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# Drilling into noise

 By Stephan LewandowskyWinthrop Professor, School of Psychology, University of Western AustraliaPosted on 17 September 2012Filed under Cognition and Klaus Oberauer

The science of statistics is all about differentiating signal from noise. This exercise is far from trivial: Although there is enough computing power in today's laptops to churn out very sophisticated analyses, it is easily overlooked that data analysis is also a cognitive activity.

Numerical skills alone are often insufficient to understand a data set—indeed, number-crunching ability that's unaccompanied by informed judgment can often do more harm than good.

This fact frequently becomes apparent in the climate arena, where the ability to use pivot tables in Excel or to do a simple linear regressions is often over-interpreted as deep statistical competence.

The graph below illustrates this problem with the global temperature data: although there is no question that the trend is increasing, it is always possible to cherry pick periods for analysis during which there is no significant increase in temperature. Of course, those “analyses” are a meaningless distraction from what is actually happening on our planet (the only one we've got, by the way).

Similar comments apply to some of the analyses reported in the blogosphere of our recent data on rejection of science and conspiracist ideation. We have already dealt with the "scamming" issue here and here, and we will not take it up again in this post.

Instead, we focus on the in-principle problems exhibited by some of the blog-analyses of our data. Two related problems and misconceptions appear to be pervasive: first, blog analysts have failed to differentiate between signal and noise, and second, no one who has toyed with our data has thus far exhibited any knowledge of the crucial notion of a latent construct or latent variable.

Let's consider the signal vs. noise issue first. We use the item in our title, viz. that NASA faked the moon landing, for illustration. Several commentators have argued that the title was misleading because if one only considers level X of climate "skepticism" and level Y of moon endorsement, then there were none or only very few data points in that cell in the Excel spreadsheet.

Perhaps.

But that is drilling into the noise and ignoring the signal.

The signal turns out to be there and it is quite unambiguous: computing a Pearson correlation across all data points between the moon-landing item and HIV denial reveals a correlation of -.25. Likewise, for lung cancer, the correlation is -.23. Both are highly significant at p < .0000...0001 (the exact value is 10 -16, which is another way of saying that the probability of those correlations arising by chance is infinitesimally small).

What about climate? The correlation between the Moon item and the "CauseCO2" item is smaller, around -.12, but also highly significant, p < .0001.

Now you know why the title of our paper was “NASA faked the moon landing—Therefore (Climate) Science is a Hoax: An Anatomy of the Motivated Rejection of Science.” We put the "(climate)" in parentheses before "science" because the association between conspiracist ideation and rejection of science was greater for the other sciences than for climate science.

(As an intriguing aside, by the logic that's been applied to our data by some critics, the larger correlations involving other sciences would suggest that AIDS researchers—keen to get their grants renewed?— scammed our survey to make AIDS deniers look bad.)

But we can do better than extract a signal by simple correlations.

Far better.

This brings us to our second issue, the role of latent variables.

To understand this concept, one must first consider the fact that on any cognitive test or survey, any one item, however well designed, will not provide an error-free measure of the psychological construct of interest. No single puzzle can tell you about a person’s IQ, no single question will reveal one’s personality, and no single moon landing will reveal a person’s propensity for conspiracist ideation.

So the correlations we just reported constitute a better signal than the noise that overwhelms a selected few cells of an Excel spreadsheet, but they are still "contaminated" by measurement error or item variance—that is, the data reflect the idisosyncracy of the particular item in addition to information about the construct of interest, in this case conspiracist ideation.

What to do?

Enter latent variable analysis, also known as structural equation modeling (SEM).

SEM is a technique that estimates latent constructs—that is, the hypothesized psychological construct of interest, such as intelligence or personality or conspiracist ideation. SEM does this by considering multiple items, thereby removing the measurement error that besets individual test items.

We cannot get into the details here, but basically SEM permits computation of the error-free associations between constructs, such as one's attitudes towards science and one’s conspiracist ideation. It is because measurement error has been reduced or eliminated, that correlations between constructs are higher in magnitude than might be suggested by the pairwise correlations between items.

And because SEM removes measurement error, the associations between constructs are particularly resilient, as we showed earlier when all observations are removed that might conceivably represent “scamming.”

When the long-term temperature trend is ignored in favour of a few years of declining temperatures after a unique scorcher, this is missing the statistical forest not just for a tree but for a little twig on a tree.

Likewise, when the associations between latent constructs in our data are ignored in favour of one or two cells in an Excel spreadsheet, that’s missing the statistical forest not just for a little twig on a single tree but for a single leg of a pinebark beetle on that twig that’s eating its way northbound through the Rockies as the globe is warming.

Comments 201 to 239 out of 239:

1. "...cuts both ways.

No, it does not - as explained by:

a) risk management practices in the face of entirely unacceptable outcomes;

b) that whole thing about potentially seriously disrupting our utter dependence on the sole ecosystem we have access to;

c) various analyses that indicate that delay in the face of climate change, rather than immediate action, is the choice that wastes money when assessed over appropriate timescales;

...as examples.

For still another perspective you could look at this series of articles by our host, and the references contained therein.
2. @267: Yes, it does. Uncertainty of outcome is NOT the friend of any action or inaction to prevent that outcome. The less the uncertainty of the outcome, the more called the action or inaction is. The more the uncertainty, the less called the exact same action or inaction is.

Your "no, it does not" is simply wrong.

Now, if you want to argue that the uncertainty of catastrophic warming is now low enough to warrant action against it, we can talk about it. But that's a different argument entirely. The higher the uncertainty, the less warranted the action, period.
3. "Uncertainty of outcome is NOT the friend of any action or inaction to prevent that outcome."

Apart from the fact that this appears to clash with your claim that "The more the uncertainty, the less called the exact same action or inaction is.", you might wish to read the articles I linked to which demonstrate the opposite for certain cases.

Or consider this. Let's say for sake of argument that there is uncertainty about the possible detrimental impact of a new medical practice, but that the available evidence suggests that there is a 5-10% chance of its widespread use wiping out all human life on earth within a century and 10-20% chance of severely and permanently injuring more than 20% of the population. Would you say that the uncertainty of outcomes and/or uncertainty about the likelihood of various outcomes would mean we should merely allow the practice to proceed or that we should ban it, or that either or both of those uncertainties has no bearing on how policy should respond? Please be specific as to which type of uncertainty factor in to your answer and how.

Given that you assert "The more the uncertainty, the less called the exact same action or inaction is.", if the probability estimates were even less certain (e.g. 3-20% chance of human extinction and 0-30% of permanent severe injury to 20%+ of the population) how would your answers change?
4. @270: Lotharsson, I have trouble understanding you. In my book, "uncertainty is not the friend of action or inaction" *means* that "the more uncertainty, the less called the action or inaction is". You can replace the word "called" with "justified", if that helps.

In your example, the more uncertainty is there in the words "there is a 5-10% chance of [the medical practice] wiping out all human life", the less called the ban on the medical practice.
5. " I agree with symmetrical risk analysis."

Please define what that term means to make sure we're on the same page.

"The idea of an infinitely bad outcome of which the tiniest possibility is to be avoided at all cost..."

...isn't what I said. I said sufficiently bad so as to be unacceptable.

And in the case of climate science, the assessment of the likelihood of bad consequences is way higher than "the tiniest possibility", so you appear to be trying to shift the goalposts.

I would expect many of the potential outcomes identified by climate scientists to be considered "unacceptable" by almost everyone, but in order to avoid presuming your opinion I asked *you* what your threshold of unacceptability was. So far you have not answered and I do not expect that you will.

What is the rational risk management response to "There's a small chance that by doing this we could wipe out all human life on earth"? Or what does best practices corporate risk management say is the response to actions for which "there's a small chance if we do this we'll send the company irretrievably bankrupt"?

There is no other rational response than "OK, let's not do that, or at least not until we can do more analysis to figure out whether we can be confident that chance is *essentially zero*."

" In any case, runaway cooling would be far worse than runaway warming, as you know."

Huh? Where did this non sequitur come from? No-one has talked about runaway warming, let alone runaway cooling - and no scientist I'm aware of today is concerned at all about the possibility of runaway cooling. (And I'm not at all sure that runaway cooling would be "far worse" than runaway warming given that the consequences of runaway warming would already be absolutely horrific.)

"...where is the science that tests the hypothesis that business-as-usual emissions will cause nett harm?"

As I stated on the other thread, I and others have already pointed you to enough evidence underlying cause for concern - and I've pointed out why "nett harm" is the wrong standard in the face of uncertainty of outcome that can't strongly rule out egregiously bad outcomes. I won't repeat it here, nor in response to future repeated requests.

But I will repeat my observation for hopefully the last time that you haven't presented your own assessment of the probability distribution of outcomes, nor any evidence to support your position that there's nothing to worry about - and add that I have reached the point where I am fairly confident that you will not do so.
6. I will illustrate my answer to your example. If the "5-10% chance of [the medical practice] wiping out all human life" comes from controlled experiments and measurements, that's one thing. If the "5-10% chance of [the medical practice] wiping out all human life" is just something someone said in the watercooler talk, that's something else exactly. In the first case, the action (or inaction) is more warranted than in the second.
7. @272: Lotharsson, this -- "There is no other rational response than "OK, let's not do that, or at least not until we can do more analysis to figure out whether we can be confident that chance is *essentially zero*."" -- is completely incorrect. The rational response in the case of low uncertainty is not "OK, let's not do that while we gather enough data", but rather "Whatever, do it or don't do it, if you have been doing it unknowingly that's fine too, because we are still gathering data, and are not yet ready to say what's better: doing it or not doing it."
8. Fair enough Hank, I have trouble understanding you too.

For example '"uncertainty is not the friend of action or inaction" *means* that "the more uncertainty, the less called the action or inaction is".' makes no sense to me.

1) I assume by "called" you mean "called for"?

2) What do you mean by "uncertainty" here? Is it "we don't know which outcome will eventuate, although we can estimate the likelihood of different outcomes with specified confidence intervals"? Or is it a measure of how widely the realised outcome is likely to deviate from the (statistical) expectation of outcome?

3) What do you mean by "more uncertainty" here?

4) Action and inaction on any given issue are mutually exclusive. I am failing to understand how *both* can be simultaneously called for by higher uncertainty, regardless of the definition of "higher uncertainty".

In my book "uncertainty is not the friend of X" means that uncertainty does not motivate or call for X - but rather the opposite.

And by certainty here I mean much the same as what Lewandowsky meant in those articles I linked to - that we have a pretty good idea of what outcome will eventuate, and the likely deviation from that expectation is low.
9. @275. For 1, yes, by "called", I mean "called for".

For 2, please note that "we don't know which outcome will eventuate" is connected to "how widely the realised outcome is likely to deviate from the expectation", so your suggestion for me to pick either one or another is misguided.

Likewise for 3, "more uncertainty" means both which outcome will eventuate or how much the outcome is going to differ from the expectation, you pick your view, that's the same thing.

For 4, there's nothing strange in both action and inaction being uncalled for, that's called (no pun intended): "we don't know enough, so do whatever until we investigate, we can't tell you whether either action OR inaction is good or bad anyway".
10. "The rational response in the case of low uncertainty..." [I presume you meant low certainty] "...is not "OK, let's not do that while we gather enough data", but rather "Whatever, do it or don't do it, if you have been doing it unknowingly that's fine too, because we are still gathering data, and are not yet ready to say what's better: doing it or not doing it.""

I disagree.

1) "Low certainty" doesn't automatically mean you you don't know enough to figure out whether it's better to do or not to do it. (And in almost every real world example, that judgement of what is "better" requires weighing probabilities because very little is 100% certain in a complex system. The more certain you are the tighter your probabilities are, but it's a sliding scale rather than a binary switch and you have to make decisions based on the certainty you have.)

2) If you mean to argue that "The rational response to an inability to determine likely outcomes with sufficient certainty to make informed policy decisions is to keep doing it", I'd be a little closer to accepting it - but not much because even then it's not hard to think of examples where this response is highly irrational, and not doing something that hasn't been done before is far more rational. If it were *always* rational, then would it be rational for a child playing with fireworks to continue playing with them on the basis that they don't have enough data to know whether it will be better to play or not to play, and to continue to do so *until* they have enough data to realise the danger? The danger isn't eliminated *because* the child doesn't have enough data, so it's not at all clear to me that this is a solidly rational principle.

3) It doesn't seem to apply to climate science where we already have enough data to know that doing what we're doing is shifting our ecosystem out of the climate it evolved within, and doing so way faster than it has ever been known to adapt to in the past. We have 10,000+ years of historical evidence that says that climate supports that ecosystem which supports human life - and evidence supporting a very plausible case that too much of this may severely screw things up for several billion people. Especially in a system with very long lag times which makes it very hard to turn around if more research gives you more confidence you're going in the wrong direction.

There's a huge difference between risk management for a system for which there are a few known benefits and a few known detriments but none of the latter are severe enough that we recoil from them, and a system where the known potential detriments are that severe. In the former you can balance positives and negatives because you can live with both. In the latter you can't. (That's kinda what "unacceptable" means!) By analogy you don't start totting up the potential benefits of a bushfire severe enough to entirely raze your town to see if they offset the massive negative before you decide whether to try and prevent it or not. (Or at least I wouldn't. Your mileage may vary - and if it does, we will have found the nub of our difference.)
11. @277: Lotharsson -- "If it were *always* rational, then would it be rational for a child playing with fireworks to continue playing with them on the basis that they don't have enough data to know whether it will be better to play or not to play, and to continue to do so *until* they have enough data to realise the danger?" -- it *is* rational for a child to pay no special attention as to whether or not they are playing with fireworks until someone tells them not to play with fireworks. That's the entire point. An unknowing child has no way to distinguish fireworks from crayons or food, they get to know the difference by experimenting. That's perfectly rational. Perhaps the best illustration of the rationality in that is that if there was noone to tell children that fireworks are dangerous, we'd still like children to play with them. Perhaps cautiously, but still play.
12. Nub found!

Surely "we have a pretty good idea of what outcome will eventuate, and the likely deviation from that expectation is low.." is open to debate?

This 'very certain' projection is based on modeling of a very complex system, and most of the robust measuring of this system is only beginning now.

No amount of modeling and remodeling the past seems to help, that only inflames the discussion.

Your position (perhaps?)seems to be: "The outcome IS reasonably certain, and it is surely not good, therefore we MUST act now... (and my addendum: '... even if we are not entirely certain how to go about it and regardless of the as yet unknown consequences of these actions").

I must also say, I do appreciate you (and all) debating this, and appreciate the amount of thought and typing gone into these replies.
14. @278: Glad we found it. If you are saying that it is not rational for a child to play with something that they don't know, no matter how cautiously, then I suggest we, as a humanity, stop doing things we haven't been doing already. Forget exploration of space or ocean deeps, who knows what horrors might be lurking there... Who's to tell that we won't invoke some power that will destroy the earth, better not do it, I guess.
15. Working my way down the page: Coupla nitpicks on which I feel I must comment:

Chris #251 “….many countries (some major economic powers like Japan, Germany and France) can run their economies using well under half the per-capita greenhouse gas emissions of others (e.g. the US)…” Talking nuclear power here!(IMHO a good idea)

J Bowers # 252 “…. higher food prices and decimated agriculture (the very foundation of civilisation)…”

So 40% of US corn currently (ie right now) going to ethanol and so escalating international corn prices, and thereby starving people NOW, is a GOOD idea? Even though corn is one of the least efficient crops for this purpose and production of a litre of corn ethanol likely results in greater CO2 emissions than does producing and burning a litre of petrol. How does this help?

Who does this help? (answer, only some farmers and the people they vote for).

Re child and fireworks #227 : Perhaps not a suitable analogy. The child does not even suspect the outcome, so can come to no conclusion at all. An advising adult knows the outcome with certainty.

Likewise your ‘wildfire’ analogy. #264 In fact we already know very well from previous experience what the likely outcome will be, and so would in fact be foolish to not prepare for it.

A more apt fire analogy of the climate debate may be this: “Hmm, escalating temperatures, dry forests, we therefore predict there is a 95% chance a fire will occur today, at 3.00 PM. Let’s commence with the fire hoses now. Yep, there may be some water damage, destroyed furnishings and floor covers and broken windows, and likely you will have to replaster, rewire and repaint, but we ARE 95% sure. (They’d be better in this case to check if there really was a fire was coming before starting the pumps).
17. Concerning risks, presumably some of the folks here have found their way to psychological peace of mind while not maintaining home or auto health insurance policies?

Is the ~US\$4 trillion/year handed over to the global insurance industry wasted money? Does that money mysteriously vanish as is supposedly the case with conjectured expenditures required to mitigate AGW? Is it the case that the low probability of disaster for purchasers of insurance policies means they are being tricked into buying something they don't need? Is the global economy buckling under this shockingly large and (we're lead to believe by people on this thread) unnecessary economic load?

If those who eschew insurance are wrong in their calculations, is it OK for them to pass their costs along to other people?
18. @285: What about the chance of catastrophic conditions, Doug? What about casuality (as in, suppose we reduce emissions of CO2 - at great cost to the economy - how much is this going to affect temperatures and with what certainty)?
19. Hank: "At great cost to the economy."

The vanishing money problem again. Will it be shot into space? Will the current accounts of nations around the world then be adjusted to make that money disappear, erase it from history? How does the world suffer the crippling burden of insurance today?

Chances? See (sigh, again) the IPCC reports, which continue to same the same thing a bit more urgently with each iteration. The accepted lowermost threshold for what's going to happen to the climate is "bad." You disagree for reasons that can't be fully articulated.

How do you propose to pay for your unreasonable disagreement?
20. I love the last claim by the authors, "that’s missing the statistical forest not just for a little twig on a single tree but for a single leg of a pinebark beetle on that twig that’s eating its way northbound through the Rockies as the globe is warming."

Of course pinebark beetles thrive in a forest due to drought, not warming, and as scientists know, precipitation/drought level does not follow warming, but is selective by region.

This highlights better than anything else could that it is in the author's best interest to cherry pick as much of their data as possible, and jump to whatever conclusions suit their premise best.
21. The skinny on pinebark beetles from USDA.

Susceptible to cherrypicking, so best read the whole thing. Be suspicious of short quotes.
22. "Surely "we have a pretty good idea of what outcome will eventuate, and the likely deviation from that expectation is low.." is open to debate?"

No - in that quote that you repurposed I was defining the metric "certainty", not asserting we have complete certainty about the climate system or ecosystem. But nevertheless:

Your position (perhaps?)seems to be: "The outcome IS reasonably certain, and it is surely not good, therefore we MUST act now...

No on two counts.

It is that:

1. We are already certain enough that completely unacceptable (very very bad) consequences have likelihoods significantly higher than zero (and if we keep emitting enough are ultimately very likely), and ...

2. ...that fact alone is enough for standard risk management practices to kick in and say we MUST act so as to avoid those outcomes.

3. And as a bonus, we already know enough to be pretty confident that acting now to avoid those potential outcomes is cheaper than acting later.

Many proponents of business as usual cite the fact of any amount of uncertainty in climate science projections as a reason for business as usual. I'm pointing out that is fallacious - that all policy decisions about all complex systems operate in the presence of some uncertainty, but that "some uncertainty" is not the same as "we know nothing at all, and in particular we don't know whether acting or not acting is better". (And that is where some of the hypotheticals discussed above differ from the current climate science situation.)

Others claim insufficient certainty to justify anything except business as usual. However it's not usually clear that they are genuine because they don't specify the level of certainty that is required to act, and that claim appears to be at odds with the current level of knowledge we have. (And citing insufficient certainty is a well-known tactic previously used for delaying action on tobacco, CFCs, ...)

...(and my addendum: '... even if we are not entirely certain how to go about it and regardless of the as yet unknown consequences of these actions").

I disagree. The uncertainty about acting lies on the other foot at least with respect to the climate system and ecosystem (as my previous comment about asymmetry indicates) - which has been my point all along.

Business as usual amounts to a giant experiment on the only climate system and ecosystem we have. The outcome of that experiment started out with enormous uncertainty over a century ago. That uncertainty has been whittled down over the decades of climate science research, but some still remains on various questions - as frequently cited by proponents of business as usual as a (fallacious) reason for not acting to stop that experiment. (You appear to have done exactly that in your comment.)

If that uncertainty is a factor in making policy decisions, then the only known-safe course is to stop the giant experiment because we know with certainty that the climate and ecosystem worked well for humanity before we started significantly impacting them with emissions (let alone other human impacts).

And I disagree further. We have a pretty good idea of how to go about it.

And I disagree still more. We have a pretty good idea that acting now is a lot cheaper than acting even a few years from now.
23. "Perhaps not a suitable analogy. The child does not even suspect the outcome, so can come to no conclusion at all. An advising adult knows the outcome with certainty."

Perhaps not the best analogy, but still servicable.

Firstly, advising adults don't know the outcome with certainty! After all, many children have played with fireworks in the past and not come to significant harm. But some have. Which outcome will eventuate in any given episode of a child playing with fireworks? No-one knows for sure beforehand - but they absolutely know there's a non-trivial chance of seriously adverse consequences.

Most people agree that not knowing the outcome with certainty doesn't mean adults should allow children to play with fireworks with impunity. They seem to think that there's enough information to make policy decisions other than "unfettered play as usual"! They generally insist on all sorts of precautions for play - some of which impose "costs" on the children by controlling and limiting or even entirely prohibiting their play - even though all of the impacts of those costs are themselves not completely certain or not completely known!
24. "...no distinction can be drawn between omission and commission, or action and inaction—the risks and benefits of both must be considered as if they were choices."

Good - agreed.

"...foregoing a benefit is just as bad as incurring a cost"

Also agreed.

I meant something else by asymmetric. I meant that the downsides can reach "completely unacceptable", whereas the upsides have no balancing equivalent. (This is pretty much by definition of "completely unacceptable"!)

"I don't have a harm threshold that is unacceptable."

Hmmmmm...interesting. I suspect we have found another nub.

"No matter how bad an outcome, as long as it's sufficiently unlikely it's acceptable."

I'm with you as long as "sufficiently unlikely" equals zero - or perhaps if you twist my arm, something very very small. However that's not the type of probability that climate scientists attach to some (of what I consider) very very bad outcomes if we continue business as usual. So this exercise is interesting - but doesn't relate well to climate science concern.

"As I understand it, risk = badness of outcome x likelihood.

As a hypothetical in order to explore this concept, what "badness" would you assign to an outcome of (say) all human life is extinguished within five years? (What is your definition of "badness" here? How is it measured?) Is there a probability of such an outcome do you find acceptable per se, or does it truly depend on what benefits you might get in exchange?

Assuming the latter, and explore further by way of an additional hypothetical, if there's (say) a 10% chance of an action (or inaction) completely wiping out humanity - which implies the additional costs of foregoing all future benefits to humanity from all sources for all time - what benefit(s) (at even a 90% chance of achievement) would you consider to fully offset that and then some? Please give at least one example of a tradeoff that you would think is a good deal.
25. "In fact we already know very well from previous experience what the likely outcome will be, and so would in fact be foolish to not prepare for it."

And so with climate science concern, your overhyped analogy about the consequences of mitigation notwithstanding.

We have a lot of evidence (including evidence gleaned from the past experience of the globe) that bad to very very bad outcomes are on the way if we continue, and yet people insist that we do not take action to avoid them.

We also have economists saying that over 2-3 decades the cost of starting mitigation now is cheaper than the cost of delaying action, and yet the same people still clamour to pay the extra costs.

Go figure.

I note that you say the cost of starting mitigation now is cheaper than doing so at a later date. (and this has been said by many others).

Agreeing, in fact, that action CAN be delayed, albeit at great cost.

My case is that we SHOULD delay such action while we continue to assess the issue, and the supposed solutions. (such assessment is already ongoing).

An economic study from Britain concluded that cost of mitigation at a later date would be greater, but would be paid by a population which is seven times wealthier than that of today.

Doug Bostrom #287. "The disappearing money". You are correct in that it does not disappear.

But tripling or quadrupling the cost of energy simply takes money from the pockets of all, especially the poorest (who spend a greater proportion of their income on energy) and puts it into the pockets of government, some financial trading corporations, into government bodies such as the EPA, and the pockets of the bloating UN and World Bank (The World Bank would like to be the arbiter of all carbon trading).

If we rush in I fear we will very likely end up with a world still producing similar amounts of anthropogenic CO2, just managed very differently.

Some are perhaps less interested in saving the world, but just like the idea of running it. (and no, I'm not talking conspiracies here, just opportunist maneuvering by parties with parallel interests.)

And, it does not have to be like that, if approached with care and science instead of panic and knee jerk reactions. Fifty years more research is a hell of a long time in terms of research, but an insignificant amount of time in terms of ecological change.
27. "An economic study from Britain concluded that cost of mitigation at a later date would be greater, but would be paid by a population which is seven times wealthier than that of today."

How much "later" to reach seven times current wealth?

I have seen a study that says (IIRC) delaying for about eight years will increase the cost of modifying energy infrastructure by something like 4x. In that case better hope that 7x wealth turns up in no more than about 14 years. Given what we know about world and national economies and growth rates, do you feel that lucky? I bet you don't act as if you do in other areas of your economic activity.
28. Markx, you've simply restated the "vanishing money" argument another way. It doesn't add up.

Will the EPA suck vast amounts of taxpayer dollars out of the economy and use it to retire public debt? No.

Will financial trading corporations hoard enormous amounts of cash without investing it? Trillions of dollars entirely sequestered from the economy? No.

Will the World Bank hoard enormous amounts of cash without loaning it? Sequester enormous amounts of cash? No.

What's the current balance sheet of the United Nations look like? Fat with cash? No, the opposite. You imagine that'll change? Why? How? What's the specific mechanism?
29. "But tripling or quadrupling the cost of energy simply takes money from the pockets of all, especially the poorest (who spend a greater proportion of their income on energy)..."

And your argument is poor because no-one is advocating that alone - and because it ignores the costs to the poor of climate change due to business as usual.

I don't recall seeing scientists seriously arguing that energy costs will be quadrupled if we seriously attack the problem - in contrast I have seen papers arguing that within 2-3 decades low- and no-carbon energy costs could be below current costs.

"Fifty years more research is a hell of a long time in terms of research, but an insignificant amount of time in terms of ecological change."

This is entirely incompatible with current evidence - both economic and scientific.

(Also, we've had >100 years of climate science research - how much is enough to generate valid concern? I've asked a number of self-styled skeptics who appear to be 'high proofers' - i.e. 'it's too uncertain, let's just wait until we do some more research' - what evidence they would accept as motivating serious action and to date few have made any serious attempts to grapple with the question.)

You can find papers that estimate that the last seven years of delay have already made the task of mitigation about 30% more difficult.

Or you can go here. Note section 2 - it's not the rate of emissions that matters to the climate, because it's the total anthropogenic emissions over time that most strongly influences the total amount of global warming the earth will experience.

And we've already used up a hefty portion of that total emissions budget if we want to stick to a 2C rise which was previously considered the threshold of "dangerous climate change" (noting that recent scientific work now suggests "dangerous" becomes evident at more like 1C - which we're already going to blow past.)

Then check sections 3 & 4. What are the constraints if we want to limit the globe to a total emissions budget that gives us a 50% chance of not rising beyond 2C? The longer we wait to start reducing emissions, the worse the emissions rate reductions have to be.

We could start now and reduce by a few percent per year (challenging, but well within our reach).

We could wait a mere eight years and start in 2020, but then we need to drop by a very challenging 10% per year - and even then the evidence suggests a very good chance that won't be enough.

We could wait a mere thirteen years to 2025 - and then we need to immediately cease almost all emissions.

On that basis, is it even meaningful to ask the question of how bad will it be if we wait until 2062?

(Oh, and read the rest of the article which has some discussion of what might happen if we significantly exceed 2C.)

You could also read papers on the ecosystem that indicate that the current rate of stress imposition (on top of all the other anthropogenic stresses) is pretty high and the impacts are getting worse with increased warmth. On that basis, how bad will the impact of 50 years of business as usual be? Do you actually have a scientifically informed opinion on this question, or are you basing your argument on ignorance of that particular field?
30. Lotharsonn #297.

Well, I hate to tell you this, but under your scenarios we are doomed.

China is busy opening a new coal fired power station about every 10 days (and this is a GOOD thing, having traveled extensively in China I have seen everywhere little factories, farms, businesses, all burning wet dirty coal in little old furnaces).

I can't see this economy stopping growth within 13 years. And no matter what token gestures tiny emitters such as Australia make, China matters.

My opinion. Well, I'm not sure how you measure or define "stress imposition" but I do have a lot of faith in science to continue to come up with leaps forward in efficiency (GM crops spring to mind, contraception is another, Internet communication another - educating (as opposed to indoctrinating) the populace- incredible gains in genetics both in plants and animals (aside from the miracle of GM) - efficiency gains in transport ....

All these things will continue at the same pace with or without the imposition of taxes/fees - have you really cut back your petrol usage by any more than you would have because it has gone up a dollar in the last 5 years? - answer is no - you already feel it in the hip pocket and buy and use cars as efficiently as you want to fit your lifestyle. Lets whack a bigger tax on it - and bring forward your frugality, say, five years?

Then what - an additional tax is needed every year?

"Will the World Bank .....Sequester enormous amounts of cash? No."

Sequester a proportionately enormous amount of power and political influence? Yes.

Remember the golden rule: He who has the gold, Rules.

(ie ...he who dispenses the cash, makes the Rules)
32. Sorry, my #299 is in reply to Doug at #296.
33. China's also installed the WE of 30+ nuke plants in solar domestic hot water heat in the past few years. Notice how economic growth crashed to a halt?

Sequester a proportionately enormous amount of power and political influence? Yes.

That's not even a claim of magical cash disappearance. Also it's starting to sound like not-a-conspiracy.
34. "Well, I hate to tell you this, but under your scenarios we are doomed."

You're not telling me anything I don't already think is quite likely.

"I do have a lot of faith in science to continue to come up with leaps forward in efficiency..."

Efficiency is completely meaningless if your ecosystem substrate unravels. Most people pushing this line appear to be blissfully unaware of how utterly dependent we are on the ecosystem.

"have you really cut back your petrol usage by any more than you would have because it has gone up a dollar in the last 5 years?"

Yes, and also because I wish to reduce my emissions. And I'm seeking to cut it more. But that's me. In broader terms a price on carbon will motivate manufacturers to offer still more efficient models and consumers to buy them.

You could posit alternative policy decisions to attempt to achieve suitable reductions and I'd probably be right there with you.
35. Doug #301 "China's also installed the WE of 30+ nuke plants in solar domestic hot water"

I was astonished in China 12 years ago - solar hot water systems were everywhere even then - amazing arrays on top of apartments - in spite of the haze of coal smoke blotting out the sun in hte big cities. I think 1. They are cheap and 2. They save consumers money.

Nuclear power ? Good idea, very sensible. Three gorges dam project and hydro power? Great idea.

An aside: Today in one of the local English language papers I read how Europe and USA were applying punitive duties on Chinese solar cell arrays. Stating they had received government subsidies. Now, every European and US solar cell factory has received huge government subsidies, but in spite of that the Chinese versions are far cheaper. That is the real problem.

Question: Does this sound like the behavior of governments which are interested in saving the world?
36. Lotharsson at #302 "You could posit alternative policy decisions to attempt to achieve suitable reductions and I'd probably be right there with you"

In truth, I think it is happening now and has always happened through economics and need. And fast as it can happen. All the hype about taxes and carbon credits will just create another parallel industry and channels of wealth creation.
37. .... and the funny thing about all this is that we will probably run out of oil much more quickly than peole expect:

OPEC is probably overstating their oil reserves by 300 billion barrels.

Lucky we have discovered all this lovely shale gas! AND it's cleaner burning, too.
38. "Wiping out the human race would be worth about 210 billion DALYs."

And if your accounting method must asses the loss of DALYs for every future descendant, the number is stupendously increased.

Humans also care greatly about additional factors beyond DALYs, but at least this is a start.

"...then there's no positive goal I can think of ... that would justify exposing ourselves to that chance. "

OK, good - we've established asymmetry of risk may exist in the sense that I was using the term - some impacts are so detrimental that at even low probabilities there is no viable way for a positive co-impact to offset them.

Given that there is simply no viable offset for some risks, what risk management response would you have if the evidence indicated that such a risk was present? Does this differ from risks for which viable offsets are plausible?
39. "However the scientific evidence with which I'm familiar does not suggest that the annihilation of the human race by global warming is remotely plausible."

Neither have I, but I've seen evidence that probably gets a lot closer to your DALY count than you realise.

For example, I've pointed you to an article that I suspect you haven't read where one scientist says the research indicates that a 4C future is "...incompatible with an organized global community, is likely to be beyond ‘adaptation’, is devastating to the majority of ecosystems, and has a high probability of not being stable.". Assuming for the sake of argument that the risk description is supported by the evidence, and given that the evidence strongly indicates that we're currently heading merrily for 4C and above, how many DALYs would you estimate that to cost? Given that "likely" tends to be used to indicate a probability a lot higher than 1%, would that risk offsettable?

I've seen another quote to the effect that at something like 4C warming the carrying capacity of the earth will likely be reduced to about one billion humans. Assuming for the sake of argument that the claim is supported by suitable evidence, that implies a minimum of 180 billion DALYs by the time that state is reached (and probably many more billions of DALYs on the way to that state, plus all lost descendants if you count them). What approximate probability of such an occurrence would you consider to delineate the boundary between offsettable and not offsettable for that risk?

The IPCC AR4 concluded that business as usual would result in somewhere between 1.6C and 6C+ warming by the end of the century (with more to come, and noting that IIRC this is on a different baseline to the paper referred to in the article above). The centre of the range is at about 4C. This recent paper suggests we could easily hit 4C during the 2070's - or even earlier. Accordingly, what do you reckon the chance of staying below 4C is? And if the argument that if we get to 4C it may be very hard to keep warming to that level - or even keep climate stable - has any merit, then we're at significant risk of even higher temperatures.

Those assessments might shed some light on whether your question is sufficient for the task: "For example, how likely is it that with BAU emissions we will *exceed* the optimal temperature posited by the IPCC health chapters?" Firstly, you might wish to provide a reference to the IPCC defining an "optimal temperature". When I read AR4 WG2 Ch. 8 I don't see it. But I do see the following quote in the chapter's Executive Summary [my emphasis]:

"Projected trends in climate-change-related exposures of
importance to human health will:
• increase malnutrition and consequent disorders, including those relating to child growth and development (high confidence) [8.2.3, 8.4.1];
• increase the number of people suffering from death, disease and injury from heatwaves, floods, storms, fires and droughts (high confidence) [8.2.2, 8.4.1];
• continue to change the range of some infectious disease vectors (high confidence) [8.2, 8.4];
• have mixed effects on malaria; in some places the geographical range will contract, elsewhere the geographical range will expand and the transmission season may be changed (very high confidence) [8.4.1.2];
• increase the burden of diarrhoeal diseases (medium confidence) [8.2, 8.4];
• increase cardio-respiratory morbidity and mortality associated with ground-level ozone (high confidence) [8.2.6, 8.4.1.4];
• increase the number of people at risk of dengue (low confidence) [8.2.8, 8.4.1];
bring some benefits to health, including fewer deaths from cold, although it is expected that these will be outweighed by the negative effects of rising temperatures worldwide, especially in developing countries (high confidence) [8.2.1, 8.4.1]"

The word "optimal" does not appear anywhere in that chapter, and it also says [my emphasis]:

"Overall, climate change is projected to have some health benefits, including reduced cold-related mortality, reductions in some pollutant-related mortality, and restricted distribution of diseases where temperatures or rainfall exceed upper thresholds for vectors or parasites. However, the balance of impacts will be overwhelmingly negative (see Section 8.7)."

It seems highly unlikely that the IPCC specified what you claim it did without massively contradicting those quotes. (Or if it did, then the IPCC is also quite confident of the answer to your question - we will easily exceed whatever the "optimal" temperature is and enter a region of overwhelmingly nett negative health impacts.)

Furthermore, the IPCC chapter I quoted indicates a number of effects that all need to be taken into account - and notes that they affect different populations differently, so any "optimum" is not going to be global unless you are willing to tot up negative effects in some places (which tend to be the poorer regions) and positive effects in others (which will probably turn out to be the richer ones) and collapse them into a single metric. That IPCC chapter does not do so.

So you might wish to read that article, or the underlying paper which argues that we already have little to no chance of limiting warming to 2C, and argues from its references [20] and [21] that updated understanding of impacts means that 2C should now considered the start of "extremely dangerous" climate change rather than merely "dangerous". (I've linked to the references because you seem to be entirely incapable of finding them on your own, even when pointed to the article which leads to them, despite proving more than capable of complaining that no-one has provided you any evidence. You'll have to learn though - you'll need to follow citations within those references to get to some of the evidence they refer to, and follow citations within those, and so on...) It would be fruitful to mentally do a rough accounting of the risks outlined in those portions of the literature and consider whether they reach the threshold of "unacceptable", and if not whether it is even plausible that sufficient positive benefits could accrue to offset their sum.

In that vein you might also look at the recent paper from Hansen that argues that we can now be confident that extreme weather events - which are having significant detrimental impacts whether one measures DALYs or DOLLARS - can be much more confidently attributed to the climate change we have already experienced. And then project those consequences forward to a world with rather a lot of additional warming...
40. Markx and I found something to agree on, I think!

Nuclear and hydro power: both workable as long as all the accounting is done properly, contexts acknowledged, responsibilities fully confronted, caveats remembered. Three Gorges has some notable warts, for instance but a serious argument can be made that it's the lesser of evils to choose from. Same deal with nuclear power in general; serious blemishes some of which can definitely be erased, some perhaps not, leaving nonetheless a qualified alternative to caveman combustion.

Choices here are constrained; the perfect can indeed be the enemy of the good. We should be mindful of our habits; our predilection for burning hydrocarbons should have been under continuous scrutiny and reassessment with an eye to modernization from the very first barrel burned. We forgot to do that, something we should have remembered regardless of whether C02 emissions became a salient issue.

Human nature at its finest. Party on until the keg runs dry, leaving a hangover.
41. "...with early global warming causing a net decrease in deaths."

I reckon it's quite likely you'll find this to be the case for either (or both of) one region of the world, and one or two specific cause(s) of mortality. It's also possible that you are recalling an earlier and now superseded analysis.

Whereas the easily found chapter summary that I cited reports a (necessarily rough) aggregation of the global effects of several different health impacts. And if I'm not mistaken the level of concern in the literature is now distinctly higher at lower levels of warming.

Do you wear out the spot you're standing on by going around in circles so much?

The question is clearly not about fake science. (If it were, would you really need to ask?)

It is about your assertions about a specific paper which you indirectly refer to but don't specifically cite.

And it has been already answered, although that seemed to have eluded your comprehension and I have been wondering how long it would take you to twig to the fact. To reiterate for the last time, I rejected the frame and assertions embedded in your question.

(The question is also quite amusing coming from someone who seems unaware of significant parts of climate science - even the easily found material on specific issues they claim to have an interest in - and yet seems quite sure that those parts don't indicate a robust case for concern.)
43. "The lead author kept his methods secret for 5 years, which made them unreplicable."

I shouldn't have to spell this out...

As I said, I reject your false premise(s). Publishing one's methods in enough detail for amateurs without appropriate domain expertise to "replicate" them - especially somewhat error-prone and conspiracy-minded amateurs who throw tantrums and need a lot of hand-holding and distract from actual scientific work - is not a necessary condition for a scientific paper. Not even if you repetitively chant that it is!

Publishing one's own data for anyone to play with has not been a prerequisite for scientific papers for almost the entire history of science. Interestingly publishing one's data and code is becoming more common *in* science these days, due in no small part to climate science leading the way over the last decade or two - but I don't see you arguing that practically all papers published in all of science before the last couple of decades are all "unscientific".

It seems to me that the most charitable interpretation is that you are applying current practices to a paper produced before those practices became common place without understanding your anachronistic fallacy, but a less charitable intpretation is that you are (deliberately or otherwise) missing the forest of the process of science for the trees.

Replication of computation (as you appear to imply by the term "replication", which others tend to dub "auditing") is pretty much the least useful technique to assess a scientific paper, and over the history of science repeating tests of a hypothesis, at a minimum by repeating the experiment but even more powerfully by attacking the hypothesis using different data sets and/or different methodology, has been waaaaaaay more important.

What do we find when we assess the paper that you assert, assert, assert on fallacious grounds is "unscientific"? The original conclusions have been strongly confirmed by attacking the hypothesis with other data sets and other methods!

(And one didn't have to wait for those to show up. Even McIntyre's correction, once McIntyre's error in selecting the correct number of significant components (with far more impact than the MBH error, and havent' we heard McIntyre get the wrong number of components again lately?) was corrected led to results not strongly different from the original paper! Yet amazingly one can still find plenty of people willing to tell you otherwise, due in no small part to McIntyre publishing breathless claims based on his faulty correction and doing little to nothing to correct the faulty impressions thus generated. One can also find people claiming that these fallacious claims indicate there's nothing to worry about, even though if McIntyre's faulty graph were correct it would add weight to the case for higher climate sensitivity thus more concern. It can also be strongly argued - see some of the info that John Mashey has published - that McIntyre continued to make unsubstantiated overhyped - and even arguably false - claims long after the error in his correction was pointed out. So I'm guessing since you're keen on rejecting unscientific claims that you reject pretty much all of these claims and implications from McIntyre, except for the minor error in the original MBH procedures which is now moot due to subsequent research?)
44. While we're at it here's a link to John Mashey on McIntyre's unscientific work re: The Hockey Stick.

And that comment is specifically ignoring the problems with his statistics and claims about statistics - although it links to a couple of posts that do.

Useful reading when deciding whether McIntyre's work is "scientific" or not ;-)
45. "...here is Mann's rebuttal to criticism of his statistical techniques:..."

If you have to resort to such easily perceived lies - and a private definition of the word "rebuttal" - then you should consider not resorting in the first place.

Mann's rebuttal to McIntyre's criticism of his statistical techniques pointed out in some detail exactly how McIntyre made a much larger error than MBH did.
46. " If you've ever made software you know that all software has bugs. Keeping those bugs secret violates the epistemological hygiene of science."

Repeating those claims does not make them true, nor does trying to use big words to imply standard practices should be retroactively applied before they were developed. Unless of course you have developed a time machine, in which case let me be the first to congratulate you on your impending Nobel Prize, fame, and influx of great wealth!

"Auditing" remains just about the least powerful technique for catching scientific errors, much like black box testing remains one of the least powerful techniques for detecting bugs. Much better techniques exist and science has relied upon them for centuries - sans "auditing". In all that time, no-one ever suggested scientific papers were "unscientific" because they were "unaudited".

When I worked on software systems that had direct and significant financial impacts, we did not rely on black-box testing for the financial calculations for precisely that reason. We wrote specifications for how the computations should work (much like a published paper specifies its methodology at a high level). We paper tested the specifications in as much detail as we could. When satisfied at that level we built implemented the specification not once but twice, using two different teams and two different software stacks. We then meticulously compared results for as many and devious cases as we could come up with. (And yes, we caught bugs that black box testing would not have caught - including some in other layers of the software stacks.)

Science is rather different to commercial software development (which usually doesn't do two different implementations). Even so the analogy between the dual-implementation methodology and a researcher using a different data set and research methodology should be obvious, as should the power of this methodology to find issues that can't be found by black-box testing a single implementation.

I note that you have refrained from suggesting that older papers which did not publish their data and code are "unscientific". You don't seem to have the courage of your own convictions - which is probably wise, because you'd have to throw out an awful lot of really important work if you actually applied that criterion.
47. "Mann himself admits in that WSJ article (which you should read) that his secret method preferentially filters for hockey stick signals where there are none in the data."

And as I have pointed out and which you apparently aren't savvy enough to grok, Mann has pointed out that the effect is minimal; it produces hockey sticks at least an order of magnitude smaller than that of the MBH papers and it also produces upside-down hockey sticks.

This indicates that this effect does not explain the much larger hockey stick shape in the MBH98/99 papers. That shortcoming might explain why McIntyre was caught out egregiously cherry-picking small portions of a large result set in order to try and claim the Hockey Stick was all down to this effect. You know, actually and actively mining for hockey sticks like he accused Mann et al of inadvertently doing.

"Why? Because after the statistical errors are corrected, his paper produces a non-HS-shaped curve."

Unfortunately that's false. I'd say you were lying, but since McIntyre is more than happy to encourage people to believe it - aided and abetted by failing to correct the results of his much more impactful error - you may just be ignorant.

I am rather amused, however, that you are so heavily invested in the fallacious narrative that has been spun around this paper, even though it has been both confirmed and overwhelmingly superseded.

Why do you think that is? It seems like one heck of a ... wait, look over there, a squirrel!
48. "But at best it results in two papers being published—one "buggy", one correct."

Which generates further research, which ultimately resolves the issue by identifying which one is buggy.

You don't seem particularly familiar with how science works.
49. And continuing on discussing why your use of "at best" is fallacious, you might consider these comments by chris on another thread regarding real life examples dealing with contradictory papers:

"...Work was reassessed, other labs performed experiments, critical comments were published and new papers subsequently submitted and published and papers were even retracted.

That seems to be the "norm" in science and scientific publishing and it's how issues are resolved and scientific fields progress..."
50. Is the science of statistics "all about differentiating signal from noise" as alleged by Drs. Lewandowsky and Oberauer? If so, this science is incapable of shedding light on the matter that is at issue between the "skeptics" and the "realists."

A "signal" is a chunk of mass-energy that propogates from the past toward the future. It cannot propogate from the future toward the future toward the past as to do so would be to violate Einsteinean relativity from the required superluminal speed. Thus, a signal can carry information from the past toward the future but cannot carry information from the future toward the past. It follows that discrimination of signal from noise is useful in communications systems and useless in control systems, for the outcomes of events lie in the past for communications systems and in the future for control systems. A control system is what our politicians are attempting to create through such measures as cap and trade of permits for CO2 emissions.

Fortunately, though an application of logic light can be shed on the matter that is at issue. Logic makes a different kind of discrimination. This is between inferences that are correct and inferences that are incorrect. Through the use of this idea, a decoder of can be constructed that provides information about the sequence of outcomes in the future; there is no violation of Einsteinean relativity. This idea has been successfully tried in meteorology; it has not been tried in climatology.

A requirement for construction of the decoder is of the description of the underlying statistical population. Thus far, no such population has been described for global climatology and it follows that light cannot currently be shed on the matter that is at issue between the "skeptics" and the "realists."