple benefits there is no point in not doing these things. Reducing black carbon and tropospheric ozone, conserving and restoring ecosystems and agricultural soils, limiting population by ensuring that everyone has access to safe water, sanitation, health and education and increasing R&D into energy systems – are simply some of the ways of making cost effective changes.’

        Remember – it is best to not speak and be thought foolish than to speak and remove all doubt.

      • If the cost is huge — and the net result is to just move the CO2 production from Europe or the US to China where coal is the #1 fuel — then more CO2 is produced AND the economy is ruined.

        No good deed goes unpunished — environmentalists are responsible for more CO2 being produced in China than if they had shut their mouths and let the jobs stay in Europe or North America.

        But the environmentalists prefer to do the dumb thing for the right reasons so they can feel good about themselves.

    • Nope. Decarbonizing is the little (=HUGE) sting in the tail you were working up to. Unnecessary and counterproductive.

      “2,100 ppm by 2100!” should be the world’s motto.

  45. Bad Andrew

    “Catastrophic climate change at some point is the future seems certain”

    How is this anything other than scaremongering?

    What constitutes “catastrophic”?

    To what range of dates can we narrow your “some point in the future”?

    “Seems” certain? What does that mean?

    This is a joke.

    Andrew

    Andrew

    • Yet multiple people on this thread asserted that mitigation was certain to lead to catastrophe, and you didn’t attack their certainty. Only conclusions you dislike are aggressively challenged, while dubious assertions that are “friendly” pass without comment.

      Thus the zealot practices his faith, mistakenly thinking himself “skeptical.”

      • How’s about somebody builds a spacecraft that has a 50/50 chance of making it to space and back safely. Nobody can prove that it’s not going to burn up on reentry, but nobody can prove that it will, either.

        You game?

      • We KNOW that the UK’s wind turbines failed spectacularly this winter and the only reason millions did not freeze to death is that old fossil fuel power plants still exist. The “mitigation” planned is to shut down all of the fossil fueled power plants and build more wind turbines guaranteeing a spectacular failure leading to a significant loss of life.

        “Britain’s wind farms almost ground to a halt during the coldest spells in December, it has emerged.

        As temperatures plunged below zero and demand for electricity soared, figures reveal that most of the country’s 3,000 wind turbines were virtually still, energy experts say.

        During some of the chilliest weather, they were working at less than one-hundredth of capacity, producing electricity for fewer than 30,000 homes.”

        http://www.dailymail.co.uk/news/article-1345233/Its-use-waiting-turbines-warm-snow-returns.html

        On the other you want to mitigate WHAT? WHAT has actually happened that needs mitigating?

      • sunshine –
        First an apology for mistaking your intent yesterday.
        Second – something to give you even less confidence in the wisdom of the UK plans for the future –

        http://www.telegraph.co.uk/news/uknews/8545306/Wind-farms-Britain-is-running-out-of-wind.html

        It’s something some of us knew about, but that the media hasn’t picked up on till now.

      • It’s already doing so, even at the very preliminary stages of its implementation. Staple wholesale grain and food prices have risen about 75% year-to-date; farmers are getting more for subsidized biofuel-dedicated crops than food crops. Guess which they prefer to grow.

        With full-bore mitigation, population crashes and extreme violence by those resisting the culling are easy to guarantee.

      • “population crashes and extreme violence by those resisting the culling are easy to guarantee”

        You guarantee it, huh? No “skepticism” about that prediction?

      • Nope, because human beings are observed everywhere to struggle very hard to survive when they are being arbitrarily deprived of the normal means of doing so. The revolutions recently and on-going in the ME have food pricing as a stronger driver than any political ideology, e.g. Keep your eye on China; its power and food shortages are spiking; the gubmint has even resorted to actually increasing electricity prices, much to its own chagrin and the distress of the public. (Not strongly AGW related, other than the burden of making up for crop shortfalls at high spot prices on the world markets; just bad weather luck affecting crops and hydro, etc. Plus jumping coal costs (which are a windfall for Australia, however.) )

        This is a minute pre-taste of what real energy cost jumps can achieve. Stay tuned.

    • ‘Recent research, however, suggests that there is a possibility that this gradual global warming could lead to a relatively abrupt slowing of the ocean’s thermohaline conveyor, which could lead to harsher winter weather
      conditions, sharply reduced soil moisture, and more intense winds in certain regions that currently provide a significant fraction of the world’s food production. With inadequate preparation, the result could be a significant drop in the human carrying capacity of the Earth’s environment.’

      ‘The research suggests that once temperature rises above some threshold, adverse weather conditions could develop relatively abruptly, with persistent changes in the atmospheric circulation causing drops in some regions of 5-10 degrees Fahrenheit in a single decade. Paleoclimatic evidence suggests that altered climatic patterns could last for as much as a century, as they did when the ocean conveyor collapsed 8,200 years ago, or, at the extreme, could last as long as 1,000 years as they did during the
      Younger Dryas, which began about 12,700 years ago.’ http://www.s-e-i.org/pentagon_climate_change.pdf

      At some the stage this interglacial is likely to end and the world will become a whole lot chillier – and there is some suggestion that this can happen within a short period. It seems certain to a high degree and I did think that was clear in what I was saying. It is the nature of Earth systems to change abruptly, fluctuate wildly and then settle into a new pattern. We are not very good at analysing chaotic systems. There are a couple of techniques involving an increase in autocorrelation and, a posteriori, dragon-kings. But you can’t have it both ways. You can’t say that Earth systems are chaotic – and that there is no risk from anthropogenic greenhouse gases. Well you might but it an internally inconsistent argument.

      One of the mechanisms discussed at the Woods Hole Oceanographic Institute (that I linked to) was to do with ice loss in the Arctic influencing atmospheric and ocean coupling and reducing thermohaline circulation. This potentially results in cloud and ice formation and runaway global cooling. This seems like a narrative with some merit. The system has control variables and multiple feedbacks and I am certain that we do not know enough to geoengineer the planet by burning more coal to hold off the next glacial – something that is likely to exacerbate the plant physiological changes that are evident. Ecologies are dynamically complex as well and just as uncertain.

      The actions I suggested are essentially the Copenhagen Consensus and the Millennium Development Goals but with a couple of obvious additions that enhance health, agriculture and the environment and reduce greenhouse gases in the atmosphere. And if I say ‘seems like’ a lot – it is because I don’t really know with any certainty but we can make the world and human populations a whole lot more resilient to anything that happens than it is at the moment. I suggest that you really don’t know any better either.

      • As a candidate for setting off a “wild swing”, CO2 has really lousy credentials. There are zero historical or paleo-historical precedents, to begin with. So it’s special-pleading hand-waving. The only reason it’s even on the table as a focus is that it offers such lovely leverage for “management” of producers and users of energy. Which is everyone.

  46. “Yet multiple people on this thread asserted that mitigation was certain to lead to catastrophe, and you didn’t attack their certainty. ”

    That’s because I’m a Denier, Robert. I’m not obliged to help “your side”. If you need help supporting your position, go get Steven Mosher or Dr. Curry or Al Gore or to help you, ’cause I ain’t gonna.

    Andrew

    • The results of cutting off or slashing access to affordable energy are hard to question. That’s a high-certainty prescription for mass death and uprisings. Such “catastrophes” are easy to stimulate and simulate, unlike the black swan results of mild increases in the slope of the historical temperature trajectory.

  47. Let me see if I understand this:

    Magnitude of possible catastrophic event/magnitude of uncertainty (more uncertain is a smaller number) = magnitude of required action.

    This is perfect. This relation exactly represents the thought process used by those who invariably find the risk to be ‘bigger than we thought.’ The less we know about something, the more we need to do about it. And every crisis can be ranked according to its potential impact.

    • Old rules: Ignorance is bliss.
      New rules: Ignorance is OMG Ponies!!!

      Given how much they underestimate their own ignorance, I don’t know if there’s enough adrenaline to go around.

  48. > The Precautionary Principle in the absence of quantified risks is equivalent to Pascal’s Wager.

    I’d like to see a formal proof of that. As far as I can tell, this only is the usual libertarian Internet claptrap.

    • Hampton Hill

      Simple stuff.

      There might be a bogeyman. If there is, it costs me little to believe. But it might cost me alot of I don’t. If there isn’t, I lose little by believing anyway.

      The difference between the bogeyman, god and climate change is that the cost of believing in climate change is extremely high as well.

      But the parallels betwen that belief and religious belief are striking. Just substitute ‘evil’ for CO2 and ‘The Fall of Man’ for the Industrial Revolution and you have just about wrapped up The Book of Genesis.

      Perhasp few believers truly consider themselves to be The Saviour, come to cleanse us form all our sins. But plenty have strong John the Baptist tendencies….warning of the perils to come unless we change our wicked ways…..Intoxicating stuff!

      • > There might be a bogeyman. If there is, it costs me little to believe. But it might cost me alot of I don’t. If there isn’t, I lose little by believing anyway.

        I see no reason why it cost you not to believe in the bogeyman.

        > The difference between the bogeyman, god and climate change is that the cost of believing in climate change is extremely high as well.

        Exactly.

        > But the parallels betwen that belief and religious belief are striking. Just substitute ‘evil’ for CO2 and ‘The Fall of Man’ for the Industrial Revolution and you have just about wrapped up The Book of Genesis.

        This explains the basis of that libertarian claptrap.

        ***

        I am afraid you just proved the opposite of what you were trying to do. There is no **equivalence** between the PP and Pascal’s Wager. The rhetorical effect is so intoxicating as to have become a libertarian claptrap.

  49. Been there done that like in 1999.
    ————————————————-
    4) It is clear enough that a change of 20 C would be cataclysmic, whether that change is a warming or a cooling. It is also clear enough that a change of 0.2 C is of little consequence, and may be on net beneficial. There is no reason to believe that this function is linear. The contemplated changes (~2 C) are large enough that we can not have total confidence that the impacts will not be catastrophic.

    5) There is no plausible argument that any particular climate change will have a beneficial impact comparable to the worst plausible case negative impact.

    6) The risk-weighted cost of unrestrained anthropogenic perturbation must therefore be dominated by the fact that the plausible worst cases have more cost than the plausible best cases have benefit.
    ————————————————–

  50. HOLDING ALARMISTS TO ACCOUNT IN AUSTRALIA

    http://bit.ly/mwHONb

  51. Alan Sutherland

    Imagine we are in the middle of the little ice age. It is uncertain whether temperatures will increase or get colder. There is also the hypothesis that the climate does not change. So there are three possibilities each with their own likelihood, two with ranges of severity. Which, at that time, should we have chosen to use the precautionary principle for? If one had a greater degree of uncertainty, is that the one we should choose?

    Could we have done anything about it anyway?

    Now we have recovered from the little ice age, we can in hindsight say that it warmed a little. The seas discharged a little more CO2. There was actually no problem.

    So in today’s world, what are the new set of possibilities? It is uncertain that temperatures will decrease or perhaps get a little warmer. There remains the hypothesis that climate does not change, but a rational person would say that it did change from the little ice age, and also from the medieval warm period. What should we guard against? And can we do anything about it anyway?

    In 2100, we will have found out there was no problem. No, that is not right. In 2020 we will have found out there is no problem.

    These are intellectual games.

    Alan

  52. Judy – to respond to your original contrast of A1 and A2:

    I think there is much less difference in the two arguments than meets the eye. In the Weitzman framework, if one strips out the fancy mathematics, what is meant by “increasing uncertainty” is still “increasing the likelihood attributed to catastrophic scenarios” (it is a convention that increasing the spread in the probability distribution of some scalar – in this case, some proxy for “harm” – is called “increasing uncertainty”). In your A2, what you call “decreasing uncertainty in the likelihood of catastrophic scenarios” also implies “increasing the likelihood” attributed to such catastrophic scenarios. (Note that I’m not clear how one expresses this kind of “increased likelihood” in possibilistic terms).

    In both cases, decision-making requires us to assess how much weight to give to the catastrophic outcomes, given the evidence. For decision-making that uses probabilities, you still have to decide what PDF to use. Similiarly, if possibility theory admits that evidence can make an event “more likely”, then the requirement to be able to rank scenario classes as more or less likely than each other leads to something that looks a lot like probability in the end, and the debates about whether a risk justifies action should depend on how one evaluates the evidence, and one’s aversion to risk, rather than the terminology used to quantify risk (or not).

    I am still thinking about other aspects of your post, eg, the threshold of plausibility for precautionary arguments.

    –Paul

  53. Jack Hughes

    Climate science chapter XVII

    Ready, fire, aim.

    • Jack Hughes

      Climate science chapter XVIII

      Ready, fire, aim, OUCH!

      (Knew I should have worn my Kevlar shoes).

  54. Judith, You suggested I wait for this thread to make my point. I am not sure that this is the right thread, but here goes.

    As I see things, people who know far more about this than I do, are finding more and more reasons why the the so-called science, the so-called physics, which claims to show that CAGW is happening, is just plain wrong. In other words, it is becoming more and more certain that there is no physics to support CAGW.

    If this is true, then the case for taking no action to reduce the emissions of CO2 is becoming quite clearly the way to go. What I cannot judge is whether you feel that the evidence we are getting on a routine basis, is having any effect on the way you look at CAGW. Is anything changing your mind?

    • Joe Lalonde

      Jim,

      The problem is that uncertainty is only being addressed in climate science.
      As far as the rest of the sciences are concerned, they are 100% accurate right from the 300 year old theories.
      Considering there has been great technological advances, yet the science is not reviewed that they may be incorrect.
      So we have a vast amount of scientists shoveling garbage science as this is the careers that they are the experts in with a vast amount of “Peer-reviewed” backing.

      Any person who does not conform to the current science individuality areas is ignored no matter how good the measurements are or what technology was developed to show the mistakes.
      The complexity of planetary science is mind boggling complex in the interaction to understand how motion and mass and gases interact just on the planetary level.

      • Joe Lalonde writes “Any person who does not conform to the current science individuality areas is ignored no matter how good the measurements are or what technology was developed to show the mistakes.”

        I agree, and I hope you agree with me when I say that this is wrong. If the data shows that the science is wrong, then all true scientists should shout this from the rooftops. My voice is a very, very minor one indeed. But that of Dr. Judith Curry is a very loud one. That is why I am trying to find out whether all the data etc. that has been published recently showing that the physics behind CAGW is just plain wrong, has changed her thinking. The fact that she will not address this subject is, in and of itself, interesting.

      • And if she doesn’t agree to share your hallucination, will you:

        a) Decide that since a scientist you respect doesn’t agree with your belief that the principles of radiative physics have been repealed, maybe you, the non-scientist, have the story wrong.

        b) Judith Curry is in on it too! The conspiracy is everywhere!

      • Robert writes “And if she doesn’t agree to share your hallucination, will you:”

        I have no idea where this comes from. I am simply trying to find out whether the latest information we are getting about CAGW is causing Judith to change her mind. I could easily understand that it has caused her to change her mind; and, by the same token, I could just as easily understand that she has not changed her mind. I am trying to find out whether she feels that the latest information we are getting, is important or not. It would also be nice to find out, whatever she thinks, why she feels the way she does.

      • What latest information? GIRMA’s graphs?

      • JCH writes “What latest information? GIRMA’s graphs?”

        The latest information I referred to originally was Roy Spencer’s paper on his blog, that claimed to show that there was climate data to support Henrik Svensmark’s theory of a connection between GCRs and clouds. This convinced Roy, that Svensmark might be correct. However, there is all sorts of data that we get on a daily, weekly, monthly, and yearly basis. I would leave it up to Judith to select which data or other information she found to be relevant.

      • http://bit.ly/jwCHiR

        More about the Pacific Decadal Oscillation

        Q. Who named the PDO and can you give me more indepth information?

        A. The term PDO was coined in about 1996 by Steven Hare at the University of Washington. He, along with colleagues Nathan Mantua, Yuan Zhang, Robert Francis and Mike Wallace discovered the pattern as part of work on fish population fluctuations. They have online papers that provide excellent information.

        Q. How does this affect climate?

        A. The change in location of the cold and warm water masses alters the path of the jet stream. Put simply, the jet stream in the northern hemisphere delivers storms across the United States. The PDO phase that we appear to have entered will act to steer the jet stream further north over the Western United States.

        Q. How does that affect the weather and climate in my area?

        A. See the NOAA Climate Prediction Center for weather and climate seasonal outlooks.


        Q. If we are entering a different phase, how long will it last?

        A. We don’t know, but based on past evidence, as shown by scientists Steven Hare and colleagues at the University of Washington, it is likely to last 20-30 years.

        Q. What about El Niño and La Niña?

        A. These will still continue, they are a pattern that can be thought of as lying on top of the large scale temperature distribution determined by the Pacific Decadal Oscillation.

        Q. What is the connection between ocean height as observed by TOPEX/Poseidon and ocean temperature?

        A. When the surface layer of the ocean is warmed it expands and hence results in a higher surface.

        Q. Will we have a drought in southern California?

        A. If the Pacific Decadal Oscillation has switched we are likely to have 20-30 years with lower rainfall that we have had since the late ’70’s. We will still have winter rains, but the number of really wet years is likely to decrease.

        Q. I have heard that some scientists do not agree that the Pacific Decadal Oscillation has switched, what does this mean?

        A. Some scientists say it’s too soon to tell whether the temperature shift is part of a long-term cycle. Scientists will be studying many types of data and watching to see how temperature patterns across the Pacific ocean evolve over time.

      • Hi Girma,

        The PDO and the east Asian jet stream are related but should not be seen in isolation from ENSO.

        ‘The Pacific/ North American teleconnection pattern (PNA) is one of the most prominent modes of low-frequency variability in the Northern Hemisphere extratropics. The positive phase of the PNA pattern features above-average heights in the vicinity of Hawaii and over the intermountain region of North America, and below-average heights located south of the Aleutian Islands and over the southeastern United States. The PNA pattern is associated with strong fluctuations in the strength and location of the East Asian jet stream. The positive phase is associated with an enhanced East Asian jet stream and with an eastward shift in the jet exit region toward the western United States. The negative phase is associated with a westward retraction of that jet stream toward eastern Asia, blocking activity over the high latitudes of the North pacific, and a strong split-flow configuration over the central North Pacific.

        The positive phase of the PNA pattern is associated with above-average temperatures over western Canada and the extreme western United States, and below-average temperatures across the south-central and southeastern U.S. The PNA tends to have little impact on surface temperature variability over North America during summer. The associated precipitation anomalies include above-average totals in the Gulf of Alaska extending into the Pacific Northwestern United States, and below-average totals over the upper Midwestern United States.

        Although the PNA pattern is a natural internal mode of climate variability, it is also strongly influenced by the El Niño/ Southern Oscillation (ENSO) phenomenon. The positive phase of the PNA pattern tends to be associated with Pacific warm episodes (El Niño), and the negative phase tends to be associated with Pacific cold episodes (La Niña).’

        The decadal effects are caused by changes in upwelling of cold and nutrient rich water in the north and south eastern Pacific are very well demonstrated – with important feedbacks on winds and cloud.

        Burgmann et al (2008) discuss this in terms of a Pacific Decadal Variation (PDV) – and describe the sea surface temperature signature as ‘characterized by a broad triangular pattern in the tropical Pacific surrounded by opposite anomalies in the midlatitudes of the central and western Pacific Basin.’ Their study uses a variety of data sources to examine decadal variability of surface winds, water vapour (WV), outgoing longwave radiation (OLR) and clouds. They conclude that the ‘most recent climate shift, which occurred in the 1990s during a period of continuous satellite coverage, is characterized by a ‘La Niña’ SST pattern with significant signals in the central equatorial Pacific and also in the northeastern subtropics.

        Burgman, R. J., Clement, A. C., Mitas, C. M. , Chen, J. and Esslinger, K. (2008), Evidence for atmospheric variability over the Pacific on decadal timescales GEOPHYSICAL RESEARCH LETTERS, VOL. 35, L01704, doi:10.1029/2007GL031830, 2008

        Verdon and Franks (2006) used ‘proxy climate records derived from paleoclimate data to investigate the long-term behaviour of the PDO and ENSO. During the past 400 years, climate shifts associated with changes in the PDO are shown to have occurred with a similar frequency to those documented in the 20th Century. Importantly, phase changes in the PDO have a propensity to coincide with changes in the relative frequency of ENSO events, where the positive phase of the PDO is associated with an enhanced frequency of El Niño events, while the negative phase is shown to be more favourable for the development of La Niña events.’

        Verdon, D. and Franks, S. (2006), Long-term behaviour of ENSO: Interactions with the PDO over the past 400 years inferred from paleoclimate records, Geophysical Research Letters 33: 10.1029/2005GL025052.

        ‘During the 1997–1998 El Niño, observations indicate that the SST increase in the eastern tropical Pacific enhances the atmospheric convection, which shifts the upward motion to further south and breaks down low stratiform clouds, leading to a decrease in low cloud amount in this region. Taking into account the obscuring effects of high cloud, it was found that thick low clouds decreased by more than 20% in the eastern tropical Pacific… ‘

        Zhu, P., Hack, J., Keilh, J and Zhu, P, Bretherton, C. 2007, Climate sensitivity of tropical and subtropical marine low cloud amount to ENSO and global warming due to doubled CO2 – JGR, VOL. 112, 2007

        It is this change in cloud that dominates ENSO modulated global energy dynamics – everything else merely redistributes energy between atmosphere and oceans. A 20% change in cloud cover in the tropical eastern Pacific is very significant.

        The nutrient rich upwelling enhances biological productivity – remember that this is a hydrological and biological pattern primarily. More salmon in US streams, increases in seal pup weight in Monterey Bay and phytoplankton abundances not seen since the 1970’s in the central Pacific show convincingly that the system shifted after 1998.

      • Oh – I forgot to say that this makes absolutely no difference to the risks of anthropogenic greenhouse gas emissions in a dynamically complex system.

        We are all part of the way in understanding these most interesting complexities. For instance, what are the control variables? What drives upwelling in the eastern pacific – see this http://www.osdpd.noaa.gov/data/sst/anomaly/2011/anomnight.5.30.2011.gif – which then moves across the Pacific in the typical V pattern of a cold PDO?

        I would look to cold currents from low latitudes cooling the sea surface and allowing deep ocean currents to push through the thermocline. This would be a process driven by ozone warming and cooling from solar UV drift feeding into the polar fronts.

        A most interesting speculation.

        What we have is an absolute inability to predict what could be quite significant effects and should at least put into low cost strategies.

      • And if she doesn’t “share your hallucination”?

  55. Joe Lalonde

    Judith,

    I really don’t mind if any of my comments are deleted.
    This at least shows you’ve read it and they always leave more lingering doubt that science may have been incorrect on assumptions that not all avenues have been explored.

  56. Judith,

    I think you give this notion far more weight than it deserves (that uncertainty strengthens the case to act). As has been pointed out, we are nowhere near able to quantify, or speak knowledgably about the tails.

    Rather, this is a simple appeal to ignorance. I have an hypothesis that disaster will strike, until that possiblity can be eliminated, we must act; and the less certain we are, the more unable we are to eliminate that possiblity.

    A smple appeal to ignorance.

  57. I do like the difference between risk and uncertainty as you describe. It seems to me that CAGW proponents want to conjure risk from thin air by creating an hypothesis (catastrophic warming) then appealing to ignorance to produce risk.

    In your lexicon, there is an hypothesis about which we are uncertain and we can talk of uncertainty and acknowledge that we can say nothing about risk. At least that’s how I understand what you wrote, and I like it.

  58. MacViolinist

    I’m inclined to approach this differently. I’m inclined to think about certainties and risks.

    For example, it is certain that the climate has changed in catastrophic ways in the past. It is certain that it will change in catastrophic ways in the future.

    What are the risks of sitting around and pointing fingers at ourselves and saying, “Bad boy. No carbon for you.”

    What are the risks of preparing for a major shift in global climate (warming or cooling)?

    To me, the Mississipi river is an instructive example. It’s a powerful force of nature that ultimately wants to go where it’s forces demand. We’ve been fighting it’s known tendency to change since the 50s or so. Eventually, The river will win. It will overcome our levies and change course. It’s inevitable.

    In spite of billions of dollars spent to contain a change that wasn’t clearly understood or defined at the time the levies were built, we are going to lose to natural variation.

    There is uncertainty about where the river will go. There was risk involved in not acting. But pretending that we could have a shot at stopping the change has upped the ante several hundred million times.

    When the Mighty Mississippi changes course, the damage will be devastating because we have assumed that our effect on it was relevant.

    I think discussions about climate ought to take a lesson from this. Instead of arguing about fat tails, uncertainty, and risk–which are just constructs and excuses to argue, after all–we should do the opposite. Let’s look at what is certain and prepare for it.

    Another way of saying that is this: what is the probability that the climate will not change significantly in the next x years? The larger x gets, the closer to 100% the probability of change becomes and the smaller any uncertainty model becomes.

    What’s the risk of ignoring climate variability and not preparing for it? The larger x gets, the larger the risk becomes. Because we can be certain that no matter how much carbon we produce or don’t, the climate will change. The more we think we can affect it on a global scale, the more we will continue to create massive vulnerabilities in sensitive areas.

    My point is not to shut down a discussion of how to reduce various pollutants. I think that it’s basic common sense that we not pump a bunch of toxins into the atmosphere.

    But to me, that’s a separate discussion. The discussion at hand boils down to this: why debate models of uncertaintay when we have certain information at our disposal? Why have the conversations about risks that accompany these uncertainty models, when we can have conversations about the risks of known events?

    ~MacV

    • MacV

      My point is not to shut down a discussion of how to reduce various pollutants. I think that it’s basic common sense that we not pump a bunch of toxins into the atmosphere.

      But to me, that’s a separate discussion. The discussion at hand boils down to this: why debate models of uncertaintay when we have certain information at our disposal? Why have the conversations about risks that accompany these uncertainty models, when we can have conversations about the risks of known events?

      The obvious answer is because, if you take the uncertain risks of rapidly accellerating CO2-concentrations and warming seriously, actions follow that are very different than those you would take based only on resilience arguments or reducing air toxins. There are multiple time-scales at work, and if even median mainstream projections are correct, CO2 mitigation has a kind of urgency that (say) preparing for the next ice age, or even reducing mercury emissions, does not.

      –Paul

    • MacV: The answer is that once the time x becomes large there is nothing to do at this time to prepare. Say it is certain that we will have another ice age in 10,000 years. So what?

      As an aside I must point out that after the 1936 flood we embarked on a systematic flood control program to keep it from happening again. But that program was killed by the enviros in 1968 with NEPA. Most of the dams were never built, so here we are again. This flood did not have to happen. Here was a case where we actually did plan to prevent the disaster, but then changed our minds.

    • William Norton

      Good comment.
      Another interesting case to study would be the beach and channel stabilization efforts on the Atlantic and Gulf coast. Many scientists say we are wasting out time trying to “rebuild” erroding beaches and keep manmade channels open. The people who use those beaches, channels, and harbors beg to differ.

      At present, the users (who are the vast majority of our citizenry) have smacked down the scientists and beach replenishment and channel dredging continues. However, the scientists are a clever lot, and they have many ways to thwart the will of the people, enter the Environmental Impact Statement.

  59. Paul Vaughan

    Flowery protracted abstract philosophy is crushed by simple observation:

    1) http://tallbloke.files.wordpress.com/2011/05/roe-milankovitch.jpg
    2) http://wattsupwiththat.files.wordpress.com/2010/08/vaughn_lod_amo_sc.png
    3) http://wattsupwiththat.files.wordpress.com/2010/09/scl_northpacificsst.png
    4) http://wattsupwiththat.files.wordpress.com/2010/09/scl_0-90n.png
    5) http://wattsupwiththat.files.wordpress.com/2010/12/vaughn_lod_fig1a.png
    6) http://wattsupwiththat.files.wordpress.com/2010/12/vaughn_lod_fig1b.png
    …where SCL’ = rate of change of solar cycle length = solar cycle deceleration.

    What the mainstream appears to have overlooked is very simple:

    Solar max interrupts the semi-annual heat pump. The frequency of pump outages controls multidecadal oscillations (via hydrology). Interannual spatiotemporal chaos makes this difficult or impossible to see using linear methods.

    To develop conceptual understanding:

    a) Exposition of p. 433 [pdf p.10]:

    Sidorenkov, N.S. (2005). Physics of the Earth’s rotation instabilities. Astronomical and Astrophysical Transactions 24(5), 425-439.
    http://images.astronet.ru/pubd/2008/09/28/0001230882/425-439.pdf

    b) Figures 8, 11, 13, & 15:

    Leroux, Marcel (1993). The Mobile Polar High: a new concept explaining present mechanisms of meridional air-mass and energy exchanges and global propagation of palaeoclimatic changes. Global and Planetary Change 7, 69-93.
    http://ddata.over-blog.com/xxxyyy/2/32/25/79/Leroux-Global-and-Planetary-Change-1993.pdf

    c) everything written by Tomas Milanovic at Climate Etc.

  60. The cargocult cliche has been done to death, but it is relevant to remember you’re most likely to fool yourself. We must be skeptical of our own ability to keep our bias removed from the 1. evaluation of complex climate system models, and 2. abstract economic thought experiments, because the subjectivity that is inherent in this kind of discourse.

    This thread (and many others) is full of intelligent people that can and do come down on both sides of almost every argument. How is this going to change?

    Actions of ommission/commission requires coming down on one side, so there’s going to plenty of people hollering that you’re wrong, and plenty of risk that you actually took the wrong action. Many know-nothings on one side will in some way will prove wiser than experts/professionals on the other side.

    My take on the uncertainty issue is that the difference in +1C (mild) +3C(climate model) and +10C (outlier) scenarios are really just different people’s intuition, all with valid scientific arguments that rationalize them. This strikes me as pretty similiar to the state of knowledge faced by business leaders. Although there is always a Paul Krugman forecasting doom, and some guy with a newsletter predicting DJI at 20,000, yet we as an society/economy are able to make choices and actions in the face of this uncertainty. Two elements that seem to help is 1. accountability – decision makers live and die (not litterally) by the outcomes, which forces them to confront any biases that color their thinking. 2. multiple camps are available so not everyone is forced to take action based on what they beleive to be the wrong theory.

    I know climate change poses some different problems than my capital markets metaphor, ie tragedy of the commons, etc. But the humility to not force someone to accept your best-guess or pdf of economic dammage seem is a requisite to policy that can be democratically implemented.

  61. One factor is being left out of the extreme scenarios. They do not happen like The Day After Tomorrow, instantaneously. Suppose the extreme scenarios happen, is it reversible as the warming is occurring? For that matter, is it possible to tell what scenario you are in as it is happening, or is the warming accelerating? For example if the next 20 years shows .2C of warming, does that give us any information about which scenarios are more likely?
    Tamino told me that the models show accelerating warming, so even the low amount of warming since 1998 doesn’t invalidate any extreme scenarios.

  62. marcopanama

    In more ancient times, the Mayan priests, when faced with the uncertainties of climate change, supposedly threw more virgins into the volcano to appease the climate gods. Are we not doing the same thing now? There is absolutely no way of knowing in advance that any attempt to mitigate or not mitigate will have either a positive or negative effect in the long run.

    Chief Hydrologist suggests that we are in danger of triggering a tipping point into the next Ice Age by adding CO2. Others think that the only thing holding off that tipping point is our continued land use changes and CO2 production, in which case we presumably need to emit exponentially more CO2 just to hold off the inevitable freezerino.

    Any action (or inaction for that matter) invokes the Law of Unintended Consequences. From our experience in the Internet world, wow, isn’t it cool that we have all these location-based services, credit cards usable worldwide, etc. But wait – what about our Personal Privacy? As Scott McNealy, founder of Sun Microsystems famously said, “You have no privacy – get over it.” There is no going back to that supposedly simpler time. We all have to adapt.

    In the same way, human evolution, which includes land use and CO2 emission, is inextricably intertwined with the natural climatic evolution and all of its chaotic variability. There is no going back to some climatic “simpler time” minus the effects of human activity. Our only rational course is, as the docs say, “Watchful waiting,” studying the systems and learning more and more about how they operate and adapting to what is actually happening. Attempts to predict the future and change it are as futile as believing in the Rapture and killing your children in preparation.

    This is a great discussion – thanks to all who have contributed such excellent insight.

    • We have had the virgins and volcano discussion before – it was politically incorrect but the majority were for keeping virgins and throwing weird uncles and mothers in law into the volcano.

      Your argument is that we can’t pick the future at all (with which I agree) – so we should just keep increasing carbon dioxide (already at levels not seen in 10 to 15 millions years) relentlessly higher?

      • Chief –
        so we should just keep increasing carbon dioxide (already at levels not seen in 10 to 15 millions years) relentlessly higher?

        Given the following, I’m not sure “we” (the developed nations) have any choice if we’re to survive economically. The developing nations are NOT going to voluntarily stop emissions and revert to total poverty. Nor do we have the power to force them to do so. Or, in my case, the desire.

        http://www.guardian.co.uk/environment/2011/may/29/carbon-emissions-nuclearpower

        And if we don’t survive economically, then “we” won’t survive the crash if/when it does come.

        Stacked binary sets given the inevitability of continually increasing CO2 –

        1. Climate will crash – or not. (realizing, of course, that the coming ice age is …..still coming – sooner or later)

        2. If no climate crash – the developed nations will survive – or not. (realizing that the developed nations will self destruct economically, among other ways, if the alarmists have their way – ala present UK intentions)

        3. If climate crashes – it will go hot – or cold. (realizing that either is survivable IF sufficient power is available – meaning that we haven’t backed ourselves into a non-survivable corner by depending on power sources that won’t work under the prevailing conditions. Note that windmills don’t work well with no wind, for example. )

        Those are the broad choices as I see them at present. Lots more to be said on the subject – but not right now.

      • G’day Jim,

        It is a matter of emphasis. Simply thinking about industrial emissions of greenhouse gases is not all that useful. They are likely to increase as you say until the technology is such that other sources of energy are cheap and plentiful. I expect that might be Lerner fusion – a small decrease in plasmiod radius should see fusion of hydrogen and boron.
        That would be a game changer. Or else 4th generation nuclear – for which there is 40 years of prototypes and several operating facilities.
        A game changer enough in many parts of the world.

        But equally there are things that could be done about black and tropospheric ozone, population, agriculture and ecosystems – all of those things I mentioned above that would have significant effects in limiting the multiple radiative forcings from anthropogenic greenhouse emissions. There is in reality no great urgency to change the way energy is produced. We can the reduce the effects of industrialisation on the atmosphere by 50% much more quickly by addressing these other issues first and realise as well other humanitarian and ecological benefits.

        In economics it is not us or them – the global capitalist system has much more resilience if there are multiple loci of economic strength around the planet. I rather agree with you that developing – and most developed – nations are not going to chose expensive over cheap energy – and I would encourage them in that from the sidelines. A lot cheaper in the long run to support peoples democratic urges, champion free trade and model good corporate governance.

        The tax in Britain is one thing. They need to go to a higher proportion of nuclear energy and need to supply a sufficient return to investors. In Australia, a $30 tax is the fruit of a Labor and Greens alliance, is not nearly enough to result in energy substitution and is simply going to be churned between producers, government and taxpayers. A waste of time. I will be a little hard done by – but I’ve been offered a company car including fuel and servicing amongst other things. See if I give a rat’s arse.

        There is no simple dichotomy, no black and white, no hot and cold. If I mention something people assume it is a prediction rather than simply an unquantified entry in a probability distribution function. But globally, we are all better off if we go down certain paths rather than others. Indeed multiple paths and multiple objectives aimed at creating a brighter future for all of us.

      • The bottleneck right now is getting the Decarbonization Juggernaut to acknowledge and properly take on board the science which disputes and (IMO) even disproves the importance of CO2 increases in any plausible (and even a big chunk of implausible) magnitude. The only hard data that stands up to real world replication/falsification testing is agricultural productivity increases.

        So the problem is a concocted one; not real. The solutions offered are not on-point, and the pronouncements of their promulgators give excellent cause to believe that their goals are not climate-rescue at all, but the same-old same-old: “Power Over The People”.

      • G’day Brian,

        I think that most warming between 1976 and 1998 – the only period of surface warming in the last 50 years is dominated by changes in the Pacific. Most warming occurred at the transition points in 1976/1977 and 1998/1999. We know clouds are involved from surface observations and from CERES. The ISCCP-FD and ERBE data show cloud changes dominating over any possible change in radiative forcing caused by greenhouse gases. The clincher is that the planet hasn’t warmed for more than a decade – it was a little bit warmer mid decade and a little bit cooler at either end – again due to ENSO in particular. As the peer reviewed science keeps saying – this is likely to persist for another decade at least.

        The question about productivity is important. Plants are more commonly limited by phosphorus or nitrogen in the environment than carbon. Where nutrients are artificially supplied – extra carbon might stimulate growth. In the wild there is a different dynamic. We know that plants control water loss through the stomata that exchange oxygen and carbon dioxide. Where concentrations of carbon in the atmosphere are elevated – the number and size of stomata decrease and water is conserved. Thus significant changes in hydrology and terrestrial plant physiology. We know also that small changes in conditions in water change ecological assemblages significantly in the single celled base of global food chains.

        Ecologies and populations – and indeed climate itself are chaotic. That is – there are control variables and multiple feedbacks. These systems are dynamically complex and have specific properties. Fluctuations are damped – they tend to settle down into a particular state until the pressure from relatively small changes in control variables results in instability in the system as a whole which fluctuates wildly before settling into a different state entirely. This can be seen in the Pacific – a system with control variables and multiple feedbacks – climate shifts. Extreme changes between warm and cool oceans in 1976/1977 and 1998/1999 – settling into a period of more frequent and intense La Nina (and cooler global surface temperatures) to 1976 and more frequent and intense El Nino (and warmer surface temperatures) to 1998.

        http://www.esrl.noaa.gov/psd/enso/mei/

        This is a whole different way of understanding Earth systems and leads to a whole different view of uncertainty and risk. The outcomes in dynamically complex systems – for either ecologies and climate – is not knowable. The mathematical approaches to complex systems is essentially limited to developing heuristic algorithms for what are variously known as noisy bifurcation, dragon-kings, catastrophes (in the sense of Rene Thom) and tipping points.

        If we assume that the solution space encompasses all of the historical permutations of climate and ecologies – many of these states would be a catastrophe in the common sense of the word. And by the nature of the beast – they can happen within a decade.

        We are in an unhappy place. Simply because most of what has been said in wrong and a cloak for social democrat values – doesn’t mean that the converse is necessarily true. Indeed, that we have limited and conflicting data, the theories are incomplete and the models uncertain.

        But that there are still things that can and should be done to make the world richer and more resilient and to reduce emissions at the same time. You should not confuse me a social democrat.

      • At the end of a winding road, you still come back to “reduce emissions”. Given that said (CO2) emissions are much more certain to benefit food supplies than they are to influence climate and/or temperatures, reduction seems like a perverse and foolish option.

  63. For the last year, CAGW proponents have been whining that there should be no C in CAGW because they never claimed catastrophes were in the offing. Yet the whole concept of the precautionary principle is that the risk of catastrophic damage justifies action the more uncertain that risk is.

    Yet another example that you cannot be a progressive without embracing your inner cognitive dissonant.

  64. The April UAH anomaly was plus 0.12 degrees C – and as I keep saying the month to month variations in global surface temperature are ENSO for the most part – and marches to a different drum entirely.

    Conditions are still very cool in central Pacific.
    http://www.osdpd.noaa.gov/data/sst/anomaly/2011/anomnight.5.26.2011.gif

    The SOI remains positive.

    http://stateoftheocean.osmc.noaa.gov/atm/soi.php

    LA Nina is hanging on in the SH autumn.

    http://stateoftheocean.osmc.noaa.gov/all/

    It will weaken further in the SH winter, as it does, and seems likely to intensify again towards the summer.

    The typical pattern of a cool phase of the Pacific decadal oscillation is for 20 to 40 years of more intense and more frequent La Nina.

    Pick the warm and cool phases here – http://www.esrl.noaa.gov/psd/enso/mei/

    Hint – there are 3 shifts and these tend to start with extreme and abrupt state fluctuations.

    As keeps emerging in peer reviewed literature – the likelihood is for temperatures to decline over another decade or 3. It makes no difference at all.

    David above argues against preparing for an ice age in 10,000 years. Putting a number on these things is not even nearly theoretically possible. David indulges here – as many do – in the informal logical fallacy of argumentum ad ignorantum. An argument from an extreme ignorance. You tell each other stories with a great deal of hubris – from both sides of the climate wars – in a superficially scientific idiom. It is an entirely laughable conceit.

    Things will warm or cool past the next climate shift in a decade or 3? I will give you even money on cooling – but the changes (natural or anthropogenic) we know will be abrupt and nonlinear.

    So the question comes back to the sort of actions the world can take to reduce our emissions at the same time as making global economics more resilient. I have suggested several ways – and versions are quietly taking shape all over the planet.

    I suggest that both sides of the climate wars have lost the battle along with the plot. In critical ways this seems to be dengenerating into fairy stories. ‘In the same way, human evolution, which includes land use and CO2 emission, is inextricably intertwined with the natural climatic evolution and all of its chaotic variability. There is no going back to some climatic “simpler time” minus the effects of human activity.’ We need to keep emitting industrial quantities of greenhouse gases because we can’t the predict the chaotic evolution of climate? Can people please think before they blog or is this asking too much.

  65. marcopanama

    @ Chief

    “We need to keep emitting industrial quantities of greenhouse gases because we can’t the predict the chaotic evolution of climate? Can people please think before they blog or is this asking too much.”

    Oh please, don’t put words in my mouth. I made no statement about what we should or should not do. Watchful waiting and adaptation do not imply doing nothing. In fact, you and I are in violent agreement about both the unpredictability of the future and the desirability of shifting to non-fossil fuels for a variety of reasons. What I am not in favor of is dismantling our civilization based on a presumption of what the distant climate future might hold, when we don’t understand totally the natural “forcings” that are driving it. Lerner fusion? Bring it on. I completely believe that we will find a new large scale energy technology long before the CO2 “problem” sends us to our doom. In the meantime, we have to live with the land use and CO2 forcings that we have already created and that will persist for some time into the future, which may or may not be significant and may be positive or negative.

    The plot as such looks to me like an interesting scientific question (influence of CO2) coincided with a period of natural warming to create a political jihad that, like Communism before it, renounces market and natural forces in favor of central planning and autocratic control, to in some way save us from ourselves even if we have to destroy civilization to do it. I say, put our resources into developing real, practical, cost-effective alternative energy sources, not into political control by taxation and legislation.

    • “dismantling our civilization”

      Only if your civilization was founded and thrives exclusively on offshore oil rigs.

      My civilization is a little more robust.

      • You don’t use oil or consume any products or services that use oil?

        Wow. How are you accessing the Internet … carrier pigeon?

      • Robert,

        Did you know today is Memorial Day? Take a breath and a moment to remember those who have gone before you, whatever strange country you seem to be living in.

        Andrew

    • I am not sure it is necessarily a distant future. Climate shifts have been occurring every 20 to 40 years. We have been calling them oscillations – and I suppose they are of a sort. Bistable states although non-Gaussian and non-stationary. It goes beyond fat tails of a power distribution into extreme states that can’t be predicted at all.

      But there are ways forward that don’t involve global co-operation in setting a carbon price. They have lost this argument – even in Australia although still trying with government support. Even if they succeed – the government will lose in the next election and the whole thing be dismantled.

      I think there is a risk of practically anything the world has ever seen – and some of these things can happen in a decade or less. In a sense – the scenarios for either biology or climate in a dynamically complex system are a whole lot worse than anything the global warmists ever dreamt of.

  66. Climate Etc., Uncertainty, risk and (in)action, 5/28/11

    Weitzman On modeling and interpreting the economics of catastrophic climate change says,

    [I]t is nevertheless undeniable that, at least in principle, fat-tailed CBA [Cost Benefit Analysis] can turn conventional thin-tail-based climate-change policy advice on its head. This paper shows that it is quite possible, and even numerically plausible, that the answers to the big policy question of what to do about climate change stand or fall to a large extent on the issue of how the high-temperature damages and tail probabilities are conceptualized and modeled. By implication, the policy advice coming out of conventional thin-tailed CBAs of climate change must be treated with skepticism until this low-probability, high-impact aspect is addressed seriously and included empirically in a true fat-tailed CBA. Weitzman, ML, On modeling and interpreting the economics of catastrophic climate change, Review of Economics and Statistics 91(1): 1-19, Feb. 2009, p. 2.

    This is a most pregnant, honest paragraph. He says we can conceptualize departures from realistic probability densities that will cause our formal decision process to turn out any way we want. The math, at least, won’t blow up on us. Weitzman also tells us here that the standard decision process, based on climate models and realistic probabilities, is falling jelly-side-down.

    Note the arrogance in the presumption that policymakers are intellectually vulnerable to such manipulation. And note the ethical misconduct suborned from economists and climatologists that goes beyond that already committed in AGW.

    And note the political implication underlying the notion that nations even have climate policies. To a libertarian, an advanced society would not have a climate policy. Most countries today don’t’. Climate policy is not a goal of Marxism/socialism, but rather is a propaganda means to the end game when self-rule is over and the government controls all energy use.

    Perhaps in the end the climate-change economist can help most by not presenting a cost-benefit estimate for what is inherently a fat-tailed situation with potentially unlimited downside exposure as if it is accurate and objective—and perhaps not even presenting the analysis as if it is an approximation to something that is accurate and objective—but instead by stressing somewhat more openly the fact that such an estimate might conceivably be arbitrarily inaccurate depending upon what is subjectively assumed about the high-temperature damages function along with assumptions about the fatness of the tails and/or where they have been cut off. Even just acknowledging more openly the incredible magnitude of the deep structural uncertainties that are involved in climate-change analysis—and explaining better to policymakers that the artificial crispness conveyed by conventional IAM-based CBAs [Integrated Assessment Model–Cost Benefit Analyses] here is especially and unusually misleading compared with more ordinary non-climate-change CBA situations—might go a long way toward elevating the level of public discourse concerning what to do about global warming. All of this is naturally unsatisfying and not what economists are used to doing, but in rare situations like climate change where DT [Dismal Theorem: price of future consumption, E[M|λ] for λ, the lower bound on consumption, large] applies we may be deluding ourselves and others with misplaced concreteness if we think that we are able to deliver anything much more precise than this with even the biggest and most detailed climate-change IAMs as currently constructed and deployed. Id., p. 18.

    Weitzman hides in no closet. His brags that work is neither accurate nor objective. He is squarely in bed with Paul Feyerabend (Against Method, Farewell to Reason), and his mentor, Karl Popper (falsifiable induction, Definitions do not matter). See David Charles Stove, Popper and After: Four Modern Irrationalists, 1982. http://nekhbet.com/popper/index.html .

    Nassim Taleb emerges again, Whack-A-Mole-like in Climate Etc., this time as some kind of support for the existence of fat-tailed probabilities densities. The best introduction to Taleb imaginable is the collection of 64 one-star reviews (out of 590) on Amazon for Taleb’s The Black Swan

    http://www.amazon.com/Black-Swan-Improbable-Robustness-Fragility/product-reviews/081297381X/ref=sr_1_1_cm_cr_acr_txt?ie=UTF8&showViewpoints=1

    or the similar 53 one-star reviews (out of 467) for his Fooled by Randomness at

    http://www.amazon.com/Fooled-Randomness-Hidden-Chance-Markets/product-reviews/1400067936/ref=sr_1_3_cm_cr_acr_txt?ie=UTF8&showViewpoints=1

    An excellent Review of Taleb’s The Black Swan is on line from one of his professional peers, Eric Falkenstein, PhD.

    http://falkenblog.blogspot.com/2009/03/review-of-talebs-black-swan.html .

    Adopting Martin Gardner’s definition of a crank, Falkenstein deduces that Taleb is a classic crank. That, too, as Falkenstein recognizes Taleb as a Popperian.

    These authorities — Weitzman, Taleb, Popper, and earlier, Arthur Dempster’s DS model of evidence, IPCC confidence levels, non-objective Bayesian decision making, “subjective probabilities”, and undefinable null hypotheses – are subjective, irrational, and incoherent. They are in short, anti-science, and encourage malfeasance by scientists.

  67. Judith Curry

    This thread has drifted into philosophical deliberations that (IMO) have little bearing on real life.

    The statement (however it’s parsed):

    uncertainty makes the case for action stronger, not weaker

    is an oxymoron.

    It says (my version):

    we have no real notion whether AGW will have a net positive effect, a net negative effect or no discernable effect at all on our climate and our environment; as a result, we must take drastic and undoubtedly painful action now to stop it

    Huh??

    Did I hear that right?

    This is the sort of jumbled reasoning that creates loss of public confidence in climate science; you don’t need to have a PhD in a climate-related science to see that it is totally illogical and contrary to all common sense.

    It is unclear to me why the “party line” should now shift to this illogical (and “wishy-washy”) premise from the very certain and confident AR4 position just four years ago:

    The understanding of anthropogenic warming and cooling influences on climate has improved since the TAR, leading to very high confidence that the global average net effect of human activities since 1750 has been one of warming…

    Most of the observed increase in global average temperature since the mid-20th century is very likely due to observed increase in atmospheric greenhouse gas concentrations.

    For the next two decades, a warming of about 0.2°C is projected for a range of SRES scenarios. Even if the concentrations of all greenhouse gases and aerosols had been kept constant at 2000 levels, a further warming of about 0.1°C per decade would be expected.

    Etc.

    You write:

    My argument is that the level of uncertainty is too great for a pdf of climate outcomes to be useful in the context of the precautionary principle.

    My version:

    we do not know enough today about the possible long-term effects of AGW on our climate and resulting impacts on our environment to warrant any actions now to mitigate against it.

    Now that makes sense to me (and I believe to most of the general public).

    Max

  68. Max,

    ‘we do not know enough today about the possible long-term effects of AGW on our climate and resulting impacts on our environment to warrant any actions now to mitigate against it’

    I find your final comment utterly incomprehensible. But you have agreed before that we might usefully do stuff that is relatively low cost and has humanitarian, environmental and agricultural benefits. These are pretty well defined and include the Millennium Development Goals and the Copenhagen Consensus priorities. In Australia for instance we could reverse all our emissions through restoring fertility to agricultural soils and improving fire and ecosystem management across landscapes.

    We could offset emissions by many times by managing the nuclear fuels cycle on a regional basis at least. Ramp up fuel supply – take back waste – store for a relatively short time and then reprocess for much more efficient 4th gen plants using a range of materials including thorium and plutonium. We have the technology.

    People talk about fat tails in a power distribution – I have used a version of these for decades for extreme rainfall prediction. But really – the suggestion is that power distributions underestimate the risk of extreme events in dynamically complex systems. But not knowing anything in detail about the nature and extent of the risk of greenhouse gas emissions – and continuing anyway in the great atmospheric experiment – is taking an uncertain risk with potentially grave consequences.

    It is not the only risk we face. Getting the energy supply and food resources equation right this century is, I believe, the difference between the human race not surviving and thriving into an incredible future – as my breathless enthusiasm for space opera suggests.

    I just got the Google Chrome blue screen of death message ‘he’s dead Jim’ for the first time. Coincidence? I think not – it’s Freemasons.

    • CH;
      Apparently your arguments and positions logically reduce to the Precautionary Principle. We deniers and doubters can go along with that IF it is opened up to encompass the entire range of Climate Shocks. Of which Cooling is the far more likely and devastating.

      And that preparation is in the direction of maximizing both flexibility and energy availability, from all sources. Especially from CO2-rich ones, just on the off-chance, minute though it is, that the AGW theses have a smidgeon of truth to them.

      • It boils down to being risk adverse and cheap as a $3 suit. What are the cheap solutions? In Australia we are going to restore carbon levels in agricultural soils and try to manage landscapes better. No problem – hardly any discussion even. Potentially 20% and 100% of our emissions per year respectively for the foreseeable future. Black carbon – 40% of radiative forcing globally and very significant in the Arctic. Kills a million and a half people a year. Tropospheric ozone – 10% of the radiative effect. Very bad for people, environments and agriculture.

        Well off people who are educated and have good health systems, safe water and sanitation have fewer children.

        We actually need energy that is less costly than coal to meet the 3% per year increase in food and energy supply target. We cannot supply enough food and other resources to people with existing technologies. Cheaper energy sources will displace carbon intensive sources very quickly.

        AGW is utterly the wrong way to think about climate – climate is complex and dynamic and can and has changed catastrophically within a decade.

      • I doubt black carbon kills anyone.

        “The particular type of emissions that gets talked about now as the main health concern is called PM2.5, or ultra-fine particles smaller than 2.5 microns in diameter. According to Environment Canada’s emissions inventory, Ontario’s coal-fired power plants released 699 tonnes of PM2.5 in 2009. Is that a lot? One way to tell is to compare it with another source nobody worries about: residential wood fireplaces. According to the same Environment Canada emissions inventory, Ontario residential wood-burning fireplaces released 1,150 tonnes of PM2.5 in 2009, 65% more than all the coal-fired electricity generation together.

        That does not mean Ontario has a crisis of air pollution from wood fires. It means PM2.5 emissions from coal-fired power plants are at levels well below what is considered not a problem when coming from other, more picturesque sources.

        The Ontario Clean Air Alliance has published claims that Ontario’s coal-fired power plants cause 316 deaths, 440 hospital admissions, 522 emergency room visits and 158,000 minor illnesses each year. Its numbers are based on a 2005 simulation study for the provincial government that focused almost entirely on the effects of PM2.5. (It also considered ground-level ozone, but emphasized that most of the ozone precursors originated in the United States).

        How plausible are these claims? If correct, they imply that wood-burning fireplaces cause 520 deaths per year, etc. But that is nothing compared with the implied effects from people driving on unpaved roads. According to Environment Canada, dust from unpaved roads in Ontario puts a whopping 90,116 tonnes of PM2.5 into our air each year, nearly 130 times the amount from coal-fired power generation. Using the Clean Air Alliance method for computing deaths, particulates from country-road usage kills 40,739 people per year, quite the massacre considering there are only about 90,000 deaths from all causes in Ontario each year. Who knew?”

        http://opinion.financialpost.com/2011/05/16/ontarios-power-trip-the-failure-of-the-green-energy-act/

      • Chief,
        What are those cheaper alternatives that will displace coal?
        It is coal and nuclear that permit the prosperity that leads to the social outcomes you list.
        Adaptation is the only way to deal with a changing climate. Mitigation by way of CO2 is an unmitigated non-starter. The sooner we give it up the more money we will have to accomplish the worthy goals you outline.
        Carbon black could have been remediated and reduced by now, except for the waste of resources on CO2.

      • I saw that pea. Cheaper energy is an absolute good, notwithstanding the horror with which Ehrlich regards it. Its pursuit has nada to do with climate concerns.

        And renewables are driving costs in the opposite direction at unprecedented speed.

    • Chief

      I think Brian H has done a good job of responding to your post in which you wrote to my sentence:

      ‘we do not know enough today about the possible long-term effects of AGW on our climate and resulting impacts on our environment to warrant any actions now to mitigate against it’

      Your response:

      I find your final comment utterly incomprehensible. But you have agreed before that we might usefully do stuff that is relatively low cost and has humanitarian, environmental and agricultural benefits.

      Chief, the point is 1) that we (including you) do not have an earthly notion of whether added atmospheric CO2 will have a) a beneficial impact on our climate, b) a detrimental impact or c) (most likely, IMO) no discernible impact at all.

      Beyond this, we do not have any good ideas on what we could do about our emissions. By this I mean: specific actionable proposals that can be demonstrated to have a perceptible impact on our climate, which can be estimated, and which we can pass a “cost/benefit” test.

      Simply arm-waving and saying, “it could be so horribly bad because climate can change real fast and we are reaching unprecedented high levels of CO2 and don’t know how disastrous it could really be, so we have to try to do something about it, even if our efforts may not be 100% successful” is nothing else than “Chicken Little” alarmism and misguided actionism.

      Judith is right: Let’s figure out what the hell we’re talking about before we charge off and battle an unknown (and quite likely, imaginary) computer-generated “hobgoblin”.

      Of course, she wrote it much more eloquently and nuanced than that:

      My argument is that the level of uncertainty is too great for a pdf of climate outcomes to be useful in the context of the precautionary principle.

      Now let’s get to the very valid comment by Brian H.

      Let’s say we shut down and decommissioned coal mines and coal-fired power plants, stopped new offshore drilling for oil and gas plus the development of shale oil and gas, moved away from nuclear power as too risky, spent trillions to subsidize non-viable windmills and solar panels to squeak by in avoiding a total blackout by imposing exorbitant taxes on energy in order to force people to cut back its use.

      IOW, we have reduced our flexibility and the potential availability of fossil fuels (as Brian H writes), at the same time that political pressures (following Fukushima) are working in the direction of shutting down the nuclear option, as well.

      Then – oops!

      The models were all wrong (as they have already been for the first decade of this century).

      It starts getting cold – REAL cold (due to natural factors, which the models forgot to include).

      Ouch!

      Now we have crops failing all across Canada, Russia and the northern parts of the USA, Europe and China plus a lot of folks freezing in their marginally heated homes.

      “Precautionary principle”, indeed!

      As they say in New York City: fuggidaboudit.

      Max

      • Chief

        NEWSFLASH

        Germany Turns Back on Nuclear Power

        The new plan foresees all of Germany’s nuclear plants going offline by 2021 — with one possible exception

        One plant, possibly Philippsburg I in the state of Baden-Württemberg or Biblis B in Hesse, will, however, be kept in “standby” mode as a reserve should extra energy be needed. It would be used to produce energy if there appeared to be a risk of power shortages, for example on cold, gray winter days when there is little solar energy available and when neighboring countries have little energy available for export, due to their own needs.

        (Just in case we got our figures wrong on those wind farms and solar plants…)

        Words are cheap (particularly just before election time).

        Let’s see what REALLY happens.

        Max

      • COAL!!!!!!!!!! Make a come back. Thanks ecoloons!

  69. “it’s Freemasons.”

    Oh no. The CH has resorted to a Robertism. He’s obviously run out of gas… or hydro-power. ;)

    Andrew

    • Andrew-
      I think that “It’s the Freemasons” is about to become a standing joke on this blog – along with the “virgins and volcanoes”. :-)

      • Two Freemasons and a virgin walk into a bar…

      • …..and order a round of “volcanoes”.

      • And the bartender says, “What is this, some kind of a joke?”

      • And the virgin murmurs to the bartender, “Joke, shmoke. These two masons are starting to get too ‘free’ with me, so slip them a couple of KO drops – as a ‘Precautionary Principle'”

  70. Chief

    I think Brian H has done a good job of responding to your post in which you wrote to my sentence:

    ‘we do not know enough today about the possible long-term effects of AGW on our climate and resulting impacts on our environment to warrant any actions now to mitigate against it’

    Your response:

    I find your final comment utterly incomprehensible. But you have agreed before that we might usefully do stuff that is relatively low cost and has humanitarian, environmental and agricultural benefits.

    Chief, the point is 1) that we (including you) do not have an earthly notion of whether added atmospheric CO2 will have a) a beneficial impact on our climate, b) a detrimental impact or c) (most likely, IMO) no discernible impact at all.

    Beyond this, we do not have any good ideas on what we could do about our emissions. By this I mean: specific actionable proposals that can be demonstrated to have a perceptible impact on our climate, which can be estimated, and which we can pass a “cost/benefit” test.

    Simply arm-waving and saying, “it could be so horribly bad because climate can change real fast and we are reaching unprecedented high levels of CO2 and don’t know how disastrous it could really be, so we have to try to do something about it, even if our efforts may not be 100% successful” is nothing else than “Chicken Little” alarmism and misguided actionism.

    Judith is right: Let’s figure out what the hell we’re talking about before we charge off and battle an unknown (and quite likely, imaginary) computer-generated “hobgoblin”.

    Of course, she wrote it much more eloquently and nuanced than that:

    My argument is that the level of uncertainty is too great for a pdf of climate outcomes to be useful in the context of the precautionary principle.

    Now let’s get to the very valid comment by Brian H.

    Let’s say we shut down and decommissioned coal mines and coal-fired power plants, stopped new offshore drilling for oil and gas plus the development of shale oil and gas, moved away from nuclear power as too risky, spent trillions to subsidize non-viable windmills and solar panels to squeak by in avoiding a total blackout by imposing exorbitant taxes on energy in order to force people to cut back its use.

    IOW, we have reduced our flexibility and the potential availability of fossil fuels (as Brian H writes), at the same time that political pressures (following Fukushima) are working in the direction of shutting down the nuclear option, as well.

    Then – oops!

    The models were all wrong (as they have already been for the first decade of this century).

    It starts getting cold – REAL cold (due to natural factors, which the models forgot to include).

    Ouch!

    Now we have crops failing all across Canada, Russia and the northern parts of the USA, Europe and China plus a lot of folks freezing in their marginally heated homes.

    “Precautionary principle”, indeed!

    Max

  71. Jim Cripwell

    On March 29, 2011 at 7:10 am you start off with a premise:

    it is becoming more and more certain that there is no physics to support CAGW.

    and then you ask Judith:

    If this is true, the case for taking no action to reduce the emissions of CO2 is becoming quite clearly the way to go. What I cannot judge is whether you feel that the evidence we are getting on a routine basis, is having any effect on the way you look at CAGW. Is anything changing your mind?

    I would not expect Judith to go on record with your preamble that there is no physics to support CAGW but Judith has gone on record here with:

    My argument is that the level of uncertainty is too great for a pdf of climate outcomes to be useful in the context of the precautionary principle.

    which pretty much agrees with the second part of your question, namely that this is not the time for mitigation action in view of all the uncertainties in the science supporting CAGW.

    This appears to be her opinion on this (which may or may not wholly agree with either yours or mine).

    Max

    • I sometimes think of “odds” as a ring-toss game. I imagine a field of opaque bottles, with all possible outcomes randomly distributed among them. You get ‘X’ tosses — one in the case of committing to mass global mitigation.

      What are the chances of ringing the neck of one of the very few AGW bottles? Versus one of the many “stable or cooling” ones (which explode destructively when hit with the “mitigation” ring)?

      I don’t want that particular ring thrown. Let’s use the “Precautionary Adaptation” one, instead.

  72. The Precautionary Principle is, in principle, no bad thing. In practice, it falls into the hands of scammers, notably the insurance industry, who gull clots into paying premiums for things that are statistically hardly likely to happen; or the pensions industry, which also employs armies of top notch scientists called actuaries, who being so brilliant failed to notice people were living longer & longer which is why so many near pensioners prospects are screwed. Why should the Precautionary Principle when in the hands of AGW-ers not be equally self serving and incompetent?

  73. Tom Scharf

    “So when you take uncertainty into account, it actually leads to the decision that we should take action more quickly.”

    Nice bumper sticker.

    Less information does not make decision making more certain. This nuance is misplaced.

    I remember when I was a kid there was a frightfest over losing one link in the great food chain causing a catastrophic chain reaction that would result in a mass extinction. Oh how fragile the food chain is !

    Asteroids
    Comets
    Flu pandemic
    Bioterror
    Black holes
    Gamma rays from exploding stars
    Over population
    Alien invasion
    Nuclear war
    HIV
    Cancer
    Economic collapse
    Food shortages
    The Canadians!!!!!
    Water shortages
    Zombies

    and that’s just from watching CNN for 20 minutes.

    • Less information does not make decision making more certain.

      Different problems have different uncertainties; so it’s perfectly possible for greater uncertainty in the situation can lead to greater certainty as to the correct course of action.

      If you are certain a sick child is not septic, you may be uncertain as to whether they should be hospitalized and treated for their sickness.

      On the other hand, if you are uncertain whether the child is septic, you can be certain of their need to be admitted and treated. Uncertainty can lead to greater confidence and vice versa.

    • Latimer Alder

      In UK we have BSE/CJD as well.

      From memory the Chief Medical Officer promised us something like 1/3 of the population falling dead in the street by now (c 20 million souls) from having eaten a hamburger back in the 80s/90s

      I believe the total number of CJD casses that *may* have had something to do with BSE is less than 50.

      I guess that overestimating the seriousness of a problem by a factor of 400,000 isn’t bad for a government employee in need/want of extra funding for his pet project. Seems like climatologists have learnt a lot from him.

      You can read a great book about many of these scares/hysteria by North and Booker ‘Scared to Death’.

      What they show is that all scares follow similar patterns of hysteria. Global warming is no different. And all scares turn out to be orders of magnitude less severe than feared. I’ve seen no reason to believe that global warming is any different.

      • CJD in Canada, about 1 per million people per year die from it. Not sure if this iis both types, or just the “spurious” one (no burgers needed). A friend recently died from it.

      • “From memory . . .”

        Memory is not reliable, especially when colored by partisan feelings. Much research has confirmed this.

        Citation please.

      • Rob Starkey

        LOL you have better odds of getting a citation from Latimer than I do of getting those fearing AGW of providing back up data to support the AGW FEARS they claim

      • He gave you one – go read the book.

  74. Am I right in thinking that:

    If Judith Curry is right and the 90% confidence levels for the warming due to a doubling of CO2 are O degC and 10 deg C, there will be a 5% chance of having warming greater than 10 degC ?

    Whereas , if we knew that the 90% limits were more like 1.5 degC and 4.5 deg C there would be hardly any chance at all of even 6 degrees warming or more?

    So, am I still right in thinking that this would indeed be case of an increased uncertainty leading to an argument for greater levels of action to curb CO2 emissions?

    • tonto52, 6/1/11, 1:00 am, Uncertainty, risk

      IPCC uses three different scales for confidence levels — all subjective. They are scales for the investigator-believers to say how they feel about the data and results. These confidence levels have nothing to do with parameter values, or the chances that an actual value will be inside the bands quoted. In other words, they are not confidence limits. This applies to your 90% confidence questions.

      The reported climate sensitivity range is 2.1 – 4.4ºC, mean 3.2ºC, is the range produced by GCMs. AR4, ¶8.6.2.2, p. 630; Table 8.2, p. 631. These models are all tuned to demonstrate that CO2 and not natural forcings cause global warming, and are adjusted to agree based on several dozen intercomparison programs. AR4, ¶8.1.2.1. The models differ primarily because of variations in their representation of clouds or water vapor feedback. AR4, FAQ 8.1, p. 601. However, IPCC claims the uncertainty in radiative forcing is almost entirely due to radiative transfer assumptions. AR4, ¶2.3.1, p. 140.

      IPCC says that models “do not provide a perfect simulation of reality”. Nevertheless, their climate simulations exhibit chaos, from which IPCC concludes that the climate system itself must be chaotic. Bold added, AR4, ¶1.5.1 Model Evolution and Model Hierarchies, p. 113. IPCC seems to regard model runs as climate experiments. Model responses are not even independent, which would give weight and accuracy to their mean response. Of course, no scientific model is perfect. IPCC inserts that superfluous exaggeration to disguise its confession that its models do not provide even a defensible prediction of reality.

      IPCC’s conclusion that the climate is chaotic, and therefore unpredictable, is an excuse for the failure of its GCMs to demonstrate any predictive power.

    • tonto52

      So, am I still right in thinking that this would indeed be case of an increased uncertainty leading to an argument for greater levels of action to curb CO2 emissions?

      Greater uncertainty as to whether there is a problem and , if so, how serious this problem could be

      EQUALS

      greater reason for action to mitigate against the problem?

      I hardly believe so, tonto.

      There is GREAT UNCERTAINTY as to WHEN our planet will be hit by a major asteroid, although it is fairly CERTAIN that this will happen again some day, and – when it does – it is fairly CERTAIN (based on previous incidents) that the impact on our environment and on human society will be DISASTROUS.

      Let’s start spending trillions of dollars per year to mitigate against this impending disaster, just because of the high level of UNCERTAINTY involved.

      Sounds like the “Chicken Little” approach (beware “Foxy Loxy”, tonto, he’s got his hand on your wallet).

      Max

  75. Jeff Glassman

    These models are all tuned to demonstrate that CO2 and not natural forcings cause global warming, and are adjusted to agree based on several dozen intercomparison programs. AR4, ¶8.1.2.1. The models differ primarily because of variations in their representation of clouds or water vapor feedback. AR4, FAQ 8.1, p. 601.

    This is correct.

    Despite the IPCC concession that “cloud feedbacks remain the largest source of uncertainty”, all the models cited by IPCC in the AR4 section you cite have assumed strongly net positive feedback from clouds:

    Ch. 8 (p.630):

    The cloud feedback mean is 0.69 W m-2 °C-1 with a very large inter-model spread 0f ±0.38 W m-2 °C-1

    IOW, IPCC has shown no “uncertainty” regarding the sign of the cloud feedback, just in itsmagnitude. This has a strong impact on the model-based 2xCO2 climate sensitivity (p.633):

    Using feedback parameters from Figure 8.14, it can be estimated that the presence of water vapour, lapse rate and surface albedo feedbacks, but in the absence of cloud feedbacks, current GCMs would predict a climate sensitivity (±1 standard deviation) of roughly 1.9°C ± 0.15°C (ignoring spread from radiative forcing differences). The mean and standard deviation of climate sensitivity estimates derived from current GCMs are larger (3.2°C ± 0.7°C) essentially because the GCMs all predict a positive cloud feedback (Figure 8.14) but strongly disagree on its magnitude.

    Cloud feedback increases the sensitivity by 1.3°C .

    Has IPCC’s “largest source of uncertainty” been cleared up by Spencer + Braswell?

    This study based on CERES satellite observations shows strongly negative overall cloud feedback with warming over the tropics.

    At the same time a newer model study by Wyant et al. using superparameterization to better simulate the behavior of clouds, also shows a global net negative cloud feedback with warming.

    If these new findings cannot be refuted, it appears that the net cloud feedback is very likely to be strongly negative rather than positive, as assumed by the IPCC models.

    These new findings would lead to a 2xCO2 climate sensitivity of 1°C or less, as has been estimated separately by Lindzen + Choi 2009 with 2011 addendum and Spencer 2011.

    So it looks like the 3.2°C ± 0.7°C climate sensitivity estimate is crumbling. The “uncertainty” appears to be in how much too high this estimate has been (rather than if it is too low).

    Max

    • Continued.

      Manacker cited a IPCC paragraph on feedback parameters based on a chart from Soden and Held (2006). AR4 Figure 8-14. Soden and Held held,

      Our results further indicate that while the change
      in cloud forcing may not accurately represent the sign
      or magnitude of cloud feedback
      , it does provide a useful
      metric for assessing intermodel differences in cloud
      feedback.

      Citations deleted, Soden, B.J. & I.M. Held, An Assessment of Climate Feedbacks in Coupled Ocean–Atmosphere Models, J.Clim., v. 19, pp. 3354-3360, 2006, p. 3360.

      Soden is a contributing author to AR4 Chapter 8, and that chapter cites Soden and Held (2006) 15 times. Also writing contemporaneously with AR4, Lead and Contributing Author David Randall wrote,

      The representation of cloud processes in global atmospheric models has been recognized for decades as the source of much of the uncertainty surrounding predictions of climate variability. Despite the best efforts of our community, and notwithstanding the achievement of significant advances, … , the problem remains largely unsolved. At the current rate of progress, cloud parameterization deficiencies will continue to plague us for many more decades into the future. The cloud parameterization problem is “deadlocked,” in the sense that our rate of progress is unacceptably slow. Randall, D., M. Khairoutdinov, A. Arakawa, and W. Grabowski, Breaking the Cloud Parameterization Deadlock, AMS, November, 2003, 1547-1564, pp. 1547-8.

      More specifically, IPCC said,

      [A] now-classic set of General Circulation Model (GCM) experiments ¬ produced global average surface temperature changes (due to doubled atmospheric CO2 concentration) ranging from 1.9°C to 5.4°C, simply by altering the way that cloud radiative properties were treated in the model. It is somewhat unsettling that the results of a complex climate model can be so drastically altered by substituting one reasonable cloud parametrization for another, thereby approximately replicating the overall intermodel range of sensitivities. … The model intercomparisons presented in the TAR showed no clear resolution of this unsatisfactory situation. Citations deleted, ¶1.5.2, id., p. 114.

      Nevertheless, IPCC said,

      The successes of the current models lend some confidence to their results. For a challenge to the current view of water vapour feedback to succeed, relevant processes would have to be incorporated into a GCM, and it would have to be shown that the resulting GCM accounted for observations at least as well as the current generation. A challenge that meets this test has not yet emerged. Therefore, the balance of evidence favours a positive clear-sky water vapour feedback of magnitude comparable to that found in simulations. TAR, ¶7.2.1.3 Summary on water vapour feedbacks, pp. 426-7.

      As to successes, if a model has a surplus of variables, it can be tuned to most anything. And so it is with the GCMs. However, a model tuned in this fashion lacks a controlling cause and effect relationship, and so has zero predictive power. A change of any parameter in a tuned model can cause the model range to exceed what the investigator might consider realistic. IPCC appears to find this principle unsettling.

      As to water vapor, it is key to the simplest theoretical grounds for assessing cloud feedback. The paper by Randall, et al. (2003) is a pitch for a “Manhattan Project” for cloud parameterization. Id., p. 1562. It is for superparameterizations of climate simulation … at a very high computational price , which at that We do not claim … will solve all of our problems. Id. The promise is that In a few more decades it will become possible to use such global [superparameterizations] to perform century-scale climate simulations, relevant to such problems as anthropogenic climate change. Today’s graduate students may be lucky enough to work with such models, later in their careers. Today, though, incorporating water vapor and temperature in clear and cloudy regions is a work in progress on parameterization. Id., pp. 1551-2.

      Under superparameterizations, The total increase in computation, relative to current climate models, would … be on the order of 10^6. … A GCM that uses a superparameterization can be called a “super-GCM.” Id., p. 1553. The justification includes that super-GCMS [could] explicitly simulate fractional cloudiness. Id., p. 1555. In addition,

      A super-GCM can provide global simulations of
      the statistics of mesoscale [10 to 100 km] and microscale cloud organization,
      which can then be compared with observations
      compiled by the International Satellite
      Cloud Climatology Project (ISCCP)… Id.
      , p. 1556.

      At last! IPCC reports

      The ISCCP shows an increase in globally averaged total cloud cover of about 2% from 1983 to 1987, followed by a decline of about 4% from 1987 to 2001. Citation deleted, AR4, ¶3.4.3.2 Satellite Cloud Observations, p. 276.

      and
      The ISCCP data have greatly aided the development of cloud representations in climate models since the mid-1980s. However, existing data have not yet brought about any reduction in the existing range of simulated cloud feedbacks. Citation deleted, 4AR, ¶1.5.2 Model Clouds and Climate Sensitivity, p. 116.

      And it continues to search for some physical cause for cloud feedback:

      Several studies suggest that the sign of cloud feedbacks may not be necessarily that of CRF [Cloud Radiative Forcing] changes … . Bold added, AR4, ¶8.6.3.2.2 Interpretation of the range of cloud feedbacks among climate models, p. 637.

      Until then,

      The correct simulation of the mean distribution of cloud cover and radiative fluxes is therefore a necessary but by no means sufficient test of a model’s ability to handle realistically the cloud feedback processes relevant for climate change. Bold added, TAR, ¶7.2.2.5 Representation of cloud processes in models, p. 431.

      Based on the simplest theoretical grounds, IPCC data suggest a warming from 1983 to 1987, and a cooling from 1987 to 2001. Randall, et al., teach that this cannot be confirmed with contemporary GCMs.

      The pitch for the climate Manhattan Project is not so important for what it promises at any cost, but for what it says about the state of the representation of cloud feedback in today’s models. They are unable to confirm what is known on the simplest theoretical grounds.

      Justified by the anthropogenic alarm, simulation power grows perpetually to exceed the state-of-the-art in computational power. As GCM resolution shrinks to zero and the number of cells grows to infinity, the product of the two is not the indeterminate 0 • ∞, but equal to whatever might be available. Instead, the next order of business for climatology before absorbing the GDP is to develop a model for climate on the scale of the simplest theoretical grounds. Until the GCMs and model on the simple scale agree, the forecasts for climate sensitivity should be taken with a grain of sea salt.

  76. manacker, 6/2/11, 0743 am, Uncertainty, risk

    manacker deduced:

    >>IOW, IPCC has shown no “uncertainty” regarding the sign of the cloud feedback, just in its magnitude.

    notwithstanding that IPCC made its contrary position explicit. From before the Third Assessment Report,

    The sign of the net cloud feedback is still a matter of uncertainty, and the various models exhibit a large spread. Bold added, TAR, TS, pp. 49-50.

    and persisting into the Fourth,

    In spite of this undeniable progress, the amplitude and even the sign of cloud feedbacks was noted in the TAR as highly uncertain, and this uncertainty was cited as one of the key factors explaining the spread in model simulations of future climate for a given emission scenario. This cannot be regarded as a surprise: that the sensitivity of the Earth’s climate to changing atmospheric greenhouse gas concentrations must depend strongly on cloud feedbacks can be illustrated on the simplest theoretical grounds, using data that have been available for a long time. Satellite measurements have indeed provided meaningful estimates of Earth’s radiation budget since the early 1970s. Clouds, which cover about 60% of the Earth’s surface, are responsible for up to two-thirds of the planetary albedo, which is about 30%. An albedo decrease of only 1%, bringing the Earth’s albedo from 30% to 29%, would cause an increase in the black-body radiative equilibrium temperature of about 1°C, a highly significant value, roughly equivalent to the direct radiative effect of a doubling of the atmospheric CO2 concentration. Citation deleted, 4AR, ¶1.5.2 Model Clouds and Climate Sensitivity, p. 114.

    This highly significant cloud cover feedback is global. The simplest theoretical grounds include a cloud cover increase with increasing specific humidity and a cloud cover decrease with increasing solar activity. GCMs parameterize those clouds, but only at the cell level, reporting a global climate sensitivity, but not reporting a global cloud cover. IPCC said,

    Kaufman et al. (2005) [ The Effect of Smoke, Dust and Pollution Aerosol on Shallow Cloud Development Over the Atlantic Ocean] conclude from satellite observations that the aerosol indirect effect is likely primarily due to an increase in cloud cover, rather than an increase in cloud albedo. AR4, ¶7.5.2.1 Aerosol Effects on Water Clouds and Warm Precipitation, p. 560.

    IPCC here suggests that cloud cover increases do not cause a cloud albedo increase. This is an unfortunate consequence of GCM modeling at the cell level, coupled with IPCC’s treatment of aerosol effects within a cell, absent a cellular cloud fraction integrated into a global cloud cover. See for example AR4, Figure 2.10. Kaufman et al., went on:

    We find that cloud cover is affected mainly by air temperature at 1000 hPa, temperature difference 1000-750 hPa, the aerosol optical thickness, sea surface temperature, and the winds. Citation deleted, id., (not paginated).

    which they then connect to TSI:

    This suggests that the aerosol indirect effect and in particular the increase of cloud cover can serve as a possible explanation to the observed changes in surface illumination. Kaufman, et al., 2005.

    and IPCC supplies the temperature-water vapor link:

    Trends in specific humidity tend to follow surface
    temperature trends with a global average increase of 0.06
    g kg^–1 per decade (1976–2004). The rise in specific humidity
    corresponds to about 4.9% per 1ºC warming over the globe.
    Over the ocean, the observed surface specific humidity
    increases at 5.7% per 1ºC warming, which is consistent with
    a constant relative humidity. Over land, the rate of increase is
    slightly smaller (4.3% per 1ºC), suggesting a modest reduction
    in relative humidity as temperatures increase, as expected in
    water-limited regions.
    AR4, ¶3.4.2.1 Surface and Lower-Tropospheric Water Vapour, p. 272.

    IPCC cannot bring itself to say that cloud cover depends on specific humidity.

    To be continued.

    • Jeff Glassman

      Further to your post:

      Does increased cloud cover result in warming or cooling?

      I do not believe that GCM simulations are required to answer this question. Just step outside with a thermometer on a day with scattered clouds.

      The major effect of clouds is to reflect incoming solar radiation during daylight hours. Any secondary effect of trapping outgoing LW radiation (primarily at night) is of secondary importance.

      Over half of the Earth’s albedo comes from clouds. Estimates from ERBE observations indicate that clouds reflect more energy than they trap overall. Estimates of the net cooling effect vary from a net -28 W/m^2 to -18 W/m^2 based on various studies, compared to an estimated warming effect of doubling CO2 of +1.66 W/m^2

      Does increased specific humidity lead to increased cloud cover?

      You have asked this question, which IPCC has skirted around.

      But let’s look at the long-term NOAA record of tropospheric specific humidity and compare this with the HadCRUT globally and annually averaged land and sea surface temperature anomaly over the same period:
      http://farm4.static.flickr.com/3343/3606945645_3450dc4e6f_b.jpg

      While we see several short-term “blips”, where SH and temperatures appear to move in lock-step, we see that the overall long-term correlation shows SH decreasing as temperature increases.

      Doesn’t make sense, does it? What about Clausius-Clapeyron?

      So knee-jerk reaction #1 is to say, “the observations must be wrong”.

      But let’s carry it one step further.

      If an increase in SH leads to an overall increase in cloud cover, the opposite should also apply: a decrease in SH should lead to less cloud cover.

      This, in turn, should lead to more incoming radiation reaching the surface and hence to increased warming.

      So an observed increasing long-term trend in global temperature could well correlated logically with the observed long-term decreasing trend of SH if one simply reverses the causer/effect hypothesis

      Or am I missing something here?

      Max

      • Jeff Glassman

        There is a typo in my post.

        The 2xCO2 forcing is 3.71 W/m^2 (the 1.66 W/m^2 figure I cited is the IPCC estimate of the net radiative forcing from CO2 from1750 to 2005).

        Sorry.

        Max

      • manacker, 6/6/11, 12:53 pm, Uncertainty, risk

        The link you gave me confirms your chart, but you already knew that. The data, however, had no date, I was unable to find a source in a reasonable amount of time. It has this ambiguous note at the bottom:

        >> NCEP Reanalysis Produced at NOAA/ESRL PSD at http://www.esrl.noaa.gov/psd/data/timeseries/
        Date submitted: 6/6/2011 at 16:09

        Is this saying that the data on the page was reanalysis, produced according to information at the link? Or, is it saying that for the reanalysis, one should go to that link? I navigated to the link, found some information on specific humidity, but no annual data!

        I’m left with a link that you didn’t use that confirms IPCC’s text. I haven’t found an explanation for the difference in the two tables of data. I’ll have to leave it at that. Sorry.

  77. manacker, 6/5/11, 8:41 am, Uncertainty, risk

    You said you do not believe GCM simulations are required to answer the question Does increased cloud cover result in warming or cooling?. We could pose an unlimited number of questions GCMs need not answer. Science doesn’t require GCMs to answer any questions, nor to replicate climate in any manner, realistic or otherwise. However, the GCMs remain no better than scientific hypotheses until they are validated. They have never been validated, and worse — they fail to replicate paleo climate, or, in the alternative, objectively reject that era from their domain. In the modern period, the prospect for GCM validation is quite poor because of the unrealistic way they represent cloud cover, a dominating feedback based on the simplest theoretical grounds.

    We should inform readers here that the author of your linked chart is yourself. That chart doesn’t agree with IPCC’s figures in which it claimed that specific humidity increased with surface temperature between 1976 and 2004. AR4, ¶3.4.2.1; see my post at 5:32 pm, above. I tried to verify your references, and the link to Specific Humidity (NOAA) at http://www.cdc.noaa.gov/cgi-bin… etc. appears defunct. Instead, I found http://www.ncdc.noaa.gov/bams-state-of-the-climate/2009-time-series/humidity . This cite shows a chart with Specific Humidity records from three different sources within the period of about 1969 to the present. They are in close agreement with each other, and show SH anomaly clearly increasing about 0.3 g/kg over the period. This agrees with AR4 and contradicts your chart.

    The objective to debunk IPCC, i.e., show H0 (AGW does not exist) is true, is done most easily and least argumentatively using IPCC’s approved data, physics, and analysis.

    • Jeff Glassman

      You wrote:

      We should inform readers here that the author of your linked chart is yourself. That chart doesn’t agree with IPCC’s figures in which it claimed that specific humidity increased with surface temperature between 1976 and 2004. AR4, ¶3.4.2.1; see my post at 5:32 pm, above

      The graph I posted shows clearly the source of the data on both the tropospheric specific humidity (NOAA published record) and global temperature anomaly (HadCRUT). All you have to do, Jeff, is read the footnote on “Source”.

      Now to IPCC.

      Of course it does not agree with IPCC, who is selling us the message that specific humidity increases in march-step with temperature according to Clausius-Clapeyron to essentially maintain a constant relative humidity (thereby resulting in a major positive feedback from water vapor with warming).

      So this information is played down (AR4 WG1 Ch.3, p.271):

      The network of radiosonde measurements provides the longest record of water vapour measurements in the atmosphere, dating back to the mid-1940s. However, early radiosonde sensors suffered from significant measurement biases, particularly for the upper troposphere, and changes in instrumentation with time often lead to artificial discontinuities in the data record…Consequently, most of the analysis of radiosonde humidity has focused on trends for altitudes below 500 hPa and is restricted to those stations and periods for which stable instrumentation and reliable moisture soundings are available.

      Smacks of: “When the readings don’t agree with the theory, there must be something wrong with the readings.”

      The NOAA record is still available on line, so if it was total garbage, I’m sure NOAA would have retracted it.

      OK. The data I downloaded was up to 300 hPa (instead of 500 hPa), but that has not made much difference in the trend.

      So let’s “inform readers” that the data I posted come from NOAA references, which are cited and can be checked online.

      OK?

      Max

      PS If you can find that I made a mistake in downloading or plotting the cited NOAA data, please let me know so I can correct my graph. Thanks.

      • Jeff Glassman

        Back to your post on observed versus modeled atmospheric water vapor content trends with warming

        Coming back to the IPCC stand on specific humidity (AR4 WG1 Ch3, p.273), a 2002 study by Elliott et al. is cited:
        http://journals.ametsoc.org/doi/pdf/10.1175/1525-7541(2002)003%3C0026%3ALTHTRI%3E2.0.CO%3B2

        A closer look shows why results above 500 hPa were eliminated from the study. These are the results, which showed both less absolute moisture content (lower specific humidity) as well as lower relative humidity with warming (the curve I posted goes to 300 hPa at all latitudes). These would kick out the whole concept of a positive water vapor feedback with warming, so would be very embarrassing for IPCC.

        Elliott et al. conclude, based on the selected data below 500 hPa only that SH (moisture content) increased slightly with warming, but not at a rate sufficiently strong to maintain constant RH, as is assumed by the IPCC models in estimating water vapor feedback.

        IPCC also cites a shorter-term study by Minschwaner & Dessler (2004):

        Conversely, a combination of Microwave Limb Sounder (MLS) and Halogen Occulattion Experiment (HALOE) measurements at 215 hPa suggested increases in water vapour content with increasing temperature…on interannual time scales, but at a rate smaller than expected from constant relative humidity.

        A closer look at the study confirms slight increase in moisture (SH) with warming, but only at a small fraction of the rate needed to maintain constant RH.
        http://mls.jpl.nasa.gov/library/Minschwaner_2004.pdf

        The analysis suggests that models that maintain a fixed relative humidity above 250 mb are likely overstating the contribution made by these levels to the water vapor feedback.

        This is a very polite understatement, if one looks at Fig. 7 in the report. I have extended this graph to show the full specific humidity impact with 1°C warming.
        http://farm4.static.flickr.com/3347/3610454667_9ac0b7773f_b.jpg

        As can be seen, the “constant RH assumption” exaggerates the actually observed moisture increase with warming by a factor of around 10:1 (and hence the model-based water vapor feedback estimates).

        I discussed this all several months ago with Gavin Schmidt at RealClimate, who did not address the M+D study but debated the validity of the NOAA data with me for a while before simply censoring out my posts.

        The point is quite simply: The IPCC assumption of essentially constant relative with warming is not supported by the physically observed data, therefore the assumption of strong water vapor feedback with warming is also not supported by the observations.

        One can blame the observations for this (as IPCC has done) or one can admit that water vapor feedback with warming does not appear to be based on an essentially constant RH with warming, as IPCC assumes, but a much lower increase in water vapor with warming.

        Max

      • manacker, 6/5/11, 12:19 pm, Uncertainty, risk

        The graph I posted shows clearly the source of the data on both the tropospheric specific humidity (NOAA published record) and global temperature anomaly (HadCRUT). All you have to do, Jeff, is read the footnote on “Source”.

        I read the footnote. I tried to open the source for the specific humidity data. The source no longer exists. You say it’s still available on line. I’ll happily recheck your work if you’ll tell me where I might now find the data you used.

        I found a similar source, still referenced to CDC. It is quite different, and in fact agrees with IPCC’s description that I gave you.

        I mentioned that the graph was yours not to pick on you, but because you posted it as you might a source. It’s a nice graph, but it is a picture of your position, not confirming of it.

        ECMWF subjected radiosonde data to a couple of “reanalyses” to correct some defects in the records. See AR4, ¶3.4.1.3 Reanalysis, p. 269. IPCC hedged its reliance on radiosonde, saying,

        Additional information on water vapour can be obtained from satellite observations and reanalysis products. Satellite observations provide near-global coverage and thus represent an important source of information over the oceans, where radiosonde observations are scarce, and in the upper troposphere, where radiosonde sensors are often unreliable. AR4, ¶3.4.2, Water Vapour, p. 272.

        For more on the problems see AR4 Supplement, ¶3.B.5.1, Evolution of the Observing System: Radiosondes, p. SM.3-6. These reanalyses were occurring between the TAR and AR4. IPCC is drifting away from reliance on radiosondes. That NOAA might have indeed retracted the data on which you relied seems likely. Or perhaps you got linked to the wrong record? Regardless, your graph is certainly not current.

        You say, Of course it does not agree with IPCC, who is selling us the message that specific humidity increases in march-step with temperature according to Clausius-Clapeyron to essentially maintain a constant relative humidity (thereby resulting in a major positive feedback from water vapor with warming).

        What IPCC says is that the water vapor capacity increases according to the CC equation. It also says in several places that the RH is approximately constant. This implies that SH increases with T. This results in a major positive feedback from water vapor only in IPCC’s world where it keeps cloud cover constant with unpublished, primitive, unsatisfactory, failing parameterizations. IPCC admits that cloud cover is linked to albedo, and suggests strongly in places that cloud cover increases with moisture. The combination is an omitted, powerful, dominating negative cloud albedo feedback working against puny cloud and water vapour GH effects.

      • Jeff Glassman

        The raw NOAA data are available at this link:
        http://www.cdc.noaa.gov/cgi-bin/data/timeseries/timeseries.pl?ntype=1&var=Specific+Humidity+(up+to+300mb+only)&level=300&lat1=90&lat2=-90&lon1=180&lon2=-180&iseas=1&mon1=0&mon2=11&iarea=1&typeout=1&Submit=Create+Timeseries

        Hope this helps.

        BTW I agree with what you have written on IPCC’s approach to greatly exaggerate water vapor feedback by simply ignoring the physical observations, which show a much smaller increase in water vapor with warming than the IPCC assumption of essentially constant RH. This results in a greatly exaggerated 2xCO2 climate sensitivity.

        Added on top of this exaggeration is an even worse misrepresentation of the impact of cloud changes with warming (cloud feedback) and a total ignoring of any naturally caused changes in clouds (cloud forcing).

        You mention the poor parameterization of clouds in the GCMs cited by IPCC (to arrive at the strongly positive cloud feedback).

        As you know from AR4 WG1 Ch.8 (p.630) IPCC models estimate the feedbacks to be
        +1.80±0.18 W/m^2 °C – water vapor
        -0.84±0.26 W/m^2 °C – lapse rate
        +0.26±0.08 W/m^2 °C – surface albedo
        +0.69±0.38 W/m^2 °C – clouds

        The impact on the 2xCO2 climate sensitivity (p.633):
        +1.9°C ±0.15°C – including all feedbacks, except clouds
        +3.2°C ±0.7°C – including all feedbacks, including clouds

        So, leaving the exaggerated water vapor feedback aside for now, we see that the model-assumed cloud feedback has a major influence on the 2xCO2 CS.

        OK. IPCC does concede:

        Cloud feedbacks remain the greatest source of uncertainty

        And this uncertainty is undoubtedly related to the high reliance on model simulations (rather than physical observations) and the poor parameterization of clouds in the models cited by IPCC.

        As we both know, physical observations of CERES satellites since AR4 was published (Spencer + Braswell) have shown that the net cloud feedback over the tropics is strongly negative, rather than positive, as assumed by IPCC.

        In addition a study using superparameterization to better simulate the behavior of clouds, also shows a strongly negative net overall global feedback from clouds.
        ftp://eos.atmos.washington.edu/pub/breth/papers/2006/SPGRL.pdf

        -0.970 W/m^2 °C – SW reflection
        +0.085 W/m^2 °C – LW absorption
        -0.885 W/m^2 °C – net overall cloud feedback

        It is easy to see that correcting the IPCC CS of 3.2°C for the difference in cloud feedback would have a major impact, bringing the 2xCO2 CS down to around 0.6°C to 1.0°C, with all feedbacks.

        Max

      • Max, Hardly anyone would come out with an answer this low. Its just as likely to be 10 degC as the figures you’ve mentioned.
        So, tell me, do you think the IPCC have deliberately exaggerated the problem?
        Are they part of a hoax or do they genuinely feel the problem is larger than your calculations would indicate?

      • tonto52

        You write (to my post citing various studies on overall net cloud feedback and its impact on the model-derived IPCC 2xCO2 climate sensitivity estimate):

        Max, Hardly anyone would come out with an answer this low. Its just as likely to be 10 degC as the figures you’ve mentioned.
        So, tell me, do you think the IPCC have deliberately exaggerated the problem?
        Are they part of a hoax or do they genuinely feel the problem is larger than your calculations would indicate?

        There are a lot of different statements/questions there so let’s go through them step by step:

        Max, Hardly anyone would come out with an answer this low.

        Not true, tonto. Both Spencer (2011) and Lindzen + Choi (2009, with addendum 2011) have come up with a 2xCO2 CS estimate of around 0.6-0.7C, based on CERES and ERBE satellite observations.

        Its just as likely to be 10 degC as the figures you’ve mentioned.

        Please refer me to the studies based on physical observations that show this statement to be true.

        do you think the IPCC have deliberately exaggerated the problem?

        I think thy have “exaggerated” the 2xCO2 climate sensitivity (see posts to Jeff Glassman), as well as the assumed future CO2 levels in most of the model-based “scenarios and storylines”, and thus have greatly exaggerated the projected future warming from increased CO2. Whether they did this “deliberately” or not, I’ll leave up to you to speculate.

        Are they part of a hoax or do they genuinely feel the problem is larger than your calculations would indicate?

        I would not call IPCC “part of a hoax”. I would simply say that IPCC is a political organization whose charter is to investigate and report the ”scientific basis of risk of human-induced climate change, its potential impacts and options for adaptation and mitigation”, IOW to evaluate the risk of human-induced climate change and any negative effects it may have on our society and environment. No significant human-induced climate change or no substantial negative impacts means no need for IPCC to continue to exist. No bureaucratic committee wants to be irrelevant and therefore disbanded, so it would only be natural that the IPCC agenda would include self-survival. In order to ensure this, it embraces eagerly any scientific reports, which support its message of significant human-induced climate change possibly leading to negative impacts, while ignoring those studies, which do not. I would not call this a “hoax”, simply “agenda-driven science for self-survival”, which has resulted in a corruption of the IPCC process.

        do they genuinely feel the problem is larger than your calculations would indicate?

        I cannot vouch for how any one member of IPCC “genuinely feels”. It appears that the current IPCC chairman, Rajendra Pachauri, may really believe that the “problem is larger than my calculations would indicate” (unless he is a fantastic actor), while it was also true that a past IPCC vice chairman, Dr. Yury Izrael, openly stated that he did not believe that AGW is a real problem.

        Hope this has answered your questions, tonto.

        Max

      • manacker, 6/6/11, 7:12 pm, Uncertainty, risk

        What you claimed was IPCC’s charter, to investigate and report the “scientific basis of risk of human-induced climate change, its potential impacts and options for adaptation and mitigation”, was actually its own Principles Governing IPCC Work, 10/1/1998, available on line.

        It’s charter actually read,

        The IPCC was established by UNEP and WMO [World Meteorological Organization] in 1988 to assess the state of existing knowledge about climate change: its science, the environmental, economic and social impacts and possible response strategies. http://www.unep.org/Documents.Multilingual/Default.asp?DocumentID=43&ArticleID=206&l=en .

        Thus IPCC changed its own charter from a scientific investigation into advocacy for political purposes. By assuming AGW, it distorted all its analysis from investigating whether it exists into demonstrating how bad it was going to be. It erased, minimized, or ignored natural causes of climate to insert manufactured and exaggerated manmade causes. Examples on request. What isn’t fraud is delusion.

        Any scientist worthy of the title should rise in protest.

      • Low sensitivities don’t hold up to the observations. Take the last 50 years. We haven’t seen the sun get stronger, the temperature has gone up by maybe 0.6 C, CO2 has gone up by 20%. A sensitivity of 1 C per doubling would account for maybe 0.25 C of this 0.6, while a sensitivity of 3 C would account for 0.75 C, but we can assume aerosols reduced it down to 0.6, since observations support global dimming in this period. Anyway 1 C per doubling falls short by a significant margin that they don’t account for, and they have to ignore global dimming too.

      • If you don’t like aerosol dimming, some might attribute the difference to thermal lag of the oceans. These effects are negative, and can add to account for a 3 C sensitivity explaining a 0.6 C rise.

      • The IPCC do say that effects, other than CO2 increase, contribute to global temperature change but , taken collectively , they have so far approximately cancelled out each other.
        My arithmetic for a 2x C02 would be:
        Present Warming: 0.75deg C
        Current warming Rate 0.15 deg C per decade
        Time to 2x C02 (BAU scenario) approx 100 years
        So 0.15 x 10 +0.75 = 2.25 deg C
        Further warming due to time lag at end of 100 year period ~0.75 deg , probably over several decades.
        Which means a 3 deg C figure for climate sensistivity is not inconsistent with current levels of warming.
        Of course , it could turn out worse than this. The seas may start to become net sources of Co2 if they warm.
        Methane released from a warming Tundra could accelerate the warming process and make the above calculation look hopelessly optimistic.

      • tonto52

        Like JimD, you appear to be reaching into a bag of rationalizations to cover up the fact that 20th century warming does not support a postulated 2xCO2 sensitivity of 3C, but rather one of around 0.7C (if half the 20th century warming is attributed to natural forcing, as the many solar studies I cited indicate).

        CO2 release from the ocean? Gimme a break, tonto. (We are supposed to be worrying about “ocean acidification”, instead – and, hey, where is all that “missing” CO2 from human emissions going?)

        Methane from a warming tundra? That’s been going on forever, tonto. (Besides, methane is included in IPCC’s “other GHGs”.)

        Don’t dig up all these rationalizations to explain why the observed warming does not support the beautiful hypothesis.

        Read Feynman instead (then fix the hypothesis).

        And, while you are at it, explain why it has not warmed for over one decade now, despite CO2 concentrations reaching record high levels (and IPCC projections of 0.2C per decade warming).

        Max

      • JimD

        I see you are reaching into the bag of rationalizations why it has not warmed as much as the models tell us it should.

        The fact of the matter is that IPCC has relied in AR4 on models, which assume a strongly positive net feedback from clouds, while subsequent physical observations show that the primary impact of clouds with warming is increased albedo and higher SW reflection resulting in an overall negative cloud feedback.

        You say “Low sensitivities don’t hold up to the observations. Take the last 50 years.”

        No, Jim, let’s take the entire 20th century.

        The solar activity in the 20th century was the highest in several thousand years, according to several solar studies, which attribute half of the observed 20th century warming to this factor (Shapiro et al. 2011, Scafetta + West 2006, Solanki et al. 2004, Shaviv + Veizer 2003, Lockwood + Stamper 1999, Geerts + Linacre 1997, Gerard + Hauglustaine 1991).

        Aerosol dimming is included in IPCC’s estimates of anthropogenic climate forcing components AR4 WG1 SPM , Figure SPM.2. The radiative forcing from CO2 alone (1750 to 2005) is stated to be 1.66 W/m^2, while that of all anthropogenic components (including aerosols, land use changes, surface albedo, other GHGs) is 1.6 W/m^2. So “aerosol dimming” is no big deal, Jim. It can be ignored, along with all the other anthropogenic components beside CO2 (according to IPCC).

        “Hidden in the pipeline” is a postulation based on circular logic.

        “Thermal lag of the oceans”? How does that ” account for a 3 C sensitivity explaining a 0.6 C rise”?

        So let’s look at 20th century warming.

        HadCRUT tells us we had 0.66C linear warming over the 20th century.

        If half of this can be attributed to solar activity, that leaves 0.33C for anthropogenic factors. Let’s say IPCC is correct and CO2 forcing = net forcing from all anthropogenic factors, this means that the observed 2xCO2 sensitivity is around 0.7C, as I calculated earlier. It is a simple calculation, using the IPCC assumptions.

        IOW your statememnt

        Low sensitivities don’t hold up to the observations

        is incorrect.

        Max

      • The reason I don’t take the whole 20th century is that there is a debate about the sun strength increasing from 1910-40, which I suspect it did and accounts for 0.2 C. To avoid that whole issue, and move to where we know what the sun actually did, I would take 50, or better still, the last 30 years, when the sun was constant except for the 11-year cycle. The warming rates, given the CO2 increase rate, agree well with 2.5 C to 3 C sensitivities, and not at all with 1 C sensitivity. The decadal rate (2000’s minus 1990’s) is near 0.15 C per decade despite the flat plateau, which is due to a warm early 2000’s period, and possibly the long solar minimum at the end.
        If you have to take the whole 20th century (30% CO2 increase), my attribution is 0.7 degrees of which 0.9 is CO2, 0.2 is the sun, and -0.4 is aerosols, as I have posted before.

  78. Max,
    The IPCC do make the point of not attributing all warming to increases in CO2 concentrations. Yes Total Solar Irradiance (TSI) has slightly increased and other GH gases have considerably increased, but, so too have particulates which cause cooling. The IPCC say these other factors just about cancel out each other.
    I was just wondering how much we agree on here. Are you saying otherwise?
    I just get the feeling that you seem happy to quote the IPCC, when it suits your purpose, but at other times so make unsupported claims to justify your argument that CO2 emissions aren’t a potential problem.
    You do whatever it takes to get a lower answer for 2x CO2. That doesn’t strike me a taking a responsible scientific position.

    • tonto52

      I just get the feeling that you seem happy to quote the IPCC, when it suits your purpose, but at other times so make unsupported claims to justify your argument that CO2 emissions aren’t a potential problem.

      Sorry about your “feeling”, tonto, but let me explain why it is unfounded.

      IPCC was set up to study human-caused climate change, its negative impacts and possible adaptation and mitigation strategies. This is its charter, its “raison d’etre” and arguably its strength.

      So when IPCC tells me that all anthropogenic forcing components other than CO2 (aerosols, albedo, land use, other GHGs, etc.) essentially cancel one another out, I have to accept this as likely to be correct.

      When, on the other hand, IPCC tells me that all natural forcing components (consisting only of direct solar irradiance) have been essentially insignificant, I wonder how accurate this assessment really is. especially in view of known pre-industrial cold periods, which coincided with very low solar activity (Dalton, Maunder). I then read in a footnote that IPCC concedes that its “level of scientific understanding” of <em"natural forcing components (including solar)"</em is low. I think, “well, in that case I’d better look somewhere else for this information where the ‘level of scientific understanding’ may be a bit higher than that of IPCC”. I do look elsewhere and – viola! – I find several solar studies, which show that roughly half of the observed 20th century warming can be attributed to the unusually high level of 20th century solar activity (highest in several thousand years, it is reported).

      Based on this information and published atmospheric CO2 data I can now estimate the CO2 impact on observed past warming and the observed 2xCO2 impact (or climate sensitivity), leaving out (for now) any notions of energy “hidden in the pipeline”..

      So you see, tonto, it all follows a logical trail, admittedly one of someone who is rationally skeptical of the IPCC party line and, as such, requires empirical data rather than simply model simulations to be convinced.

      Max

  79. Max,
    PS I just noticed that you claim that “HadCRUT tells us we had 0.66C linear warming over the 20th century.”
    Why linear? Is that just a way of downplaying the total warming? What would you say that was?
    My height is 190cm and has been since I was about 20. But my linear height at that age would have been quite a bit less as I had a growth spurt in my late teens. My linear height may now be quite a bit more than that, and it does seem extraordinary to use the term linear this way!

    • I would add that attributing 0.33 C to the sun in the 20th century requires an enormous positive feedback in addition to any reasonable TSI increase. So by applying this positive feedback to the sun, you can remove it from the GHGs, but unfortunately the timing of the solar increase within the 20th century doesn’t work either as the majority of the warming has been recent when TSI measurements don’t indicate the sun doing anything much.

      • “The decrease in Earth’s reflectance from 1984 to 2000 translates into an albedo decrease equivalent to a forcing of 6.8W/m^2.

        That is almost 3 times as much warming as claimed by the IPCC for warming caused by CO2 from 1850 – 2.4W/m^2.”

        http://sunshinehours.wordpress.com/2011/06/01/decrease-in-cloud-cover-causes-3x-as-much-warming-as-co2/

      • Positive albedo feedbacks from melting ice and reducing cloud cover would be important to consider if this data is trustworthy. It kills the ideas of Spencer and Lindzen to have cloud cover decreasing as the earth warms because they are saying the reverse should happen.

      • Jim D

        You’ve got the cart before the horse here.

        Palle et al (cited elsewhere here) have shown that the total albedo has decreased over the period 1985-2000, while cloud cover also decreased (resulting in global warming), and has reversed itself since then, with increased cloud cover. (resulting in slight cooling).

        Spencer + Braswell showed, based on CERES observations, that the net feedback from clouds with warming temperature over the tropics was negative, instead of positive as estimated earlier by the IPCC models while conceding “cloud feedbacks remain the largest source of uncertainty”

        Spencer has postulated elsewhere that natural factors, such as PDO swings, might be the underlying cause for changes in cloud cover, which result in changes in global temperature, IOW that clouds act as part of a natural forcing, rather than simply a feedback to anthropogenic (or other) forcing.

        I do not see any logical problem with Spencer’s postulation or with the Spencer + Braswell or Palle et al. observations. If you do, please be a bit more specific.

        Max

      • Yes, the spontaneous clouds idea. How do clouds change their annual average global albedo spontaneously when their individual lifetime is minutes to hours? Where does their memory reside? Surely there is an underlying change like aerosols, the oceans, the land, or the sun, even GCRs: something with a long-term memory. Can Spencer have clouds both as a negative feedback (more temperature means more clouds) and a negative forcing (more clouds means less temperature, which everyone agrees with by the way)? This is a prescription for an oscillatory behavior that in the long term cancels out. Also, PDO type ocean effects have an amplitude of 0.2 C, and should be given their due weight. 0.2 C is also an estimate of the 11-year solar cycle impact. I only discount them because of their measured amplitude, not because I don’t think they exist. Even without feedback, CO2 doubling far exceeds these, so attention to them is disproportionate to their effect.

      • Jim D, 6/7/11, 9:06 pm, uncertainty, risk

        Yes, the spontaneous clouds idea. How do clouds change their annual average global albedo spontaneously when their individual lifetime is minutes to hours? Where does their memory reside? Surely there is an underlying change like aerosols, the oceans, the land, or the sun, even GCRs: something with a long-term memory.

        What you’re missing is the phenomenon of feedback, a System Science concept of modern origin, much more recent than, say, the greenhouse effect. The origin of feedback in climatology was probably in a paper by Hansen, et al. (1984), and attributed to Bode (1945). IPCC adopted the term, redefined it in twice, both wrong, and leaving out the most important, most powerful feedback of all – cloud cover. Feedback is the generation of a signal from within a system in the form of energy, displacement, acceleration, temperature, pressure, or material, that is transported to the inputs to the system to modify those inputs. It’s a concept that is most troublesome to represent in IPCC’s radiative forcing paradigm for want of flow variables.

        Feedback, and especially, clouds, do not have memory, and are not normally modeled to have memory. Except in cases of rare catastrophic feedback (Hansen’s perennial tipping points), the modification of the system inputs goes away when the inputs go away. What happens with cloud cover is that it tends to increase with increasing humidity, and to decrease with increased solar activity. These are the first order effects, where a second order effect is that cloud cover eclipses or reveals surface albedo, so a net albedo effect is important.

        Cloud cover increases with sea surface temperature, and is well-reported over the tropics and subtropics. The cause is increased specific humidity and the certainty of a surplus of cloud condensation nuclei. It is not relative humidity, which tends to stay rather constant. One of the major sources of CCN is sea salt, so even if Earth were to be volcanically inactive and entirely covered with water to be dust free, clouds would still be present.

        Cloud cover decrease with solar activity. This is most obvious in diurnal cloud cover graphs, which seem abundant enough online. Cloud cover over the ocean increases every day beginning in the sunset hours, and decreases during the day in rather a 24 hour sinusoidal pattern, to a first approximation. The ocean, being quite dark, is the primary accumulator of solar energy, and so we’re concerned first about over-ocean cloud cover. A tiny bit of reasoning reveals that cloud cover decreases with increasing solar activity, whether it is due to Earth’s rotation or, by rational extension, to variations in solar activity.

        The increase in cloud cover with humidity is slow, and a negative feedback. It mitigates warming from any cause, natural or manmade. It is slow because the ocean accumulates solar energy over a long period of time to distribute the energy back to the atmosphere. Some the energy exchange takes place over a year as surface currents move slowly poleward, and some energy exchange is extremely long, as the thermohaline circulation from the headwaters at the poles to the Ekman pump at the Equator is on a millennium scale.

        The decrease in cloud cover is rapid, essentially instantaneous compared to climate scales, and is a positive feedback. The more active the Sun, the less the cloud cover, causing an increase in insolation.

        The lifetime of individual clouds doesn’t enter into the global effects. Clouds are continuously being created and destroyed. What counts is not their average lifetime, but their average extent, especially over the ocean.

        IPCC reports only coarse cloud cover modeling in its GCMs. It’s a modeling crutch called parameterization that substitutes poorly for emulation. The GCMs model climate in a network of cells, each cell with its own fractional cloud cover between zero and one. The models do not use a total cloud cover, even though that parameter is implied in IPCC’s definition of its radiative forcing paradigm.

        Furthermore, IPCC has not even reported, much less analyzed, a total cloud cover by integrating the fractional cloud cover over the cells. IPCC is left with a model that does not represent the dominant feedback in all of climate – cloud albedo, or more specifically cloud cover.

        The result is that for lack of the cloud cover positive feedback, IPCC misses the fact that surface temperature is determined by solar activity, and for lack of the cloud cover negative feedback, it overestimates climate sensitivity by a factor of 4 to 10.

      • Jim D

        I would add that attributing 0.33 C to the sun in the 20th century requires an enormous positive feedback in addition to any reasonable TSI increase.

        No, it does not, Jim. I would add that it requires thinking outside the box.

        Direct solar irradiance is very likely not the only mechanism by which the changes in solar activity influence our climate. The many solar studies I cited simply used empirical data going back to pre-industrial cold periods coinciding with periods of low solar activity in order to estimate the impact of the unusually high level of 20th century solar activity (highest in several thousand years). These show that most of the 20th century solar impact occurred in the warming of the first half, with only a small percentage in the warming of the second half. There have been several suggested mechanisms here, although these have not yet been scientifically corroborated (just like the premise of a potential serious threat from AGW has also not been scientifically corroborated).

        Still a lot of “uncertainty” out there, Jim.

        Max.

      • Max, Maybe you could knock out a few lines of creative “outside the box arithmetic” to show how a slight change in the TSI of just a couple of watts per sq mtre can produce 0.33C of warming ?

        Mann’s hockeystick graph attracted an awful lot of attention which you’ll no doubt be aware of. It wasn’t the only hockey stick graph and the interesting thing is they all show the modern warming trend started at the beginning of the 20th century. Now, whether that was due to changes in land use, changes in the TSI, or the effect of small increases in CO2 and other GH gases is a matter of some debate. It was probably a combination of all these factors so it cannot be assumed that early 20th century warming was entirely natural.

      • tonto52

        Max, Maybe you could knock out a few lines of creative “outside the box arithmetic” to show how a slight change in the TSI of just a couple of watts per sq mtre can produce 0.33C of warming ?

        For a clue check:
        Shapiro et al. 2011, Scafetta + West 2006, Solanki et al. 2004, Shaviv + Veizer 2003, Lockwood + Stamper 1999, Geerts + Linacre 1997, Gerard + Hauglustaine 1991 among others.

        Max

      • tonto52

        “Mann’s hockey stick”?

        That’s been dead and buried for years. Let it RIP.

        Max

      • Yes, we agree that the sun hasn’t done much in the second half of the 20th century, and the relevance is that most of the warming occurred in that half. This would support the idea that the sun didn’t contribute much if anything to the recent warming. CO2 accounts for it with a moderate positive feedback, and has the property that its effect is bigger in more recent years as the warming is. Coincidence? No.

      • tonto52

        Yes the sun hasn’t done much at all recently. In fact the TSI has fallen which has offset the warming due global pollution

        Indeed. HadCRUT attributed the “lack of warming” over the past decade (despite CO2 concentrations reaching record levels) to “natural variability” (a.k.a.natural forcing), while IPCC told us in AR4 that the total effect of “natural forcing components” since 1750 was essentially negligible compared to the impact of CO2.

        Hmmm… But IPCC told us it should warm by 0.2°C per decade.

        And, using IPCC’s 2xCO2 climate sensitivity and the observed increase in CO2 concentration from 369 to 390 ppmv, it should have warmed by 0.26°C over the 10-year period from the GHE

        So we have:

        – 1750-2000 BIG impact from CO2 (1.65 W/m^2); other anthropogenic factors cancel one another our; negligible impact from natural (solar) (0.12 W/m^2) over 250 years.

        – 2001-2010: ZERO overall impact despite major increase in CO2; ergo: major overriding impact from natural (solar?) over 10 years.

        Riddle: What’s wrong with this picture?

        [Answer: I’d agree with Kevin Trenberth that it is a “travesty”.]

        Max

    • tonto52

      You question why I have referred to the linear rate of warming in the HadCRUT record.

      The answer is quite simple: this is the way IPCC compares warming trends over different periods (AR4 WG1 SPM, p.5) (bold face by me)

      Eleven of the last twelve years (1995-2006) rank among the 12 warmest years in the instrumental record of global surface temperature (since 1850). The updated 100-year linear trend (1906 to 2005) of 0.74°C [0.56°C to 0.92°C] is therefore larger than the corresponding trend for 1901 to 2000 given in the TAR of 0.6°C [0.4°C to 0.8°C]. The linear warming trend over the last 50 years (0.13°C [0.10°C to 0.16°C] per decade) is nearly twice that for the last 100 years.

      Get the point?

      Max

      PS There are two hidden bits of “smoke and mirrors” in the IPCC paragraph I cited. Can you find them? (It’s sort of a “what’s wrong with this picture” riddle.)

  80. Jim D,
    An “enormous positive feedback”. Yes you are right. It would require that.
    Climate deniers, sorry skeptics, don’t seem to have any problem with the concept of large positive feedbacks if they are applied to climate forcings caused by changes in the TSI! Unlike, of course, when CO2 is the forcing agent.
    I wonder why that is? :-)

    • tonto,
      Why do true believers, er AGW convinced, persist in putting words in skeptic’s mouths?

    • tonto –
      If you go to this link, I was the system engineer for the satellite data that provided some of what went into this report.

      http://www.climatemonitor.it/wp-content/uploads/2009/12/1974.pdf

      I was also system engineer for a satellite crop program, part of which necessitated serious cloud cover, persistence and effect assessment.

      I’m one of those “skeptic” types in part because what I learned on that program said that cloud effects are NOT what JimD or a lot of other people think they are. They’re a lot closer to what Spencer and Lindzen think.

  81. tonto52

    [tried posting this earlier, but it got stuck]

    Yes the sun hasn’t done much at all recently. In fact the TSI has fallen which has offset the warming due global pollution

    Indeed. HadCRUT attributed the “lack of warming” over the past decade (despite CO2 concentrations reaching record levels) to “natural variability” (a.k.a.natural forcing), while IPCC told us in AR4 that the total effect of “natural forcing components” since 1750 was essentially negligible compared to the impact of CO2.

    Hmmm… But IPCC told us it should warm by 0.2°C per decade.

    And, using IPCC’s 2xCO2 climate sensitivity and the observed increase in CO2 concentration from 369 to 390 ppmv, it should have warmed by 0.26°C over the 10-year period from the GHE

    So we have:

    – 1750-2000 BIG impact from CO2 (1.65 W/m^2); other anthropogenic factors cancel one another our; negligible impact from natural (solar) (0.12 W/m^2) over 250 years.

    – 2001-2010: ZERO overall impact despite major increase in CO2; ergo: major overriding impact from natural (solar?) over 10 years.

    Riddle: What’s wrong with this picture?

    [Answer: I’d agree with Kevin Trenberth that it is a “travesty”.]

    Max