Lol. Try reading the actual IPCC report some time. The blue line is based on 5 and only 5 papers. Not exactly “the entire field”
Anyway, the facts speak for themselves. There is a serious problem with the chart in the IPCC which you have been unable to explain. There is overwhelming evidence that the climate models have been fudged to fit the instrumental record. If that means that the authors of 5 papers are intellectually dishonest or incompetent, then so be it.
The issues are different but related. How is it that models with very different assumptions can all fit the instrumental record well? Obviously they’ve been tuned to fit the instrumental record. Which calls into question the attribution graph.
So it’s entirely possible that Richard Lindzen’s estimate of sensitivity is consistent with the temperature record, right?
How did you come to the conclusion that it is based on 5 papers? My reading is that this actual graph (Fig. 9.5) may be from one paper but that this one paper was a model intercomparison paper that looked at the results of models from many different groups. I think there have been other papers that have reached the same conclusions and these conclusions seem to have been endorsed by the community as a whole.
Well, the facts may speak for themselves but what you claim are not the facts as I see them. What I see is you find one little thing you don’t understand about the plot. We gave you one plausible explanation (i.e., that the slight downturn seen before the volcanic eruption is not statistically significant and could just be internal variability). You admitted that you don’t know whether it is statistically significant or not. There are, by the way, other plausible explanations. For example, if you look at the plot I linked to previously showing the solar variations, you will see that in addition to a general trend, there are the 11 year oscillations due to sunspot cycles. How the climate responds to these oscillations is complicated (e.g., there is some damping and phase shifting due to the fact that they are fairly rapid in comparison to some of the relaxation times in the climate system) and they could conceivably be playing a role too.
At any rate, just because noone here can give you a definitive answer to your question just means that there is something that we have plausible explanations for but are not sure of the answer to. That is hardly surprising given that none of us are experts in the field.
There is in fact no evidence of this that I know of. There is only evidence that you and some others believe this, based largely on your ignorance of climate models and how they work and making incorrect analogies to more statistical / empirical modeling.
Well, let’s see, one explanation requires us to believe that pretty much everyone working in the climate model field is incompentent or intellectually dishonest while another explanation requires us to believe that someone outside of the field posting on a messageboard is mistaken. Hmmm…Which to believe!!!
It is not clear exactly how well each individual simulation in Fig. 9.5 exactly fits the instrumental record since we can’t distinguish the individual ones. What is clear is that the envelope formed by the different simulations does a good job of fitting the instrumental record when anthropogenic forcings are included and not when they are not.
Well, I don’t know off the top of my head what Lindzen’s current estimate is. However, my impression is that his estimates are really out in the weeds of the estimated probability distributions for climate sensitivity derived from various different methods, as discussed in Section 9.6 of the IPCC report.
By reading the “supplementary materials” and studying table 8. Many many papers did an “A + N” simulation. Only 5 did “N” simulations.
So I’m not attacking an entire field. I’m attacking the IPCC’s spin of 5 papers. Not that I’m afraid to attack an entire field, of course.
The problem is that your “plausible explanation” leads to the same conclusion.
I am of course open to considering other explanations. As things stand now, it seems pretty clear to me that the models have been “adjusted” or “tuned,” or – to put it bluntly – fudged.
“Tuning” would also explain how models that incorporate widely different sensitivities to CO2 all match up with the instrumental record.
That’s possible, but it’s not an answer to the question I’m asking.
I don’t quite understand your objection to tuning, or adjusting models. It looks like you object to any adjusting at all, which I find an unsustainable position. By nature of the complexity of the systems involved, any modeling will have to be simplified in order to return a result in any reasonable amount of time. Also, in some rare cases models that do not entirely match up with observed data may be a result of some process either unknown, or not known in enough depth. I doubt this is the case in this circumstance, but I like to cover all possibilities.
Adjusting models so that they fit known data is a reasonable thing to do, IMO.
Now, if your point is that they are adjusting the models far more than they should, then I would like to see some support for that. Over adjusting the models implies that the model should be reexamined if the data it produces is that far off the mark.
Let me present you with a hypothetical example of tuning, and you can tell me if you think it’s reasonable.
Suppose that you create a climate model that assumes great sensitivity to CO2. You run it for the 20th century, and the model’s predicted temperatures overshoot the instrumental record by a large amount. To fix this problem, you adjust the parameters concerning volcanic forcings and solar irradiance to pull the temperatures back down and fit the temperature record. Even the IPCC admits that scientific understanding of most of these other forcings is “low” So your adjusted parameters are totally defensible.
Now that the model has been tuned to fit the instrumental record, you run it again, except without any CO2 forcing. Lo and behold, the temperature output is a complete mismatch with the instrumental record.
You then infer that the warming reflected in the instrumental record must be due to CO2.
Ok, do you think that this is a reasonable inference?
This statement is true but somewhat deceptive in this context in regards to these two natural forcings. For example, if you look at Fig. SPM-2 on p. 16 of the Summary for Policymakers of the IPCC report, you will see that the level of understanding for solar is low in the sense that the error bars are large relative to the size of the forcing…i.e., the error is large in relative terms. However, in absolute terms, e.g., compared to the forcing due to CO2, these error bars are still quite small. I think the same holds true for volcanic forcing although it is not specifically included in that plot “due to their episodic nature”.
As that plot clearly shows, the biggest source of uncertainty in forcing is due to man-made aerosols…and, as I have noted above, this uncertainty is probably the single largest source of error one has in trying to estimate the climate sensitivity from the 20th century temperature record. But, the IPCC makes no bones about this and the uncertainty is incorporated into their projections. So, the fact that you can fit the 20th century record with a range of assumptions for climate sensitivity and aerosol forcing is well-understood.
I’m a little confused. Are you saying that even if the IPCC characterizes the scientific understanding of a forcing as “low,” they can still set forth a (wider) error bar and be confident that the magnitude of the forcing falls within that error bar?
I have been without internet access for a while, so this reply is late and very much out of sequence. Sorry!
I disagree with the assertion that ‘science is inductive’. Some science proceeds in a deductive fashion. If the scientist designs an experiment to test a given hypothesis, he can make deductions based on the results.
And in any case, I don’t know what ‘definitively prove anything’ has to do with this discussion. My contention has nothing at all to do with anyone definitively proving anything, or indeed failng to do so. I’ll re-state my contention.
There is a widespread and prevailing consensus about AGW, partly based on some scientific research, and the way that research has been interpreted/reported, and partly based on popular media coverage and common perceptions about complex issues. My contention is that there is still ample room for doubt about the AGW theory and its associated implications, even among intelligent and well-informed people, and that there are many parallels in history (both recent and not so recent) that ought to alert us to this fact.
I am not referring to wilful disbelief or a ‘head in the sand’ mentality. Nor am I in the pay of Big Oil, or a smug ‘well you can doubt anything’ intellectual relativist. I’m referring to a fascinating aspect of human nature, which is the capacity for widespread and popular delusion, and self-delusion. People often develop a cognitive model that says ‘all this is known, proved and understood’ about things that are not known, not proved and not understood. This happens time and time again in human society, and it’s really rather fascinating.
Sometimes, this phenomenon is relatively trivial and need not worry too many people e.g. belief in astrology. Sometimes, however, people insist that their beliefs and/or conclusions should serve as the basis for large-scale changes in human society, policy and legislation. At these times, it is more important than ever for sceptical voices to be heard, and for us to heed the many reminders from history that sometimes the things ‘everyone knows’ aren’t really known at all.
You say it does, others say that it either does not serve this purpose, or that it does not serve this purpose very well, or that it serves other purposes and other agendas.
I am reasonably familiar with what the IPCC’s reports assert. (As familiar as a scientifically literate non-specialist can be). But I also know some good questions to ask before we start instigating wholesale changes, some of them backed by legislation.
I’d like to know if we’re dealing with a falsifiable hypothesis, and if so what efforts have been made to break it?
I’d like to know who funds the IPCC? I think this is a good question because I’ve spoken to many professional scientists who have told me about the so-called funding trap. If you run tests for a year and say ‘No results’, maybe you won’t get any funding next year. If you say ‘tentative support but further tests are required’ then maybe you will. So you interpret the results in such a way as to suggest there are some positive indications, but nothing conclusive, and that further research is warranted.
I’d like to know if the IPCC was steered to, in effect, collate all the evidence that suggests AGW is a reality, or whether equal effort was made to collate information from the sceptics, the doubters and the dissenters. I’d like to know if the ‘credible sources’ fallacy has been at work, i.e. ‘we have collected data from all credible sources - and if you say AGW isn’t supporpted by the facts you’re obviously not a credible source’.
I’d like to know if other institutions, with as much claim to my time and respect as the IPCC, have come to different conclusions.
I’d like to know if all of the contributors to the IPCC report actually agree with the published findings, or whether some of them feel that their own views and beliefs have been mis-interpeted, massaged to fit the overall picture, or mis-applied.
The same federal government that has other bodies ‘specifically chartered’ to inform it on issues of national security. The same federal government that stated as matters of known and provable fact that Saddam Hussein possessed weapons of mass destruction ready for immediate use. Some of us voiced doubts at the time, and were told we were mindless, drivelling scepetics who would leave the nation wide open to attack.
We agree.
Whether or not a consensus is ‘strong’ may be in the eye of the beholder, or in the eye of the government official determining policy. The astrological community worlwide would tell you there is a strong scientific consenses supporting the basic tenets of astrology. You and I may not agree, but they think so. Homeopaths assert there is a strong scientific consensus concerning the basic tenets of homeopathy, and some of them want taxpayers’ money to be devoted to homeopathic practices and treatments, even though it is completely bogus.
While it is fun to see you stoop to mild sarcasm and reduced to ad hominem stabs, it doesn’t really help your case at all. To an onlooker, it might suggest a touch of desperation.
How do you know that I wasn’t reading this literature? Are you jumping to conclusions? How very unscientific. I would have thought it more pertinent to ask the question first.
The same federal government that committed massive amounts of money to developing the ‘Star Wars’ defence program, even though no-one in the scientific community felt it was viable at the time. I’m sure Reagan had good access to institutions and organisations whose role it was to inform him about these things.
‘We have been wrong or cluelessly unreliable many, many times before, but we’re pretty sure we’re right this time’. It’s easy to be confident you’re right when you are referring to the future. The question is not whether this administrative body feels confident about something. The question is whether there is any good basis for ‘feeling confident’ this time, bearing in mind the lessons of history. There are tipsters at every race course who may have lost on every horse race in the past year, but they have very strong confidence in the tip they want you to buy today.
So now science is a matter of adjudication? News to me.
Some might look at this remark and feel it looks like you adopt a dismissive and petulant tone when you see any opinion you don’t like or share. That would be unfortunate. I’m sure you are neither dismissive nor petulant, and that this was a rash, uncharacteristic outburst.
No. This is no more my conclusion than yours is ‘All dangers are real’. But I suspect you knew this even before you posed the question.
Exactly what they said before invading a country and killing hundreds of thousands of civilians to hunt down those pesky weapons of mass destruction. Whoops. It’s always a good idea to ignore ignorant views, by definition. But are you the one to decide what constitutes ‘ignorant’? And ‘bias’ is often a matter of where you stand. Eliminate ‘ignorance’ by all means, but it’s not a good idea to ignore voices that may be sceptical, or that want to ask searching questions about how a given conclusion was arrived at, just in case mistakes have been made. Thinking errors are rife, and have arisen many times in history, often with tragic consequences. History is full of ‘known facts’ equivalent to ‘The Titanic cannot sink’ and ‘This Union Carbide factory in Bhopal is perfectly safe’.
Well, if the error bars represent a 90% probability of the value being found within that error bar (which is what I seem to recall is the convention that the IPCC uses for their error bars), then it represents such a probability whether or not the scientific understanding is high or low. Admittedly, however, if the understanding is lower, there may be more subjective judgement or disagreement concerning what the error bar is.
Well, it makes it necessary to come up with some sort of proposed mechanism to provide such amplification and some evidence that this mechanism really operates. (As I noted though, there is the additional problem that even if you vastly amplify the solar irradiance signal, you still aren’t able to get the right time-dependence for the warming especially as seen for the last 30 years or so. So, in fact, it seems very likely that you need to propose a forcing based on solar that has a different time-dependence than the total solar irradiance signal.)
It is worth noting, by the way, that when I talk about some amplification being necessary, I am talking about amplification above and beyond the understood positive feedbacks in the system. I.e., it is true that the current best estimates of warming due to CO2 also require some amplification of the warming due directly to the radiative effects of the CO2 (by a factor of 2 or so). However, in this case, we have basic physical mechanisms explaining this (e.g., the water vapor feedback and the ice albedo feedback). Furthermore, these amplification mechanisms are expected to operate essentially independent of the type of forcing and thus are also already included in any estimate of the effects of the solar forcing. So, you need an additional amplification mechanism specific to the solar forcing to have it account for the current warming. (The situation is, in fact, even worse than this because essentially the only way that the current warming could not be due largely to greenhouse gases is if the scientists are wrong about the net positive feedbacks believed to apply essentially independent of forcing. So, what you need to also have is something that damps the CO2 forcing specifically…or something which damps all the forcings, which then consequently requires an even stronger amplification specific to the solar forcing.)
I guess this is a side issue we shouldn’t spend much time on but I am puzzled how you feel that your description somehow gets science around being inductive. (Can you give an example of a deductive conclusion you can make from the results?) Certainly, the idea that science can be deductive would appear to come as a surprise to the philosophy of science community! It is true, for example, that in mathematical physics, one can often use deduction to rigorously prove something about a mathematical model of a physical system but, of course, this only proves that fact about the model…not about the physical system itself.
First of all, I would note that the consensus on AGW that I am interested in is that within the scientific community studying the problem. I am not really talking about the larger “consensus” influenced by the media, etc. (And, in fact, I think studies such as the one by Naomi Oreskes suggest that the consensus is much stronger within the scientific community in the peer-reviewed literature than it is amongst the general public influenced by the media and so forth.)
I will occasionally point to facts such as the growing number of oil and power companies that accept the science of AGW and endorse doing something about it but that is only as one additional, admittedly indirect, piece of evidence of how strong the scientific consensus has become. (I.e., so strong that many companies that had strong reasons of self-interest to be skeptical…and initially in fact were very skeptical…have changed their views.)
As for skeptical voices being heard, I am not against them being heard. However, what I am arguing against is the idea of using this notion as a way of taking the scientific debate out of the scientific community where it belongs and putting it instead in the public community where it really does not belong. In other words, what I see when I look at history is a history where the people who are losing the debate in the peer-reviewed scientific community try to take their case directly to the public where the flaws in their scientifically-poor arguments are not as readily detected. We see this, for example, in the fights against evolution.
So, I guess I would try to push you to be more specific about what you are proposing here. You seem to be against the notion that public policy should be based on the best science as we currently have mechanisms set up to determine the best science, in this case, through the IPCC, the National Academy of Sciences, and the various professional scientific societies such as the AGU and the AMS. So, I would ask what specific mechanisms you propose to replace this and, particularly, mechanisms that you would argue are less likely rather than more likely to be co-opted by politics or special interests.
Well, again, who are these others and how credible are they? Why should we give such weight to their opinions over those of the National Academy of Sciences, the American Association for the Advancement of Science, the AGU, the AMS, … (See this Wikipedia page for a discussio of the scientific opinion on climate change.)
Here is more information about the NAS. Although it was chartered by the federal government, the NAS is an organization run by scientists, not the federal government. You are essentially arguing against a strawman here. I was not trying to argue that the federal government is infallible (or, for that matter, even that the NAS is infallible). Implicit in what I was saying, however, is that I do think that one of the federal government’s wiser moves was to seek out independent scientific advice in this way. You may feel otherwise in which case you might want to try to argue how the NAS has led the federal government astray many times. (I am in fact quite sure the NAS has been wrong before…Like I said, it is not infallible, because science itself is not infallible…but I do think it is something that has worked remarkably well.)
Unfortunately, your examples (above and below) don’t speak to that issue at all since they don’t reference the NAS’s views on Saddam’s WMD program or on the SDI (“Star Wars”) missile defense program. [I should note that, on the latter, while I am not sure if there were any relevant NAS reports, I am quite proud that my own professional society, the American Physical Society, weighed in with a quite skeptical, if not downright negative, report on SDI soon after Reagan proposed it…just as a lot of scientific professional societies are weighing in on climate change now.]
As for your Iraq example, first of all, this was more an intelligence question than a scientific question. And, second, I think this stands at least as much as an example of poor government use of available information…and in fact selective cherrypicking of the available information. This is exactly the sort of thing that a rational science- and fact-based policymaking process should try to prevent.
Well, this is exactly my point. We want to have the federal government listening to what scientists have to say in regards to public policy. Unfortunately, you seem to want to do away with this or maybe turn it in to some sort of free-for-all where each side gets to trot out their own “pet scientists” and government officials or the public are supposed to adjudicate on issues that they don’t have the background or knowledge to adjudicate on.
Do you think that the National Academy of Sciences endorses these viewpoints? This is exactly the point that I am trying to make of why we need to listen to reputable scientific organizations such as the NAS. I am not sure what your point is exactly since you haven’t really spelled out an alternative.
It is hardly an “ad hominem stab” to call your evidence anecdotal when in fact it is anecdotal and to refer to it as “one person’s impression” when in fact all you presented was your impression with no facts whatsoever, let alone references to the peer-reviewed literature, to back it up.
I inferred that you weren’t from your incorrect claim that “As I recall, no-one said anything about global warming”. This would suggest that either your reading of the scientific literature was extremely limited or your memory is quite faulty.
Fine…so what then do you propose as an alternative to decide between different scientific claims?
I may have been a bit harsh but I find it kind of annoying when people adopt this sort of attitude that any opinion is as good as any other when in fact one can easily determine which opinion is correct and which is not. That paper that George Will referred to was not ambiguous. It clearly stated the assumptions under which they were predicting glaciation in the future and Will conveniently chose to ignore these assumptions even though the assumptions rendered his point completely incorrect.
Well then, tell me exactly what that long laundry list was supposed to tell us then and how they apply to this particular situation.
Well, again, you are not really presenting any sort of alternative here. I have presented the best way that I know how to use science to inform public policy. You have presented some “feel good” ideas about listening to skeptics and wondering who is to decide who is ignorant and who is informed. Fine, tell me your alternative specifically and explain how it will lead to a better application of science to public policy than mine. As Ross Perot once said, “I’m all ears.”
Somehow, I left this point I meant to make out of my last post:
You are really missing the boat here. In fact, the NAS was not “wrong or cluelessly unreliable many, many times before”. What I presented to you was evidence that in fact at a time when there were some scientists who were presenting alarmist worries about global cooling as you yourself have pointed out (albeit in an exaggerated manner), the NAS weighed in to clearly state that it was not yet possible to predict the future course of the climate. So, in other words, I am presenting you with an organization with a track record of not being overconfident in their claims.
You seem to be making the argument that because there were any scientists who were making alarmist claims then that turned out to be incorrect, we can’t believe any claims scientists make now, no matter how universally they seem to agree. If you in fact are making a different argument, please explain exactly what it is.
There have been hypotheses…the one that comes to mind is the cosmic ray hypothesis…but the evidence that this mechanism really operates and that it can reproduce the observed warming trend is just not there. (Let alone an explanation of why the known mechanism due to greenhouse gases is not operating … or at least being damped out.)
If scientific understanding of some entity is low, then the range of defensible values relating to that entity is high. It’s as simple as that.
I wasn’t aware anyone was proposing that cosmic rays amplify the effect of solar irradiance. Do you have a cite for such a claim? Also, what evidence would support such a hypothesis?
Well, it may be “high” on a relative scale, but again not nearly high enough to explain the warming seen in the last ~30 or so years.
Well, I think that the technical statement would be that cosmic rays amplify the effect of variations in solar activity (because this solar activity modulates the cosmic ray intensity hitting the earth)…but that seems to be pretty closely related to solar irradiance.
Just to provide a little more concrete evidence (in addition to that contained in the Global Cooling Myth thread at RealClimate that I mentioned previously), I tried typing some relevant words (fossil + fuels + warming) into the search function at Science magazine over the period from Jan 1970 to Dec 1979 and here is a list of 32 articles that it brought up. Just to give you the title and abstract of the 1st one listed (from August 1976):