Thanks for the post, intention. kimstu has responded very nicely to most of the points that I was planning to, but I did want to add one comment on this point: I don’t think the logic is quite right in your comment quoted above. It is not just that we have experimental evidence for warming and want to find the cause. In fact, we also know theoretically what sort of perturbation we are putting on the climate system by the rise in greenhouse gases and we have estimates from various sources of what sort of warming that ought to be causing. Some of these estimates are from climate models…which I know you don’t trust…but we also have estimates from past climatic events such as the ice age – interglacial cycles. So, if you want to argue for a very low climate sensitivity, you also have to explain what sort of huge forcing we are overlooking that caused the change in climate from ice age to interglacial! Otherwise, you are looking at a climate sensitivity of roughly 0.75 C per W/m2 and this leads immediately to the prediction of a roughly 3 C equilibrium rise for a doubling of CO2 levels.
kimstu, welcome back. Glad that the UK was good to you. Crocuses are always nice.
You seem to be under the misunderstanding that I have to prove that the climate is just undergoing natural fluctuations. Science doesn’t work that way. The null hypothesis is always that fluctuations are natural, and you need to show that they are not. Then, and only then, could we move on to look at why the climate is unusual or anomalous.
So, bring it on. Until the bogus “Hockeystick” was published, it was known and widely accepted (see Lamb’s work on this question) that the temperature during Medieval times was warmer than today. This was based on a wide variety of proxy measures (treelines, wine cultivation extent, etc.) as well as anecdotal reports.
But when the Hockeystick was published and erroneously given star billing by the IPCC, this general knowledge of the MWP was suddenly assumed to be completely overthrown … but as is now known, this assumption was based on falsified data, bad and cherry-picked proxies, and erroneous math. Subsequent studies claiming to “replicate” the hockeystick are all based on the same cherry-picked proxies, proxies that have been condemned by a number of people including the NAS panel. Heck, let me pick the proxies, and I’ll show you a warm or cold period wherever you want one.
The Greenland ice core records clearly show that the Holocene has been a couple of degrees warmer than today. There is also evidence of ice-free summers a couple of times in the Holocene, and those haven’t been seen lately. Warming from 1920-1945, which even the IPCC says was natural fluctuations, was as long and as strong as the recent warming.
So how is this period unusual?
I await your demonstration that the current climate is anomalous or unusual.
w.
jshore, I sent the name of the new study regarding the Santer et al. findings in the so-far vain hope that you would read it. Instead, you have just repeated the same arguments you made before, which we have already discussed at length.
One of the best things about science is that it is always evolving, as new discoveries are made and new studies written. If you want to be taken seriously when discussing a particular issue, it’s valuable to read those new studies, to see whether your previous understanding is either supported or changed.
Since this recent study supports my position on the Santer paper rather than yours, I can understand if you don’t want to read it. But if you do, I’m glad to discuss it with you, as I find your insights to be valuable.
All the best,
w.
This might be of interest: Climate Change: The Deniers a series the National Post in Canada ran, profiling scientists who buck the conventional wisdom on Global Warming.
intention: I chose my words pretty carefully when I said there was ‘a preponderance of the evidence’ that AGW was happening to some degree. That’s not to say it’s been proven. But I’ve read a number of papers over time that have looked at various aspects of warming and concluded that it’s real. Yes, the absolute numbers are so small right now that there is still plenty of uncertainty. There are good arguments on the opposing side which must still be overcome. I believe the burden of proof is on AGW proponents. My feel about where the science is right now is that there have been enough studies which have found positive results and correlations that it seems there is likely some forcing of global temperature due to influence from humans. Where I think the science is on really shaky grounds is when it tries to extrapolate this into the future and making predictions. And most especially, when politicians then use that extrapolated science to promote various regulations, taxes, and intrusiions into the lives of the people. Given the current state of the science, it seems to me that right now our primary effort should be in several areas: Research into ways to sequester carbon or otherwise clean the CO2 out of the atmosphere, more research aimed at understanding what the true risks and costs of various actions would be. The only thing we should be frantically doing at this point is trying to learn more about the problem while picking some low-hanging fruit to lessen CO2 emissions.
What we’re not ready for are huge global treaties that start picking CO2 targets and enforcing mandated reductions of CO2 emissions - partly because any truly effective measure would also be horrendously expensive, and partly because such treaties generally become exercises in who can gain advantage over the other signees.
Here’s the thing: We’re going burn oil and keep burning it until it’s too expensive to burn anymore. Period. Oil is a fungible resource. If we lower our demand for gasoline by cutting consumption, and the Chinese don’t follow suit, all we will simply drive down the price of oil for Chinese consumers, and they will consume more of it. Conservation that drives down the price of oil also drives down the competitiveness of alternatives, which slows the adoption rate of alternatives.
Either way, that oil is getting burned. So we’d better also research ways to live with that.
There’s only one way to keep that oil in the ground - make it uneconomical to pump it out. Find a cheaper alternative. That will kill oil consumption in short order.
No, I’m not. I don’t think it’s up to you to prove that the AGW hypothesis isn’t true. I’m simply saying that the points you made don’t constitute convincing arguments against the AGW hypothesis.
No, I don’t think this is an apt description of the way science works. We don’t just automatically assume some null hypothesis and require that the null hypothesis be definitively disproved before we consider other hypotheses.
Rather, we look at the relevant phenomena as a whole, in the light of a whole range of possible scientific explanations, and try to figure out what hypothesis best accounts for them.
In the current state of our knowledge on climate change, AFAICT, we’re confronted with (at least) the following major issues:
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We know that anthropogenic industrial development has been rapidly and significantly increasing atmospheric concentrations of greenhouse gases such as carbon dioxide.
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We know that according to fairly straightforward atmospheric physics, the thermal phenomenon called (somewhat misleadingly) the “enhanced greenhouse effect” will respond to increased atmospheric concentrations of greenhouse gases by producing increased global temperatures at and near the earth’s surface.
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We know that there is at least some strong evidence that global temperatures have been rising in recent decades, too much and too fast to be convincingly explained by natural climate forcings.
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We don’t know exactly what other physical mechanisms besides the greenhouse effect are reacting to the anthropogenic increases in greenhouse gases in the very complicated system of global climate, nor exactly what other climate forcings are active, nor exactly how the effects of all the different forcings interact with each other, nor what their net results will be in terms of overall changes to global climate patterns.
Issues (1), (2) and (3) are what make the AGW hypothesis a reasonable best guess as a general description of current trends in global climate. Issue (4) is what makes it so uncertain.
We’ve got the increased CO2, we’ve got an apparent increase in temperatures, we’ve got a well-understood basic theory (greenhouse effect) linking increased CO2 to increased temperatures…but we can’t be sure what else is going on in the climate, or how all the other climate stuff is interacting with the artificially-simple model of the greenhouse effect considered as an isolated phenomenon.
Despite all these admittedly grave flaws and uncertainties, though, the AGW hypothesis still seems to be outperforming competing hypotheses as a general explanation of current climate trends. We should certainly not accept it as anywhere near definitively proven, but neither should we refuse to consider it as a working theory just because we haven’t definitively disproven other possible hypotheses.
AFAICT, what you’re talking about is Hubert Lamb’s work on the “Medieval Warm Epoch”, an inferred period of unusually high temperatures about 700-1000 years ago in parts of northern Europe. For one thing, as Lamb died in 1997 at the age of 84, his research on the subject (although deservedly acclaimed as pioneering) had ceased to be cutting-edge even before Mann et al. started publishing temperature reconstructions in 1998. For another, regional climate effects are not necessarily reliable guides to global ones. We can’t assert (and AFAIK, Lamb himself never did assert) that evidence for a high-temperature Medieval Warm Epoch in a limited area in northern Europe necessarily implies higher global temperatures overall at that time.
And I have to remind you again that your characterization of the so-called “hockey stick” temperature reconstruction as “bogus” simply is not an accurate reflection of the opinion of most mainstream climate scientists. I’m not knocking your right to hold whatever opinions you like about any scientific research; I’m just pointing out that you can’t simultaneously claim to be in touch with the scientific mainstream and also dismiss Mann et al.'s work on temperature reconstructions (and other work replicating their results) as completely false or worthless.
Well, I think it’s going to take a long time before it can be conclusively “demonstrated” that the current climate is “anomalous”, at least to the level of significance and certainty that you’re willing to accept. But I don’t buy your claim that it’s necessary for me to demonstrate that in order to justify serious consideration of the AGW hypothesis as an explanation of current climate trends.
Kimstu: Excellent post.
This series of profiles by journalist Lawrence Solomon came up in a recent climate thread. jshore pointed out a few of its factual errors in this post (and a few others came up in other posts in that thread):
The rest of your post I basically agree with, though (and I swear I had planned to say that even before reading the kind compliment in your most recent response! ;)).
Hell, forget the IPCC and the industry spokespeople and the overwhelming majority of peer-reviewed published research: when Sam Stone and I agree about an issue to this extent, that’s proof that there’s a consensus. 
kimstu, you mentioned that I am talking about average temperature. I gave a variety of reasons why I think it is a very poor metric for the state of the earth’s energy balance, but unfortunately, it’s the one everyone uses, so I have little choice but to use it myself.
There’s further discussion of this issue here.
All the best,
w.
Once again, I strongly encourage anyone who believes that the climate models produce skillful results to read the discussion here. It is a clear exposition of why the models don’t converge, why they are only first-order approximations that diverge after a very short time unless artificially constrained … which of course means that the results can’t be trusted.
w.
Thanks for your response, intention. My slightly snarky response would be that if you didn’t want me to repeat the points that I made in that other thread, perhaps you could have given a more accurate summary of the Santer paper and the issues surrounding it?
Well, I would not say from the abstract that it completely supports your original position on the Santer paper (which includes the misconceptions that I noted in the post above on this subject), but it does argue for the position that some of the error in the data sets is likely in the RSS data set and that the now-corrected UAH data set (modified from the version used in the Santer paper) is more accurate that the RSS data set and that, if this is so, then there is still not the expected magnification seen in the tropics.
I do want to read it, but the practical realities are that neither my company nor I myself get geophysics journals, which means I am left either to shell out $9 to AGU for a copy of that article or to make a trip to a local university to make a photocopy. I am currently debating which course of action I want to take.
This all seems to relate more to weather forecasting than climate forecasting. It is well-known that the sensitivity to initial conditions means that weather forecasts can’t be made beyond about 1 or 2 weeks. However, forecasting climate is a different problem. For example, you would rightly deride me if I told you what the weather was going to be here on July 4…However, if I wanted to bet you that the average temperature in July would be higher here than the average temperature in March, you’d probably not want to bet against me, even if I gave you 100-to-1 odds.
Dilemma solved! Check your email, jshore, and I hope I caught you before you shelled out nine bucks unnecessarily! 
As a wise person on a messageboard I was reading once said (post #143 to be exact), “One of the best things about science is that it is always evolving, as new discoveries are made and new studies written.” It seems to me that you want to believe in even one new study over older studies if it supports your point of view but will dismiss a whole bunch of new studies over older studies if you prefer the viewpoint of the older studies.
The problem with the work prior to the 1990s is apparently that it tended to rely heavily on reports from just one section of the Northern hemisphere…and to the extent that other areas were considered, the proxies were not investigated carefully enough to note that the warming that occurred vaguely during the Medieval times was asynchronous in different places so that the global temperature did not deviate as much. (It is also worth noting that the global temperature has risen quite substantially since the time in the 1960s when Lamb’s first studies were done.)
You make all sorts of claims about Mann and subsequent studies that are not supported, e.g., by the NAS panel report. And, the NAS panel did express some concerns about bristlecone pine proxies. However, their conclusion was not that all studies that involved these proxies were completely meaningless, as you seem to believe. (I believe that they also noted that the Moberg study didn’t use any tree ring proxies in getting the multicentennial variations.)
And, yes, the NAS panel was more cautious in the conclusion regarding whether the late 20th century was warmer than any time in the last millenium (calling it “plausible,” meaning supported by several different studies and with no clear evidence contradicting it). However, they certainly did not conclude that it was warmer during the Medieval Warm Period than in the present.
By the way, it also does not seem to be correct that up until Mann et al. was published in 1998, it had been universally believed that there had been an MWP that was warmer than the present. For example, in this paper from Hughes and Diaz in 1993, they are already strongly questioning whether the Medieval warm period was really a global event and noting the asynchronicity of the warming in different areas.
jshore, if you truly believe that forecasting the climate 100 years from now is in any way comparable to predicting whether July will be warmer than March, I fear that I don’t know what to say in response … for one of the few times in my life, I’m speechless. That has to be the most … the most … nope, can’t think of a word. Speechless. The brilliance of your analogy leaves me without a response.
w.
You are correct, before Mann/Bradley/Hughes made the claim in 1998, Hughes had made the claim in 1993. However, the claim didn’t gain much traction until the “Hockeystick” paper1998, and for a good reason … it wasn’t true.
There is a good overview of a very large number of scientific papers supporting the global nature of the MWP available here.
w.
Well, I gave what I thought was an accurate summary of what I thought the issues were … whether there had been a larger temperature rise in the troposphere than at the surface (there hasn’t), and whether the models were more believable than the observational data (I say no, you say yes). Perhaps I misunderstood the issues, could be, I’ve been wrong before, but I gave it my best shot.
My thanks to kimstu for providing you with a copy of the paper. My main conclusion from the new study is that no, the science is by no means settled enough, and the climate models are by no means accurate enough, to say that it is more likely that the models are right and the observations are wrong.
Which is my position about the climate discussion in general. We don’t have enough information to make the most basici decisions, like deciding if our observational data is accurate for heaven’s sake, much less enough information make multi-billion dollar decisions at this point. Because of this, we should take actions that we know will be beneficial no matter which way the frog jumps.
What are some of these actions?
• Start with the three “R’s” - reduce, re-use, recycle. This is far and away the most cost-effective answer to a host of energy and resource related problems.
• Put money into increased R&D regarding energy efficiency.
• Put money into increased R&E regarding alternate sources of energy.
• TEST THE CLIMATE MODELS, INSTEAD OF BLINDLY FOLLOWING THEM based on the brilliant insight that since July will likely be warmer than May, climate must therefore be predictable … riiiight.
What else?
• Increase research into how to survive droughts, which are one of the world’s largest climate-related killers. There are some innovative and low-cost responses to drought that could save thousands of lives, but which need money for further research, education and outreach.
• Plant trees, and then plant some more trees, then plant some more, especially in Africa. Again, this will have immediate beneficial effects (increased food, firewood, shelter, etc.). In addition, if NASA is right and the temperature rise is due more to landuse changes than to CO2, we’ll be working on reducing the long term warming as well.
These are all activities that we can undertake today, which we know will bring both immediate and long-term benefits, with no wasted money, no carbon trading dollars flowing to India to be spent on coal fired power plants (or flowing to Al Gore to heat his swimming pool), no restriction of the global economy, and most important, no impoverishing of the poor countries. Because make no mistake, anything that slows the world economy kills poor people in a myriad of ways, both slow and fast.
One of the most pernicious and pervasive myths of the push to cut down CO2 is that it will not hurt the poor. The poor, in this CO2 discussion, are as usual totally invisible … but their hunger, illnesses, and deaths are no less real. To protect them from the vagaries of nature as we in the industrial world have protected ourselves, they need energy. Energy for transportation, energy for food, energy for heating them when they are cold and cooling when they are hot, energy to produce the medicines and clothes that shield them from nature’s miseries, energy for refrigerated food storage and transportation to alleviate shortages, energy for all of the things we take for granted in the industrialized world.
People think “oh, cutting down on energy, that’s a good thing” … and for the overwhelming majority of computer owners, and for me, and for Al Gore, that’s true. But I’ve lived a good chunk of my life in some of the world’s poorer countries, and I know that for the poor of the world, that’s a slow death sentence. India and China know that very well, they live with it and die with it every day, which is why they laugh when people propose that they sign on to these ridiculous Kyoto-like schemes …
… because if they didn’t laugh, contemplating the cost to their people in disease, hunger, and death would make them cry …
w.
Of course, analogies are never perfect and I am not claiming that the projections of climate over the next 100 years are on as solid a footing as predicting the seasons. However, my analogy is closer at least in the sense that it compares two things which are both predictions on climate, whereas you were mixing in ideas that have great relevance to weather prediction but much less to climate prediction.
I don’t see much of an overview…just a large collection of discussions of how these people interpret certain papers in the literature. And, who are these people you might ask! I find it sort of curious that you would choose to believe that the Idso clan’s review of the literature is more reliable than that of, for example, the IPCC (which concluded again in its 4th assessment that “Average Northern Hemisphere temperatures during the second half of the 20th century were very likely higher than during any other 50-year period in the last 500 years and likely the highest in at least the past 1300 years.” (In IPCC-speak, “very likely” means it is estimated to be true to a >90% probability and “likely” means it is estimated to be true to a >66% probability.)
For someone who sees themselves as being skeptical, it is quite curious that you seem to know for a fact certain things like that there has not be a larger temperature rise in the troposphere than at the surface (presumably in the tropics). How do you come to these definitive conclusions on subjects which I admit remain uncertain and still areas of active research?
As I noted, a better way to put the question is what one suspects concerning the breakdown that is seen whereby all the models and data sets do show the tropospheric magnification of fluctuations on the monthly to yearly timescale but 3 of the 4 data sets (really two data sets each analyzed by two different groups) do not show this magnification when one looks at the temperature trend on the multidecadal timescale. So, the question is: Is there really new physics coming in at the multidecadal timescale that is not captured either by basic theory or by a wide variety of models incorporating a variety of different phenomena and employing a wide variety of different parameterizations OR are some of the known issues with the data quality on multidecadal timescales to blame?
I in fact agree with you that on this particular issue, there is no definitive conclusion. However, it is one rather small issue. There used to be a paradox on the level of the global temperatures (surface vs. tropospheric) and now the only remaining paradox concerns this question specifically for temperatures in the tropics (and depending on which data sets you believe to be more accurate). In almost any field of science, there are always certain issues where there is something like this that is not understood; as creationists are fond of pointing out, this is even true of more mature theories such as evolutionary theory, cosmology, and so forth. (And, it’s most definitely true of bio-genesis where we are still almost completely in the dark!)
In fact, both China and India have ratified the Kyoto Protocol and are parties to it. Admittedly, the protocol does not require any emissions cuts from them; however, as the process continues down the road and technologies to reduce emissions are developed in the developed world, their time will come. (Also, to a certain degree, the developed world can get emissions credits by supporting projects that reduce emissions in the developing world.)
In fact, this argument of how it is more difficult for the developing world is one of the reasons why they were exempted from emissions reductions in this round…which caused much consternation amongst people who were opposed to the protocol. (It certainly seemed to be the most widespread issue for opposition in the U.S. Senate.) So, it seems like there is no way to make everyone happy…Either we will have you complaining about what such emissions restrictions will do to the poor countries or we will have others complaining that Kyoto is just socialism by wealth-transfer from the rich countries to the poor countries. Perhaps the fact that we have people making both of these arguments is evidence that we have reached a reasonable compromise!