The typical conservative holds opinions on issues such as health care, government economics, and international relations that I may or may not agree with, but I respect as their own political beliefs.
Except one. Since when did rejecting the science of climate change become a trademark of the typical conservative? Why is science – and not just the implications of the science, the actual analysing of the graphs – such a political subject?
Think about it. Science is designed to remove political biases and follow an approved method so that repeating the same process will produce the same result. If it doesn’t, the hypothesis is proved erroneous or incomplete.
So why should political opinions influence the honest interpretation of a physical event? As Greg Craven says in his video Why There is Still Debate,
Now, you probably don’t find it surprising that more Democrats than Republicans believe in global warming, and ordinarily I wouldn’t either. But I’d been steeping myself in this question of how do you go about deciding what to believe about what’s going on with the physical world, and this split along political party lines about a physical reality just sort of blew me away. Why the heck should political belief influence one’s assessment of what is physical reality? I just got this ridiculous picture in my head of a Democrat and a Republican standing and looking out the same window—the Democrat saying “Gee, it’s pouring rain out there,” and the Republican saying “No, it’s a sunny blue day.”
The truth lies in confirmation bias. As we explain in the post Science, it is scientifically immoral – but very possible, especially with the Internet – to start with a conclusion that seems politically or socially acceptable and then build a scientific argument around it. To eliminate personal bias, scientists always start with evidence, and then choose a conclusion which seems logical.
Liberals tend to be okay with the idea of fighting climate change, because they don’t really mind regulation, and believe that the government should spend money to help as many people as possible. Preventing future natural disasters and food and water shortages seems like a good way to help people.
Conservatives, however, tend to be very opposed to regulation. Climate change is inconvenient for all of us, but especially for those on the right, as fixing the problem seems to require action that sharply contradicts their ideological beliefs.
The solution to this dilemma, of course, seems to be to decide not to believe in the problem so they won’t have to face the solutions.
Many conservatives take this quite lightly, and don’t think about the issue very much. The people whose views they support also claim that humans are not causing climate change. It seems convenient. So they accept it.
But some of the more hardcore skeptics of anthropogenic climate change make quite an amazing effort to create scientific arguments which support the conclusion they like. As Michael Tobis explains on his blog Only in it for the Gold,
The denialists are now trumpeting a very silly argument that El Nino (a quasiperiodic oscillation with energy in the 2-10 year band) is dominating secular trends in global temperature by an argument that I summarized in seven steps recently.
I would like to start the day with a shorter summary:
1) El Nino dominates interannual variability.
2) Frantic armwaving, accompanied by sciencey-looking charts and graphs.
3) Therefore, warming is predominantly due to El Nino.
4) Therefore, very not the IPCC.Of course conclusion 4 will resonate with the Not the IPCC crowd. It is the conclusion they want, er, I mean, the conclusion that their serious thought has led them to in the past, right?
The trouble is, their argument goes like this
1) The sun is the source of atmospheric energy
2) Frantic armwaving, accompanied by sciencey-looking charts and graphs.
3) Therefore, warming is predominantly due to solar changes.
4) Therefore, very not the IPCC.
As we explained on the post All Over the Map, skeptics can’t seem to agree on a consistent explanation for why humans aren’t causing the Earth to warm. In fact, each of them seems to have a different theory. They all contradict each other, but they all support the same ultimate conclusion (“very not the IPCC”) so they all endorse each other.
Does this not show blatant confirmation bias?
So I’ll make it easy for the conservatives who refuse to accept the problem of climate change because they don’t like the solutions.
Firstly, they seem to oppose action on climate change because they don’t want to be subjected to economic costs and government regulations unless it’s absolutely necessary. They don’t want to take that chance.
(I’m leaving out the part about how action on climate change could actually help the economy and jumpstart some new industries, as well as how, if we had carbon-free energy, regulation wouldn’t be necessary. Let’s not overcomplicate things here.)
However, how would the government act in the times of a crisis, such as a natural disaster or an invasion? Would they be sure to be democratic and preserve everyone’s civil liberties? Or might they compromise these for the sake of natural security? Might they ration food? Impose a curfew? Call in the army to restrain any looters? Make quick decisions without a formal vote?
How did events such as Hurricane Katrina, World War II, or 9-11 affect people’s freedoms? What can we learn from history here? There’s nothing like a disaster to bring out the draconian side of any government.
Also recall how disasters can impact the global economy. For example, Hurricane Katrina affected the transport of oil and caused the first-ever gas prices above $1/L here in Canada. We can be pretty sure that the economy won’t handle disasters well.
Even the most die-hard conservative skeptics have to admit that they might be wrong. There might be a chance, however small it seems to them, that global warming is worth fighting. And this only covers costs for the economy and civil liberties. It doesn’t go into food security, water security, disease, refugees, continuous sea level rise, droughts and floods, or prolonged heat waves.
I would argue that the economic costs and government regulations that would be necessary for even a mid-range climate change scenario would be much worse than those from mitigating the problem and reducing our emissions. This hypothesis has been quantified in the Stern Review, which suggests that action on climate change would cost about 1% of GDP, while the consequences of inaction would cost about 20% of GDP.
And that’s only GDP. Let’s not forget that not everything in our world can be measured in dollar value. What does the life of a person cost? What is the monetary value of the oceans?
So conservatives don’t want to take action on climate change because they don’t want to run the risk of economic harm or a draconian government.
However, if they accept that they might be wrong, a picture appears of much more economic harm and a much more draconian government.
Isn’t it a better bet to take action, and avoid the much greater damage to civil liberties and the economy, rather than clinging to a strategy that will only be beneficial if all the scientific organizations in the world are totally wrong?
ClimateSight 
Katrina’s impact wasn’t so much the transport as the refining of oil, by the way. If you’re interested in the geopolitical impact that damage to the oil supply (i.e. through climate change or the resulting instabilities that will appear), I highly recommend The Last Oil Shock by David Strahan. It’s not the best book on oil impact on our culture (and in fact, it spends its latter segment focusing in great detail on his native Britain…) but the opening chapters show just how vulnerable the world is to this. (For a Canadian perspective the best book is Why Your World Is About To Get A Whole Lot Smaller, by Jeff Rubin. Better book overall, but on a slightly different subject.)
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As to the general thesis of this post, I highly recommend The Second National Risk and Culture Study: Making Sense of – and Making Progress In – The American Culture War of Fact (*phew*). It looks at the way arguments are presented in polarizing social issues and tries to see how people make such decisions.
Essentially, what they did was simple: concurrent with the IPCC report in 2007, they released summaries to sample groups that were very similar to the IPCC report in that they said “the globe’s warming, we’re the ones doing it, it’s going to be bad, but we can stop it IF…”. Half of the people got summaries that suggested increased antipollution regulation, while the other half got revitalization of the nation’s nuclear power industry. What they were interested in wasn’t the group’s response to the proposed action, but rather how the group assessed the validity of the facts.
Among the “liberals” (they use a two-axis system similar to the Political Compass; full disclosure, I’m about -8/-7 on that), the results weren’t all that unexpected: reactions to both reports were similar, with the only serious difference being the “nuclear” group was less likely to give knee-jerk opposition to nuclear power (probably because they see it as a solution to a problem they acknowledge as serious). Both groups trusted the science in the study regardless of the outcome.
However, the really interesting thing lie in the responses of “conservatives” (the paper refers to them as “individualists and hierarchs”, referring to economic and social stances respectively.). Give them the antipollution one, and unsurprisingly, they see red – but interestingly, they don’t choose to accept the science and provide an alternative solution, but rather they choose to reject the science flat-out. They were even more skeptical than a control group of conservatives who didn’t receive a report one way or the other! Conservatives who got the nuclear version, though, were much more likely to accept the science and start advocating for action!
I’d like to note at this point that the two reports contained exactly the same factual information, and only differed in their prescriptions. I’d also like to say that both prescriptions are legitimate methods of tackling the problem (reduction of current emissions by restricting cheap carbon fuels + releasing restrictions on new emission-free power), so the impact was purely based on the reader’s ideological outlook – which was apparently better at shaping their view of reality than their trust in science!
What seems to be the case, throughout the entire study, is that people are more likely to perceive the credibility of information presented to them as high if they agree with the conclusions presented. This study looked at the general public, and didn’t factor in level of scientific education (climate change was just one of the issues it studied; you don’t need scientific training to have an opinion on gun control or the Iraq war), so it may not be surprising that the public as a whole forms opinions based on presented consequences rather than independent evaluation of scientific observations.
This may be why, as Michael Tobis and Lou Grinzo have noted, we can’t win the public by presenting information. A while back, Michael Crichton (in full kook mode) debated Gavin Schmidt (best known through RealClimate) over climate change, and the consensus on the outcome is that Crichton creamed Schmidt simply because he realized that facts were for losers. The inactivists seem to understand this, while those of us in the reality-based community seem to miss the point. (If we hold an opinion of “the science will vindicate us”, we’re no better than an inactivist – do we have enough time to waste saying “you’ll come around when you see more evidence?”)
There are a few activists out there who seem to get it in their new messaging approaches (to wit: Van Jones, Obama’s “green jobs czar”, on the economic approach; it’s a shame the “climate change -> national security risk” argument hasn’t found a true champion yet, but it’s in the same boat), but even that has its issues by appealing to rationality. If there’s one thing the current issue du jour in the US (health care with the mob protests) has shown, it’s that rational motivation is a hell of a lot quieter than irrational pathos. (This may explain why anything Al Gore does, even when it’s good messaging like his Repower America ads, gets demonized by association.)
There’s a saying about the left: We’d rather be right than win. Maybe that has to change – but can it change without losing focus on what is right?
Thanks for all those links, Brian. More citations are always good, and that’s a very interesting study. Many people really don’t think like scientists, yet they seem to think they’re good enough to surpass the word of NAS et al.
The political compass website is very interesting. I’m in the same quadrant as you which didn’t surprise me. A lot of the time, when people say they hate socialism, what they really hate is fascist authoritarianism – upper left box. Stalin and Gandhi simply can’t be compared, even if they did have similar economic principles.
Be advised that there are legitimate concerns with the PoliticalCompass methodology; I choose it because they get the right idea and express it clearly, not because it’s academically rigorous. The basic concept of separate axes is not well enough understood, particularly in the US where the two-party system lends itself perfectly to a narrative of just one axis.
The more I think about how scientifically-informed people stick to the “facts”, the more I suspect it’s Dunning-Kruger en masse. The upper-quartile effect in Dunning-Kruger (the part that causes the most competent people to underrate their own performance) appears to stem from the more competent people overestimating the performance of their peers as opposed to underestimating their own performance. Apply this to science: Are scientists and science communicators simply overestimating how scientifically literate the rest of the world is, or even how much the rest of the world values scientific knowledge?
I’ll see if I can figure more of this out with a literature search later this week. (I have an exam today and can’t spend too much more time in the blogosphere.)
Well, that was an interesting test. What would you guess someone who ran a reference blog which showed all views of AGW to be? So very near to dead center, even I was amazed.
BrianD, I am not surprised by the conservative responses. I am really surprised; however, that they needed to run such a marketing test. Why?
Read the report, CoRev. It’s always a good idea to go to the original source.
The quick-and-dirty is that there is selective perception of facts in the “culture wars” (that is, people arguing about how the world ought to be tend to perceive how the world actually is; normative and prescriptive statements get confused). This study was an attempt to try to spot trends and patterns in such selective perception and try to understand why this happens, allowing us to develop the tools needed to break ideological gridlock and get to productive discussions.
Look at the health protests in the US right now; that’s what happens when polarizing methods are used. No policy discussion, just ideological sniping from entrenched positions. (To be fair, the same sort of thing happens if the left gets riled up on something (i.e. PETA), but the current situation is a perfect example since the protesters aren’t even talking about what’s actually in the bill, instead listening to people who share their ideology. This follows the same pattern described in the study I cited when it talked about HPV vaccinations, except it’s used to spread disinformation instead of facilitate communication.) Such communication techniques could be used, hypothetically, to break the logjam and get both sides talking.
Or, to quote the abstract itself, Such [communication] techniques can help society to create a deliberative climate in which citizens converge on policies that are both instrumentally sound and expressively congenial to persons of diverse values. I’m sure everyone can agree this is a sound goal.
Kate got a perfect example of what this paper studies, taken to the extreme, in citing Greg Craven: I just got this ridiculous picture in my head of a Democrat and a Republican standing and looking out the same window—the Democrat saying “Gee, it’s pouring rain out there,” and the Republican saying “No, it’s a sunny blue day.” The study is an attempt to try to figure out WHY people act in this way, so we don’t fall into that trap when discussing social issues.
The problem with all social sciences is that the human mind and human societies are very difficult to understand, since we can’t stop them and take them apart to look at the underlying mechanisms. (Some of us, including my lab, take up a synthetic methodology instead, but this is is a minority view. I have a book on the subject coming out soon, if you’re interested, but a spectacular introduction to synthetic methods is Valentino Braitenberg’s Vehicles.) The common approach to handling this analytic problem is to look for patterns and trends, building a model capable of explaining them. This is done, frequently, through clever experimental design and statistical know-how. While it often makes mistakes (any fuzzy subject matter always does!), it can at least illuminate a way to make progress.
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By the way, I found an alternative to PoliticalCompass that doesn’t suffer from quite the same set of methodological problems. For one, it doesn’t really start with a preconceived notion of what the two axes are (it uses a statistical technique called principal components analysis to define two axes based on your results such that people in the same location in the grid answer questions similarly; one of the axes turns out to correspond well with left/right economics, while the other isn’t quite as easy to pin down, but is named here as pragmatic/idealistic. If you don’t know what PCA is, Tamino did an excellent series of posts on it starting here). This jives a bit more with similar academic work done on actual polling (for instance, Paul Krugman summarizes similar work on the US congress’ historical record).
Of course, this test does have a massive problem that PoliticalCompass avoids — namely, it has “no opinion” options. These are easy to program but massive dark clouds on the survey from a psych perspective, since people tend to choose middle-ground options way more often than even “slight yes/no” answers. Thus, if a person “leans” to one side or another, they should answer as such but are more likely to choose the information-free “no opinion” option, preventing the test from taking the information it needs and giving too many “center” results. (The flipside opinion, that PoliticalCompass gives too many polarized results, may seem valid but it actually isn’t. What actually happens is that you “zoom in” on the center.)
Brian – the grid/group axes used in the cultural cognition project are very different from the political compass. It doesn’t use any kind of left/right political dimension at all, but it does start from a theory about cultural attitudes.
And you overstate the results of the study: “Conservatives who got the nuclear version, though, were much more likely to accept the science and start advocating for action!”. No, they didn’t. They showed slightly elevated assessments of the societal risk from climate change than the control groups (remember, it was just a survey with fixed multiple choice questions). The key point is that their assessment of the risk never even approached the assessment of people at the other end of the group/grid axes. I posted the key graphs here (with some corrections from the original paper, after a correspondence with the authors):
http://www.easterbrook.ca/steve/?p=730
I think the cultural cognition effect clearly explains how many people filter evidence to fit their world view. But unfortunately, it doesn’t really tell us what to do about it. Individualists don’t simply go out an advocate climate action when presented with evidence in the right way. For that to happen, they have to hang out with a peer group who also advocate strong action. What we’re really looking for here is a political earthquake, but I don’t see any signs of it happening in North America soon.
I think we should still have hope for a political breakthrough. I was listening to this podcast yesterday (apologies if only Canadians can download it – I don’t know if it’s geolocked or not), where David Suzuki interviews a lot of people about climate change and sustainability. Al Gore (who I’m hesitant to endorse because skeptics fall all over themselves bashing him, despite no scientist ever citing him, but who knows a heck of a lot about climate policy) said something along the lines of, “Politics are a lot like climate. They don’t always change in a linear fashion, where small changes merit small results, in the slow, one-step-forward and two-steps-back manner we’re used to. It can happen, and it has happened, that suddenly a lot of progress can be made in a short amount of time.”
I think it would be okay if it was any country other than the US that’s in this situation. The US is possibly the most conservative country in the world, and this influences their climate policy greatly. I mean Canada’s in much the same situation, mostly because our PM hails from the land of the tar sands, but we’re such a small economic power comparatively that nobody really cares what we do. The US, however, will influence all the other countries that haven’t yet taken action on climate change. China, India, and yes, even Canada, won’t take significant action unless and until the US does.
I believe that for the world to successfully fight climate change, all that needs to happen is for the US to begin their fight, and that will be the tipping point that merits non-linear progress.
Steve: I didn’t say PoliticalCompass and the study used the same axes; I used the former as an example of a two-axis system since I find it communicates the idea better than the latter.
The line about “advocacy” comes from an interview between one of the authors (Donald Braman) and Gwynne Dyer, drawn from episode 1 of the Climate Wars podcast (roughly halfway through). I should have mentioned that too.
Sorry if there was any confusion. I should have communicated better.
No problem. I followed the reference from Gwynne’s book, because his description sounded both fascinating and too vague. But I ended up having to contact the authors of the study to understand what their result actually show. I try to read the original paper for all such studies now, because even the most honest of writers (and Dyer is normally excellent) manage to get the results and implications wrong from time to time. And there’s already way too much noise being injected into the climate change discussions.
I don’t think the communication gap here can be bridged. Think about the dynamic between a parent and child discussing risk. Whether the topic is crossing the street, talking to strangers, using the stove, driving a car, setting off fireworks, or balancing near a cliff, mom is likely to overstate the risks a little. “Ask a mom and you get a worst-case scenario.” She is attuned to the downside; she knows what the worst possibility is and over-weights its likelihood. If you cross the street alone, she knows you’ll get hit by a car. If you talk to a stranger you’ll get kidnapped. And she doesn’t just overweight the risks; she also under-weights the benefits – how much fun you are likely to have doing the forbidden thing, whatever it might be. And she doesn’t trust her kid to judge the risks for himself.
So mom exaggerates. But the kid *knows* that mom is a worrywart, so the kid automatically discounts everything mom says. If mom says something is risky there’s probably *some* risk there, but it’s sensible to figure it’s being overestimated by at least an order of magnitude. So you can pay a little attention to mom’s worries, but not too much – you don’t want to take her too seriously. And mom *knows* the kid is discounting what she says and not paying close attention, which gives mom *even more* incentive to exaggerate, which gives the kid *even more* incentive to discount.
This is a stable equilibrium. Once started, the dynamic is nearly impossible to break because it would require both parties to change at the same time.
Conversations between environmentalists and enviroskeptics have that exact dynamic. Environmentalists are “mom”. They “have to offer up scary scenarios, make simplified, dramatic statements, and make little mention of any doubts”, to quote Stephen Schneider. They do this partly because that’s what gets publicity and funding, but they also do it because if they accurately portrayed their certainty level it would give “the other side” a reason to ignore them. So they exaggerate a bit. They also tilt the playing field in various ways. They avoid public debates, they share data and methods only with fellow travelers to the extent they can get away with this, they try to avoid even *mentioning* anybody on “the other side”.
The skeptics *know* this is happening, so they discount the claims they hear made by environmentalists. The environmentalists *know* their claims are being discounted, so they find every excuse to build them up even more.
A stable equilibrium.
I’ve gotten in the habit of checking the reports as well (even adopting Eli Rabett’s mantra, “RTFR”), which is how I tracked down the original. I just assumed the line from the podcast (which doesn’t appear in the book version, IIRC — my copy’s on loan) about conservative advocacy was said in good faith and removed from the original for any of a number of procedural reasons (perhaps the result was present but not statistically significant, or subjectively observable but objectively unquantifiable – both problems in social sciences that can cause results to go unreported since peer review often asks for statements like that to be removed).
Although I haven’t mentioned that aspect of it in other places where I’ve mentioned the study, I’ll avoid bringing it up anywhere in the future. (Even those of us experienced in both communication and scientific practice occasionally screw up, so I’m thankful for the reality-check.)
Still, I’m too shy to contact the authors – it’d be very interesting to hear what they had to say (within the limits of privacy, of course).
Glen – that’s a very interesting way of looking at it, and something I hadn’t quite considered. However, we have to examine two things:
1) The media, journalists, and advocates will exaggerate. The NAS, IPCC, etc will not. Their reputations are staked on it and they will not make claims they can’t back up. So it depends on if the skeptics are listening to the “environmentalists” or to the “scientists” – and if they’re equating the two.
2) This phenomenon doubtlessly accounts for a lot of the conservative skepticism out there, but as we see in the most recent post A Well Documented Strategy (it’ll be in the “Top Posts” sidebar), there are people out there who are deliberately trying to deceive us. So there are people who will carry on ignoring the claims of their opponents no matter their credibility.
And please, please look up the story of that Schneider quote before you go around quoting it!! https://climatesight.org/2009/04/12/the-schneider-quote/ and if that doesn’t seem like enough you can visit his full explanation of it at http://stephenschneider.stanford.edu/Mediarology/MediarologyFrameset.html
I’ve read Schneider’s account and yours but I think the quote is just as damning in its full context as in all the partial ones. Either version describes pretty well what the IPCC does. (Incidentally, if you really want to address damning quotes from folks on your side of the aisle, you should get Phil Jones to clarify what he meant by, “Why should I make the data available to you, when your aim is to try and find something wrong with it.” http://www.theregister.co.uk/2009/08/13/cru_missing/ )
The IPCC definitely plays the “mom” role. The IPCC offers up lots of “scary scenarios” – as per Schneider’s suggestion – in a context that is meant to imply to the reader that these are certain or near-certain outcomes, but they don’t follow the sort of rules that would give such claims accountability. First we got the claim that these are just “scenarios”, not “predictions” but somehow we should still treat them as if they had some degree of predictive power. Then when they got flack over the fact that many claims being made wouldn’t pass a 95% confidence interval – the usual standard used in scientific disciplines to exclude a lot of results that are likely due to chance alone – the IPCC just invented new terminology – “likely”, “highly likely”, and such – so they could still include claims in their documents that were subjectively believed to be only 90% or 80% or even 66% certain. A more responsible scientist might prefer to *leave out* claims with only an 80% certainty and instead try to base conclusions and discussions on evidence we can actually be pretty sure of. Or qualify the premises or do a larger study or something until they *get* 95% certainty. But the IPCC is about politics; its purpose is to make a scientific-sounding case for a particular outcome so they can’t just go excluding weak evidence; they have to find reasons it’s okay to include it. They also apply the rules on publication date and such selectively so that studies and comments they like get in and those they don’t like get excluded. The scientists who do this – fudge the rules to make the case look stronger than it is to whatever degree that they can get away with – do so because they think this issue is *really important*, too important to wait until we have an *actual* scientific consensus before doing something about it. They’re jumping the gun just a little, figuring that that eventually the science will pan out to support the claims being made today.
The NAS isn’t nearly as bad as the IPCC, but they do engage in some science-by-press-release. If you read the underlying documents it tends to be pretty sound but if you go by their public statements – even accurately reported ones – you get a warped view of the findings that has a particular deliberate slant to it. Notable example: the chief *interesting* finding of the NAS hockey stick study was a confirmation that indeed we couldn’t reliably conclude anything about whether the MWP was warmer than today. In their public statements they buried the lede and instead emphasized “temperatures warmest in 400 years!” That is to say, that it’s been warming since the LIA. We knew that already; it wasn’t news. The *news* was “temperatures NOT proven warmest in 1000 years”. And then there’s the whole bristlecone thing, but I don’t think that mistake was deliberate; I think the NAS investigators honestly believed the “independent” confirming studies in their spaghetti chart actually were independent and not flawed in the exact same way as the study they were looking at; they were careless and got fooled. But I don’t let Mann & company off the hook so easily; there do seem to exist a few deliberate deceivers on your side, just as there do on the other side. Or perhaps they’re all just people who believe their own PR.
In short, I do think that some of the environmentalists who are exaggerating their certainty levels are scientists working through scientific organizations; it’s not just reporters and politicians and PR flacks doing this.
I personally would find the case for worrying about AGW a lot stronger if I didn’t see such tactics being used – if the scientists involved published their data and methods promptly, disclosed all their doubts, went out of their way to emphasize rather than hide the uncertainties involved, and directly confronted their critics. But I don’t expect them to do that, because they are stuck in the “mom” mindset.
And thus, I am stuck in the “kid” mindset. :-)
When you’re creating scientific reports which will influence policy you want to include the worst-case scenario. If there’s an 80% chance of something awful happening, you want policymakers to know about it. It’s not a crime to make a claim which is uncertain, as long as you acknowledge that it’s uncertain.
In World War II, did Churchill say, “I’m not 95% sure that Hitler has plans to take over Britain, so I’m not going to tell anybody it’s possible”? Should he have? Is there sense in withholding information from the public just because it’s uncertain? That makes it seem like it’s impossible, which is just as bad as claiming it’s absolutely guaranteed.
There’s also a fallacy of dismissing someone’s words simply because they’re describing a drastic scenario. It doesn’t fit with our learned assumptions (being, in a Western society, that nothing truly awful can really happen to us) so we are automatically predisposed to believing claims which seem closest to what we already know. This helps filter out a lot of rubbish, but, when the drastic-sounding claims are coming from a credible scientific body, is it really the best strategy for risk management?
It’s sort of like believing your doctor when he tells you that you’re healthy, that maybe your blood pressure and cholesterol are a little high but it’s nothing much to worry about…..but then a few years later he tells you that you’re going to have a heart attack any day now. The idea seems impossible to you. So you dismiss it, simply because of what it is, not because of how it is backed up.
Forget all the PR statements if you’d like – those are really just for the people who don’t want to read, or can’t understand, the scientific reports. They’re obviously more drastic because many people could interpret the inherently uncertain language of science to mean that scientists aren’t sure. Basically, scientists have to translate their scientific statements into something that the public will understand. They’re expected to do this, especially when studying an issue of public importance. They’re not trying to exaggerate anything, just to state it in the language of their audience, which is inherently more simplified and dramatic than scientific reports. As you’ve shown, it’s possible to overshoot and have people disregard you for another reason. But even when the perfect balance is kept, the public can fall into the trap of ignoring you just because of what you say – not why you say it.
It’s an issue of scientific literacy. Which you obviously have – so you can forget the PR stuff, which isn’t intended for you anyway, and go download the reports to really keep an eye on this issue.
Keep in mind that the IPCC still does eliminate a lot of risks because they don’t know them well enough. The release of methane hydrates from the permafrost, which has triggered major climate changes and extinction events in the past, is not included in the models because nobody knows at what point they will be released – yet it could easily end up being what kicks us over a tipping point. They don’t understand exactly how or when the Greenland and Antarctic ice sheets will melt, so they only include thermal expansion in their estimates of sea level rise.
Yes, the models are uncertain and often wrong, I wholeheartedly agree – but skeptics tend to assume they’ll be wrong in the direction that everybody wants, where global warming turns out not to be a problem after all, whereas the past few years have taught us that they’re almost always too conservative and things turn out worse than we thought.
Have you seen the video Nature of Science by Greg Craven? It does a great job of explaining how science is uncertain, how unconscious assumptions of what we think we know (eg that everything is going to be okay) skew our risk management skills, etc. I think you’d enjoy it. If everyone knew about this kind of stuff, nobody would have to make simplified PR statements.
> The IPCC offers up lots
> of “scary scenarios” – as per Schneider’s suggestion – in a context
> that is meant to imply to the reader that these are certain or
> near-certain outcomes,
Perhaps you should read them again, they are on-line, you know. These are _most likely_ outcomes. With lots of scatter _to both sides_.
> A more responsible scientist
> might prefer to *leave out* claims with only an 80% certainty and
> instead try to base conclusions and discussions on evidence we can
> actually be pretty sure of. Or qualify the premises or do a larger
> study or something until they *get* 95% certainty.
So you don’t know the difference between hypothesis testing and risk assessment. A policy maker wants to know about _all_ serious risks, also the low probability ones.
> Notable example: the chief *interesting* finding of the NAS hockey stick
> study was a confirmation that indeed we couldn’t reliably conclude
> anything about whether the MWP was warmer than today.
You just illustrated the point that science illiterates will misunderstand, intentionally or otherwise, any statement of uncertainty that scientists bother to make. Read it again, this time with comprehension. It is very close to the uncertainty statements in the original papers. (And the MWP as a whole being warmer than today: in your dreams.)
> But I don’t let Mann & company off the hook so easily;
> there do seem to exist a few deliberate deceivers on your side,
> just as there do on the other side.
Libel (before the comma, that is). Did you ever meet an active research scientist?
About “sides”, I would like us to be on the same side, that of the truth. I admit to being a bit naive there.
Easy there, Martin…..play nice…..I want this discussion to continue but I don’t want any violations of the comment policy (aggression, name-calling, etc). Thanks. :)
climatesight, would you please bullet-list my violations (or near-violations) and why they are? Thanks!
“So you don’t know the difference between hypothesis testing and risk assessment.”
“You just illustrated the point that science illiterates will misunderstand, intentionally or otherwise, any statement of uncertainty that scientists bother to make.”
If you had said something like “it’s important not to do this” instead of “you, personally, are guilty of this”, it would have seemed much less aggressive and less intended as an insult. But don’t worry too much about it. Just remember that people will pay more attention to your ideas if you’re nice about them.
Thanks
Kate
Hmmm. Thanks, I’ll try to… goes against the grain as a scientist though.
We’ve known all along that this public “debate” is not one of science but one of politics……:)
climatesight, if you want to prevent aggression in the discussions, one good tip is to refute falsehoods immediately as they occur. A suavely brought, well-packaged falsehood makes folks like me see red. Take care of it on the spot.
You knew that the claims I refuted were false, didn’t you? If not, why are you blogging? Do your homework… yes, it is a lot, and not all of it easy. I have a background in geophysics — not specifically climatology — and it took me several years to read up.
And the “reading up” that is needed is not only, or even principally, in the science… it is learning to know and recognise all the talking points and their most effective refutations, i.e., more of a lawyer’s than a scientist’s job.
Tamino does a good job on the science, but his refutations are often humorless — he is a poor lawyer [compliment]. Eli Rabett again is much better at the tone of murderously gentle ridicule that most effectively disarms the most outrageously dumb talking points. You’ll have to find your own style. But it is hard work.
All the best
Thanks. I’ll give some thought to all of that. Of course I knew the claims were false, but I hate the shouting matches that so often occur on blogs like these. I’m trying to find the best way to prevent them. And if I am willing to delete a comment that’s aggressive on the side of the debate I don’t like, I’m obliged to do the same for those I agree with.
Climatesight: I’m going to ignore Martin because our worldviews are too far apart – it would take us too far afield to try to reach any sort of consensus on the underlying facts and he’d have to be willing to explore the arguments against his views, which by his tone I suspect he’s not willing to do. Plus, like he said, having such conversations “is hard work.” :-)
But I find the question you originally posed interesting. I should first warn you that I’m not a conservative, much less a “typical” one – I’m an ex-liberal libertarian. But I think I understand both sides well enough to understand where some of the differences in perspective are coming from. I agree that there’s some confirmation bias going on, but I don’t think you’ve fully captured the underlying dynamic – the nature of the biases that are being confirmed. I think conservatives base their conservatism – and environmentalists their environmentalism, and liberals their liberalism – on deep insights that are rarely well-articulated or communicated. If you’re in the tribe, you already understand these things so you don’t need to discuss them; if you’re not in the tribe you have too little shared context to make it worth discussing. But I’ve been trying to figure it out for a while and I think I have at least a hint of a glimmer of an understanding of my own underlying thought processes. So let’s see where we can go with it.
People do have a status-quo bias – they tend to expect the future to be like the past – and I agree that we shouldn’t reject predictions because they seem extreme. However, one bias I think I share with many science-minded conservatives is that I find it deeply unintuitive that the climate could be dominated by significant positive feedback effects. Positive feedback processes are rare because they are unstable – they tend to amplify any initial random perturbation. They tend to explode. The climate does not seem to do that. You could get scary scenarios by looking at the plausible positive feedback effects you can find currently in operation or expect to kick in in the future, assuming they’re all additive and projecting it forward, but in fact every feedback effect has to have some *effective range of operation*. It’ll kick in, then it’ll run out of steam and other effects will dominate.
For example, take the one feedback everybody knows about – the ice-albedo effect: In the warming direction, once all the ice has melted, that effect stops. In the cooling direction, once all the planet is covered with ice, that effect stops. Somewhere in the middle there’s one or more peaks to the strength of the effect. So you can’t modify your sensitivity estimate by X to account for this effect – it has a variable kick to it and the size of that kick will shrink as the planet warms. (IPCC actually does take this into account in the most recent simulations but it’s an underappreciated point in the public dialog)
So, I find large multipliers and “tipping point” scenarios inherently implausible and tend to discount predictions that suggest them. Environmentalists, on the other hand, are used to thinking of the planet as fragile, on the verge of collapse and in need of protection. So they have a low bar and I have a high bar to accepting doom-and-gloom claims.
Which brings us back to the issue of scientific certainty. The 95% confidence standard is of course arbitrary and does undoubtedly exclude many true claims from consideration. But it’s also *necessary*, because scientists are constantly testing zillions of scary hypotheses that might plausibly be true and without some sort of filter we’re bound to accept a large number of false claims. “Plausible” cannot be our cutoff. Even “highly likely” isn’t good enough. Something that seems to work reasonably well as a cutoff is “this correlation is significant to at least the 95% level, we have an underlying theory of causality that explains a mechanism that would produce this relationship, and our data and methods are publicly available so the result can easily be verified by other scientists.” Greg Craven is right that we can never expect absolute certainty from science, but we *can* expect better than we’ve been getting on this issue so far. We can expect climate claims to be subject to the same sort of statistical tests and meet the same statistical standards as claims we accept in other scientific fields.
Some of the work the IPCC bases its conclusions on meets this standard, and some does not. If they were reaching conclusions I found plausible for other reasons I’d be less likely to gripe. But since the conclusions are implausible, I have to be a stickler with respect to how they were reached. If the process by which the conclusion was reached falls down, I have to conclude that the IPCC has thus far failed to make its case. “Extraordinary claims require extraordinary evidence”.
Which does not mean any *particular* alternative hypothesis is correct. It means other hypotheses might be worth considering, but maybe we don’t have the answer yet. Maybe the IPCC has part of the answer and other people have other parts. Or maybe the IPCC *is* correct and will manage to prove it even to my satisfaction after a few more iterations, after which I’ll be able to climb on board.
The math on whether it’s worth “doing something” is similar. To claim we need to invest in stopping global warming is to claim not just that this is a big problem, but that it’s a bigger problem than *every conceivable other problem* we might use the same resources to address, which is a pretty big claim. To answer Greg’s old “what’s the worst that could happen?” question, the worst that I could imagine happening is that we waste resources for the next century making tiny steps towards addressing a small- or non-problem and as a result, when the *next* big threat to humanity comes along we don’t have the resources to address it. Could be a meteor, a plague, some sort of resource crunch, but whatever it is, slowing things down by even 1%/year means the planet is less than half as wealthy and technologically capable in the future than it might otherwise be, which could mean the difference between being able to trivially afford to fend off the next threat and total collapse of civilization. Somewhere in that range – though a little less worth worrying about – is the possibility that the next threat is something we *can* deal with but to do so causes a huge government crackdown and economic cost to a degree that wouldn’t have been necessary if we hadn’t wasted all this money addressing climate change. In any case, that’s how “my own logic” applied to the general question of hypothetical near-existential threats suggests we hold off a bit on reacting to this *particular* one.
What you say about the climate being stable, not exploding, being resistant to positive feedbacks – do you have any citations to back that up? All the research I’ve been exposed to shows that the climate can change even faster than we first expected – look, for example, at how the interglacial warming can’t be explained simply by solar changes. It was the geological feedbacks of greenhouse gases that made it warm as quickly as it did. I’m trying to find some examples for you but I’m getting REALLY tired of every second Google result being “top 10 reasons global warming is a hoax” or something to that effect. Heartland et al. Anyone with more experience in this issue want to step in with some citations of historical tipping points?
Something seeming “unintuitive” isn’t good enough in science. You need evidence. You need to at least remember that you’ve read it somewhere credible. Where have you (recently and credibly) read that “the climate does not tend to explode”? Or is that just an assumption you make?
Yes, feedbacks do run out of steam, but there are many feedbacks which are all interconnected. The ice-albedo warming, for example, would cause warming which would trigger the ocean-solubility warming, and there is so much CO2 in the oceans that it could just keep coming and coming. There is plenty of time for significant damage to be done before all the feedbacks run out of steam. As this study (er, press release of a study….I need access to these journals) shows, the positive feedbacks within the climate are enough to counteract the logarithmic forcing of CO2 so much that the relationship between our CO2 emissions and total temperature change is linear.
Again, what do have to back up your belief that feedbacks are inconsequential? Why do you think that they are “rare”? Is it through scientific research, or is it just your own thoughts? The findings of the IPCC seem “implausible” to you because you hold assumptions about climate sensitivity which contradict the prevailing scientific beliefs. If you compare the conclusions to the most recent science, they’re not implausible at all. They’re very scarily plausible. You have to decide whether you trust your own amateur judgement and analysis of scientific events more than you trust that of scientists who have dedicated their career to climate. Read the posts Making Up Your Own Science and The Credibility Spectrum for more.
It’s not enough to simply decide not to believe in the power of feedbacks and tipping points because they seem unintuitive. To justify this non-belief you have to scientifically refute the mainstream. All you’d actually have to do would be to build a valid climate model that showed that climate sensitivity was less than 2 C (most models put it around 3 C). If you can do that, then you’d have a chance at convincing us that climate change isn’t something to worry about.
You also seem to imply that you think the IPCC is separate to all other science. That is untrue – the IPCC does not do any of its own research, it simply compiles that of all peer-reviewed science since their last report, in a way that’s concise and comprehensive enough for policy makers to view all at once. It isn’t the IPCC versus everyone else. The IPCC iseveryone else in the science world.
Climate claims are absolutely subject to the same tests and standards as other areas of science. Remember, this is all based on century-old physics. The actual “hypotheses” began in the early 1800s. The calculations of CO2’s forcing were created in the late 1800s. A great book, available online, on the history of climate science is The Discovery of Global Warming. Reading it, you’ll find that every step of current climate theory was carefully challenged. It wasn’t thrown together in an afternoon by Al Gore.
AGW is not a theory. It is the logical product of theories, as Michael Tobis eloquently explains. If you want to prove that AGW is implausible – prove Fourier, Arrhenius, Milankovitch, Callendar, Keeling, etc wrong. The idea that the warming we’ve already experienced is caused by us has very high confidence. The IPCC puts it at >90%, and that’s in 2007 (each report gets successively more confident, and the IPCC is often criticized as too conservative in its claims). The next level of certainty is >99%. So chances are that it passes the 95% test. The idea that human activity is a radiative forcing on the climate (whether or not we’ve seen the effects yet) holds even higher confidence.
The work that does not meet the 95% standard is the little details. How much it will warm, how much CO2 is safe, when the ice sheets will break up……those are the predictions which are subject to a lot of uncertainty. A lot of this uncertainty comes from emissions scenarios, ie whether or not we decide to act on this problem. However, when these projections are proved wrong, it’s almost always because it turns out worse than we expected. Hoping that the uncertainty in climate models will fall on the side of everything working out okay is, unfortunately, quite naive.
So yes, the basic mechanisms of climate change being bad hold very high confidence. But scientists like to talk about new, cutting-edge research and ignore the stuff which is already well-understood. Even in the popular press, you hear more about scientific uncertainties than you do about certainties. So the idea of high climate sensitivity is probably a lot less uncertain than you may think.
I find it interesting that your idea of the worst possible scenario has to do with economics – human-created – whereas mine is geological. Isn’t it easier to manipulate a system that we, ourselves, created? We can change our economic system if we have to. We can create money out of thin air if things get really bad. We can’t change the physical laws of the Earth.
Your last point….that the money would be better spent elsewhere…..assumes that climate change is separate to other problems. Personally, I can’t think of a problem which wouldn’t become worse with climate change. Whether it is environmental, social, economic, political, public health……wars, diseases, unemployment, loss of liberties….would all become worse in an unstable climate.
It also assumes that our money would be “wasted” if we acted on climate change and it turned out to be a non-problem. The most basic action needed is to get off fossil fuels. Even if climate change was false, we’d also have avoided an oil crisis, as oil supply will almost certainly peak within my lifetime. America would have more energy independence and be less reliant on politically unstable countries like Iraq for their resources. Countless deaths would be avoided from pollution and smog. Cleaner, more efficient technologies would be available on the market and to developing countries.
It also assumes that climate change action would cost a lot. Check out the video “Risk Management”, also by Greg Craven, which explains what he found when he looked for the worst-possible economic scenario.
It also assumes that endless growth is the only way to solve problems, and that GDP is an accurate measurement of quality of life. It assumes that we’re trapped in our current economic system. Go read some David Suzuki.
Finally, be nice to Martin. You’re assuming he’s closed-minded. Remember that you’re the one who’s disputing the prevailing scientific opinion on climate sensitivity.
(Requests for some of our regular commenters, like Brian, who are well-phrased in climate science: I’d love some citations of 1) paleoclimatic tipping points and 2) feedbacks increasing climate sensitivity.)
I changed my mind about Martin. Thus:
Martin:
Easy answers first: Yes, I’ve met research scientists. In fact, my dad was a research scientist. Regarding Mann, Wikipedia’s entry on Defamation says “an insulting statement that does not actually harm someone’s reputation is prima facie not libelous.” Plus he’s a public figure, plus if his reputation survived the Wegman Report he’s libel proof, plus it was unfalsifiable opinion, all valid defenses. Not to mention that I offered a caveat and (including the caveat) reasonably believe what I said. Apart from those few teeny tiny little nits, I’m sure you have an an excellent case and should run right out to waste money consulting lawyers about it. :-)
I disagree with your ranking of Tamino relative to Rabett. I read Tamino regularly because he’s usually smart and conscientious; I gave up on Eli because he comes across as more interested in point-scoring than honest discussion. Some people give their opponents some benefit of the doubt while others assume their opponents are lying weasels and try to construe any statement in the worst possible light. You can guess which I prefer.
There’s a big gap between what is generally known, what is reflected in the literature, and what is reflected in surveys such as the IPCC reports. I suppose we shouldn’t be surprised at that after reading this (funny!) story of how to publish a scientific comment in 1 2 3 easy steps:
So with regard to “what is known” about the MWP, please let me know what, if anything, you disagree with in McIntyre’s recent Ohio State presentation:
Click to access ohio.pdf
No, it’s not a peer-reviewed paper, but it’s the best general-audience summary of recent issues and meta-issues related to proxy-based climate reconstruction that I know of. Climatesight, I’d appreciate your take on it too. Thanks!
I’ve been reading both ClimateAudit and RealClimate from the start and my take on the proxy controversy is that Mann and his co-authors appear to be guilty of confirmation bias – they *expected* their studies to show record-high recent temperatures relative to the last thousand years or so, so they ended up accidentally cherry-picking proxies and methods that did seem to show that. We know this because if we test their studies using more recently-collected out-of-sample data, the conclusions collapse. The conclusions also tend to collapse if we specify data selection criteria and methods *in advance* from the entire universe of data available and use either all the data or the most current data or the data sets best thought to reflect temperature by their originators.
My own professional area of expertise is software quality assurance so I’m pretty familiar with this dynamic: the people who invent a new algorithm or process often aren’t the best people to test it. People grow attached to their code/conclusions and resist testing in ways that might show a weakness or failure. In that light, looking at McIntyre as the “tester” of the Hockey Stick, I see that he found fatal bugs such that that product shouldn’t have been “shipped”. The “spaghetti chart” at first seemed like a possible workaround but on closer inspection has the same fatal bugs and also is not yet in a shippable state.
So, contrary to the IPCC claims, we *don’t* know from sophisticated proxy studies that temperatures are historically unprecedented. Independent of that, we have direct evidence to suggest that in a great many specific locations they aren’t (most notably: old higher treelines. Also: old foliage and sediment revealed by retreating glaciers). Which means we have some safety buffer – temperatures in those regions would have to get a lot warmer before they were “unprecedented”. Which puts us further away from any hypothetical “tipping point” than was previously thought.
If, as some suggest, the multiproxy issues “don’t matter”, that section should be removed from the IPCC report and any conclusions that depended on it – including sensitivity calculations – correspondingly weakened. All the professional associations can then reassess any statements they want to make about it. Until that reassessment is done, it’s sensible to take IPCC-inspired confidence statements with a grain of salt.
The IPCC does *not* simply summarize all the available research; the lead authors have an agenda, a point of view they are trying to express and they tend to systematically exclude research that runs counter to that view. They also use the IPCC as a platform for making claims that go beyond what the report actually says. McIntyre’s presentation I linked above touches on this a bit; another relevant data point is Chris Landsea’s resignation letter: http://www.climatechangefacts.info/ClimateChangeDocuments/LandseaResignationLetterFromIPCC.htm
We already knew it was warmer in some locations – especially northern Europe. Nobody’s disputing that. But what we care about is the world overall. Take 10 minutes and watch this video: http://www.youtube.com/watch?v=vrKfz8NjEzU
And if you’re looking at the world overall, nobody cares about the hockey stick! It’s outdated! Yes, Mann made some mistakes, but as the NAS found, the conclusion did not “collapse” (I don’t know where you got that from). If you want to refute paleoclimatology the figure to examine is from the most recent IPCC report: Figure 6.10 b, the “hockey team.”
You have lost a lot of credibility to me now that you’re claiming that the IPCC has an agenda and stifles opposition. Give me one example of an article running counter to the IPCC’s conclusions that was peer-reviewed, had stood up to criticism (ie not Baliunas’ study), was submitted to the IPCC, and was refused. I’ve yet to find something that even meets the first 2 criteria.
Or perhaps you’re rehashing the story of Benjamin Santer? Sorry, but nobody’s going to believe you there. You can accuse someone of having an agenda and stifling opposition as much as you want. You can yell as much as you want. But unless you can provide a tangible example of how the IPCC has failed to include reputable studies which oppose their conclusion, it’s an empty claim.
> Anyone with more
> experience in this issue want to step in with some citations of
> historical tipping points?
Well, Snowball Earth comes to mind. And the following Hothouse Earth. With the added merit of actually being mediated by variations in CO2, and not much else.
Glen: I changed my mind about you too — too much work :-)
…and no, I don’t take fringe blogs seriously. Call me closed-minded, I’ve been called worse.
About positive feedback, it is a very common misconception that it _must_ cause a runaway / tipping point. Just not so. If sensitivity without feedback is S0, and with feedback S, then we have
S = S0/ (1 – f)
where f is total feedback (including the interactions between different feedback contributions). This formula is obtained as the sum of an infinite geometric series:
1 + f + f^2 + f^3 + f^4 + … = 1/(1 – f).
representing the feedback feeding back upon itself, over and over again. 1 is the original forcing.
As you see, for f -> 100%, we get S -> inf, runaway. For f 2.0.
All right! People are starting to use physics equations in the comments! I officially have a very nerdy blog.
Climatesight: I’ve watched the video you just referred me to and, sad to say, it didn’t say anything I didn’t already know. Please, *please* read this paper I referred you to earlier; it covers not just the hockey stick and the response to it but also the spaghetti charts produced by “the hockey team”, what proxies they have in common, what’s wrong with those proxies, how sensitive they are to appropriate variation of inputs, what happens when you update the proxies, and how the IPCC responded to attempts to include this info. It’s an easy read! It’s got friendly pictures and charts, you’ll be through it before you know it, and then you can tell me how wrong I am and assign me another long video to watch. :-)
That link again:
Click to access ohio.pdf
I’m sure it’s very convincing, and that all of its arguments seem totally logical. But if it’s supposedly so good, why can’t he get it published – even though science is all about disproving hypotheses?
I find it interesting that it is addressed to an audience of laypeople, instead of the scientific community. What does that tell us? It’s a PR project, not a scientific one. Chances are, the scientists aren’t listening to him. This could mean that the vast majority of the climate science community is biased against the conclusion that everyone wants – for climate change to not be a problem after all. Or it could mean that it’s obvious to anyone who has studied this stuff that McIntyre’s wrong. Given the track record of skeptics’ claims, I know which one I’d place my money on.
Personally I don’t know a lot about the technicalities of climate proxies. So it all comes back to credibility. I don’t trust my own analysis of the data, given competing points of view. The arguments might seem totally logical but that may or may not mean they’re scientific.
So on one hand, we have a speech by a fringe blogger. A speech that anyone could make, that doesn’t have to fit any sort of scientific standard, that just has to keep people’s attention. On the other hand, we have the largest peer-reviewed project in the history of science.
Are the 45 pages worth my time? Given the credibility of the source, I doubt it. Like I said, I don’t trust my own analysis. I’m not saying that the IPCC is necessarily right and McIntyre is necessarily wrong. But for the purpose of risk management, I know which one I’d place my money on.
How does one embed links here? I tried doing so earlier using standard HTML and the links got stripped. So I’ve been settling for standalone links, but that’s kind of ugly when the links are long.
I’d forgotten about Santer – that was *ages* ago!
On a brief review of both sources, I’d say the McIntyre paper covers essentially everything in that “Climate Denial Crock” video *except* for what’s specifically wrong with Mann08, since that came out after the OSU talk. We can discuss that if you like but the flaws are similar to those of the other studies. Google “inverted Tiljander” for a cute twist, though…
But if it’s supposedly so good, why can’t he get it published?
Wow. I hadn’t expected you to be *entirely* unaware of McIntyre, or quite so reluctant to check out a recommended source. I looked at *your* links without whining nearly this much; how about some quid-pro-quo? :-) Okay, fine…so let’s back up a bit. On your “credibility” scale, Stephen McIntyre rates quite well in that, among other things, he periodically publishes articles and comments related to climate issues in the peer-reviewed literature. Articles and comments which I have read, and you have not. To bridge that gap I *could* recommend you read specific published papers of his, but you wouldn’t really grasp the significance without also reading the papers he’s responding to, the comments and responses to comments on both sides, the NAS study, the Wegman Report, and a bunch of background info that puts all of these in context so you can figure out what the interesting underlying issues are.
It would take you weeks to get around to reading all that source material even if you were really really motivated to do so just based on my say-so that there’s something interesting, nay crucial, there towards understanding why a lot of skeptics are skeptical. And it would take me quite a while to walk you through it. Doesn’t seem practical.
So instead I am suggesting you read just *one* article of his which is essentially a survey of the academic back-and-forth over this one issue. It is a summary from a lecture he gave at Ohio State University; this lecture was aimed at college students in the geology department who weren’t necessarily assumed to be familiar with the literature. So it is an excellent high-level summary. But it includes six pages of references to a variety of published papers in the literature if you want to immediately dive in deeper and check up on questionable claims.
I find it interesting that it is addressed to an audience of laypeople, instead of the scientific community. What does that tell us?
Not much, actually, since he initially assembled most of it as background material for a talk he was invited to give to the American Geophysical Union – a bunch of scientists. However, *that* talk was not written up in such a readable fashion as this one, was *way* more technical and less wide-ranging than this one, so it seemed less suitable as an initial recommendation for an overview. If you reeeaally want that one there’s a powerpoint version floating around and the abstract can be found here: http://adsabs.harvard.edu/abs/2006AGUFM.U11B..05M
So. That link yet again. A paper titled “How do we know that 1998 was the warmest year of the millennium?”, is still here: http://www.climateaudit.org/pdf/ohio.pdf Now that you know it’s based on material that was solicited by and delivered to scientists – climate scientists, even – and is backed by, responds to and references multiple published climate papers, I’m sure you’re dying to read it. And I’m dying to hear what you think of it.
All right. Reading them now. My apologies if I seemed at all hard-headed before. I’ve been very busy. It’s not an excuse, but it’s a contributing factor.
I’ve heard about McIntyre finding mistakes in GISS data and GISS fixed it and thanked him. That’s great. That makes me respect him. Steve McIntyre on his own isn’t too credible. Steve McIntyre in collaboration with other scientists, peer-review, or organizations like NASA gives him a lot more respect. This is why I was wary of checking out this presentation. I doubted it would change my mind on anything, given its credibility.
And yes, there we are, all done. He certainly shows that more and better data is needed. I certainly agree. More and better data is always needed. I like how he advocates having the raw data available to anyone. Obviously it can’t be published in the journals for the purposes of space requirements (especially in something as data-intensive as climatology), but you should be able to download it at least, like you can with GISS (not every individual station but the global averages).
However, given the credibility of the source, I can’t help feeling that this speech is likely one-sided, and there is probably more to the story. I feel skeptical, not a Fred-Singer-skeptical, but a normal-scientist skeptical. I want to see what Mann and the NAS say about bristlecone pines – perhaps there’s a deeper explanation than the cherry-picked statements McIntyre quoted. McIntyre has brought some fair criticisms of a single graph. That in no way invalidates the graph, let alone all of AGW and the related policy implications. We shouldn’t put Copenhagen on hold because of this.
I’m going to go see what others say about the MWP and the Hockey Stick. I’ll get back to you if I find anything interesting.
From RealClimate (no more or less credible than McIntyre) I found a lot more explanations regarding the current theories of paleoclimate modeling and how the HS abides by them. It also obviously addresses McIntyre’s claims (which seem to be more about PCs than the reliability of tree rings). It also shows why they picked the data they did – because it explained the variance in the underlying data, rather than fitting a pre-conceived conclusion, as MM claimed. I still think more and better underlying data is needed, as always, so we’ll see what happens in the years to come.
From another post we find that “Rutherford et al (2004) demonstrate nearly identical results to those of MBH98, using the same proxy dataset as Mann et al (1998) but addressing the issues of infilled/missing data raised by Mcintyre and McKitrick, and using an alternative climate field reconstruction (CFR) methodology that does not represent any proxy data networks by PCA at all.”
So that’s both sides of the debate from non-peer-reviewed, nearly identical styles of blogs written by publishing scientists. What does the NAS say?
The press release (you have to pay for the actual report) states that the NAS puts high confidence that it’s warmer now than at any time in the past 400 years, but puts less confidence before that. So they’re sort of neutral. Not too pushy one way or the other.
We already know the implications of “what if the hockey stick were right”? This post explores some of the implications of what would happen if the hockey stick were wrong.
See, as I’m not a scientist (yet), I merely find it interesting to know the details of debates like the HS, but it isn’t a very important question. The ultimate question is always, “Is this a threat worth addressing?” My answer is still yes.
> As you see, for f -> 100%, we get S -> inf, runaway. For f 2.0.
Oops. Seem to have forgotten about HTML…
Should be
As you see, for f -> 100%, we get S -> inf, runaway. For f = 50%, we get
S = 2*S0, or as a series,
1.0 + 0.5 + 0.25 + 0.125 + … = 2.0.
The key phrase from your first link is, regarding bristlecones: “the fact remains that including these data improves the statistical validation over the 19th Century period and they therefore should be included.”
The NAS said bristlecones shouldn’t be used as a temperature proxy because there are serious known issues with using them as such – that signal is widely understood to reflect other factors besides temperature which we don’t yet understand well enough to factor out. But without bristlecones, the reconstructions “have no statistical skill”. The RealClimate crowd wants to use bristlecones anyway, because they “improve the statistical validation” of the studies. That is to say, adding a bunch of invalid data as an input to their algorithm makes the math work better, generating numbers that are easier to defend as valid and publishable. And yes, it is true that including bristlecone data “improves the statistical validation”; it is also true that throwing in US stock market prices for the same period would “improve the statistical validation” given their methods, but doing so would make the legerdemain more obvious.
The Mann study found the results it did because it used both invalid methods (decentered PCA) and invalid data sources(bristlecones). Rutherford et al (2004) did fix the PCA-related method errors but kept the same invalid data sources, as did all the other studies alleged to “reach the same conclusion”. If you remove the invalid data sources – data sources that the NAS agreed were invalid and “should be avoided”, everybody agrees that these models lose statistical skill, which is why all the NAS could conclude with reasonable confidence was that it seems to be warm now relative to the Little Ice Age 400 years ago. They found that some weaker claims about earlier periods were merely “plausible” (as opposed to, say, “likely” or “well founded” or “reasonably proven”) and anything past a thousand years back was hopeless. (okay, they didn’t actually say “hopeless”. The actual phrasing was that such claims were “still less certain” than the claims that had only been found “plausible”.)
The claim that Mann & company do what they do – insist on using obsolete versions of data the NAS says shouldn’t be used at all in their studies – because they are “fitting a preconceived conclusion” is actually my take on it, not McIntyre’s. McIntyre tries to remain neutral as to *why* these mistakes are still being made and mostly does a pretty good job at that.
Okay, let’s throw out the bristlecone data. Has anyone else done a reconstruction that doesn’t include bristlecone data? Has the NAS?
Again, I don’t really care whether Mann is right or wrong, I just find it mildly interesting. What I care about is the implications of AGW. Which don’t change even if you take the HS out completely.
“Pre-conceived conclusion” – why would anyone have this pre-conceived conclusion? Aren’t we all biased to the status quo and happy scenarios? Why would anyone want AGW to be true?
The key phrase from the myths-versus-facts RC post is: “Thus, even if there were errors in the Mann et al (1998) reconstruction, numerous other studies independently support the conclusion of anomalous late 20th century hemispheric-scale warmth.”
I think the paper you’ve just read shows pretty conclusively that the “numerous other studies” being referred to here weren’t actually independent; they all recycle variants of the same relatively few data sources. Once McIntyre managed to shake loose enough information on data and methods to evaluate these it was clear that using slightly different – and arguably better – input data sets reverses the conclusions of ALL those studies – it is possible to use the exact same methods with similarly valid data sets to show with the same “statistical skill” that late 20th century hemispheric-scale warmth is not anomolous relative to a thousand-year scale.
(To be fair, a few of the responses to M&M in that myths posting were valid. Some of the stuff McIntyre originally got his hooks into was statistically improper but didn’t “matter” – then or now – to the final results. Figuring out which parts *did* matter wasn’t clear until much later when more data was available. The Wegman Report helped a lot in resolving these claims and counter-claims from a statistical perspective.)
To quote from M&M’s testimony to the NAS: “Virtually all subsequent multiproxy studies benchmark themselves against MBH, which thereby has almost certainly influenced proxy selection in these later studies.”
Okay, let’s throw out the bristlecone data. Has anyone else done a reconstruction that doesn’t include bristlecone data? Has the NAS?
Sure. Several reconstructions have been done that abide by the NAS recommendation to avoid strip-bark samples. Page 37-38 of the OSU presentation features one such: Loehle & McCulloch 2008. It has a really warm MWP. Also see the discussion of “Ocean Sediment” studies (page 34-36); almost all of these show a warm MWP relative to the modern era, so any reconstruction that emphasizes them will also do so.
Strangely, none of this information shows up in the IPCC report, and attempts to include it are rebuffed.
Which reminds me: you asked me to name one study that runs counter to the IPCC’s views which they refused to include. Answer: Millar et al. 2006. McIntye discusses this on page 22 of the OSU talk. Millar et all “modeled paleoclimate during [the MWP] to be significantly warmer (+3.2 deg C annual minimum temperature) and slightly drier (-24 mm annual precipitation) than present.”, which casts doubt on the multiproxy-related conclusions because that same region should have been *cold* at that time according to the relevant proxy used as an input to the multiproxy studies.
Glen Raphael:
In short, you’re saying that if you pick the temperature proxies that show a warm Medieval Warm Period, then the final reconstruction will show a warm Medieval Warm Period? Yeah, that’s science all right!
You know, you’re supposed to pick the proxies that agree most with the current known temperature records. Not pick the proxies that suit your preferred conclusion so that you can, um, conclude with your preferred conclusion.
Strange that you never asked whether Loehle and McCulloch’s ‘paper’ was based on proxies from a single region. Is it because Loehle and McCulloch happen to agree with your predetermined conclusion?
— bi
The fact that Glen Raphael refers to a reconstruction by Loehle (2007, “corrected” in Loehle & McCulloch 2008) informs me that he isn’t realistic about climate reconstructions. The mess from Loehle was rather effectively debunked by RealClimate here:
http://www.realclimate.org/index.php/archives/2007/12/past-reconstructions/
In general reference to articles published in the pseudo-journal “Energy and Environment” indicate an unrealistic approach to science in general.
As for reconstructions not using bristlecone pines, that’s been done by legitimate researchers, including Mann et al. 2008:
http://www.pnas.org/content/early/2008/09/02/0805721105.full.pdf+html
Note that they do multiple reconstructions with subsets of proxies, include reconstructions which don’t include any tree ring data at all.
The reconstructions of Loehle, and papers published in Energy and Environment in general, are simply not credible. The fact that Glen Raphael refers to them argues against his credibility.
That PNAS article is fantastic! “Recent warmth appears anomalous for at least the past 1300 years whether or not tree ring data are used.” Why didn’t Steve McIntyre mention this in his speech? Oh, wait….
No, NAS did not say they were invalid, they just made the throwaway line “should be avoided” without justifying that it must be avoided. There’s nothing wrong with using bristlecone data if you use it properly.
This may help:
[video src="http://geotest.tamu.edu/userfiles/216/NorthH264.mp4" /]
with reference to:
Click to access testimony7-19-06.pdf
Use Google Scholar, not Google, to find scientific work.
Once you’ve found a search string that gives you useful results,
compare the results from Google, and Google Images, using the same search terms — that’s often a measure of which blogs are spinning out PR rather than relying on the published science..
frankbi wrote: Strange that you never asked whether Loehle and McCulloch’s ‘paper’ was based on proxies from a single region. Is it because Loehle and McCulloch happen to agree with your predetermined conclusion?
I don’t quite know what to make of your comment. The worldwide coverage of the proxy locations used for Loehle and McCulloch can be seen on a map here. Some of the individual source proxies are listed and attractively plotted (both individually and together) here. Some of these proxies naturally have better historical coverage than others. If you can suggest any other long-term non-tree-related proxies that have been explicitly temperature-calibrated by their originators in the published literature that L&M might have missed, I’m sure they’d be happy to include it in the next paper. Or you could make your own!
Steve McIntyre notes on that page that the Loehle paper is properly seen as a variation of Moberg et al 2005; most of the criticism the Hockey Team have leveled at the one apply with just as much force to the other. That said, I’m sure it’s not a perfect study; it’s just a data point. If you have a more specific criticism to make you’re going to have to be more, well, specific. (A link to whichever RC post you’re getting your info from might work better than a snide remark. :-) )
Thanks to all the well-informed folks who came to join in this discussion.
Energy and Environment…..yes, of course, that makes sense!
Does anyone know about the Millar et al paper? Is it valid? Was it actually presented to the IPCC?
Listen to North in the video.
The NAS decided to address the right question: “Does it make any difference?”
And answered it.
Loehle (2007) was originally published in Energy and Environment, which is not a recognized science journal. That study has a *lot* of problems. Some of the obvious data handling problems were fixed by Hu McCulloch, in the later “corrected” version, but many substantive issues remained.
For a full discussion of the paper, along with good general discussion of climate reconstructions:
http://www.realclimate.org/index.php/archives/2007/12/past-reconstructions/
It’s also mistaken to claim or imply that all the multi-proxy studies based (at least partly) on tree-rings use the bristlecone proxies used in MBH98 and MBH99. As I recall about half of the the studies cited in IPCC AR4 WG1 spaghetti graph did not include the bristlecone data sets.
You should also be aware that MBH98 and 99 tentative conclusions have been greatly strengthened and extended with Mann et al 2008, published in PNAS. As in the Proceedings of the National Academy of Science.
I’m not aware of one single multi-proxy study in a peer-reviewed science journal that shows a MWP significantly stronger than the present, much less any that shows a multi-decadal period of warming comparable to that from 1970 to present. Or even warming over any century in the last millenia or two close to that of the 20th century.
By the way, there’s no reason to concede that realclimate.org and climateaudit.org are equally credible (as you appeared to do above). McIntyre has exactly one (1) peer-reviewed article in a scientific journal (GRL in 2005). That’s it. There is no way you can call him (or McKitrick) a scientist, although both have training in statistics.
On the other hand, Realclimate is a blog written by some of the top climate scientists, many of whom have publication records in the hundreds.
That’s a good point about credibility. Is there any kind of easy way to tell how many papers a scientist has published on a certain topic?
Don’t let folks like this lead you around by the nose, dunk your face in a pile of something and insist that you explain it.
Check the _assumptions_ they are trying to get you to take for granted.
What’s the assumption he’s trying to sucker you with?
“… they refused to include. Answer: Millar et al. 2006.”
How can you check the statement?
Clue:
http://www.google.com/search?q=IPCC+date+cutoff+research
First result for that search:
The IPCC: A Guide For Journalists | SEJ
Research on climate change is a continuing process, so the IPCC in each assessment … The Fourth Assessment Report’s cut-off date was in December 2005. …
See the trick being played here?
My goodness!
What a simple but effective way to mislead me!
I seem to give others the benefit of the doubt and assume that they are as ethical and honest as I aspire to be.
I should learn a little caution in this approach.
Well, I see that I was not the only one to chime in …
Regarding the McLean, de Freitas and Carter paper that Michael Tobis was discussing, you may be interested in these discussions of the associated PR campaign, the organizations behind those PR efforts and their political ties.
Deepclimate.org is mainly about these kinds of issues – much more coming on this here in Canada and elsewhere.
Wow, the gang’s all here! Tamino: how do you justify that Mann08: (a) didn’t update to use later proxies where available, and (b) used inverted Tiljander as a substitute hockey-stick source?
The deal with Mann08 is that it has *two* proxy sources for a hockey stick. (1) the usual tree rings (2) a sediment core which is being misused. If you leave out (1) you get a hockey stick due to (2) and vice-versa so you can claim the study isn’t “sensitive to” (1). If you leave both (1) and (2) out, well, the study is “sensitive to” that.
And — don’t _worry_ about having been taken for the ride, once.
Just learn to recognize it. Google the claims, google the names, before deciding your topic or your blog is the appropriate place to try to provide a detailed reply.
It’ll tie you up for ages, and won’t change the ride at all for the next person who gets taken for one.
It’s a familiar ride — once you start to see it happening over and over to new bloggers.
There’s a reason that people who read the science don’t try to chase down the nonsense whenever it pops up somewhere else, whether it’s a blog from someone new to the science who’s sincere, or a new denial blog, or an old one that doesn’t work very carefully to check sources.
There’s a reason a lot of us who don’t have anything new to contribute don’t try to start blogs, or run around replying on many of them. Some of us like me can do no more than point to competent reference librarians, encourage people to learn how to look things up, and offer little examples of searching.
Search for the best answer already given, and point to it.
This came out today, it’s brilliant, and the idea is the same for climate science too:
Thanks. I’ve learned my lesson. I’d been hesitant about starting a blog because I worried about shouting matches like these happening, which were way over my high-school head.
In the future, I won’t even try to debate technical issues like these – I’ll send them straight to people like you who know what they’re talking about.
Oh, and, the _second_ result for that same Google search?
You’ve really got to watch these people.
Get this:
“… May 2006, the IPCC’s cut-off date. …”
That’s from the Heartland NIPPC denial site.
All right Heartland! Gotta love those people! They provide good entertainment if nothing else.
> “See the trick being played here?”
Nice work, Hank.
re climatesight’s
> “Is there any kind of easy way to tell how many papers a scientist has published on a certain topic?”
You might already be familiar with this (and I myself have not yet tried it), but in his book Greg Craven recommends using the H-index that’s calculated by a free program called Publish or Perish (which gets the data from Google Scholar) – he says the program’s available at http://www.harzing.com/pop.htm
(I suspect this doesn’t tell you what topic they’ve published on, though. But that’s something you can filter for, at scholar.google.com )
Thanks. I’d heard of it but I couldn’t remember what the name was or how to find it.
Glen Raphael:
Ah, I stand corrected on that point. So, you’re saying that Loehle and McCulloch took some temperature proxies from all over the world, and then assigned arbitrary weightages to the diifferent proxies in such a way that the final temperature reconstruction agrees with their desired conclusion?
Maybe you should also be a bit clearer about what you mean by
because it does suggest that they are assigning weightages arbitrarily.
— bi
A key finding from the updated ‘hockey stick’ (Mann 2008):
“Recent warmth appears anomalous for at least the past 1,300 years whether or not tree-ring data are used. If tree-ring data are used, the conclusion can be extended to at least the past 1,700 years, but with additional strong caveats.”
It’s right there in the abstract.
http://www.meteo.psu.edu/~mann/Mann/articles/articles.html
As for the Loehle reconstruction, as Tamino and Deep Climate note, it was published in Energy & Environment, which is a non-peer-reviewed social science journal about which its editor once said:
“I’m following my political agenda — a bit, anyway. But isn’t that the right
of the editor?”
Click to access ChronicleEd.pdf
Further, Loehle only used 18 proxy record in his global temperature reconstruction. Mann et al.’s 2008 reconstruction used 1,209 proxy records.
http://www.realclimate.org/index.php/archives/2008/09/progress-in-millennial-reconstructions/langswitch_lang/in/
Comparing Loehle to Mann is kind of a joke.
More on Loehle’s reconstruction:
http://www.climateaudit.org/?p=2380#comment-162058
http://www.climateaudit.org/?p=2380#comment-162146
@Glen Raphael,
Please, don’t bother us with papers published on fringe/crank/low-quality journals such as Energy and Environment. Loehle & McCulloch 2008 was published in E&E, so that’s enough to avoid reading it.
As for your other statements, every one of them is wrong: on feedbacks, on climate economics, on McIntyre’s work and conduct, etc.
– Avoiding dangerous climate change won’t bankrupt us. Please read the literature on climate economics.
– Committing resources to climate change mitigation and adaptation will also solve other big problems, namely oil depletion, ocean acidification, coal pollution (in mining, energy production and waste management), incorrect management of biomass (pressure on forests for land and fuel needs, health problems derived from the incorrect burning of biomass, etc), food security, water security, etc.
– McIntyre has little credibility left. Publishing in E&E, launching unfounded attacks on scientists, presenting “research” on the astroturf conference organized by the Heartland Institute and other activities speak volumes of his commitment to scientific conduct and scientific integrity.
– The NRC panel, which included delayers like John Christy, has largely validated the “hockey stick”. If you wanted to give a balanced view of the report you would say that the panel findings’ were in general agreement with known climate reconstructions but the panel is less confident on climate reconstruction going far in the past.
– The ice-albedo effect doesn’t stop when the ice is gone. Ice not only reflects solar radiation, it also hides a dark sea. I won’t even mention the huge quantities of carbon stored in northern latitudes, the region that’s experiencing strong warming (polar amplification)
I’ll let you figure you out the consequences of an ice-free sea.
climatesight: I’m kind of sorry I dragged you into this. Taking a *big* step back from the fray: the question of whether what Mann and his various associates are doing is valid is really, really contentious. There are a bunch of very loud, very well-funded, very credible (by your scale as well as mine) scientists who believe the multiproxy project is basically on the right track, perhaps making a few minor mistakes along the way but nothing too serious and nothing that can’t be fixed with a few minor tweaks. This is probably the majority viewpoint among those who specifically call themselves “climatologists”. This is the group that finds it easiest to get published in the major journals and easiest to get their views reflected in the IPCC.
There is an active debate between that group and a very diverse opposing camp. Many of those in the opposing camps are not “climatologists”, and base their views/objections on grounds that relate to other disciplines. Both figuring out what is true and what we should do about it is a large interdisciplinary problem requiring expertise in *many* fields, so a lot of the disagreements are between groups with different specializations.
As one example, you could view the Wegman Report as a small group of expert statisticians saying, in essence: “these climatologists are all out to lunch; they’re using math they don’t understand to reach a meaningless conclusion. They should go talk to some statisticians before somebody gets hurt!” You could then view the NAS Study as a group of expert climatologists responding, in essence “No, no, this is just the way things are done in our field and it’s generally a reasonable way to do things.” Besides those two groups, there are many other groups of specialists each with their own “consensus” that’s likely to diverge a bit further. The economists, the dendrochronologists, etcetera.
Having followed the debate through many rounds and some degree of depth, I personally find the “statistician” side of the argument more credible. (I even think I have a few unique insights that add to their argument which I hope one day to publish). But because that first group I mentioned is so dominant, for every point I make now, for every point anybody tangentially related to “my camp” makes, you will probably be able to find with a little searching – at a minimum – an old RealClimate posting that claims to be a devastating rejoinder to it. Or perhaps a wikipedia article sourced from the RC article. If all you want to do is confirm your prior view that the skeptics are all idiots, dupes, probably republicans funded by Exxon, it’s very easy to do – just assume that RealClimate posting is correct and stop there. And maybe that’s the best we could hope for here and I was naive to expect more.
On the other hand, if you want to understand skeptics to the extent that you could either convince them to change their view (if it’s wrong) or change your own views to be more correct (if it isn’t), you might need to seek out and read, not just the information sources that reinforce your own view, but those that challenge it. Read what’s actually being said on both sides to see whether the arguments are convincing instead of going primarily on tone and credentials. (there’s a really good Richard Feynman essay that says all this better, but I can’t find it at the moment, alas…)
On the other hand if you don’t want to investigate, understand and address skeptical views, you might not want to post blog entries of the form “Hey, skeptics! I think you think X, so why don’t you believe implication Y?” It’s like catnip, I tell you… :-)
I’ll try to respond to specific points that have been made above as time permits, but I’m way outnumbered now that you’ve brought in all the heavy artillery so it might slip a bit. For what it’s worth, I am not trying to mislead you. I’m just trying to figure things out, same as you.
Then explain the Energy and Environment citation. And the claim that the Millar et al paper was “refused” by the IPCC when it was published after the research cutoff for AR4 inclusion. If you’re not misleading me, someone else is misleading you.
I was unwilling to read the McIntyre papers simply because I didn’t want to get bogged down in a scientific debate which I really had no place in. Once you persuaded me to read them, I was very willing to understand and accept your position. I was skeptical as always, but your logic was good. You had me going for a while. The bristlecone pine inclusion in particular had me questioning Mann and the IPCC.
But see this most recent post. I wanted to read further into the issues. I knew there had to be more. So I went and asked people like Tamino who really know their stuff in this area…unlike me. I found their explanation more compelling and credible. Especially the PNAS paper. If climatologists are doing stats all wrong, you’d expect that at least the NAS would know about it. They’re a little more persuasive than RC. Back-and-forth blogs always have rebuttals. That’s expected. But the NAS is far more comprehensive and nonpartisan. Far more credible. Keep in mind that until Tamino et al came in, I held RC and Mann’s explanation of the HS on a fairly equal footing to McIntyre’s. I know my credibility and my biases. You’re talking to someone whose obsessive interest in the subject was basically born out of Greg Craven’s videos.
Oh, and again, the E&E citation and Millar claim. That damaged your credibility so much that I gave up on your claims.
I am very willing to understand how skeptical arguments work. I tend to go a little crazy if I read too many of them, especially of the Heartland variety, so I try to keep myself sane. I tend to read about them, and read all the rebuttals and re-rebuttals, rather than actually debating and discussing them. Just because I don’t want to debate issues I don’t yet fully understand doesn’t mean I’m not interested in fully understanding them.
Another reason I tend not to debate these issues is because I’m not interested in changing the minds of skeptics. Not at all. It’d be great if I could, but that’s not what matters to me. What matters to me is the average person, and what they would think reading this. Any replies I write to skeptical comments are purely for their benefit.
But when an issue like this comes up, my scientific ethics surpass the biases of my current opinions so much that I question myself a little more than what is probably justified. I guess I’m young and gullible. But I’m learning. Given the track record of your side of the debate, I know that I should investigate their claims very thoroughly. I’m willing to change my mind. But so far, my mind hasn’t been changed.
If you read the paper you’ll find that Millar et al. are specifically looking at “Whitewing Mountain and San Joaquin Ridge, Mono County, Sierra Nevada”. This was anything but a global study.
Oh, and they also used pine tree rings.
“They also used pine tree rings.” Brilliant.
Hank: you might be right that that paper missed the publication cutoff. I’ll investigate further. Officially, the paper had to be available in the form of “a reasonably accurate draft” by May 2005 and either published or “in press” by December 2005. The paper in question was actually submitted to the journal in May 2005 so it could have made both of those deadlines, but it might not. I’ll see if I can figure out more once I track down the relevant reviewer comments. If I can confirm that that paper was *properly* excluded, I’ll have to meet climatesight’s challenge with a different example. (Pielke actually blogged a *looooong* list of papers he thought were invalidly excluded, but I didn’t want to inflict that on our poor host without more vetting. :-) )
Lucas and many, many others: climatesight asked if anyone had done a study without bristlecones. I had a reference to one example handy and gave it. In that context it is kind of irrelevant whether it was published in what you believe to be an especially well-regarded journal. Or heck, if it was published at all for that matter. Feel free to suggest better studies, but the two-minutes-hate on E&E is a bit silly. Though I know that’s one of the “official talking points” on your side, so don’t let me stop you if that’s really what floats your boat…
If it’s in Energy and Environment, I don’t think it really counts as a study.
“They also used pine tree rings.”
That was actually kind of the whole point, I think. They used tree rings but reached a very different conclusion than the other studies-that-used-tree-rings that are already built into the IPCC consensus.
(Heh, flexing my superpowers. I’m not sure I can manage to bring the entire Justice League down for every minor miscreant, but it sure was fun in this case…)
Anyway, yes, there is the Science Citation Index, which is the traditional reference for what a scientist has published and who has cited them. Nut you need access to a university library for that.
If that’s not practical you can use Google Scholar ( http://scholar.google.com ) for a good idea. Give a name and you’ll get results sorted by citation count.
For example http://is.gd/2wUb3
S2 said This was anything but a global study.
I keep forgetting I’m now talking with a *lot* of people who haven’t read the prior material. Even climatesight clearly only skimmed her one reading assignment. So: the Mann studies and the spaghetti chart studies that followed it all put a lot of weight on a particular obsolete series of tree rings (Graybill, Sheep Mountain; the latest available not-yet-used update for that region is from Ababneh, collected in 2002) that were collected in a particular local region (California), essentially under the theory that via “teleconnections” that region can be taken to reflect part of the global climate pattern . So now here we have a different study that used a different set of tree rings, also collected in California. Different local set of trees, similar region. It reached *very* different conclusions, so this ought to be reconciled somehow or at least mentioned.
For clarificiation, I certainly did read my “one reading assignment”. I was actually typing out a lot of comments to individual parts of the speech, but realized about halfway through that they could be summarized quite easily. Please don’t make personal accusations without evidence.
> ny kind of easy way to tell how many papers a scientist has
> published on a certain topic?
Are you on good friendly terms with a reference librarian? There are far more tools available than we amateurs know about or have access to.
Scholar is the only place to start from without leaving your chair:
http://scholar.google.com/intl/en/scholar/refinesearch.html
but it won’t be as useful as talking with a real librarian about this.
It’s rather amusing whenever people yelling about the Hockey Stick today cites the Wegman Report as a credible source (possibly because it jives with their bias, or they read it as such).
See, Wegman also said:
“We do agree with Dr. Mann on one key point: that MBH98/99 were not the only evidence of global warming.
As we said in our report, “In a real sense the paleoclimate results of MBH98/99 are essentially irrelevant to the consensus on climate change. The instrumented temperature record since 1850 clearly indicates an increase in temperature.” We certainly agree that modern global warming is real. We have never disputed this point. We think it is time to put the “hockey stick” controversy behind us and move on.”
Yes, the Wegman hearing does say that (pages 6-7, note the URL. At the time, the chair of that committee was someone you may have heard of). Sadly, people citing Wegman as more credible than the NAS tend to ignore this conclusion, while those citing the NAS as more credible than Wegman (i.e. not McIntyre) have moved on, though there is an updated hockey stick nonetheless.
For another spectacular example of reality denial, that’s figure 6.10 from the paleoclimate chapter of the IPCC AR4: the first indexed line, MBH99, was the first extended hockey stick. Several people – although, let’s be clear, these are NOT the same people I mentioned above – insist that the IPCC dropped the hockey stick from their report altogether. For example, see here (look at the attribution for each graph you see for a familiar name.). In other words, via inactivist logic, corroboration = deletion.
(By the way, that video includes a clip from 2007’s Global Warming Swindle in it, as many readers may know (it’s unsourced; the relevant parts have an Englishman narrating them). For extra credit, listen to that clip to judge context, then rewind and pause the clip at 1:16 to see when the events happened. This continues an ancient line of attack that has shown up here before.)
RE: climatesight said August 24, 2009 @ 2:04 pm
For academic or government scientists (such as those who write for RealClimate.org) their web pages should contain a bibliography as well as a CV. For others, Google Scholar can help.
p.s.: from that tips page:
access Google Scholar from an on-campus location of a participating library, and we’ll automatically include these links.
OR
* Click on Scholar Preferences.
* Type the name of your library in the ‘Library Links’ section.
* Click Save preferences.
* Start searching with links to your library’s resources (you may need to authenticate yourself to access these resources).
If you don’t see these links or you can’t find your campus library in the list, contact your librarian and tell them about Google Scholar’s Library Links program.
Ummm….don’t have a campus library…..still in high school!
ClimateSight: Regarding the PNAS paper that claims to reliably go back 1300 years with or without help from tree rings, you asked why McIntyre “didn’t mention” this in his OSU talk, implying a possibly nefarious purpose. Shortest answer: the paper didn’t exist yet; it came out *after* the OSU talk. Better answer: McIntyre doesn’t find Mann08 credible, so he submitted a comment to PNAS. PNAS reviewed that comment and after some back-and-forth decided it was worth publishing; it came out a few months ago and can be found here. Naturally Mann has a response to the response and McIntyre has a response to the response to the response and so on, but I thought you should know, since you asked. :-)
Brian D: writes It’s rather amusing whenever people yelling about the Hockey Stick today cites the Wegman Report as a credible source (possibly because it jives with their bias, or they read it as such)…See, Wegman also said…”
Wegman and the NAS panel are both credible authorities in their respective fields, both said some things that were pretty sharply negative about the Mann study and positive about McIntyre/McKittrik’s work, and both said some things that were conciliatory about the general project of demonstrating AGW. If you look hard enough you can find quotes from either document to strongly support either side in this debate, especially if you drop some context. Wegman was slightly less political, less inclined to waffle, than NAS, but both make concessions to both sides, which helped “your side” spin NAS as some sort of victory for Mann. Personally, I’m pretty happy with the clarity of: “Overall, our committee believes that Mann’s assessments that the decade of the 1990s was the hottest decade of the millennium and that 1998 was the hottest year of the millennium cannot be supported by his analysis.”; To agree that “modern global warming is real” is a little too vague to be as useful as you make it out to be; he might just mean by “modern global warming” the now-undenied fact that the recent instrument record shows warming.
Come to think of it, I actually agree with every single Wegman line you just quoted. So you might have to clue me in on the joke. I agree with him that MBH98/99 isn’t the only evidence for warming, it’s not the only source of consensus, the temperature record does shows warming since 1850 and I’d love to “put the hockey stick behind us and move on if it would only just stay dead. But as long as the hockey stick keeps popping up, zombie-like, reborn in each new IPCC study in a dozen different disguises, somebody has to shoot it in the face with a shotgun, metaphorically speaking…
Kate…
You have several very smart climate people talking to you here… Tamino, Hank Roberts, DeepClimate, FrankBi, Martin Vermeer…. So I’m surprised that you don’t see it. Especially after your piece about the similarities between tobacco and global warming.
This comment thread isn’t about science, it’s about media literacy. Glen Raphael (GR) sounds reasonable and engaging on the surface, but he’s merely practicing sleight of hand, and you’re letting him do it. In fact, you’ve chastised readers for not being nice to him, and then let Raphael libel professional scientists repeatedly. So you need to rethink your policy, and you need to stop letting people like GR spread misinformation.
Hank Roberts is exactly right. GR is leading you around to his talking points, and then you’re thanking him for doing so. As a professional journalist, I think you should stop doing that.
Here is a rephrasing of GR’s incredible insights, once all the jargon is removed.
I’m a skeptic, and we’re worlds apart, so we’ll never convince each other.
In fact, he’s not a skeptic because he won’t be convinced by any evidence, and skeptics are supposed to have an open mind. There were 1,400 studies — just from the last three years — presented at the emergency climate summit in March… Can he refute all of them? Any of them? One of them?
The IPCC is a flawed process motivated by politics.
So the IPCC and the 2,500 experts involved in the process are engaged in a massive deception. That strains credibility.
But then he goes even further. The National Academies of Science of in the developed world are in on it too (though not quite so openly). Does he offer a scintilla of proof? Where is the links that support his contention?
His entitled to his own opinion, but not his own set of facts. He has to work with the same facts we all must use.
I read hundreds of climate and clean tech stories and studies each week. The IPCC has likely underestimated the dangers (and I won’t link here, I do that on my site). You should have realized what he was doing at this point.
I haven’t libeled Michael Mann by suggesting that he’s deliberately manipulated data.
Speaking as a journalist, I believe that you have. But I don’t think he’ll bother with you.
Let me know if you disagree with that great statistician Stephen McIntyre said about the MWP
Call us when McIntyre publishes his findings in a reputable peer-reviewed scientific journal. Until then, what’s your point?
Let’s also not forget that McIntyre works for mining industry, and has a vested interest in the status quo. Let’s also not forget that all of this MWP stuff is just extended BS, a smokescreen. Remember that part about the 1,400 studies in the last three years?
Bristlecones shouldn’t be used in Mann’s studies
Where is his proof? Maybe he’s right, maybe he’s wrong. Maybe the NAS did say it should be discounted, but they also say that global warming is real. He can’t trust them only when it fits his argument.
Besides Bristlecones are just one incredibly small piece of the science that goes into creating the temperature record.
Loehle & McCulloch 2008 published a study that show a really warm MWP.
Tamino obliterated this comment. E&E is a notoriously bad publication.
So Kate… there is nothing here. You’ve been patient and kind, and spent a great deal of effort and, at the end of the day, you’ve let a denier publish all kinds of misinformation on your blog without one reputable shred of evidence.
Those are some very legitimate points. And I knew it must be about media literacy – I knew there must be more to the story. I just didn’t know where to look or begin. I hadn’t even heard of the PNAS paper until now.
What do you suggest I do?
I don’t want to eliminate all comments by skeptics. That would be too close to censorship because of what they’re saying, not how they’re saying it – and it would be all too easy for them to accuse me of such. As long as they’re respectful about it, I want to be open to what they have to say.
And because I have previously deleted skeptical comments which were aggressive, I feel obliged to hold the statements I agree with to the same sort of scrutiny, which is why I have warned several well-meaning and accurate commenters about abiding to the no-aggressive-comments policy. I’ve probably overcompensated a little. This is why I have allowed commenters such as Glen to verge on libel, while I’m overly stringent on Martin Vemeer. I tend to be too nice to my opponents so that they’ll listen to me, and too harsh on my allies so the opponents won’t accuse me of bias.
I don’t want to get bogged down in endless debates regarding issues which are over my head, which is what happened here.
I don’t want claims which are obviously false or misleading to go unchallenged. I can’t just ignore them – because they could seem very convincing to the casual observer.
Any thoughts? I really want to fix this so my comment policy is as effective as possible.
On the “hockey stick” issue, some good answers so far. My summary:
– The “controversy” was mostly a politically-sponsored witch hunt designed to greatly exaggerate legitimate uncertainties in an early millenium temperature reconstruction and demonize scientists.
– The authors of the early reconstruction were clear regarding the uncertainties, as is indicated by the abstract and error bars (larger as one goes back in time).
http://www.ncdc.noaa.gov/paleo/pubs/mann_99.html
– The core conclusion that 20th century warming is anomalous in the context of the last millenium and temperatures in recent decades clearly surpass MWP warmth has been validated by every legitimate peer-reviewed study since by a variety of authors.
– The most comprehensive reconstruction to date is the recent Mann et al. study, puslished in PNAS. It’s notable that the larger error bars found in earlier studies have been reduced considerably, which I believe is in part due to better spatial coverage.
Click to access mann_et_al_08_hockey_stick_upheld_pnas.pdf
– McIntyre appears to spend more time slinging mud at climate scientists (alleging fraud, for example), turning on his soap box, and boasting about himself than doing actual science. His behavior doesn’t discredit him (his few contributions to the field tends to do that), but it raises suspicion among objective observers. Example:
http://www.climateaudit.org/?p=419
“Is there any kind of easy way to tell how many papers a scientist has published on a certain topic?”
Another nice source for this, with regards to climate science…
http://www.eecg.utoronto.ca/~prall/climate/climate_authors_table_by_clim.html
“Further, Loehle only used 18 proxy record in his global temperature reconstruction. Mann et al.’s 2008 reconstruction used 1,209 proxy records.
Comparing Loehle to Mann is kind of a joke.”
And many of those 18 records were used inappropriately (see RC link). Red flags are raised when someone attempts to discredit the peer-reviewed reconstructions and then proceeds to promote the E&E Loehle piece, which is by far more flawed and statistically weaker than even the original MBH reconstruction.
Glenn writes:
“Wegman and the NAS panel are both credible authorities in their respective fields”
The Wegman Report was a politically-commissioned report. Wegman was hand-picked by a politician and his report was never independently peer-reviewed. As a result, NAS is weighted much higher.
“Wegman was slightly less political, less inclined to waffle, than NAS”
Because a more measured NAS panel didn’t quite conclude what politicians wanted, it’s characterized as “waffling”. Nice.
This is completely wrong. Two GOP senators who had already declared themselves global warming denialists commissioned Edward Wegman, then chair of the NAS’s Committee for Theoretical and Applied Statistics, to form an ad hoc committee of himself and a couple of friends and colleagues to report to them and the Energy and Commerce Committee. That ad hoc trio did not speak for the NAS at all, and the study was not a peer-reviewed scientific study – it had informal comments by a dozen people selected entirely by Wegman.
It did a terrible job – it focused on the paleontological climate community being small and not relying on the statistics community enough, for instance, but failed to even read the title of the original hockey stick paper, which was about the uncertainty in the temperature proxy. Moreover, the claim that it had no “skill” was based on coefficient of efficiency measurement vs. reduction of error, without justifying that.
So scratch the NAS said … claim.
My thoughts on comments are similar those at most reputable climate blogs… Like Open Mind, RC, and CP… I wouldn’t let someone sling mud at a scientist or study unless he or she provides a link and an cogent argument. And I wouldn’t accept links from skeptical sites, like Climate Audit or CO2 Skeptic, or Watts Up.
Now, on the surface, this may seem like censorship. But it isn’t. It’s your blog, and you get to decide what you will publish. Really you’re just asking for proof before you’ll let someone write a screed that widely considered false or inaccurate.
That isn’t censorship. It’s professionalism.
It’s also how science works. One study finds support with further research, and it builds to consensus. Explain that to your readers, the non-scientists. Don’t get sidetracked.
Even a community newspaper, struggling to fill the pages with copy, won’t publish every letter to the editor. It should be the same here. I’d surely have let Glen’s original comments stand. But as soon as he started going on about Climate Audit, I’d have snipped the comment, and included links to RC and Sourcewatch which are far more reliable, with a note that the comment was snipped for lack of source material/
Glen has got his own blog where he can talk about McIntyre or torture on 24until the cows come home. You’ll never convince him, and he’s just muddying your waters.
Richard and Hank – these are two possibilities, however, I have problems with both of them. Hank’s approach would take a LOT of time (it’s information that I would certainly want to learn about, but with the time pressures of approving a comment right away or not, it could get a little excessive). And Richard’s approach seems like I’m favouring one side over the other – if I refuse to allow links to Climate Audit, I also have to refuse links to the less credible climate blogs (none of which are mainstream, however, all the mainstream ones seem pretty reliable!)
That said, I realize that the reliable blogs tend to appropriately cite their information, and the non-reliable blogs tend to either make up stuff or distort it. So I suppose my comment policy could be, “if you make a scientific claim, you have to cite it.” If someone reads some news at somewhere like Deltoid and wants to talk about it, all they’ll have to do is take the extra step of finding the original info that Deltoid wrote about.
That seems like an appropriate approach. And it certainly upholds the purpose of my blog. Let’s go change those comment settings.
It should be pointed out that Glen’s implication that the NAS panel did not include “expert statisticians” is incorrect.
Kate, I think you shouldn’t conclude your study of the HS without considering what it means to the big picture of climate science (and specificially sensitivity), and why and how it became such a focus of denialist activity. On the former, see e.g. “What if the hockey stick was wrong” at RC. On the latter, IMHO the HS became a target not due to its intrinsic significance but because the TAR made it into a symbol of all advances in climate science.
In addition to the denialists and the fossil fuel industry, the HS had some immediate scientific opponents in some astrophysicists (most prominently Sally Baliunas) who had made their reputations on the (incorrect) idea that the Sun is a variable star that can drive climate fluctuations on the scale of the MWP and LIA. There was also the singular case of Hans von Storch, who thought that the HS was a poor choice by the IPCC and campaigned for an admission of that, but cut off contact with denialist circles pretty much the moment the NAS report came out.
Yes, I did read that RC post. I enjoyed it. I’ve heard this situation described as “attacking one hockey stick while ignoring the other five players on the team”.
ps — to elaborate a bit on what I said above when someone comes to your blog with challenging questions, it’s worth a little time and care with Google searches to find out who else has used that same userid, or those same phrases, elsewhere. You have to decide when such challengers are and aren’t worth more than a pointer to answers that have already been given repeatedly.
As to “no more or less credible” — I think that’s a first glance take — and that as you do more serious reading, you’ll arrive at conclusions based on the reading about which weblogs, scientists, and publication records are more credible. Take your time. Check the citations, read the footnotes, follow the citing papers forward in time to see whose work leads to more and better science.
[He is] entitled to his own opinion, but not his own set of facts. He has to work with the same facts we all must use.
That is a really interesting quote that gets to heart of the problem here: We do, in fact, have different sets of facts. I have read a different set of studies, papers, blogs, and articles than you have read. My opinions are founded upon the facts with which I am familiar; your opinions are founded upon the facts with which you are familiar. What I have read and the conclusions I have reached affect how I interpret new information. In order for us to have a sensible discussion rather than the sort of “yelling about” that Brian alluded to earlier, we do need to agree on a common set of facts. To do so, however, might require actually listening to the person to whom you are talking. Climatesight turns out to be pretty good at that; I’m not sure that I can say the same for all of the other locals.
I am neither a climate expert nor a statistics expert. I’m a generalist, and a bit of contrarian. Mainly, though, I’m a fan of Science itself, in the Richard Feynman sense. I have this naive vision of how Scientists ought to act. In my dream-world, when somebody asks “how did you calculate that?” Or “where’s the data you used to calculate that?”, the Scientist says “I archived the data and code on this ftp site over here; have at it. Let me know if you get stuck.” (note: McIntyre actually does this). In my imaginary world when a scientist responds to criticism, he links directly to the person or document he’s responding to so readers can get the context and judge for themselves who is right. And in my dream-world when a Scientist makes a careless mistake that somebody else notices, he says “thanks!” and fixes it. Imagine that!
In the real world, by contrast, apparently the norm has until recently been to jealously guard all your data and methods to such a degree that it literally takes convening a congressional hearing or filing Freedom of Information Act requests to pry the information loose. In the real world, one goes to great lengths never to credit or link to one’s critics or admit to even the tiniest of mistakes, such as, say, having mislabeled the location of a proxy site. Real scientists spend a lot of time editing wikipedia to keep enemy views from being represented charitably and also spend a lot of time slapping down any heresies they find in blog comments, because it’s so vitally important that heresies not be expressed. To accomplish this slapping-down, real scientists might be willing to settle for actual discussion using actual facts, and a few do, but most really prefer to rely on accusations of bad faith and on ad hominems. For instance, they’ll claim somebody’s views should be discounted because he’s a retired mining executive and somehow that means he “has a stake in the status quo” more than other people, whatever that means. Or they’ll attack a paper primarily because it was published in the wrong journal more than on the basis of whatever flaws it is specifically alleged to have. Or they will – as a transparent propaganda tactic – accuse their opponents of engaging in transparent propaganda tactics.
I think I like the dream-world better, of the two.
Glen Raphael, I’m still awaiting your answer to my question:
So how did Loehle and McCulloch weight the proxies, Glen?
— bi
My, this has turned ugly! Several commentators have made thoughtful, measured, appropriate criticisms of my views which are worthy of serious and carefully considered response. But there’s also quite a lot of mudslinging and piling-on. (The worst in terms of potential time-sink are actually the comments that combine the two – valid interesting points along with a bit of leaping-to-conclusion, ad-hominem, or bit of psychoanalysis.) I don’t want to pick-and-choose who to respond to because that would necessarily leave too many points/threads unanswered. I am, in short, too outnumbered to respond effectively. So I will bow out for now. It’s been fun. I may follow up with some of you via email later, time permitting.
@ Glen Raphael “Strangely, none of this information [Loehle & McCulloch 2008] shows up in the IPCC report, and attempts to include it are rebuffed.”
Of course none of this shows up in the IPCC, this study came out AFTER the IPCC was published. I’d love to see evidence where attempts to include it were rebuffed.
It is even worse than Hank suggests. Glen is complaining that a (thoroughly debunked) paper published not only years after the IPCC cutoff date, but after the IPCC publication date wasn’t included in the IPCC. Give me a break!
Hmm, I just realized I commented without reading the whole second page of comments. oops
Anyways I think you were on the right track in looking at the big picture. Even if you assume for the sake of argument that Mann’s work is completely wrong it doesn’t change anything about AGW. It was the second IPCC assessment report that concluded “The balance of evidence suggests a discernible human influence on global climate”. It came out in 1995, while the hockey stick came out in 1998, so clearly one can arrive at the conclusion that GHG emissions are warming the climate without a detailed proxy climate reconstruction.
All a falsification of the Hockey stick in regards to the MWP would show is that natural factors can have large impacts on climate. Nothing new there, but to borrow an analogy from a recent realcimate post:
That’s not what I said.
First of all, if you are guided by science, there is no other side. We can argue about legitimate points in the climate debate — how fast the ice is melting in the arctic, how will the hurricane season be affected by rising water temperatures — but do you really think that arguing that CO2 isn’t a GHG is a legitimate point of view?
If someone comes to a nonsmoking blog to argue that the owner is crazy for thinkng that smoking causes cancer, do you really think that commenter has scored a point if he includes a link?
Secondly, I didn’t argue that you have to cite every point… just that if you’re going to fling mud at a scientist, or suggest the current understanding of climate change is all wet, you had better be able to back it up with citations to reputable reports.
Thirdly, if you really think that Climate Audit and Real Climate are comparable, then you have some reading to do.
Don’t worry….I don’t really think that CA and RC are comparable. That’s another example of being nice to my enemies but harsh on my friends. I need to learn how to properly argue.
We don’t have to cite every point – there certainly is quite a bit which is common knowledge – if someone says “Humans are causing climate change” without a citation, I won’t delete them! However, all the points which skeptics like to make are not common knowledge. So it’s pretty much either 1) new studies or 2) skeptical claims which need citations.
Glen Raphael writes 3 long paragraphs of waffle, and then complains that because (he claims) there’s “a lot of mudslinging and piling-on”, therefore somehow this prevents him from answering the “thoughtful, measured, appropriate criticisms”.
Ah well.
— bi
Frankbi asked:
how did Loehle and McCulloch weight the proxies, Glen?
There was no weighting. The Lohe approach is to just take a simple arithmetic average from all the 2000-year non-treering series they could find that had already been calibrated to temperature in the literature. Because the series they used as inputs were already pre-calibrated to temperature there was no need for a “calibration” step or a “weighting” step in this study. This is a fundamentally different approach than that used in the multiproxy studies; it has both pluses and minuses.
The abstract is here. I’ll just quote the relevant portion:
This will probably be my last public post in this thread (assuming climatesight allows it); I’ll follow up via email with a few of you in response to other points. Or you can email me: graphael@gmail.com
This gets right to the heart of two phrases Dano uses quite a bit to make the key point here:
o The Google doesn’t have a ‘wisdom’ button.
o Denialists are best perceived (IMHO) as someone desperate to maintain the relevance of their self-identity (my point in the other comment thread). This is illustrated as a typical facet of human nature here.
Some are better at using rhetoric than others and playing whack-a-mole not only has been done a million times, but validates their frame.
We are voting on climate legislation and watching fossil fool corporations thrashing about with fake astroturf campaigns, fake town halls, fake phone campaigns, fake ‘studies’, fake this, fake that to delay the vote and continue their unfettered profits.
Best,
D
Note I was suggesting two different kinds of searches above:
New commenter here: Just google the name, userid, and some short strings from their posting, and see how many hits you get and where they are.
Then use Scholar to search for the same ideas (quoted strings) and see if they appear in journals or discussions of journals.
Then use Google Image Search for the same strings.
Frequent pattern: lots of hits at denial blogs in Google and Image Search; few or no hits in Scholar. That right there is enough to identify a lot of the regularly copypasted stuff that people will flock to dump into your blog if you start to attract any attention from serious readers.
You’ll find for example Revkin’s Dot.Earth _always_ is pounded on by these folks. It’s prominent, read by a lot of people, so they dump there wholesale, endlessly repeating the same stuff.
But this little search pattern takes only a few minutes at most, and gets you a good idea whether the new arrival is old and familiar at other sites.
Remember also you can limit a Google search to a particular site or sites.
—-
The other suggestion, which does take much longer, is to actually read the cited sources and track them forward, both to assess whether a blog has real publishing scientists behind it, and to check what people bring here. Two different purposes, different time constraints. Sometimes just looking with Scholar for the original and checking the “cited by” link is sufficient to get an idea of the weight. Or you can search by author/title and words like followup, correction, withdrawn, supported.
All this of course prepares you to become yet another amateur wannabe reference librarian (grin). Like I said before, just change a few words in this and it applies perfectly to climate blogging by those of us who don’t do science: http://imgs.xkcd.com/comics/tech_support_cheat_sheet.png
Glen writes:
“valid interesting points along with a bit of leaping-to-conclusion, ad-hominem, or bit of psychoanalysis”
I was thinking of some words to describe most of Glen’s posts here. This suffices.
Focus on the “August 24, 2009 @ 11:27 pm” post, for example. Glen starts with a few sentences that are quite reasonable and polite. The purpose is generally to set the tone and give the impression of an objective observer. Things begin to descend considerably by the 3rd paragraph, where some broad veiled ad hominens are leveled at scientists (i.e. “jealously guard all your data and methods”), among other general character attacks, rendering another line “but most really prefer to rely on accusations of bad faith and on ad hominems.” rather ironic. For example, instead of assuming good faith on the part of scientists, Glen (and McIntyre for that matter), would prefer to carefully frame difficulty accessing data in such a manner that characterizes scientists as “jealously guarding data”, implying foul play, bias or bad faith. Glen then links an article that has quite a different take:
———-
“Jones says that he tried to help when he first received data requests from McIntyre back in 2002, but says that he soon became inundated with requests that he could not fulfill, or that he did not have the time to respond to. He says that, in some cases, he simply couldn’t hand over entire data sets because of long-standing confidentiality agreements with other nations that restrict their use.
Although Jones agrees that the data should be made publicly available, he says that “it needs to be done in a systematic way”. He is now working to make the data publicly available online and will post a statement on the CRU website tomorrow to that effect, with any existing confidentiality agreements. “We’re trying to make them all available. We’re consulting with all the meteorological services – about 150 members of WMO – and will ask them if they are happy to release the data”, says Jones. But getting the all-clear from other nations could take several months and there may be objections. “Some countries don’t even have their own data available as they haven’t digitized it. We have done a lot of that ourselves”, he says. ”
———-
When someone dares to call McIntyre on this behavior, his supporters (who often engage in similar rhetoric) often feign ignorance and decry “ad hominens” leveled against him. It reminds me a bit of the antagonistic sibling who starts a fight with another sibling then when that sibling fights back, he/she yells for Mom in hopes of getting the other sibling in trouble. Hopefully, Mom is wise to this tactic.
Glen Raphael:
So you mean they gave a weight of zero to all proxy data that didn’t extend to 2000 years? Why 2000 years, and not (say) 1500? Why was there a need to throw away data that didn’t extend all the way back to 0 AD?
Sounds like there is some weighting going on here.
— bi
Glen Raphael:
Why are you unwilling to discuss the points here in public view?
— bi
So I couldn’t resist, and I started reading McIntyre’s Ohio talk as linked by Glen. And noticed that I had already read it once before (yes, I’m that closed-minded). And what impression I then came away with: most of the stuff addressed is too technical for me and I wouldn’t know one way or another — like, presumably, most readers here.
Michael Tobin in one of his posts refers to the principles that guide him when judging the validity of claims that he has no way of judging based on personal competence in the field: 1) network of trust (basically the same idea as climatesight’s credibility hierarchy; “who do you trust”); and 2) consistency of evidence. I.e., all of the widely accepted, broad theories of science, like evolution, atomic theory, general relativity / big bang cosmology etc. are backed by multiple independent lines of evidence. All of which have to be overturned to overturn the theory. New claims of evidence will be seen in this context (“what do you believe”).
There is a third principle (or perhaps a variant of the above): I call it the “peephole confidence” principle. I.e., if I catch someone stating nonsense on some small subject that I happen to know a heck of a lot about, than my working assumption will be that there’s a lot more nonsense where that came from. This happened to me, e.g., when the Heartland Institute, many years ago, started attacking Linux and free software based on what were, frankly, nonsensical claims. I was less surprised than most to see the same institute also turn up at the climate party…
With the Ohio paper I had that experience when I say McI again pushing his well-refuted insistence to use the Pearson r^2 as the metric of reconstruction quality. Sorry, but this is textbook stuff. But, you want a paper? This one gives a good overview of the issue, with figures:
Click to access Wahl_ClimChange2007.pdf
It’s really worth reading (not the whole paper, just this explanation). Doesn’t require calculus ;-)
To finish up on the “was stuff rejected and if so, why?” question: I finally found a working link to the official information regarding what comments were made, which were “accepted”, which were “rejected” and for what reasons. IPCC chapter 6 revew comments start on this page and are really interesting throughout – I recommend them:
http://pds.lib.harvard.edu/pds/view/7786989?n=1
That page says that under IPCC procedures “authors must take account of all substantive review comments”. So the question is whether comments that ran against this lead author’s research was properly “taken account of”. A somewhat larger question is whether it’s really a good idea for an IPCC chapter to rely heavily on work that was co-authored by that very chapter’s Lead Author (Briffa); that issue is broached right away (and somewhat delicately handled in response) on page n=2. The question of whether some related sources are getting special preferred treatment (notably, Wahl & Ammann 2006) is broached on page n=3 (somewhat more tersely handled), and we finally get to the question of whether they ought to mention a bunch of individual proxy studies (including Millar 2006) that suggest more past variability than the multiproxy studies in comment 6-1127 starting on page 102, which is here:
http://pds.lib.harvard.edu/pds/view/7786989?n=102
That comment gets rather firmly rejected and a lot of later comments get rejected with references back to that rejection. The rejected comment was a proposal to add something along these lines (in order to reflect the existence of a specific contrary minority view):
“That’s a good point about credibility. Is there any kind of easy way to tell how many papers a scientist has published on a certain topic?”
Not easy, the h-index goes some way towards this but it’s not practicable unless you have access to ISI Web of Knowledge or Scopus.
According to ISI, McIntyre has an h-index of 2 (based on “Hockey sticks, principal components, and spurious significance” GRL 32 (2005) & “Reply to comment by Huybers on “Hockey sticks, principal components, and spurious significance”” GRL 32 (2005)).
By contrast Gavin Schmidt’s h-index is 22, Michael Mann’s is 30 and a certain Martin Vermeer’s is 12.
Martin Vermeer! Are you a scientist? Yes you are, according to Google, you’re a professor of geodesy. Wow, we have some very educated commenters here.
[inflammatory]
Hank, given your post re cut-off dates and Millar et al.2006, I’d appreciate your explanation as to why the IPCC AR4 was able to cite Wahl & Ammann (2007) in defence of the hockey stick.
Let us step back. The Dano character was started long ago to try and track down the source of talking points repeated by seemingly reg’lur folk.
He soon found that doing searches like Hank describes found sources such as Heartland, FF, Heritage, etc. in many issues being ‘discussed’ and even covered in The Media.
On the old Tech Central Station, these astroturf and misinformation campaigns were focused in one convenient place, and one could see TCS funders bashing on Linux, Monsanto employees bashing on Tyrone Hayes and Chapela, Detroit PR firms sparking CA Gov recall campaigns, CEI lawyers using sock puppets to smear findings…
It all goes together.
The default should be that there is a FUD campaign somewhere feeding partisans and Message Force Multipliers their talking points. Not the other way around. Some of these content distribution models are a little more sophisticated today, but their audience and targets are not sophisticated so there is no need for innovation. Look at the ham-handed fake ‘town halls’ in Greeley, CO yesterday populated by oil company employees. The astroturf campaigns. The phone banks. Etc. The certain commenter above is merely changing the pitch of the parrot squawk, not the content. Nothing new, as Hank explains in detail.
Best,
D
Kate:
Martin said that he was a scientist early on. You have many highly-regarded people helping you here, as I’ve mentioned previously. I’d kill to have your readership.
And Martin’s exactly right… I can’t believe anyone would believe the Heartland Institue or Junkscience’s Steve Milloy, for example, after the nonsense they’ve spouted about tobacco and asbestos being harmless.
They are astroturfing institutions, pure and simple, and always available to the highest bidder.
http://one-blue-marble.com/blog/2009/04/21/big-tobacco-big-oil-big-coal/
[inflammatory]
Yeah… teaching is my thing ;-)
Chris S.:
…and a certain Martin Vermeer’s is 12.
Are you sure? How computed? I got no more that half of that a few months ago, and I think I did it right… needed to report it.
I’m sure there are many scientists commenting here, but you wouldn’t know if they are using a handle. E.g., don’t you wonder how Chris S. has access to ISI Thompson statistics? ;-)
Yes, I did in fact wonder that!
Martin highlights a problem with the h-index. There is more than one Martin Vermeer in the database and, not knowing whether the author of “Space-geodetic constraints on glacial isostatic adjustment in Fennoscandia” is the same person who wrote “Effects of TNF alpha on verocytotoxin cytotoxicity in purified human glomerular microvascular endothelial cells”, and not wanting to spend too much time on a throwaway blog comment, I left both in (and any other Martin Vermeers that have published), this will have increased the h-index value. I’ve assumed that Martin is the author of the geodetic constraints paper is the correct one come up with a revised h-index for Martin of 5 (but note that his ‘top’ paper has 124 citations).
Chris S. (h-index = 1; based on two 2008 papers one has been cited 5 times the other only once…early days yet.)
“as I’ve mentioned previously. I’d kill to have your readership.”
Richard (not, I assume the R. Levangie who wrote “Activities of nucleases in senescing daylily petals”), intrigued by your comment I’ve just visited your blog and it’s lovely. I particularly like the “Urban Heat Island Effect is Ruining the Arctic*” post, nice humour. I’d recommend others take a look.
Yes, Richard, your blog is very well written. I especially like how you write about Canadian climate policy a lot. The UHI in the Arctic post is very well done, however, I believe Watts’ take on that issue is that the Arctic isn’t melting at all (?)
Just as I thought.. my h-index is still 5. Chris S., sure you didn’t take any oncologists or immunologists along in the query? I’m not that Vermeer M* :-)
For Mann I find indeed 30 and for Gavin Schmidt 22, so we seem to be doing the same thing… I used the Distinct Author Set feature.
Glen Raphael, I see you sent a message to me ‘explaining’ that you’re unwilling to discuss your points in public because you don’t want to be piled upon and persecuted, blah blah blah. But none of it explains why you can’t answer certain reasonable questions.
You know, such as this question of mine:
— bi
Thanks Chris and Kate… I appreciate the kind words (and I really wasn’t trolling for compliments, just making an observation that Kate already has many distinguished readers).
And no… I’m not the R. Levangie who wrote about daylily petals… my first degree was in biology, and I had planned to do an MSc in immunology, but delayed for a year because my mentor had a full slate of grad students, ending up falling in love with wine, and then became a journalist. I was a wine, food, and travel writer before a long illness ended that career.
I was one of two students (out of 50) in j-school who had training in science (half the students had one or two degrees before doing journalism). It was a difficult program to get into, and the main reason given for the high number of applications — I kid you not — was that the applicants weren’t very good at science.
That should tell you a lot about our current predicament. And it’s the reason why I started my web site.
“That’s another example of being nice to my enemies …”
This phrase summarizes the tone of this whole discussion quite well. It’s not about science. It’s not about logic but about Your Own Logic. It’s about believes (a study is worth nothing if it is not printed on (in) the right paper).
“However, all the points which skeptics like to make are not common knowledge.”
Are you pretending that you posses all common knowledge and that whatever you don’t know can’t be valid?
Galilei’s knowledge wasn’t common knowledge until some time later. Newtons law wasn’t common knowledge before Newton. The laws of thermodynamic weren’t common logic before the laws were stipulated.
Of course I don’t know everything! I’m just saying that statements such as “humans are affecting the climate” are so well known that you don’t really need to cite them (common knowledge), whereas claims such as “the warming is caused by the sun” is not supported by any peer-reviewed science I am aware of, so if you’re going to make that claim, you better be able to back it up.
I don’t want to eliminate all comments by skeptics. That would be too close to censorship because of what they’re saying, not how they’re saying it – and it would be all too easy for them to accuse me of such. As long as they’re respectful about it, I want to be open to what they have to say.
And because I have previously deleted skeptical comments which were aggressive, I feel obliged to hold the statements I agree with to the same sort of scrutiny, which is why I have warned several well-meaning and accurate commenter about abiding to the no-aggressive-comments policy.
http://en.wikipedia.org/wiki/Aggressive
psychologically and physiologically. Some research indicates that people with tendencies toward affective aggression have -lower IQs- than those with tendencies toward predatory aggression
http://en.wikipedia.org/wiki/Assertiveness
places that uses Assertiveness well is the airvent and the blackboard
they are not deniers but looking for the truth.
RC, (Openmind?)tammys tend to be affective aggressive.
If you can keep truely an openmind, the light to which what is real will come to you.
Good luck
Yep, Richard, very nice site.
One nit I have with “The Science”: you write
The science supporting global warming — or climate change — is incontrovertible. In the last seven or eight years, it has move from strong theory to unassailable fact.
Actually it’s much stronger than that. The science has been incontrovertible, in its essence, since the experiments of Tyndall, the computations of Arrhenius, and the measurements of Keeling. We know that humans are changing the climate — and we know what variations in the same greenhouse gases we are emitting did to our planet in the past.
The only question remaining — and an important one — is by how much. We’re not any more in hypothesis testing mode; we’re in parameter estimation mode now.
What happened over the last seven, eight years, is that this known-to-exist AGW started sticking out of the natural-variability noise. Scientists love that… one more independent line of evidence that they’re holding the right end of the stick. But a rather weak one by comparison actually… more important is that this allows us another way of pinning down the likely magnitude of the effect, under conditions close to those of the 21st Century :-)
I don’t know how to formulate this journalistically, but there you have it…
I read an essay by Naomi Oreskes (it was in Gavin Schmidt’s new book with all the pretty pictures) which said that the consensus on climate change came in two stages. Stage 1 was “human emissions of greenhouse gases are a radiative forcing on the climate, eventually it’ll overpower aerosols, and we’re going to see warming of the planet eventually.” Stage 2 was “oh look, here it is.” It was very interesting. A lot of popular literature frames the issue as if the scientists noticed the warming and then tried to find a cause for it, instead of the other way around.
2000 years mainly because it’s in response to the NRC report “Surface Temperature Reconstructions for the Last 2000 Years.
The need to only use the long series comes as a result of the decision to use the simplest conceivable statistical method to combine results and the decision to try to reflect a decent spread of geographic coverage over the entire time. We just want to get a sense of the broad overall worldwide trend, not so worried about smaller-scale wiggles. If all the data sets we use are 2000-year trends it’s reasonable to just average them together. We have enough 2000-year trends that we can get decent geographic coverage (see map on the bottom of that page) without having to deal with the complexity of the weighting issues you get by mixing and matching trends of shorter lengths. In particular you don’t want to confuse strictly *local* trends with *global* ones – that’s easy to do when the distribution of your proxies changes over time.
Having made the specific set of choices he did, Loehle’s study manages to avoid essentially all the alleged problems common in the standard multiproxy approach, but it also avoids many of the alleged benefits of the standard approach and has one or two additional problems of its own. I’d actually like to say more about that – what I think the specific problems and benefits are of both types of studies – but I’m not sure anybody here other than frank cares, so I’ll leave it at that for the moment.. :-)
Oh, and here’s a list of the exact proxies used in the ’07 study along with a small-multiple chart of all of them individually so you can eyeball to check for any weirdness.
[citations needed]
Glen Raphael:
So you’re saying that, just because some people wrote a book that has the words “2000 Years” in the title, Loehle and McCulloch decided to throw away all data that don’t go back to 0 AD, because in any case there’ll be no difference in the final result except for “smaller-scale wiggles” which somehow manage to yield a different result from everyone else.
What prevents one from simply using 1,500 years’ worth of data from all the sources, for instance? (Mann et al. 2008 reports that there are 36 proxies going back to 500 AD.) It’s merely because of that book title, isn’t it?
— bi
[inflammatory]
[inflammatory]
[inflammatory]
Jeff, please stop posting these claims that I am dishonest for requiring citations and respect in the comments. The only references you used were to your own blog – we require peer-reviewed research. If you want me to publish what you write, be nice about it.
frankbi says, regarding the choice to focus on longer series:
Actually, the biggest difference between Loehle and everybody else is the fact that Loehle excluded tree-ring data. Only two prior long-term reconstructions had excluded tree-ring data: Moberg et al., 2005; Viau et al., 2006. That this produces a different result suggests the inclusion or exclusion of tree ring data “matters”; hopefully some attempt will be made to reconcile this in the next IPCC report. Loehle’s study can be downloaded from here; it’s quite short and readable.
Nothing, I suppose. Does that list exclude tree samples, are all of those proxies already calibrated to temperature in the literature, and are all the proxies archived? If the answer to all three questions is yes, we could easily rerun the study to include them and see if it makes a difference to the results, but I tend to doubt that it would. The methods section of the study says “After an extensive search, all data were used that had at least 20 dates over the 2000-year period.. We could certainly rerun it changing that “2000” to a “1500” if you have reason to think it would matter. Do you?
The “methods” section has a really nice summary of the case against using tree rings:
…various other issues discussed and eventually we get to the therefore, which is:
Thus: a reconstruction that excludes them, which does in fact find different results.
Mann et al 2008 also excluded tree rings…..and they were published in a much more reputable journal (PNAS vs Energy and Environment). And we all know what they found.
Mann 08 was almost entirely tree rings. [citation does not support argument – they did reconstructions both with and without tree rings and compared them]
[citation needed. If you post a comment and it’s rejected, posting the same comment again isn’t likely to be successful.]
“Mann et al 2008 also excluded tree rings…..and they were published in a much more reputable journal (PNAS vs Energy and Environment).”
What kind of argument is this? Are you saying that a study is not valid if it isn’t printed on glossy paper.
Are all the comments in your blog worth nothing, because they are not published in the PNAS?
(1) I said only two earlier studies had excluded tree rings, which is true.
(2) Mann et al 2008 did use tree rings to justify the conclusions of their study.
(3) When Mann08 excluded tree rings, it included new series which have an entirely new class of problems.
Here is McIntyre&McKitrick’s comment in response to Mann08:
http://www.pnas.org/content/106/6/E10.full
Relevant bit:
To clarify: Mann08 added some new non-tree-ring data sources to the mix which – when calibrated using RegEM – had a hockey-stick shape. McIntyre identified which sources these were; the most problemmatic one was the Tiljander sediment sample, which got inverted by Mann’s algorithm. Reading this data series the way the physics suggest it’s supposed to be read (according to the person who collected it), it should be telling us that it got a lot colder in the last century – colder than the little ice age, in fact. This recent cold pulse is bogus; it is believed to have come about as a result of the sediments being disturbed by modern construction. But the Mann08 mathematical process just flips that series to turn that implausibly-extreme cold pulse into an unusually-strong warm pulse, producing the overall effect that (when you combine it with all the other data) it looks like it’s a lot warmer now than in modern times.
So Tiljander sediment has issues. Mann did two reconstructions for the main study, one with tree rings and one without. The reconstruction without tree rings had Tiljander in it instead. If you exclude the tree rings and all the “upside-down series” such as Tiljander – any series whose orientation in the final mix is inconsistent with the physics of how it’s supposed to be recording temperature, the hockey stick shape goes away.
And here is Mann’s response:
http://www.pnas.org/content/106/6/E11.full
The claim that “upside down” data were used is bizarre. Multivariate regression methods are insensitive to the sign of predictors. Screening, when used, employed one-sided tests only when a definite sign could be a priori reasoned on physical grounds. Potential nonclimatic influences on the Tiljander and other proxies were discussed in the SI, which showed that none of our central conclusions relied on their use.
As I understand it, the way Mann verified in the SI that none of our central conclusions relied on their use was to run a reconstruction that excluded these series – but did include tree-ring samples!
Argh: the paragraph immediately after the link to Mann’s response was supposed to be in a blockquote – that text was written by Mann et all, not by me. (gee, what I wouldn’t give for a “preview” button here! :-) )
I’ve tried but the “preview button” doesn’t appear to be a feature on the WordPress software.
[citation needed. I understand you have your own analysis of the math but, with all due respect, it is not a peer-reviewed analysis, and does not meet our comment standards.]
I referenced none of my own work
Then whose analysis did you reference? You provided quotes from the Mann article and explained why they were wrong. However, there was no reference as to who said that Mann’s methods were wrong, and whether this statement was peer-reviewed or was simply an angry comment. It appeared to be your own analysis of the article. I am not a scientist, and so I can’t really tell whether your analysis is legitimate or not. I have to go by credibility. And when a legitimate peer-reviewed article meets an angry comment, it’s not hard to tell which can be given more weight.
If you can find a peer-reviewed article, which has not been discredited (eg nothing from Energy and Environment), which agrees with your criticism of Mann 2008, and can reference it while refraining from insulting anyone, your comment will be eligible for publication. Those are my terms, and they are clearly displayed in the sidebar. But until then, I am not going to continue this discussion with you; you are wasting our time.
All comments were made right from Mann08
All I did was quote my point of what happened from the clipped post and then quote where Mann said that’s what he did. There was only a single sentence where I pointed out infilling prior to correlation verification was mathematically wrong (that’s first year stats and not a very big deal). The rest of the post just stated what happened.
If paraphrasing what he did is bashing on the paper, perhaps you don’t like this paper very much. After my paraphrase post was clipped, I took the time to copy and paste his own quotes from the paper which are the backing up you required of me and nobody else.
Here’s what you say,
.You provided quotes from the Mann article and explained why they were wrong.
This is false.
What I did was provide statements about what the paper did and then show where Mann stated exactly what I said. – References in peer review according to your policy – which apparently only applies to me.
Then whose analysis did you reference?
Copy and paste right from the SI and PDF of Mann08.
Speaking as a classical liberal, and not a Democrat or Republican, the reason why I oppose “taking action”, specifically, government action is because government action has such a horrific track record. See R.J. Rummel’s “Death by Government” for more information. The problems and outright death that will occur because of government will easily outdo any potential climate issues.
Now, I don’t oppose taking individual action to help remedy any social, political, or environmental problem that you perceive. Just don’t use force (or ask government to use force) to get others to go along with you. So plant a tree. Reduce your own carbon footprint. If it makes you feel good and you feel you are making a difference, then good on you!
I don’t know if this is always the case. We have a lot of regulation in Canada – for example, forestry, air pollution (other than GHGs), CFCs…..to my knowledge nobody has died because of it! With the possible, indirect exception of subsidized oil.
If you can find a peer-reviewed article, which has not been discredited (eg nothing from Energy and Environment), which agrees with your criticism of Mann 2008, and can reference it while refraining from insulting anyone,
What is wrong with quoting Mann 08?
When you are quoting Mann 08, and yet coming to the opposite conclusion that they did, you’re not citing your argument. You’re citing their argument, and using your own analysis. Again, find a peer reviewed paper which affirms your criticism of Mann and concludes that Mann was wrong.
which agrees with your criticism of Mann 2008
My last comment wasn’t a criticism.
There are many peer reviewed articles which find the same problems as Mann 08 yet pre-date it. Are you interested in those?
If they pre-date Mann 08, how can they conclude that Mann 08 was wrong?
Glen Raphael, I asked:
You replied:
Loehle and McCulloch also did other things differently from everyone else. For example, no other work simply throws away data that don’t go back 2,000 years.
So on what grounds do you claim that the exclusion of tree-ring data, rather than anything else they do differently, is ‘the biggest difference’ between Loehle and McCulloch and all other work?
Do you have a citation for this claim?
— bi
I’m going to let Glen bypass the citation requirements in this discussion, simply because he began posting in this thread before the new comment policy kicked in, so I’d like to give him time to finish up. It’s not like he’s being inflammatory. Citations are still important, though, and if he can’t cite a claim we shouldn’t accept it.
nanny_govt_sucks:
Yawn.
— bi
When you are quoting Mann 08, and yet coming to the opposite conclusion that they did, you’re not citing your argument
I did not come to an opposite conclusion in the last post you clipped. In fact there was no conclusion at all.
If they pre-date Mann 08, how can they conclude that Mann 08 was wrong?
They criticize the math used to create the hockey sticks by the limitation of variance. Von Storch 04- which criticized Mann98 but did not replicate Mann98 correctly was about other papers as well. VZ04 actually made the mistake of doing the math correctly and blew the criticism of Mann98. It covered other papers as well though. There are also several other publications apply to the variance distortions demonstrated on my blog.
My blog posts are the only source I know of on the simplest form of the HS where turn key data and results can be obtained directly. That’s why I so kindly offered it to you in the first post. I thought you may want to study it and learn. On tAV criticism is accepted so if you see some point I’ve missed it would be addressed openly and honestly. I’ve found no need to censor or ban anyone in 8000 posts and a half million views.
Are you interested in quotes from these published sources about the loss of variance due to data sorting methods? They certainly apply to your field.
“which apparently only applies to me”
I had to painstakingly paste comments from Mann 08 which stated the same thing that was in each sentence of my post. That too was clipped with the claim that it was my research. I covered every single point in the post and offered to clear up any others, there was no conclusion.
The post was still clipped. How should I interpret this.
I don’t really care about Mann 98, it’s ten years out of date.
Even if you didn’t explicitly give a conclusion to your comment, the direction you were going with it was obviously “Mann was wrong, it shouldn’t have passed peer review, and so we still have no evidence that today is warmer than the MWP.”
If you had said, “Modern days are warmer than any time in the past 1300 years, see Mann et al 2008”, or “Mann 08 was proved wrong, see [insert citation here]”, that would have been perfectly acceptable. You didn’t have to painstakingly paste comments – I never asked you to. All I asked for was a peer-reviewed article which agreed with and explicitly supported your (implied) conclusion – that Mann was wrong, etc. If you believe you can prove this using your own math, that’s just fine. Go submit it to a reputable journal (again, not Energy and Environment) and, if you can get it published, bring it back here and you are welcome to tout your conclusions all over the comments and we’ll have a scientific debate.
But otherwise, you’re wasting our time. Starting now, all of your future comments will be deleted with no more replies from me – unless and until you can provide a peer-reviewed citation that backs up your basic points – because you’re wasting our time and this isn’t an issue on which we have a lot of time to fiercely debate trivial details. I have made my comment policy very explicit and I feel it is justified. Thanks for your input and farewell.
I wrote:
Frank Bi asked: Do you have a citation for this claim?
Sure. If you mean the claims about the appropriate directionality of the sediment studies with respect to temperature and that these sediments are contaminated so you shouldn’t use them to estimate modern temperatures, I believe the original citation is:
A 3000-year palaeoenvironmental record from annually laminated sediment of Lake Korttajrvi, central Finland
Authors: Mia Tiljander a; Matti Saarnisto a; Antti Ojala a; Timo Saarinen a
Boreas, Volume 32, Issue 4 December 2003 , pages 566 – 577
McIntyre spoke to Mia Tiljander to confirm his interpretation of her article was correct; that’s the reference to “personal communication” in his accepted PNAS comment. Article abstract is here:
http://www.informaworld.com/smpp/content~db=all~content=a714025453
You should be able to find the full pdf on Google Scholar. It’s a bit of a slog, though…
If you mean my claims that Mann08’s process used this as a temperature proxy despite the known contamination issue and that their process inverted the proxy, read the two PNAS comments I linked to earlier. M&M make this claim in their comment and PNAS accepted their comment so this claim is now on the record in a well-regarded peer-reviewed journal. The Mann et. al response doesn’t deny it. They explicitly agree that their method doesn’t pay attention to signal directionality (quote: “Multivariate regression methods are insensitive to the sign of predictors.”) and they say they ran some tests (in the SI) to see if excluding the bad data changed the conclusions; they claim including the bad data didn’t change the result so it’s okay for them to use it.
(A naive observer might ask, “if this data has known issues, why not leave it out?” but that’s neither here nor there.)
Why don’t M&M just make their own reconstruction using data and methods they believe are satisfactory, instead of just commenting on others’ work? The review process for articles is surely much more stringent than that for comments, so it would give their arguments more credibility.
[inflammatory]
[inflammatory]
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Frankbi:
I regard their strict and clearly-stated inclusion criteria as a feature, not a bug. There are actually lots of other studies that rely on relatively few proxies. If some study you like includes one tree ring set or one borehole series and doesn’t bother to include all the other tree ring sets or borehole series they might conceivably have included, do you claim they are simply throwing away all the data they chose not to incude? In the case of the spaghetti charts we actually know that slight modifications in input data – picking one series rather than another very like it – can reverse the medieval/modern relationship. (see the M&M NAS testimony, or the OSU talk) but we don’t know that here. Here the criteria were: We want to reconstruct the 2000 year record, so we look for 2000-year proxies. What could be simpler?
Are you perhaps assuming the more proxies, the better? There’s a problem there which is that if your method is to take an average, the more proxies you use, the flatter your result will be. Loehle arguably understates past variability because as we go further back in time and combine more proxies, the dating uncertainties will tend to flatten your peaks. (his smoothing function also flattens peaks, as does the fact that he’s using relatively low-resolution data).
Incidentally, I also disagree with your claim that Loehle’s findings were so different than those of “everybody else” that he must be doing something wrong. Moberg’s study used a lot of the same sources and had pretty similar findings. Abstract here:
http://www.nature.com/nature/journal/v433/n7026/full/nature03265.html
relevant quote:
They get that question a lot. As I understand it, M&M have a bunch of statistical arguments (which I’m not claiming to understand) to the effect that *all* the current reconstructions ultimately aren’t really valid – that the appropriate variance is too high to reach meaningful statistical conclusions going back more than a few hundred years. They tend to think the present set of reconstructions are broken in both small and large ways rather than fixable with just a few minor tweaks. So even when they make constructive suggestions – that this is wrong; it would be better if you did that instead – a regression that only did that still isn’t good enough for them to consider it publish-in-Nature quality. I think they think of “make a good reconstruction” as an as-yet unsolved problem. Some of the current methods in use might claim, say, “95% percent accuracy” but the shape of the curve is wildly different depending on which data sources you use and *all* of the resulting curves claim to be “95% accurate – the math being used can’t distinguish “good” input sources from”bad” ones. So that “95% accurate” claim is just bogus. When M&M propose alternates like that – “apple-picking” versus “cherry picking” – they are *not* holding up the result as robust or even clearly better. (Wahl & Amman didn’t seem to understand this)
Also: they’re not climate scientists, and they know it. “Auditing” a study – McIntyre’s area of expertise – takes a different set of skills than does creating the study in the first place. Maybe M&M will get around doing their own study eventually – perhaps collaborating with one of the Team members to do something everybody can agree on – but currently there’s so much bad blood between the two sides that it’s kind of unlikely.
Heck, Roger Ebert is great at entertainingly and convincingly explaining why _Transformers 2_ is a bad movie, but if you gave him the same budget to do the same project, would he have made a more successful movie?
“Citations are still important, though, and if he can’t cite a claim we shouldn’t accept it.”
Galilei’s theory was neither peer-reviewed nor could he provide any citations. Hence it was not accepted.
Kate. Personally I thought you were being a little unfair to Jeff. There is a lot to be gained by being a little more liberal with your moderation policy to allow some discussion. Extending the logic you applied to Jeff, I could argue that Lindzen has shown that observed outgoing radiative flux refutes the postive feedback and climate sensitivity suggested by climate models – and no one here would be allowed to argue with me unless there is a more recent study to reference.
Jeff was trying to show that there is support in the literature for his analysis showing that proxy reconstruction methodology distorts the true signal. The reference is relevant in spite of it pre-dating Mann 08 because the same scaling and calibration methods are employed in Mann 08.
I respect that you can run your blog however you see fit, but FWIW arguments are what science is all about. Jeff was trying to make an argument and IMO has a vaild reference to support it – whether it predates Mann 08 or not.
Layman Lurker – you didn’t read the comments where he called me a “dishonest charlatan”, among other things! His “expulsion” was almost entirely due to his personal attacks on me – none of which were published in his blog, like his other comments were. I’m not going to spoon-feed people who treat me like that. If Jeff wants to make a scientific argument which is more complicated than “my basic conclusion is this, here’s a scientific report which found the same thing”, that’s fine, but this really isn’t the right place. I’m just a lowly high school student and I can’t begin to assess arguments on their content – I have to go by credibility. A blog which is run by actual scientists may be a more appropriate place for such technical discussions.
@ nanny_govt_sucks “I don’t oppose taking individual action to help remedy any social, political, or environmental problem that you perceive. Just don’t use force (or ask government to use force) to get others to go along with you.”
But in regards to climate change such actions simply wont make the cuts that the science says are necessary to avoid the problem. In short we need more than that.
Obviously cap-and-trade isn’t perfect, but as a classical liberal you should support policy that internalizes externalities. A revenue neutral carbon tax does just that, and lets the market figure out how best to deal with the problem. Again not a perfect solution, but the alternative to action is far worse.
I said:
Glen Raphael replies:
You’re shifting the goalposts.
You compared Loehle and McCulloch to long-term and multi-proxy temperature reconstructions only, in order to conclude that “the biggest difference between Loehle and everybody else is the fact that Loehle excluded tree-ring data.”
You can’t suddenly decide to expand your comparison to include single-proxy and/or short-term temperature reconstructions to conclude that Loehle and McCulloch aren’t that different from other work in other ways.
So again, on what grounds do you claim that the exclusion of tree-ring data, rather than anything else they do differently, is ‘the biggest difference’ between Loehle and McCulloch and all other work?
— bi
Glen Raphael:
Climate auditing is “McIntyre’s area of expertise”?
Um, that just means that McIntyre’s an “expert” in a field of study which he himself made up.
Now I’m not saying that there’s some authority which decides what sort of things count as ‘fields of study’, but surely whatever McIntyre and pals are coming up with should fall under the rubric of “Science”, and should thus abide by the rules of science? Asking questions, not bothering to answer them, and then insinuating that other people are guilty of all sorts of wrongdoings — this isn’t science, this is crankery.
— bi
Frankbi:
One of them, yes. It’s the basis of his published papers and comments which have been cited in a great many other peer-reviewed papers and comments. It’s the reason he was twice asked to testify before congress, and keeps getting asked to give talks before organizations such as the AGU.
That is usually how the world works, yes. Any field you invent or make significant contributions to, you’ll probably be regarded as an “expert” in. Try it sometime and see!
So are you. First you claimed (with no evidence) that Loehle didn’t have good geographic coverage. I showed that it did. Then you implied (with no evidence, and clearly without even having read the abstract) that Loehle must be weighting the series it uses in some nefarious way to get the result it did. I showed that it wasn’t. Then you implied (with no evidence) that the choice to focus on 2000 year records must be skewing the results, by which point I’m starting to suspect you are just throwing out random objections in the hopes that I get tired of knocking them down. I’m thinking it might be time to put some burden of proof back on you. What sort of evidence would convince you? If I went out and did a study that included all available 1500-year non-treering proxies, smoothed and averaged the series and thatalso showed an MWP about as warm as the present or warmer, would that convince you? Or would you just reach into your bag for the next objection? How many objections are in that bag, anyway? Could we dump it out and lay them all on the table at once, or is there some reason I’m only allowed to see them one at a time? :-) If you’re getting these objections from somewhere else, can you point me to the original source so I can respond to that rather than your paraphrasing of it?
I do so largely on the grounds that when you exclude tree ring data from the multiproxy studies, you get similar results to what Loehle found. Tree-ring-based trends tend to dominate multiproxy results because (a) they have great temporal coverage, (b) they have *high resolution* coverage – you get one data point per year over ridiculously long periods, and (c) they have a mid-20th-century probably-CO2-driven growth pulse which “calibration” algorithms that try to match the instrumental record tend to select for. All the multiproxy studies in the “spaghetti chart” include tree rings, as does Mann08, and the tree ring data powerfully influences the final result, especially the finding that the MWP wasn’t warm.
The first indication that this might be a problem was probably the whole MBH98 “censored directory” fiasco and the underlying issue hasn’t changed much in the eleven years since then. My impression of the published and unpublished literature I’ve read is that: If you do a multiproxy study using principle components analysis and certain specific tree ring series as inputs, you tend to get some sort of hockey stick. If you do one with simple averaging and no tree rings, you tend to find a warm MWP, usually roughly as warm as the present. Since Loehle is an example of the latter approach, it found a warm MWP. I think that’s all there is to it but if you believe differently, if you think there’s something else going on, please be more specific as to why you think that and what, if anything, might satisfy you in that regard.
Okay, if Loehole et al is really that good, it would be published in something other than Energy and Environment. I’m still skeptical about this. I can’t evaluate on the basis of science – I’m not a scientist (yet) and so can’t properly make up my mind about which argument works – so I have to go by credibility. And Mann 08 still wins in my mind.
A lot of what I’ve been saying above does rely on my claim that tree rings inherently dampen the signal and can’t be used to verify whether the MWP was warm. If this claim is correct then all of the spaghetti graphs point to a wrong conclusion because they all rely on tree rings. But is the claim correct? I hear you saying that you would give a lot more credence to a source published in a journal other than Energy & Environment. Thus, try this reference instead. Practically hot off the presses!
“A mathematical analysis of the divergence problem in dendroclimatology”
Craig Loehle, Climatic Change, Vol. 94, No. 3. (1 June 2009), pp. 233-245.
abstract and pdf here
Relevant quote:
(Out of curiosity: What’s Craig Loehle’s publication index?)
All right! So tree rings are out. I think we probably knew that already. It’ll be interesting to see what the next IPCC report (it’s due in 2014 or 2015, right? I could be starting a Master’s by then….) uses for their 1000-year temperature graph. The cold bias that tree rings give was shown by Mann et al 2008, which demonstrated (without tree rings) that today is warmer than the past 1300 years – but when tree rings were used, that could be extended to 1700 years.
However, we still don’t have a reconstruction, without tree rings, in a credible journal, which shows that today is not the warmest time in the past 1000 years. This is obviously partly because paleoclimatology is very new – and partly because those studies take so much time and travelling!
As I said before, Mann08 has *two* hockey stick sources in his input proxies, which are: (1) the usual tree rings, and (2) some sediment series that were being questionably used – the “inverted Tiljander” thing I gave Frank a reference for. Mann includes *both* of those datasets to get his 1700-year claim and he includes (2) to get the 1300-year claim, so – though I haven’t verified this – I strongly suspect he can’t even get a 1300-year claim if he fixes both problem (1) and (2) simultaneously in the same reconstruction. (Source: the M&M PNAS comment and its response). I doubt later studies will get away with that sort of thing, but who knows. Certainly Mann08 won’t be the last word on the subject.
I do agree that it’ll be interesting to see what the next IPCC paper report shows. I think it is fabulous that the data and methods are starting to get archived and described well enough that when there are problems they can be found right away. The Climate Science climate is changing! Hopefully this whole debate will be resolved by the next report.
Yeah, that really would be great. Paleoclimate reconstruction methods are always in need of improvement and it would be good to get to a point where there were no known problems.
Sure. Several reconstructions have been done that abide by the NAS recommendation to avoid strip-bark samples. Page 37-38 of the OSU presentation features one such: Loehle & McCulloch 2008. It has a really warm MWP. Also see the discussion of “Ocean Sediment” studies (page 34-36); almost all of these show a warm MWP relative to the modern era, so any reconstruction that emphasizes them will also do so.
The ‘really warm’ MWP of Loehle is not there at all. It is only a little warmer than present, and much less warm than the projected temperature rise. Loehl was shooting blanks, not that you would have guessed that from McIntyre. He is a genius at creating mountains of molehills. Which I guess is all he has to go on. Either way, the case for AGW is not made by the “Hockey Stick”.
Glen Raphael:
So are you admitting that you were shifting the goalposts? (when you tried to show that “the biggest difference between Loehle and everybody else is the fact that Loehle excluded tree-ring data“)
Your “The Alarmists Do It Too!” gambit isn’t going to work, Glen.
No, Glen. Here’s the thing: if you
– do a multiproxy study
– using principal components analysis
– with proxies spanning a variety of periods
– including tree-ring proxies
you get a hockey stick (Mann et al. (2008)).
If you
– do a multiproxy study
– using principal components analysis
– with proxies spanning a variety of periods
– not including tree-ring proxies
you get — a hockey stick again (Mann et al. (2008)).
If you
– do a multiproxy study
– using simple averaging
– excluding all proxies which don’t go back 2000 years
– not including tree-ring proxies
you get no hockey stick (Loehle and McCulloch (2007)).
You see, if I do a scientific experiment where
– a change in a variable A results in a different experimental outcome,
– but a change in a variable B does not result in a different outcome,
will any rational person conclude that the main factor determining the experimental outcome is B (the inclusion/exclusion of treering data)? Yet this is what you keep doing, again and again.
A question which I meant to ask yesterday:
Which of the Tiljander series did Mann et al. use wrongly in their non-treering temperature reconstruction?
— bi
A simple question – why does science need consensus? Is science a democracy?
Frankbi:
I’m saying I’m not sure where your “goalposts” are because I can’t figure out what question you’re asking. One problem is we’re using imprecise terms (like “goalposts”, or “everybody”) for which we have different internal definitions. You wanted to know what “the main difference” was between Loehle and “everybody else”; when I pointed out some other studies that were somewhat similar and reached similar conclusions I feel like you redefined “everybody” to exclude the studies I pointed to. Even Moberg, which doesn’t even fit in the hierarchy you just gave! Perhaps by “everybody” you just meant the guys in the spaghetti chart – a specific subset of multiproxy studies, most of which use PC. So you thought I was “moving goalposts” to point to equally-credible studies that differed from those in various ways. But that’s a guess. (I also suspect arguing over who was or wasn’t “moving goalposts” is likely to annoy everybody here but you. Why not skip it? If you really need to argue about stuff like that, why not be specific enough that other people can figure out what you’re talking about? It’s silly that I have to guess what you’re accusing me of. Either spit it out, or skip it. Or take it to email.)
When I say I believe including/excluding treerings is the main difference, I agree with you that I can’t prove that from Loehle alone. I am basing that opinion on other data points in addition to Loehle, some of which we’ve already discussed and some of which we haven’t, but I consider relevant the fact that Mann08 had to find a new dubious substitute hockey-stick source in the form of inverted and construction-polluted sediments in order to keep his hockey stick in the final output without tree rings.
(It will always be possible to “get” a hockey-stick shape using PC calibrated on 20th century temps if you cherry-pick your input series to favor hockey stick-shaped data. This is called “data-mining”, and it’s easy to do by accident. But most studies that specify clear inclusion criteria in advance of doing the study shouldn’t have that problem because most of the available data sets don’t have that shape.)
As I understand it, all four of the Tiljander series Mann used were used with the wrong sign. Why the correct orientation is the opposite of that used by Mann is explained in this climateaudit post which also shows charts of two of the series as used (and gives a reference to the underlying study, which I linked to earlier).
Kate states the following:
“All I asked for was a peer-reviewed article which agreed with and explicitly supported your (implied) conclusion – that Mann was wrong, etc.”
“Starting now, all of your future comments will be deleted with no more replies from me – unless and until you can provide a peer-reviewed citation that backs up your basic points…”
Followed by this:
“His “expulsion” was almost entirely due to his personal attacks on me…”
Forgive me for being a tad confused.
“If Jeff wants to make a scientific argument which is more complicated than “my basic conclusion is this, here’s a scientific report which found the same thing”, that’s fine, but this really isn’t the right place.”
Excuse me, this completely contradicts your stated policy for posting.
If he can find something to finish up his argument in a way that follows my comment policy, that’s fine. But otherwise, he’s obviously just interested in yelling at me.
My comment policy clearly states that all scientific claims which aren’t common knowledge must be cited with a peer-reviewed source. It is the practice of science to continually challenge peer-reviewed studies, but this isn’t the right place – I have no hope of addressing technical arguments on the basis of their coherence. If I tried, I could easily let in something that was completely made up but seemed logical, and tie up all the scientists who read this blog for ages.
[inflammatory]
Fair enough Kate.
BTW, I think it is admirable that you started this blog. I respect your rules for posting as long as they are applied fairly and consistently to all posters. I just hope for your sake that it does not become an echo chamber. You will learn a lot by sorting through point / counter point discussions and keeping an open mind.
My plan exactly. Thanks for dropping in.
LBB wrote:
Okay, that’s a good question: does it really matter if the MWP was warmer than present? I hear you saying you think it doesn’t matter, but I disagree. It definitely matters, and my opinion is that, on net, a warm MWP makes dealing with AGW right now less urgent than it otherwise would be.
One reason the issue matters relates to a phrase you just used: the projected temperature rise. The “projections” you’re talking about are based on climate models and as I understand it – please correct me if I’m wrong about this – existing climate models don’t show a strong MWP. So if we accept that there was a strong MWP, that means some of the “natural variability” factors are being underestimated in our models, which might mean that “human-caused variability” is being overestimated, in which case we could reduce our estimate of the CO2 multiplier, which reduces the projected rate of temperature increase, which buys us more time.
(On the other hand, Gavin thinks this factor argues in the other direction. His argument, as I understand it, is that if the climate is more variable than we thought, then the worst case scenario is worse than we thought. Whoever is right, it’s safe to say the projected temperature rise is not going to stay the same once we update to account for a warmer MWP.)
So that’s a factor might go either way. But there’s another issue, which is that one of the most compelling rhetorical arguments AGW activists have for the need to take immediate action is based on the precautionary principle and has roughly the following form:
(1) Science thinks the world temperature is warmer today than it’s been in human history. (Or at least in a very very very long time.) We are in uncharted territory.
(2) It is at least theoretically possible that bad things happen when world temperature gets as warm as it is now or a little warmer. We might be standing on the edge of a metaphorical cliff.
(3) We have no practical evidence against point #2 because…it’s never been this warm before – see point #1.
(4) Therefore we should be on the lookout for bad things happening right now or in the near future, and we should be trying our best to back away from the edge of the cliff.
Given that context, a finding of a warm MWP gives us a lot more runway. (Or roadway, to avoid mixing metaphors.) If we think MWP was slightly warmer than today that means we’ve still got another 20 or 30 or 50 years to go before we expect to exceed the prior recent world temperature record…which is excellent news! It means most of the potential for bad things happening is a bit further away than we thought. This is the difference between being on the edge of a cliff and slowly walking towards the edge of a cliff – you have more time to ponder, less immediate risk, and more time to stop or turn around in the latter case. Right?
Glen, you’re mixing up the significance of the absolute temperature with the rate of temperature change. It doesn’t really matter when the Earth was last warmer than today. If you go back far enough you can always find such a time – right back to dinosaur ages if you need. As long as the climate was relatively stable (and even if the MWP was warmer than today, it obviously wasn’t a quick change between climatic states), life on Earth was just fine. It’s when the climate rapidly changed that problems ensued. The Discovery of Global Warming has a great overview of the discoveries and theories which are now common knowledge. (Most of this stuff was discovered half a century ago so it really isn’t discussed in a comprehensive way in the peer-reviewed literature. When I typed “Younger Dryas” into Google Scholar, I got a Nature article about some kind of prehistoric elk that became extinct in the transition.)
That’s why we’re worried about climate change rather than global warming. I think it makes more sense to look at a major paleoclimatic change which was similar in magnitude or rate to what is projected today, and use that as our model for what kind of changes we can expect. Simply examining the last time the Earth was the temperature we are projecting will only tell us what things will be like once the change has settled down into a more stable climatic state.
From my research, I have concluded that we’re not sure where we are on the cliff – we could be calmly walking towards it, but we could also be hanging on by our knuckles, and we have no way of knowing at this point. History has shown us that climate change tends to be a sheer jump rather than a gradual slide down. I believe we should walk with extreme caution, if we walk at all, because we simply don’t know where that edge might be.
I have been exempting you from the new comment policy because I wanted you to finish up your argument regarding how much confidence we can put in the MWP not being as warm as today – “grandfathering” you in, if you will. However, if you’re going to start a new scientific argument – for example, regarding how much time we have before climate change becomes overwhelming – you’ll have to provide peer-reviewed citations for whatever isn’t already common knowledge. Simple speculation or links to blogs aren’t enough. The full policy is in the sidebar.
Given that context, a finding of a warm MWP gives us a lot more runway. (Or roadway, to avoid mixing metaphors.) If we think MWP was slightly warmer than today that means we’ve still got another 20 or 30 or 50 years to go before we expect to exceed the prior recent world temperature record…which is excellent news! It means most of the potential for bad things happening is a bit further away than we thought. This is the difference between being on the edge of a cliff and slowly walking towards the edge of a cliff – you have more time to ponder, less immediate risk, and more time to stop or turn around in the latter case. Right?
I am not saying I agree with Loehle, I am just saying that the CA group have accepted his findings. If I accept them, for the sake of argument, the MWP doesn’t amout to much, especially compared to what is to come. It is what is to come that is the concern.
The CO2 going up there now, even if we stopped adding to it, will take decades to play out its effects. The climate is a large system, so all changes to it from the relatively gentle forcing of CO2 will take not take effect immediately. We also have the problem of the lag in modifying our behaviour, the drawn out battle for even such small change as that proposed by Kyoto is taking far longer to implement than was planned, and in a much milder form than was planned, and without the co-operation of the US, the largest economy in the world. So not only are we committed to the changes from the CO2 in place, we are committed to the changes from CO2 that is not there yet.
We are right on the precipice right now. Unlike the MWP, this will be protracted, the MWP as described by Loehle was relatively brief. We are looking forward to centuries of permanent change, most of which is yet to happen.
@ Glen Raphael “The “projections” you’re talking about are based on climate models and as I understand it – please correct me if I’m wrong about this – existing climate models don’t show a strong MWP.”
I think you are wrong about this. As far as I know GCMs only go back (by hindcasting) roughly 100 years or so, and they do a pretty good job of modelling the climate for the past century. Hence why we have confidence in them for the next century (though it is fair to say that the confidence decreases as we move further into the future). This is separate from the proxy reconstructions from Mann and others, and the whole MWP business.
Remember it was the Second IPCC assessment report in 1995 that the balance of evidence strongly supports AGW, BEFORE the Mann 98 hockey stick.
> (Out of curiosity: What’s Craig Loehle’s publication index?)
21 (if I did it correctly). Not bad. Lots of older forest ecology papers.
I said:
After trying the “The Alarmists Do It Too” gambit and failing, Glen Raphael replies:
I was pretty clear in pointing out where you were shifting your goalposts. There’s no need for anyone to “guess”.
You yourself, however, have been making insinuations about Mann et al. by talking about “the whole MBH98 ‘censored directory’ fiasco” and all that. Perhaps you can state clearly what you are accusing Mann et al. of?
Either spit it out, or skip it. Otherwise, methinks thou dost protest too much.
In other words, you don’t know, and you’re just going by whatever McIntyre says is true?
— bi
Glen writes:
“So if we accept that there was a strong MWP, that means some of the “natural variability” factors are being underestimated in our models, which might mean that “human-caused variability” is being overestimated, in which case we could reduce our estimate of the CO2 multiplier, which reduces the projected rate of temperature increase, which buys us more time.”
On the contrary, assuming the valid multi-proxy studies are all wrong and MWP was warmer globally than today, accepting the fatally-flawed Loehle reconstruction for example, this would imply that variability in global mean temperature over the last millenium is somewhat more than previously estimated. This tends to imply a stronger positive climate feedback. In other words, the climate is more sensitive to any change (i.e. solar/volcanic forcing) than previously estimated. Since the forcing from greenhouse gases has little wiggle room, the possibly stronger positive feedback might imply climate sensitivity (equilibrium response to a doubling of CO2) is quite high. “It’s the Sun” contrarians generally rely on strong positive feedbacks for their arguments, as the TSI change isn’t anywhere near enough to account for variations in global mean temperature. An example is Willie Soon’s comments alleging a positive feedback from both water vapor and clouds:
http://global-warming.accuweather.com/2009/04/plausible_scenarios_of_a_dimme.html
As an ironic sidenote, while a few folks are still obsessed with pointing out uncertainties with early multiproxy studies of the late 90’s, the decade of the 2000’s is almost 0.2 C warmer globally than the 1990’s average. It’s not just about the 1990’s being the warmest decade of the millenium as the early studies indicated. The 2000’s are considerably warmer.
MarkB states:
“assuming the valid multi-proxy studies are all wrong and MWP was warmer globally than today, accepting the fatally-flawed Loehle reconstruction for example, this would imply that variability in global mean temperature over the last millenium is somewhat more than previously estimated. This tends to imply a stronger positive climate feedback. In other words, the climate is more sensitive to any change (i.e. solar/volcanic forcing) than previously estimated.”
Since our host allowed this comment to stand without citation, it must be common knowledge. I have heard this point argued before (that essentially climate response must be the same regardless of the nature of the forcing)but I am not aware of the references. Could you please cite them? [I would say that it’s common knowledge, more variability = higher climate sensitivity, but references are always nice.]
I think that it is common knowledge that the physics of CO2 forcing is different then solar forcing. For example, a unit of solar forcing is strongest at the equator and weakest at the poles due to incidence angle (a unit of CO2 forcing is more globally uniform by comparison therefore by definition relatively weaker at the equator and stronger at the poles). If Svensmark is correct then there is considerable positive solar feedback not associated with CO2.
http://www.agu.org/pubs/crossref/2009/2009GL038429.shtml
In addition to the above, Meehl et al set out the response of stratospheric ozone to solar forcing in addition to the unique ocean / atomosphere resonse which I alluded to above:
http://www.sciencemag.org/cgi/content/abstract/sci;325/5944/1114
Kate responds: ”
“I would say that it’s common knowledge, more variability = higher climate sensitivity, but references are always nice.”
Read MarkB’s comment a little more carefully Kate. His clear inference is that if the MWP was sensitive to solar, then the CWP must be sensitive to CO2. I would challenge you or MarkB to find the peer reviewed references (as per your blog policy) which confirms that.
BTW another paper which lays out the climates unique sensitivity to solar forcing is Meehl et al, 2009. Besides the unique ocean / atmosphere coupling I alluded to before, it also desribes the stratospheric response of ozone to solar forcing.
http://www.sciencemag.org/cgi/content/abstract/sci;325/5944/1114
“Since our host allowed this comment to stand without citation, it must be common knowledge.”
…as must be all of Glen’s post.
” If Svensmark is correct then there is considerable positive solar feedback not associated with CO2. ”
There have been a number of studies challenging the Svensmark hypothesis in recent years. Examples:
http://www.agu.org/pubs/crossref/2009/2009GL037946.shtml
http://www.iop.org/EJ/abstract/1748-9326/4/1/014006
http://adsabs.harvard.edu/abs/2008ACP…..8.7373K
Explained: http://www.sciencedaily.com/releases/2008/12/081217075138.htm
Svensmark appears to have ignored these inconvenient studies, as have those who are promoting his work for political reasons.
MarkB, Glen was “grandfathered in” to the new comment policy because he began that particular argument before the policy started, I wanted to give him a chance to finish up. Now it appears that he has, so he is fully bound to the policy like anyone else.
Thanks for the references MarkB. My point was not to argue Svensmark, but to argue the notion that climate sensitivity implied in the MWP due to solar forcing does not mean that the CWP must therefore be sensitive to CO2. There is nothing in the literature (to my knowledge) that demonstrates this. Conversely, there is a case to be made from the literature that shows it is at least plausible and maybe even likely that climate response to different forcings are distinctly unrelated. IOW, sensitivity to one forcing does not prove sensitivity to another forcing.
[Alright, it’s obvious to me by now that this topic is not common knowledge, whether or not it’s right, but I won’t delete any past comments as it was my mistake. Future comments, as always, are subject to the policy. -Kate]
[citations needed – people are not important enough to cause climate change, scientists said there would be an ice age in the 70s]
The borehole reconstructions alone are perfectly adequate to confirm the “handle” of the hockey stick, and are completely independent of all other proxies.
Following Mann’s original publication have been the ten warmest years on record, further extending the “blade” of the hockey stick. Or as Coby Beck summarizes:
“[Accepting the attack on Mann at face value] leaves me with the dozens of other proxy reconstructions, some by the same team or involving some of its members, some by completely different people, some using tree rings, some using corals, some using stalagmites, some using borehole measurements, but all of which support the same general conclusion. And it is that general conclusion which is important to me, not whether or not one Bristlecone pine was or was not included correctly in a single 8 year old study.
The general conclusion is:
“Although each of the temperature reconstructions are different (due to differing calibration methods and data used), they all show some similar patterns of temperature change over the last several centuries. Most striking is the fact that each record reveals that the 20th century is the warmest of the entire record, and that warming was most dramatic after 1920.”
End of story.”
“the Wegman Report, . . .”
. . . was a political document ordered up and shaped by politicians, not a contribution to the scientific discourse in any sense.
An excellent discussion of how it was hacked together by deniers ignoring the peer-reviewed literature and generously plagiarizing old textbooks can be found here:
“For example, take the one feedback everybody knows about – the ice-albedo effect: In the warming direction, once all the ice has melted, that effect stops. In the cooling direction, once all the planet is covered with ice, that effect stops. Somewhere in the middle there’s one or more peaks to the strength of the effect. So you can’t modify your sensitivity estimate by X to account for this effect – it has a variable kick to it and the size of that kick will shrink as the planet warms. (IPCC actually does take this into account in the most recent simulations but it’s an underappreciated point in the public dialog)
So, I find large multipliers and “tipping point” scenarios inherently implausible and tend to discount predictions that suggest them. ”
That doesn’t follow at all. Really. Not only are you generalizing grossly from two scenarios, you have also picked two scenarios that would be a disaster for humanity if they came to pass. Yes, all feedbacks stop eventually — just, as we say in emergency medicine, all bleeding stops eventually.
An iceball earth does not support your intuitive sense “doom-and-gloom claims” are implausible. It is, in fact, a doom-and-gloom scenario, and the fact that the feedback tops out at some point is neither here nor there.
Your falling body has a terminal velocity. Does that imply jumping off a skyscraper is unlikely to hurt you?