Here's an interesting little exercise in forensics showing how far climate denializers — in this case, one of the fearless leaders, Steve McIntyre — will go to confirm their biases: selectively edit out correspondence to make it look as though the correspondents are talking about one thing, when replacing the excised portions make it clear they're talking about something completely different.
McIntyre does deserve some criticism but not the criticism that Tom wants to make. Here's some background. In describing some of the offending e-mails (which apparently followed a meeting in Tanzania), McIntyre initially seemed to assume that what the climate scientists wanted to avoid showing was the late "decline" in the Biffra tree ring reconstruction.
That claim was criticized by, among others, an anonymous Canadian blogger at the site Deep Climate. Now, there were certainly e-mails in which hiding the late twentieth century decline was discussed (the Deep Climate blogger admits that) but, as McIntye now agrees, that isn't the case with all of them and was not with a number that he quoted in his post. Rather the problem being discussed was that the Biffra tree ring construction showed that earlier periods were warmer than did certain other reconstructions. In fact, in one e-mail, Biffra says he believes that temperatures were probably as warm 1000 years ago as they are today.
That's inconvenient. It presents a less tidy picture. It raises questions. It provides fodder for skeptics. Biffra initially wanted to include this inconvenient data, but that's not what happened.
Instead, he changed his reconstruction. The new reconstruction looks more like the others for earlier periods but has this problematic late twentieth century decline.
The one that was hidden.
McIntyre did intially edit the e-mails (although he showed deletions with ellipses) and the charge has been made that he was trying to hide the fact that they weren't trying to hide the decline. They were, in fact, contemplating hiding the entire Biffra reconstruction. That's not evident. The deleted portions are somewhat cryptic and it is possible that someone could mistake concern about the reconstruction generally with concern over the late twentieth century decline.
But, more fundamentally, were McIntyre trying to make the climate scientists look bad, he did not need to edit a thing and his case is just as strong - if not stronger - given that the e-mails first discussed whether to use the reconstruction at all and then, once it was made to be more consistent, attention shifted to hiding the decline.
What they seem to have done is contemplate excluding an entire reconstruction because it raised inconvenient questions. They decided to include it after it was hastily redone to eliminate the problem. (This is not to suggest that the reconstruction is fraudulent or a lie; simply that there was concern with presenting data that suggests the reconstructions are not as reliable as they are claimed to be.) Once it was restated, it showed this hard to explain decline, so they simply omitted the problematic years. The e-mails (which McIntyre now presents in full) read like advocacy and not science. A commenter on
the Deep Climate site summed it up:
You can spin this any way you want, but there is simply no innocent interpretation of what these guys did.
The failure of many tree ring series to respond to the warming of the second half of the 20th century — the fact that the rings widths go DOWN instead of up — calls into question the whole issue of whether or not tree rings make reliable thermometers.
This obviously casts down on the meaningfulness of the long, relatively flat handle of the “hockey stick” graphs — after all, if the trees failed to respond to the warming of the 20th century, how can we know they didn’t similarly fail to respond to something like the medieval warm period?
One cannot possibly make a reasonable case that the “science is settled” in the face of contradictory and inconsistent results like these. Hence, the need to hide the divergence, so as to make the tree ring record look reliable and beyond question.
Gavin Schmidt at RealClimate is trying to dismiss this on the grounds that the “divergence” was “well known”. Well, yes, it was well known among the climate scientists — but it is preposterous to assert that it is well known to the general public, at whom the hockey stick graph is aimed.
Indeed, if the divergence had been “well known” to the public, there’d have been no need to truncate the data and replace it with the instrument record — no need to “hide the decline”. Hence, the decision to replace some data and not divulge that fact to those who viewed the graph.
Gavin, of course, knows full well the public is not educated on this issue. He is simply engaging in his own deception in an attempt to whitewash Mann, Jones and Briffa’s deception.
“Settled science”? Hardly
But there is still more.
28 comments:
This obviously casts down on the meaningfulness of the long, relatively flat handle of the “hockey stick” graphs — after all, if the trees failed to respond to the warming of the 20th century, how can we know they didn’t similarly fail to respond to something like the medieval warm period?
This seems to be the crux of your point about tidiness -- how can we rely on tree ring samples as proxy temperatures over the millennium if we can't rely on them over the past 50 years?
But Tom already addressed that in a still unanswered comment on your blog over a week ago:
"And there is other research that shows that the divergence of greatest concern (that identified by Briffa et al in 1998) is unique to recent history, which in turn implies that the fluctuation in sensitivity to temperature among certain northern hemisphere trees is itself of anthropogenic cause."
Thanks, Seth. I wish Rick would look to the primary literature rather than relying on McIntyre's dubious assessments. My (unanswered) comment you linked to is based on what I found in that primary literature. If I'm capable of understanding it, then I'm certain Rick would be too.
Seth
First, it is not unacknowledged. I have repeatedly said that the tree ring data matched temperature records for the first part of the period for which measured temperatures exist. That is given since variations in tree ring density had to be calibrated to temperature.
To say that the divergence is unigue in recent history is to say very little. Recent history is a bit over 100 years. All it means is that there was a statistically significant correlation between tree ring density and measured temperatures for 80 years ago and not for the next 30 years or so. To take the 80 year relationship and then use it to reconstruct temperatures over a 2000 year period is something of a speculative enterprise. The fact of the matter is that "other research" can't possibly show us that tree ring density matched temperature in the medieval warm periond because we have no record of the temperatures then.
Maybe the other 1900 years were like the earlier portion of the recorded era and maybe they were like the latter period.
I understand that the Team wants to argue for the latter. But to say that the fact that the divergence that calls into question the use of tree ring density to infer long term anthoprogenic cause must be of anthropognic cause is to assume the conclusion. It is to say that we think there is anthropogenic cause so any fact that complicates our story must itself be of anthropogenic cause.
Now, to be fair, they can offer other reasons to believe that is so and point to other reconstructions and that's where debate can take place. But debate is precisely what they did not want.
I know what's in the primary literature (and I don't know that McIntyre and the others deserve to be excluded from it), but, with respect to the case for catastrophic global warming, it often fails to bear scrutiny. When you raise questions, you get exactly what I've gotten here - the repition of an ipse dixit that is claimed to have some unimpeachable imprimatur of authority (its in what we have decided is the primary literature.)
But the "unanswered" point is meaningless. That the divergence is unique in recent history is not the explanation, it's the problem that requires an explanation.
Well, I'm not done but I have both acknowledged the substance of the point and responded to it.
What I have said is that the tree ring data correponded to temperature for the first 80 or so years of the period for which we have recorded temperature. That is obviously so. The tree ring data was calibrated to the temperature and if there wasn't some way to state a statistically significant correlation, we'd have no reconstruction.
But then the correlation breaks down for the next thirty years or so. I guess it's right to say that is "unique" in recent history, but, given that recent history for these purposes is a bit over 100 years and we are trying to reconstruct temperatures for a period of over 1000 years, it's not very reassuring.
How do we know that, for the 1400 years or so for which we have no temperature data, the relationship between tree ring density and temperature is like the first 80 years of "recent history" or the last 30?
To say that the divergence must have an anthropogenic cause because it is more recent than the period in which the data correlated is to assume one's conclusion. It is to say that we suspect an anthropogenic cause so the potentially fatal anomalies in the data that we are using to support an anthropogenic cause must themselves have an anthropogenic cause.
That's rather weak. It may be that the divergence can be explained away but it needs to be discussed outside of a small circle of the committed. Trying to hide it from policymakers was shameful.
I know what's in the "primary" literature although I don't pretend to be an expert or to even understand all of the intricacies of these matters. But I am an expert in translating complex things in a way that ordinarily intelligent people can understand (its called a litigator) and there are, with respect to the more aggressive views of global warming, numerous problems that no one on the Team seems to be able to answer. Or even want to. But more on that later.
As for the fact that there are more papers than this reconstruction by Briffa, that is undoubtedly so. But I am not about to read 107 tree ring papers and I don't think Tom is either. Policy makers are generally being asked to act on the basis of a small number of reconstructions. If there were 106 tree ring reconstructions that solved the divergence problem, there would have been no need to use Briffa reconstruction and make the bad part go away.
Ultimately, I think the problem here is that there is literally no way to reconstruct 1500 years of global temperature data. The best we can say is that we know that the world - or at least parts of it - used to be much warmer than today. We had picnics in Greenland and Cabernet in Surrey. The it got colder and now its getting warmer. Is it warmer today than it was 1300 years ago? I don't think we really have a clue.
I already mapped out a response to your first comment, so I'll focus on that since the second doesn't seem to present any new information (except that you don't want to read the studies, yet you're an expert at translating them).
I have repeatedly said that the tree ring data matched temperature records for the first part of the period for which measured temperatures exist.
That wasn't the unanswered part. The unanswered part is that there's a scientific, research-based explanation for the divergence -- the 'decline' in tree ring proxy reliability -- which you haven't addressed, at least until this comment.
So, let's take a look...
To take the 80 year relationship and then use it to reconstruct temperatures over a 2000 year period is something of a speculative enterprise.
By necessity, not preference or convenience. You claim at the end of the second paragraph that we "don't have a clue," but that's just not true -- we do have a clue, a scientific research-based clue. And it's not like tree ring measurements are the only proxies we have. Banded corals, ice cores, and lake sediments are also cited by the WMO brochure you link to in your previous post as proxy measurements that contribute to our understanding of climate prior to the days of the thermometer, and those studies all correlate to the graph that was used in the brochure, in addition to the measurements taken in the first decades that we do have measured temperatures. Where the divergence comes is over the last 50 years, or so, for the tree ring studies, which is explained through further research as being, as Tom pointed out, of anthropogenic cause.
Which brings us to...
But to say that the fact that the divergence that calls into question the use of tree ring density to infer long term anthoprogenic cause must be of anthropognic cause is to assume the conclusion.
No, it's providing a scientific research-based explanation for the question of why the divergence for tree ring samples at that point 50 years ago, as opposed to the other proxy measures.
Now, to be fair, they can offer other reasons to believe that is so and point to other reconstructions and that's where debate can take place. But debate is precisely what they did not want.
All debate isn't created equal. Debating a primary research-based point with primary research is one thing, and something none of those scientists feared; doing it with a partisan/ideological pre-disposition is another.
Perhaps the scientists in the emails shouldn't have worried about the latter, but -- even if that's the case -- their mistake was in presentation, not that their conclusions couldn't be justified by even the smallest of details. You want to use that decision on presentation to indict the whole process, including the scientific evidence that was at the foundation of it, but, in this case, a puff of smoke just isn't leading to fire.
I know what's in the primary literature (and I don't know that McIntyre and the others deserve to be excluded from it)
This relates to the point above about all debate not being equal. It's not that McIntyre is excluded from primary research debate because of what he's saying, but rather because he hasn't done any primary research.
its in what we have decided is the primary literature.
What is primary scientific research isn't a relative question. What is primary scientific research is clear, and, yes, in debates on scientific questions, it trumps generic commentary that uses bits of the primary research to dismiss the primary research as a whole.
Rick, have you read the TAR Chapter 2?
there's a scientific, research-based explanation for the divergence -- the 'decline' in tree ring proxy reliability --
Isn't that circular? The decline in reliability is the divergence. The lack of correlation is what requires an explanation.
Sure there are other ways of reconstructing but they both require the same kind od extrapolation from very limited data. Of course, its by necessity. That doesn't make it less difficult and potentially speculative.
Yes, there is primary and nonprimary sources but you have to admit that it becomes hard to limit that to peer review literature when you have people fighting tooth and nail ot keep contrary views out of the literature.
Yes, I have seen it. What is your point? It doesn't overwhelm me on the points that we are discussing here. And the IPCC process iteslef isn't looking very good right about now.
What is my point? Well, aren't the e-mails you have McIntyre examining here related to the assembly of the IPCC Third Assessment Report, Chapter 2?
Isn't that circular?
Nope. From the late 19th century, when thermometers started being used to measure actual temperatures, those actual temperatures tracked with proxy data from tree ring measurements (in addition to other proxy data). In the second half of the 20th century, however, the tree ring proxy data started to diverge from actual measured temperatures, while other proxy data samples did not.
So, the question became, why did tree ring proxy data start to diverge starting in the second half of the 20th century? Research was done on that question, and its conclusions point to anthropogenic causes, such as pollution.
Seth:
You said "So, the question became, why did tree ring proxy data start to diverge starting in the second half of the 20th century?"
Doesn't the article you link to say "Just why tree rings no longer provide useful proxy data for temperatures is not known."
I wrote: "Research was done on that question, and its conclusions point to anthropogenic causes, such as pollution."
The full quote from my link: "Just why tree rings no longer provide useful proxy data for temperatures is not known. There are several theories, many of which suggest that climate change itself is the problem. Trees no longer grow as they once did before the climate started changing so rapidly. But the point is, there is no question that tree-ring growth rates of the past -- before we had thermometers -- can serve as useful proxies for historical temperature data. They are much less useful now, but that doesn't matter so much because we have actual temperature records. All of this was sorted out back in 1998. It's not new, nor even particularly interesting, to anyone familiar with the science."
So, not known or confirmed, but research points in that direction. And, as the quote continues, the overall point is that, while the tree ring samples are less reliable now, they are also less needed as a result of actual temperature measurements.
Beyond that, even, if anyone wants to cling to the proposition that tree ring samples were never accurate measures of climate, there's other proxy data for historical climate measurements.
And, even further, as this post by climatologist Stefan Rahmstorf explains, even if one chooses to toss out all of the proxy measures of paleoclimatology, the whole "hockey stick," the science concerning the existence of AGW would not change a bit since 20th century data is where that argument exists, that human-made greenhouse gases are warming the earth at a rate outlined as dangerous by the IPCC. As Rahmstorf concludes, "The discussions about the past millennium are not discussions about whether humans are changing climate" (emphasis his).
Seth
If you can't see the circularity and the weaknesses in your argument, I am not sure what I can do to help you. Taking the tree ring data on its own, there is no reason to believe that within a period from, say, 600 - 2000, an observed correlation from between roughly 1860-1960 is valid and an observed absence of correlation between 1960 and 1990 is not. Other proxy measures may not have such a divergence (although the validity of those is another matter entirely), but given the absence of a lengthier period of observed temperature, they cannot be much more robust.
And that is significant. To say that we have potentially catastrophic AGW based on a bit ove 100 years of recorded data is simply not possible. Apart from the short period of time, we know that there have been significant fluctations in the climate so the mere fact of change does not tell us that much. The best we can say is that we may have AGW (I might even say probably) and there is a very small possibility that it will be catastrophic (because it would have to prove to be nonlinear and relatively impervious to countervailing tendencies and ordinary technological advances to be so). This certainly argues against indifference. It certainly does not support the Chicken Little throwing out of the baby and the bath water that Al Gore and others both want (and, at least in Gore's case) would reap enormous profits for those who bet green while they use the coercive power of government to fix the game. We have no idea whether we could reduce emissions by the targets called for by the Obama administration or "greener" negotiators. It is irresponsible to pretend that we do and far from certain that, even if we could, the benefits would outweigh the cost.
IT
They are and that is not exactly supportive of the report. But, in the absence of something more specific, I still don't know what you're driving at. I can't read minds.
Hey did you catch this, from the author of the piece in the Mail On Sunday (filled with little more than quotations from McIntyre and McIntyre acolytes) the McIntyre crowd has gone swooning for the moon over:
"I am honoured by the kind comments on my article. For the record: without Steve’s brilliant work and this magnificent website, it could not have been written. May I also pay tribute to Ross McKitrick, who gave me several hours of his time on Thursday and helped clarify the issues in my mind.
"I am not a scientist, but an open minded investigative journalist. I have not written on climate before."
Oh brother.
But, in the absence of something more specific, I still don't know what you're driving at. I can't read minds.
What I'm driving at is whether you've read it, that's all. Because if you've read it, maybe we might have a better idea how the report "misrepresented" data, rather than what McIntyre says.
Because I've read all this McIntyre business already.
You know, I had a bit worked out where I mocked the patronization you expressed to open your last comment, Rick. But I'm going to leave that aside for the sake of moving forward.
And here's why: "This certainly argues against indifference."
Now that's something we can work with, leading us to this: "We have no idea whether we could reduce emissions by the targets called for by the Obama administration or 'greener' negotiators. It is irresponsible to pretend that we do and far from certain that, even if we could, the benefits would outweigh the cost."
Actually, the 17% reduction from 2005 base levels by 2020 -- which is the Obama proposal, mirroring the Waxman-Markley bill that passed the House this summer and the one to be taken up by the Senate next spring -- is fairly widely considered to be a moderate position, coming in under the 20% of 1990 levels (representing a deeper cut than the 2005 levels being used as the baseline by the US) already pledged by the EU and the 30% being sought by the UK (scientists are calling for 25-40% cuts to hold global temperature increases at the important level of 2 degrees Celsius per year). More here.
But the real key will be reaching agreements with other nations, particularly developing ones. That's the big reason Obama is going to Copenhagen and why he made the 17% announcement in advance of the trip, to help leverage an agreement. Besides, if those agreements aren't in place, there's a shot any treaty the US signs in Copenhagen won't get the 2/3 necessary in the Congress to ratify, just like with Kyoto.
Seth:
Your assertion was that "Research was done on that question, and its conclusions point to anthropogenic causes, such as pollution."
In support of this you quote the linked article, "There are several theories, many of which suggest that climate change itself is the problem."
How does a theory suggesting something equate with research concluding something? The linked article's saying "not known" indicates the opposite.
Hi Rick. Have you supported this yet:
Combining two different measurements and pretending they are the same thing and mischaracterizing what data show has not been limited to tree ring data.
Let's break it down:
1) Combining two different measurements.
Nobody has disputed this. In fact, many more than two different measurements have been combined.
This is something you've never addressed, by the way: the reconstructions you're criticizing are not based exclusively on tree ring records (and there are many separate tree ring records).
All of the individual proxy sources that are used as a basis for the charts in the IPCC Third Assessment Report (as you've apparently moved on from the cover of the World Meteorological Organization brochure) are calibrated against what the authors separate into high- and coarser-resolution proxy indicators.
I don't know whether McIntyre -- which is where you seem to be getting nearly all of your information -- has discussed or even acknowledged this fact.
2) Pretending they are the same thing
Have you given an example of this yet? I haven't found one.
3) Mischaracterizing what data show
See 2) above.
4) Has not been limited to tree ring data.
I think this is a reference to something Al Gore said, so it's irrelevant here.
So: Can you point us specifically for your evidence in support of 2) and 3)?
By the way, feel free to cite the primary literature, as you've told us you know what's in it and, as a litigator, are expert in explaining it to us laypepeople.
I'm perfectly prepared to read 107 papers, if you'd care to cite any or all of them.
Many thanks.
Laypeople, also.
How does a theory suggesting something equate with research concluding something?
A research study can conclude by pointing to something, rather than knowing something. In fact, most scientific research does.
As evidence, here's research that points to anthropogenic causes (specifically, pollution) for the change in reaction of trees to climate.
And, as I pointed out in the part of my comment you ignored, if anyone wants to cling to the proposition that tree ring samples were never accurate measures of climate, there's other proxy data for historical climate measurements. Further, even if one chooses to toss out all of the proxy measures of paleoclimatology, the whole long stick of the "hockey stick," the science concerning the existence of AGW would not change a bit since 20th century data is where that argument exists, that human-made greenhouse gases are warming the earth at a rate outlined as dangerous by the IPCC.
Mr. Berres, see Cook et al, 2004a, Briffa et al 1998a, 1998b, and 2004, Tevini, 1994, Abakumova et al, 1996, Gilgen et al, 1998, Stanhill and Cohen, 2001, Russak, 1990, Liepert, 2002, Cohen et al, 2004, Liepert et al, 2004 ...
Of course they may all be "advocating" for varying positions. That wouldn't be political advocacy, as Prof. Esenberg suggests above, but rather scientific advocacy, which is something that takes place among scientists every day of the week, not only in e-mails and meetings in Tanzania, but in the literature as well, which is where most of their advocacy takes place.
And, speaking of circular arguments, or arguments that assume their own conclusions:
Me: Rick, have you read the TAR Chapter 2?
Rick: I have seen it. ... the IPCC process itself isn't looking very good right about now.
Seth, what then was the significance of the characterization "not known" in the article you linked to? It's not usually synonymous to Mr. Foley's "implies" or your "suggests" or "points to". I assume that wouldn't be your interpretation if someone were to assert that the cause of global warming is not known.
Mr. Foley, if the sources you cite are, as you say, "'advocating' for varying positions", that sounds inconclusive, or "not known".
what then was the significance of the characterization "not known" in the article you linked to? It's not usually synonymous to Mr. Foley's "implies" or your "suggests" or "points to".
It doesn't need to be synonymous. The bar you're trying to drive at is whether they are contradictory statements, and they're not.
Prior to something being known, it's entirely plausible -- and in pretty much all scientific cases -- to have it suggested or pointed to.
The phenomenon we're talking about, declining tree ring sensitivity to climate, is relatively new -- about 30-40 years, and it's only been directly studied in the past 20 years, or so. Research that has been done on various samples, as Tom and I have cited, points to anthropogenic causes for the phenomenon.
In other words, that research isn't conclusive, the cause isn't known, but it points to and suggests the cause is anthropogenic.
AGW is further along in the scientific process in the sense that it's been identified in studies for over 100 years, and its existence is based on long established scientific principles. As the climatologist Rahmstorf explains:
The main reason for concern about anthropogenic climate change is not that we can already see it (although we can). The main reason is twofold.
(1) Carbon dioxide and other greenhouse gases are increasing rapidly in the atmosphere due to human activity. This is a measured fact not even disputed by staunch “climate skeptics”.
(2) Any increase in carbon dioxide and other greenhouse gases will change the radiation balance of the Earth and increase surface temperatures. This is basic and undisputed physics that has been known for over a hundred years.
Conclusions are not the same as proof. All science is a tentative endeavor. Nevertheless, what McIntyre and friends are doing is picking at some very specific premises underlying some of the reasoning in selected papers.
Which is a perfectly legitimate line of attack. But even then, destroying the premise upon which a conclusion is based needs to be taken in context.
For example, if McIntyre found that Briffa deliberately selected among the density and width of growth indicators in individual trees on the Yamal peninsula and discarded others in order to make his conclusions appear more dramatic than they really are, then good for McIntyre.
But if there are hundreds of other studies relying on data independent from Briffa's that support Briffa's conclusion in that particular instance -- and there are -- then McIntyre's criticisms say nothing about them.
Seth, you're a gentleman and a scholar with the patience of Job.
A pithier solution to the "not known paradox" might be: We know for damn sure it wasn't caused by falling temperatures.
Seth: You wrote "Prior to something being known, it's entirely plausible -- and in pretty much all scientific cases -- to have it suggested or pointed to."
The example cited at the Grist site you link to is Newton's and Einstein's theories. That is an example of anamolies suggesting or pointing to insufficiency of the existing theory, not what the next accepted explanation is likely to be.
You indicate there are a variety of proposed explanations for the divergence, these have anthropogenic cause as a common element, and there is some support for each in research that has been conducted. You are not explaining how this shows that an ultimately accepted explanation will probably be one of these hypotheses or some other involving an anthropogenic cause.
Tom
When you graft actual measures on to a a line that consists of proxy measures, you are implying that two different things are the same.
It might not be so bad if you clearly alerted the reader to the fact that this is what you did, but that wasn't done.
Seth
It is fine to argue that the lack of correlation over the second third or so of the instrumental period is due to increased temperature or pollution. But if you think that the tree ring construction is worth showing policy makers, then you ought to clearly show them when the correlation ends and why you think that's not important.
Tom again
The failure to do this was a weakness in the the IPCC report and the reason that it is important is that it illustrates what I think is the rather speculative nature of reconstruction of thousands of years of temperatures based on a bit over 100 years of imperfect proxies.
Seth again
There is certainly data showing warming over the period with which we have measurments. I don't dispute that. I am not convinced by the claim that the data is corrupted (although there may be legitimate issues that ought not be treated as heresies) and I am not convinced by the claim that warming has "stopped." (We couldn't possibly know that yet and it seems to depend on how you slice the data.)
But then we get into the question of how reasonable it is to believe that AGW is an existential threat and what is to be done about it. The Gorean/Copenhagen claim that the sky is on fire and we are all about to burn to a crisp is unhelpful on that.
You are not explaining how this shows that an ultimately accepted explanation will probably be one of these hypotheses or some other involving an anthropogenic cause.
What I'm not explaining is how all of the studies Tom and I are citing are probably correct?
Let's take a trip down comment thread lane...
This initially came up after Rick approvingly cited a comment that attempted to use the decreased sensitivity of trees to climate change in the second half of the 20th century to call into question the accuracy of paleoclimatology findings as a whole (which, as a side-note, aren't based on tree ring proxy data alone). I, in turn, cited a comment by Tom that research into the phenomenon has pointed to anthropogenic causes for the decreased sensitivity of trees to climate in the last 40-50 years, thereby undercutting the claim cited by Rick that a similar phenomenon could've taken place in the medieval warm period.
Now that Tom and I have backed-up our contentions by citing studies, perhaps the next question should go to Rick -- or you -- to explain why a hypothesis w/ no research backing it up is somehow trumps a hypothesis w/ cited research, even if the conclusions of that research aren't themselves conclusive.
But, if you really want to know why I think the research I cited is correct, it's because, 1) it explains why tree ring proxy data tracked with measured temperatures for decades before only diverging in the second part of the 20th century, 2) it serves to explain why tree ring samples are the only proxy data to diverge in the middle part of the 20th century, 3) there's no evidence suggesting tree ring proxy data didn't track with other proxy data in the historical projections, and 4) there isn't any research that's pointed to solely natural causes for the divergence.
So, back to my question. Why do you think the comment cited by Rick, which implied solely natural causes explain the divergence, is probably correct? Or is it not as important for the position you're inclined to support to provide any evidence, let alone the conclusive kind?
The Gorean/Copenhagen claim that the sky is on fire and we are all about to burn to a crisp is unhelpful on that.
Rick, that's simply not happening by the major players -- those involved in actual negotiations -- in Copenhagen. In fact, the emissions cuts being discussed have ultimate goals set 70+ years into the future, hardly the sign of negotiations based on fear that the sky is on fire. But feel free to continue to use people like Gore, who aren't actually empowered in any negotiations, as a proxy that allows you to demean and denounce the process as a whole.
Did someone mention "Russia"?
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