Actually, the model runs that predict the Little Ice Age cooling on the basis of natural forcings also show that there should not have been a net warming in the 20th century on the basis of these forcings as explained here:
Okay, “predict” is not the best word here since it is a past event…“reproduce” would be better.
No, we simply can’t say that.
We can say that similar changes occurred in 1470 and 1350, and that they occurred within decades, not centuries. That was point. This current warming event is in fact proceeding more slowly than the previous two warming events, not more rapidly.
We can also say that far greater changes (in the order of 1oC, rather than the current o.6oC) have occurred C8000 years ago, and they occurred in less than 300 years, but we have no idea just how fast it was. The IPCC itself concludes that warming may have occurred at rates as large as 10°C/50 years over the past 7000 years. The problem is that these past changes have to be inferred from surrogates like gas isotopes, dendrochronology etc. because nobody had thermometers. Unfortunately we have no idea what istopes ratios or tree growth actually are in the presence of normally atmospheric composition. All our data are inherently uncertain because we have no control atmosphere in which to observe the effect of temperature on these things sans human intervention.
But we certainly can’t say that similar temperature changes in the past always took centuries. In fact do you have any evidence at all to support that claim?
No, but that doesn’t mean it hasn’t happened. Nobody has been able to produce a study showing that it hasn’t happened either. That’s the point. It’s very hard to know what has happened in the past because these things don’t leave annual scale traces. We can say where trees were or where glaciers were to within a century or so by the vegetation or dating the morraine but those things won’t let us know whether they advanced or retreated in 10 years or 100. We know for example that in less than 50 years Iceland and Greenland became totally locked in by sea ice and had to be abandoned, so the reverse change certainly happens in that sort of time scale.
That simply isn’t true. Look at the IPCC graph I provided, particularly the century 1370 to 1470. In that century temperature moved from about 0.1 degree below average to about 0.5 degrees below average. That’s a change of 4/10 of a degree, twice as much as you quote. The period 1340 to 1347 shows a 3/10 of a degree in just 3 decades and far faster than the current event. I don’t know where you got this idea that in the last 1000 years all temperature rises were less than 2/10 of a degree a century but it’s simply untrue.
Yep, that’s quite true.
Reference please.
Because I have endless references that say that is simply untrue.
“Glaciers were smaller than today and possibly melted away on several occasions in the late Holocene (ca 3950, 1410 and 750 cal. BP).”
Matthews, J.A. et al 2005. “Holocene Glacier history of Bjørnbreen and climatic reconstruction in central Jotunheimen, Norway, based on proximal glaciofluvial stream-bank mires” Quat Sci, Reviews. 24:1-2.
“AD 1783 Historic length minimum. Glacier retreats behind a prominent gorge.” {Complete with figure showing the glacier was a full kilometre short of where it is today a mere 200 years ago.]
Mackintosh, A. et al. 2002. Holocene climatic changes in Iceland: evidence from modelling glacier length fluctuations at Sólheimajökull
Can we have a meaningful reference for that claim. A graph in a foreign language with no legend tells us nothing at all.
That is perfectly true, it can not if you only look at solar activity as an absolute, which as far as I can see is what they have done. That’s one thing that everyone agrees on. However even the IPCC says that this can’t be done. For example when solar activity is combined with the vulcanism of the 100 years leading up to 1980 you can explain 100% of the temperature change. After that you need to invoke runaway and add-on effects like thermohaline circulation, which has been done by several scientists.
Perhaps more importantly nobody has ever suggested that solar output on its own can achieve significant climate change. The total energy difference is only about 1%, it’s just not enough on its own, something that the link you provide confirms, but something that has been well known for decades. However what is proposed is that solar output is not just about gross energy arriving on earth but the distribution of that energy within the atmosphere. Numerous mechanisms have been proposed for why that might be the case ranging from effects on storm formation to the breakdown of atmospheric potentials.
But I’m not really here to debate this area of climate science, which quite frankly I only vaguely understand. My point is simply that you can’t discount solar activity as a major driver simply because gross energy output doesn’t map directly onto observed temperatures. It remains a viable and hotly debated hypothesis, and an alternative to anthropogenic greenhouse gas variation, which was of course my initial point: Plausible alternatives exist. You can’t simply say that nobody has come up with a plausible alternative as you did.
If you would bother to read my posts you would see that I never suggested that was the case. It was the OP who suggested that was the case, and I explicitely said that it was not the case here.
But what the hell, attack a position that is diametrically opposite to the one I have clearly espoused. It’s easy.
I say that in this case “because A occurs after B therefore A is caused by B” does not need to apply, and that in fact “there are various ways in which we can ‘observe’ past trends in the Earth’s climate”.
Then after I say precisely that you insinuate that I said it does apply in this case, and that if I read your links I would no longer believe this.
Sheesh. I know folks get tired of people calling “strawman”, but what else can you call this. Jshore has suggested that if I read the chapter I would see something that I explicitly stated was the case in the first sentence of my first post.
Yet again, this seems to be disputing something that everybody accepts. What exactly is your point here? I at least was already well aware of that fact. Has anyone in fact disputed it? And if not then why raise it in response to my posts?
Once again this seems to be a strawman in the making. By saying this directly after quoting me you seem to be implying that I somehow don’t endorse this fact or at the very least am ignorant of it. Neither is true.
If you have appoint to make about my posts using this fact then could you please clearly state what that point is?
And at this juncture it’s worth noting that the use of “tend to show” in there. They do tend to show it, often very weakly, in the majority. Some of them tend to show exactly the opposite, that the present conditions are far cooler than they were even 1000 years ago. That is reflected in the confidence intervals on the IPCC graph.
I am getting sick and tired of these strawman misrepresentaions.
Please quote where I said that nothing can be determined about the cause of the current warming.
Please quote where I was making a case for doing nothing at all.
These strawmen are becoming more blatant by the minute. They no longer show any correlation at all to anything that I have actually said.
What they actually say is that it is not possible, ie is impossible, at this point in time. What may be possible in principle using future technology is beyond my ability to discuss. I am discussing what is possible now. And everyone agrees that it can not be separated out now.
Of course if you wish to contend that it is possible in principle now then by all means supply references to support that position. So far all the referneces say it impossible.
Oh good. Something I can nail you on.
Please quote the statement I made in this thread that implied any such thing?
A simple quite will suffice. Something where I implied evidence for human contribution comes solely from correlation.
This should be fun, given that my first sentence in this thread says exactly the opposite to that.
Tell me, do you have anything to direct at me that is actually pertinent to my posts, rather than these rather blatant misrepresentations.
Actually one model shows that. Numerous others, and I have already referenced one, show that exactly the opposite is true. Even a cursory glance at the IPCC figures shows that climate was already on the upswing by the early 19th century, well before CO2 level could plausibly have caused the reversal.
So now we get into the same old game of ‘duelling models’. The problem with models is that they are only as good as what you put into them. If you only put solar irradiance and vulcanism into the model, as it appears Crowley did, then of course things don’t tally. But when you factor in all variables, including oceanic circulation and the fact that greenhouse gas levels were not static even before the industrial revolution things you get a very different outcome.
At this pint I think we have reached an impasse, where I will endorse my preferred modellers and you will endorse yours. The nature of modelling is such that there is very little to objectively separate them beyond past forced fits. And as I have said both fit the little ice age.
So? If you have a huge debt, paying back a small amount would be pointless because it doesn’t solve the problem and is at best a a first step in a very long process?
The analogy is invalid in the context of my statement that you quoted.
A better analogy is that you have an X billion dollar debt with interest accruing at thousands of dollars daily. You are aware that when your credit rating slips by another thousand dollars the bank will foreclose. So you conclude that now is the time for your child to drop out of school and start earning $5 a day.
That particular move simply won’t prevent what is happening. It’s not the first step on along road, it’s an unworkable solution that will at best forestall the consequences by a just fraction of the time you have to deal with.
Kyoto can be thought of as a first step only in the sense of being a trial run. If your son took a $5 a day job and you knew that if he stuck it out for a day they’d give him a thousand dollar ad ay job, that would be a first step, and Kyoto may be that. But it is not in any way a first step to paying off the debt. The debt is actually increasing, and will continue to increase, far faster than Kyoto can address it.
No. What everyone agrees is that the anthropogenic vs. cyclical warming effects cannot be separated out with absolute certainty now.
That doesn’t mean that there isn’t a good scientific case for attributing a large part of the current warming to human activity. In other words, there are workable climate models that provide estimates on how much of the warming is anthropogenic vs. natural, and the estimates agree that the anthropogenic effects are outweighing the others. (And these conclusions have been reinforced by studies subsequent to the 2001 IPCC “likely mostly” report, as jshore noted.)
I think part of the problem you’re having here with what you call “strawman” arguments is due to the fact that you’re making a number of very categorical, absolutist-sounding statements that are easy to interpret in ways that you apparently don’t mean. When you state categorically that anthropogenic vs. natural climate effects “cannot be separated out”—without any qualifications that they can in fact be separated out to some extent with reasonable confidence although not with certainty, etc.—it sounds as though you mean that we’re completely in the dark as to what effects anthropogenic greenhouse gases are having on the climate. And that’s simply not true.
You are right, and AFAIK nobody has denied, that there is uncertainty about a lot of the specifics and that there are possible alternatives to almost any particular model of almost any particular effect. Nonetheless, as you yourself say, “the smart money” is still on the conclusion that most of the warming effect is anthropogenic. That’s the current consensus which is quite strongly supported. And that’s the point that you have been interpreted here as neglecting or ignoring.
Another categorical statement that is to some extent talking past your critics. Yes, as I already posted above, it is generally agreed that the Kyoto measures in themselves are inadequate to stop further anthropogenic climate forcing, much less reverse the current trend. However, as I mentioned, the chief value of the treaty is that it provides mechanisms for starting to deal with this problem. The Kyoto Protocol is an international recognition that greenhouse gas emissions are a problem and a specification of internationally agreed-upon standards and structures for assessing and reducing them. I think it’s fair to say that this does constitute a meaningful impact “beyond the symbolism”, even though it admittedly doesn’t directly solve the problem.
Perhaps it would help the communication problems here if you would give us some idea of what your own views are on climate change and mechanisms to address it. You appear to agree at least that anthropogenic global warming is probably happening, and you appear to oppose adoption of the Kyoto Protocol. What do you think we should do about climate change? What evidence or consensus would you require in order to be convinced that anthropogenic climate change is definitely an environmental problem that needs addressing? What measures would you recommend to address it in that case, and what measures do you support at present while you are apparently not convinced?
So it’s not possible to separate it out. Which is exactly what I said. The rest is simply the drgaon in Bobs garage. I say that the best experts in the world have tried for years to find a dragon in Bob’sgarage and have been unable to do so. Based on this I declare it’s impossible for there to be a dragon in Bob’s garage. Bob then employs an argument from ignorance and say that the experts simply couldn’t find the dragon with absolute certainty[ now.
I have great respect for you as a poster, but this is an argument from ignorance and nothing more. You wouldn’t apply this reasoning to anything else.
A team of the world best scientists try to separate phlogiston from coal and decalre that there’s no way they can separate phlogistin fom oxidative combustion with the nomral degrees of certianty. I say that it’s impossible to separate phlogiston from combustion. You say that cannot be separated out with absolute certainty now.
A team of the world’s best scientists try to separate Negroes form Causcaians based on genetics. They conclude that they can not separte out the races in that manner. I say that it’s impossible to genetically separate races based on genes. You say that cannot be separated out with absolute certainty now.
And so on. This isn’t the way things work. If the best scientists say that the factors can not be separted that is grounds for me to say that they can not be separated. I won’t coment on what might be possible with futre technology. but as htings stand I am justified in saying that they cannot be separted. This nitpicking addition of “with absolute certainty” and “using current technology” is a standard for an argument from ignorance. We can never know anything with aboslute certainty, and we can never declare that something will be true forever. But when we say that somehting is so we mean in the here and now.
Insofar as the best experts have searched for the dragon and the dragon can not be separted form the shadows and old paint tins it is not possible for there to be a dragon in your garage. Not with abolute certainty, not necessarily for all time. But to the extent that we can ever say that anything is impossible, this is impossible. The dragon cannot possibly exist.
Yes I can see that. I say in my opening sentence that we do not need to rely on post hoc ego proptor hoc in this case and that there are numerous ways that we can evaluate past climate. And Jshore says that I believe that we do need to rely on post hoc ego proptor hoc to evaluate past climate. I can see how that I easy to misinterpret.
What I said is that we cannot separate them out. That is the truth. Every reference so far produced in this thread says that we cannot separate them out. Now how you care to interpret that is your issue. What I said is factually correct and well supported with references.
As for your claim that we can separate this out with ‘reasonable’ confidence, how exactly are you defining reasonable? In science the normal standard for a result being deemed significant is the 95% mark especially in situations like this where we have a single sample, no controls and a highly variable system with a lot of variables. That 95% confidence limit has been considered reasonable for over a century now, We can not separate out anthropogenic effects with that 95% confidence limit. Therefore I am quite justified in saying that we can not separate them out with reasonable confidence.
What standard are you applying as being reasonable. Quite clearly you are saying that 66-90% is reasonable. But I would be interested in hearing what reasoning led you to accept this range of confidence.
You say that I make a lot of vague absolutist statements, yet this seems to be the most obvious one here. You have said that we can do this to a reasonable degree without in any way defining what reasonable is. When I say that we can not do it to a reasonable degree I can point out what I mean by reasonable, and point out that this has been considered reasonable by scientists long before I was born. You can not do that yet, but you declare absolutely that we can do it to a reasonable degree. Well I disagree.
Unless you can show the reasoning that led you to accept 66-90% certainty then it is not in fact reasonable at all is it?
Yes it certainly has been interpreted that way. Nonetheless I have never said anything even remotely like that, so it is in fact a misinterpretation. I have little interest in discussing obvious misinterpretations. Nor more obvious strawmen such as those of Jshore.
We can certainly agree that this is consensus. I think we can also agree that science doesn’t take votes on the facts, and thus consensus isn’t important. It’s simply an argumentum ad populum. There is no agreed upon Theory of climate and a great many prominent and reputable scientsists are being published regularly in reputable journals disputing every aspect of anthropogenic global warming. Hence this is a matter of mainstream scientific debate, consensus or no.
Similarly the idea that anthropogenic effects are minimal or even non-existent are also quite strongly supported. That is what makes this such a contentious issue, not the economic impacts. HIV/AIDS has far more economic impact than climate change, yet it is not contentious because the issue is settled scientifically. Only one side has strong support. In the case of climate change both sides have strong support.
I disagree.
It would help communications problems if people would address what I actually posted rather than assuming a position and foisting it on me. This isn’t simply because of easily misinterpreted statements. I had 5 posters imply that I denied global warming altogether and there was nothing in my first post that even addressed that issue, in any way, whatsoever.
My views on what to do about climate change will have to wait until another thread. I have no intention of going into them here, and at this stage the ideas are frankly half-baked. I make no pretence otherwise. Of course that doesn’t mean that I need to accept Kyoto. My ideas on how to deal with terrorism are also half-baked. That didn’t mean I needed to support invading Iraq. Like most people most of my ideas are half-baked, but that doesn’t mean that we have to accepted equally half-baked alternatives.
My views on anthropogenic climate change should be pretty clear from what I have posted. The jury is still out. This is still a matter of serious scientific contention. The bulk of the evidence suggests it’s real, but there is some good evidence that it’s not real. More importantly the evidence that it is real is equivocal and hard to separate form the noise. Even by the most optimistic standards it doesn’t meet the normal confidence expected of a scientific hypothesis. That’s my view on global warming. It’s like my view on GM foods or the overkill hypothesis of megafauna extinction or a great many other issues in modern science. It’s still way to early to call and both sides have some damn good arguments (and a few extreme lunatics).
Well the first thing I’d need is to see that magic 95% confidence limit for the idea that global warming is anthropogenic and not a natural fluctuation. Until then there is no way I’m going to accept this. 95% has been considered a reasonable confidence level for accepting an hypothesis for a long time, I can’t see any reason why it’s not reasonable to expect the same here.
Beyond that I’d like to see a model that makes testable predictions. I do a bit of modelling for my work, and I know how models are constructed. They are the classic example of what Popper called week science. They almost without fail have some sort of selection process for the data, where the best points are selected and rejected until something that meets reality is achieved. That’s in contrast to classic scientific method of proposing your hypothesis and then rejecting or accepting it. Models essentially force data to fit reality. That’s not say models aren’t a very good tool, but they are only as good as their predictive capacity. I know from experience that a model can fit the past data with uncanny accuracy, particular with modern software packages, and totally fail to predict anything at all. So the other thing I’d need to be convinced beyond that 95% limit is to see one of these long-term, multi-factor models make predictions with significant accuracy for, say, 5 years. Only then can we be reasonably sure that the factors in the models are the same ones at play in the real world. If the model fails then we clearly have no idea what factors are at play and can have no confidence that it is anthropogenic.
Unfortunately at this point we aren’t even close to doing that. And that is a large part of the reason why the most optimistic figure is that we can be 90% confident this is real, while at the low end we could actually do better at determining whether it’s real by throwing a die and dividing the result by 2.
I hardly think those are unrealistic expectations to place on a scientific hypothesis. After all I’m just asking for standard confidence limits and a testable prediction.
In case it were established to be anthropogenic to a reasonable degree? It would be simpler to ask what I wouldn’t support. Once again, bear in mind that my ideas are half-baked, but if this is real, and if it is established that a rise of >1oC are reasonably likely inside a millennium then this could be devastating. There’s very little that I wouldn’t recommend. To try to quantify that I would essentially endorse anything that is considered appropriate during war mobilisation, and that covers a lot.
In essence, ATM I support people being allowed to do whatever we like. We can’t be sure to a reasonable level that this is real, therefore it is not reasonable to force people, via fines, taxation, imprisonment etc, to do anything at all. At this point all I can really say I support is education and at best government endorsement of solutions provided there is no financial or legal threat or reward involved.
To me, this seems like kind of a mismatch between science and policy response. I agree with you that the standard .95 confidence level is the appropriate measure for determining that a particular result is approximately scientifically certain. That will apply to results about climate forcing as well, and so it should.
However, we are talking here about an effect that, as you yourself say, could be absolutely devastating, enough to justify draconian policy measures comparable to war mobilization. We’re also confronted with a couple of additional conditions:
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If anthropogenic climate change is significant, then the longer we continue our current trends of greenhouse-gas emissions, the more drastic the impacts will be.
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Even if significant anthropogenic climate change is not currently occurring, it definitely will be caused at some point if we continue increasing our emissions of greenhouse gases into the atmosphere. In other words, anthropogenic forcing either is currently a reality or will become a reality in the near future if we continue our present habits.
Public policy choices are based on rational risk assessment as well as on gold-standard scientific certainty. I don’t think it makes sense in this case to insist that we should avoid policy changes until we’re absolutely scientifically certain that anthropogenic climate forcing is already having a significant impact.
This is the sort of easily-misinterpretable statement that I was talking about. I don’t really see how recommending that people should go on doing “whatever we like”, and that the government should not attempt to change emissions activity in any substantial way via regulation or tax incentives, is essentially different from “making a case for doing nothing at all”. “Not forcing people to do anything at all” is “doing nothing at all” as far as policy is concerned.
Back in a bit with some comments about the statistical confidence level for anthropogenic contributions. Passing the “model that makes testable predictions” issue over to jshore in the meantime.
Don’t have much time now so will just say a few quick things:
(1) Poor Blake, constantly misunderstood by everyone. This must not have anything to do with his communication skills. No, it is merely the inability of all of the rest of us. Clearly.
(2) Kyoto: It is not just the first step in a long process. It is a vital step, namely to attach a price to emissions of CO2 and other greenhouse gases into the atmosphere. Do you, Blake, believe in market forces or do you believe that technology gets invented magically or just out of sheer selfless good will? Personally, I believe that economic incentives are important to advance the invention and use of technology.
(3) All your silly analogies to try to show it is essentially impossible to separate out the anthropogenic warming from the rest are just that…silly. They ignore the fact that there is a trend over time, as can be seen in successive IPCC reports, in terms of the certainty with which they can say regarding the anthropogenic signal in the warming. And, as I noted, there has already been great progress in the last 4 years.
(4) You claim, “There is no agreed upon Theory of climate and a great many prominent and reputable scientsists are being published regularly in reputable journals disputing every aspect of anthropogenic global warming. Hence this is a matter of mainstream scientific debate, consensus or no.” I actually see only a handful of such papers getting published, especially relative to the total number appearing in the field. And, my point of view is the one also shared by, for example, the editor of Science. I can dig up the quote later. There was also a paper published by Naomi Oreske (sp?) that did a study on this. While there is some legitimate argument about whether her definition of agreeing with the consensus was too broad, it appears that a tighter definition makes the fraction of papers go from almost zero to only very, very small.
Precisely. Blake, I know that you love to refute everyone by shouting, “Strawman! Strawman!” but eventually you need to accept some responsibility for the fact that your argument may be poorly phrased.
I don’t object to your characterization of the science as a situation where we can’t separate out the exact anthropogenic effects from the nonanthropogenic effects. Only an idiot would disagree with that. You’ve apparently missed the sections that I’ve objected to:
Note. You say there’s a question whether “this” (by which I assume you mean global warming) is human induced.
No, that’s not the question. The question is precisely how much of the majority of this is human induced. That’s a very different question.
You say that it’s to early to call whether human influence exacerbates the warming effect. No, it’s not. It’s well-established that human influence exacerbates the warming effect. It’s still too early to call precisely to what degree human influence exacerbates the warming effect. That’s very different.
Now, if you’re backing away from your original exaggerations, that’s well and good. But don’t think your cries of “Strawman! Strawman!” are justified. I’m responding to exactly what you said, not to some strawman position.
And no, I won’t back away from pointing out Loehle’s employment by an industry group. He’s paid to produce science with certain results, and that calls his science into question. That’s not an ad hominem fallacy; that’s impeaching the witness, which is not a fallacy. If you don’t understand the difference and prefer to believe that it means I’m unqualified to discuss the science and the politics, well, that’s why I go to therapy every day, to get over such trauma.
Daniel
But Daniel, how can you say that reports produced by agencies such as the IPCC, whose only real reason for existence is to deal with anthropologically forced climate change, shouldn’t be dealt with an equal level of suspicion as one produced by industry reports in favor of dismissing the same phenomena? Both have reasons to support their own side, so should we dismiss both sides or accept that both arguments should be considered in the context of their own self-interest.
OK, so Jshore has totally forfeited the debate and can’t even answer simple questions. All he can do now id spew rhetoric, obvious strawmen and condescending comments about “Poor opponent.” I think I can leave him right there at this stage and declare that I have overwhelmed in this debate. He simply won’t debate me on this issue.
Kimstu,
You still haven’t answered my question. I asked what reasoning you used that allowed you accept 66-90% confidence. You said that these were reasonable levels, so you must have a reason, yet you haven’t been able to present that reasoning. If you can’t do so then I am going to have to conclude that in fact it isn’t reasonable, even to you.
That isn’t probably only true in a very trivial manner. We have the technology now to sequester carbon mechanically. It’s not perfect but it’s certainly good enough to buy us all the time we need at any point we need it As a result we can reverse this effect at almost any stage we desire to, provided that we are willing to bear the quite reasonable energetic/financial costs. So the impacts need only get more drastic with delays if by drastic you mean expensive, rather than having any environmental or ecological impacts.
This is akin to a person with a progressive but entirely treatable disease delaying seeking medical aid until the test results are returned. Waiting for the results to be confirmed by science will require more expensive and extensive treatment to remediate the problem, but it needn’t be drastically different.
So no, I don’t agree with this idea that the effects will be more drastic the longer we continue.
Now that simply isn’t true. It’s quite untrue.
Look the best science in the world can’t say that the current changes are having any effect. There is simply no scientific method that will verify the claim you just made. It is pure guesswork based on wild extrapolation.
The fact is that we have no idea what the buffering and absorptive capacities of the Earth are WRT the gases, much less any climatic feedbacks that can negate the changes they induce. We may find that levels simply can’t rise beyond current levels, or that the climate will stabilize itself even if levels continue to rise.
So no, that statement is simply untrue. We can not say that climate change definitely will occur if we keep going. There is simply no way of knowing that. If you wish to contend otherwise then provide a scientific reference which shows that to be the case. And since you use the word definite then a 95% confidence is the very least we require, in reality definite should utilize 99% limit.
Look I agree with that, with a great many reservations. The problem I have is that the vast majority or proponents, including the OP, are endorsing the view that we need to implement public policy choices because the science says the greenhouse is real.
Now you at least seem to have accepted that the science does not say that greenhouse is real. The best science we have can’t say it exists to the normal limits of scientific acceptability. In short if this were any other scientific hypothesis it would never be accepted.
I’m all in favour of risk management decisions being made on these things. But that is quite a separate issue to what we have been discussing in this thread. Here we have been discussing what the science says. And the science says this can’t be established to even exist.
This is what I have a serious problem with. This conflation, often deliberate, of science with social policy. If this is being done as form of active social policy (social engineering) then that’s OK. Good governments should engage in social engineering form time to time. But let’s not pretend that it is being done because science demands it be done. It’s being done despite the best science not being able to say it exists at all with reasonable certainty.
Let’s be honest here. We are not engaging in this social engineering because of the science. We are at best engaging in it on the basis of hodge podge of equivocal science and political will mandated by the people. At worst we are engaging in it despite the best science saying we can’t know it even exists and because of political will that is not mandated by the people.
Either way this ain’t a scientific debate, it’s purely a debate between two opposing political and economic views.
I don’t think that’s wise either. Which is why it’s a good thing we aren’t doing that.
Look, ATM climate change isn’t having a significant impact. At best the impact is trivial. Nobody is suggesting waiting until it is having significant impact, we are suggesting waiting until we can say it exists to the level of normal scientific standard.
95% is not a gold standard in science. 95% id the bare minimum. Anything beyond that and you really can’t know whether you’ve just been lucky. In a lot of science even 95% isn’t considered significant enough to publish, so it certainly isn’t a gold standard. It’s the wooden nickel standard.
Dude, look at the timing of those two statements. Unless you are implying that jshore is a mindreader then he was constructing a strawman.
Well that certainly failed. Jshore simply won’t debate me. He utilizes blatant strawmen, won’t answer direct questions and is reduced to spewing rhetoric with no reference at all to the debate.
You are correct that consensus is not a particularly useful concept in science, although your statement that there is consensus but then there is no agreed upon theory and there are many disputes etc etc. seems somewhat self-contradictory to me. And, in science all knowledge is provisional. Nothing is completely settled…not gravity and not evolution (which is what creationists exploit to no end).
Where consensus is important is when science interacts with the larger world…i.e., where science meets public policy. Who is to say what gets taught in terms of evolution vs. intelligent design if not by looking at the standing of each view in the peer-reviewed scientific community? And, likewise, when decisions need to be made in terms of policies on climate change, it is important to know where things stand. That is why the IPCC was formed.
As for your AIDS/HIV analogy, I would submit that the economic impact of AIDS/HIV is not such that there are certain industries that have a lot to gain by continuing to muddy the waters. A better analogy is evolution vs. creation (even if the motivations are not economic but religious)…and given the amount of argument on that I think you would have to conclude by your logic that it is unsettled. Another analogy would be to what happened for a long time concerning the health dangers of smoking and the addictive nature of nicotine.
There is nothing particularly “magical” about 95% confidence limit, particularly when one is not dealing with a purely statistical issue. And, as has been pointed out by Left Hand of Dorkness, you misrepresent what the IPCC statement (which is a question of whether most of the warming of the last 50 years is directly attributable to greenhouse gas emissions). Plus, given the nature of the IPCC estimate of their confidence, that number is a shot-in-the-dark estimate of confidence, not a rigorous statistical estimate…a fact that we will no doubt hear about ad nauseum if the next assessment report increases the confidence above the 95% level.
Finally, it is important to recognize that the evidence for anthropogenic climate change goes beyond the issue of what fraction of the warming we’ve seen in the last 50 years we can attribute to it. The fact that CO2 levels in the atmosphere have risen by ~35% from pre-industrial values because of anthropogenic emissions is beyond dispute. It is also well-understood what strength of radiative forcing a certain rise in concentration will produce (just under 4 W/m^2 for a doubling of CO2). The only way to avoid significant warming in the future as emissions continue to rise [and as the climate system equilibrates with the level of greenhouse gases already in the atmosphere] is to posit significant negative feedback effects (especially in light of some understood positive feedback effects). And, while there have been some attempts to do this (e.g., Richard Lindzen’s “iris effect”) they have not stood the test of experiment. And, it seems unlikely to expect that such effects could be dreamed up because they would tend to imply a climate system that is much more stable than what we have observed in the past (e.g., ice age – interglacials). So, it would be necessary to also somehow explain how these feedbacks operate but how they failed to stabilize the climate during these events. It is a challenging prospect.
(1) Climate models are not statistical empirical models for fitting data. They are models that incorporate the physics (with some approximations) as currently understood. There are not even any truly “free parameters” although there are several physical parameters whose value is only known to within some range.
(2) Even if you consider the several physical parameters as free parameters, there are still many more variables that can be looked at than there are parameters…so there really isn’t an issue with being able to fit the data simply by adjusting the parameters right.
(3) And, actually predictions of future warming have been made and verified. James Hansen made a prediction as discussed here. The prediction necessarily considered different scenarios since Hansen did not have a crystal ball to predict when/if a major volcanic eruption would occur and what future emissions trends would be. (And, this has allowed people like Patrick Michaels, whose goal it is to deceive and muddy the waters on behalf of the Western Fuels Association and the Cato Institute, to make deceitful claims regarding the predictions as discussed in that link.)
At some point you need to show me these places where I said the things you attributed to me. Otherwise I have a proven strawman.
Cite!
That is not the question. The IPCC and others I have referenced have said that we simply cannot say to a reasonable degree that any of this is anthropogenic. Read the references. It says it there in black and white. We simply can not say that this isn’t natural. In toto. Not in majority.
“most of the observed warming over the last 50 years is likely [66% to 90% chance] to have been due to the increase in greenhouse gas concentrations”. That is what the science says. It doesn’t say that it is 100% likely that the majority is human induced. It says that we can’t be even 95% certain that the majority os human induced.
So if you wish to contend that it is established that the majority is human induced and the question is simply how much of that majority is human induced then provide a cite.
Cite!.
I now this is futile. I have asked you for references for several such claims now and you have been unable to provide them You will be unable to provide a refernce for this one either. You are simply making this up.
The best science says that you are simply wrong on this point. It has not been in any way established that human influence exacerbates the warming effect. If you believe4 other wise then provide your references. This constant argument form assertion established nothing.
And if you can show an example of me making an exaggeration then I won’t declare this another strawman.
Well if you are responding to exactly what I said then why won’t you quote exactly where I said those things? It seems like a simple enough request, yet I have asked several times and you are unable to do so.
Cite.
Once again I know I won’t get a response to this request for some evidence to back up your claims. But this is GD and when you don’t respond I can dismiss your claim and state categorically that it is an ad hominem.
If you have evidence that Loehle’s is paid to produce science with certain results then show it to us. Otherwise this is indeed an ad hominem. It’s a baseless attack on a scientist’s honesty. Calling it ‘impeaching a witness’ doesn’t make it les an ad hominem. You could call Loehse a child molester as well if you like. But until you present evidence it’s not an impeachment it’s an ad hominem.
Seriously, this is now getting tiresome. Every post you make these statements of fact. Loehle is paid to produce science with certain results. It is established the majority of warming is human induced, it’s well established that human influence increases warming. But you never, ever respond for my requests for references. You simply argue form assertion.
I have managed to provide references for every claim I make. I can’t see any reason why you can’t provide references for the claims I specifically request references for. At this point all we have is your baseless assertions arguing against the best and most current science in the world.
And just to clarify why that 9% figure is so incredibly dodgy and a bare minimum, not a gold standard. This is an area where we have a self-selected sample of 1. We are analyzing global warming because we know it is increasing, and we can plausibly say that it is anthropogenic. It has drawn itself to our attention precisely because it is an apparent anomaly. Those sorts of situations are always statistically dubious because we have no idea what our sample space is.
Imagine all the environmental factors you can that could respond to increasing CO2 levels. So we might look at the dominance of C4 plants, seedling growth, bird deaths, oceanic acidity, soil fertility and rainfall. And those are just off the top of my head. It’s all too easy to come up with 9 other factors beyond temperature that could be affected. The thing is that is any of those things had gone up as temperature has then they would have attracted our attention. But they didn’t, and so they aren’t the subject of massive international analysis.
Now what does that 90% confidence mean? It simply means that there is one chance in 10 that what we are seeing is a statistical accident. That might not seem to bad, until you consider the dominance of C4 plants, seedling growth, bird deaths, oceanic acidity, soil fertility, rainfall etc. If we do consider those then we realise that with only a 90% confidence at any given point in time one of them will look like it corresponds to anthropogenic CO2, no matter what the truth is or what anthropogenic CO2 levels actually are. The sample space is potentially huge because the samples self-select.
If someone 100 years ago had said that global warming would increase as it has done as a prediction then 90% would be more acceptable, But because we only selected global warming for analysis a posteriori 90% is totally unacceptable because our sample space is greater than the 1 in 10 chance of rejection.(caveat: statistically it’s not quite that simple, but the broad thrust of the point is accurate. With a 90% confidence and 10 possible factors for a posteriori analysis 90% is not a reasonable level of certainty.)
I disagree. Either something is scientifically and rigorously verifiable and replicable or it isn’t science. Consensus simply is not science, it’s an argumentum ad populum. To say that it’s important that something that isn’t science represents science at the public policy interface is a nonsense.
We say it by looking at whether it is science. If it’s science it should get taught. If it passed peer review then it is science we hope. It’s that simple. If ID passes the standards that make it scientific viz testable hypotheses and replication then it is science and suitable for teaching whether I endorse it or not. No consensus is required. Like most minor theories it probably won’t get taught, but that’s a decision to be made by teaching specialists, not a consensus of scientists. Cnsensus is not required in any way and is counterproductive.
I agree. And we know where things stand, at 66%-90% certainty. We don’t need consensus to look at the facts.
Which as precisely my point. This is not an issue where economics is at play. It’s an issue that’s contentious because the science is contentious.
Would we? Can you show me a paper published in a peer reviewed journal in the last 5 years that endorses creation? If not then we wouldn’t conclude it is unsettled by my logic.
Hence the reason why I used quotation marks. 95% is simply the figure that has been considered to represent a reasonable level of certainty that something really exists. At this point we haven’t reached that level and so it isn’t reasonable to conclude that this exists.
But it is the best figure the best science in the world can give us. SO the best probability the bet science can give us tells us that it’s not reasonable to conclude this isn’t natural.
I really couldn’t say.
Yes, I think we all agreed on that about 5 times now. You seem to reintroduce that in every post despite the fact that nobody in this thread has ever disputed it AFAIK.
In vitro or similarly controlled conditions. Under real world conditions with variable energy inputs due to aerosols, solar intensity etc, it’s less clear.
Well no, that’s not the only way. There are also buffering effects of the gas concentrations themselves.
That is true enough. And a much better representation of reality then Kimstu’s blanket statement that it is impossible for these things to happen at all.
Particularly if you first accept, as you have done, that we need negative feedbacks on climate, rather than buffering or negative feedbacks on atmospheric composition. Geochemical cycling is really not well understood at all and we really don’t; know what happens as the composition changes. It still remains challenging, but becomes much more flexible and uncertain than when we an only utilize climate feedback.
I never suggested the parameters can be adjusted. What gets adjusted, as I said above, is the data selected. All these models I have seen utilize some sort of selection. The data pool consists of ice cores, ocean sediments, dendrochronology, corals etc. as surrogates for past climate. The models then select one of those as their working pint for past conditions and add the appropriate mathematical multipliers ot the model based on that.
So while you are right that the parameters themselves may be unadjustable the modifiers for those parameters are, as are the data series used to fir the model. This is an inherent flaw of all models, nit just climate models.
To what significance was this verified? And how was it verified? That article says “the model did a reasonable job “, which hardly sounds like it was verified. Given that temperature was already on an upward trend when the model was produced, and the model was presumably calibrated it that, it’s not suprising that it was “reasonably” confirmed. A simple linear model would have been reasonably confirmed depending on how you define reasonable. A visual inspections suggests it’s not a very good fit at all, even allowing for the differences in the year of volcanic eruption.
Of course what we really need is to re-run the model with the volcanic eruption in there appropriate places, then we can say that the model does or does not fit realty. Has Hansen done this simple check, or since this is science, allowed anyone else to do it to replicate his results?
If not then we really can’t say that predictions of future warming have been made and verified at all in the scientific sense.
I am very impressed with your ability to impartially declare yourself a victor.
(1) I must admit I haven’t yet read the very recent IPCC report on this subject…but I believe there was still considerable argument about how ready technology, including carbon sequestration, is. In fact, Michael Crichton has cited a Science article to this effect to argue that scientists say that there is nothing we can do about climate change at the moment. And, while he misrepresented that article quite a bit, he was right on the basic point that this article said that the IPCC report stating we had the technology in hand at the moment to stabilize CO2 levels at some reasonable value was too optimistic. It’s curious how stabilizing CO2 levels is presented by opponents of taking action as either easy or impossible or extremely expensive depending on their motivations. (In fact, many even present things far short of a stabilization of CO2…such as Kyoto…as horribly expensive.)
(2) All of the sequestration technology that I am aware of can only act on future emissions. As several recent papers in Science have discussed, there is considerable warming “already in the pipeline” as the climate system equlibrates to the current levels of CO2. (The oceans are a huge heat sink and thus give considerable inertia to the climate system.)
(3) And, you are correct that it would be much more expensive to implement technology very quickly (e.g., outfit all power plants almost immediately) than to do it more slowly. If the goal is to save money, then the best approach is to start now, as a recent study using a coupled economic and climate model in Science showed.
Again, you misrepresent the IPCC’s statement. It is in regard to whether most of the warming seen is due to greenhouse gases…not the issue of “any effect”. And, you are making your arbitrary decision to accept only an (estimated) 95% confidence level as saying anything about this statement.
And, by the way, you are ignoring the fact that the IPCC has made several statements regarding what will happen in the 21st century at the higher level of “very likely” which means a 90-99% chance. You can see these by going and looking at the IPCC report online (www.ipcc.ch).
Again, the science is about detection at the level of what most of the warming of the past 50 years is due to. It is not about whether “the greenhouse is real”. There is a distinction even if you refuse to acknowledge it.
Well, I am glad to hear you say that you are in favor of risk management. That is indeed the prudent policy dictated by the current state of the science. The science on this issue can’t be summarized by your cute little one-sentence ditties no matter how often you repeat them. It is not a “black-and-white” thing. The state of the science is best understood by reading the IPCC report and keeping abreast of the current literature since then.
No. We are engaging it because a combination of the current state of the science and economics suggests to us that it is the wisest policy choice. I agree with you that science does not unambiguously tell us what the best policy choice is. Even if we had science that said that without intervention the earth would heat up 20 degrees and 90% of the species would die off, it would not specifically dictate a policy choice although to many of us the sort of policy choice involved would be obvious.
And, a combination of science with economics can tell us some of the tradeoffs between doing nothing in the face of uncertainty about the magnitude of the problem that we face and starting to take action now.
It is a debate with many aspects. It involves science, economics, and political and philosophical views. Clearly, these different spheres interact but it does not mean that we cannot at least approximately separate out the different aspects and ask, e.g., what is the current state of the science in regards to climate change?
I disagree that it is not having a significant impact…for some like those living in the polar regions it already is and some of the impact we are still not completely sure about. E.g., while we haven’t definitively detected an increase in hurricane intensity, there are a few papers out there now that do claim to see such an effect and see it correlated with rises in sea surface temperatures [SSTs]. Also, while no specific event such as the heat wave in Europe or Hurricane Katrina can be definively attributed to global warming, it also cannot definitively not be said not be caused by it. We are in the unfortunate situation of not being able to know exactly what effect we are having.
Furthermore, given the known inertia in the climate system and the known inertia in human societies and known inertia in ecological systems, it is unrealistic…in fact impossible…to wait until things measure up to Blake’s conception of a definitive standard without committing ourselves to significantly more effects.
I’m pretty good at that mindreader trick. However, I will tell you the secret that makes it particularly easy: the best way to predict the future is to look at the past. And, if we look at the past in this thread, we see that your statements are so confusing that noone but you seems to understand the distinctions that you later claim to have made.
Really not worth responding to.
What questions would you specifically like me to address and when are you going to answer my question regarding your views on whether technological innovation is best spurred by market forces or by instead relying just on people’s goodwill?
See, e.g., here. There was another paper reaching similar conclusions published about the same time.