Another interesting set of emails from the University of Arizona release. These ones date back to 2001, eight or nine months after the publication of the Third Assessment Report. The thread starts on 7 September, just days before 9/11, and reference is made to those attacks in the thread.
The emails show how the Hockey Team came together to attempt to thwart criticism of their field from a German geological institute. The message is from Stefan Rahmstorf to Overpeck:
Subject: Sceptics attack! [Title inferred from later emails in thread]
I thought the subject line might capture your attention ... but seriously, we're facing a concerted action here at the moment, a German geological institute has launched a well-orchestrated challenge to IPCC including a book launch, cover articles in major newspapers, a simultaneous official request in the Bundestag, etc. They have the coal industry on their side. Not surprising to you in the US I'm sure but a novelty for germany, where so far the sceptics had no ground to stand on.
The gist: IPCC is dominated by modelers and neo-climatologists; paleo-climatologists were marginalised; if you look at the paleoclimatic facts you come to opposite conclusions from the scare-mongering modelers, namely that C02 plays a minor role for climate and solar variability dominates everything.
I need to draft a response for the government and remember our Venice meeting - didn't you plan some kind of resolution, emphasising that paleo-records point at the 20th Century being extremely unusual, and emphasising that many records are threatened due to glaciers vanishing? Does this resolution exist, so I can quote it as an example of internationally leading paleoclimatologists supporting IPCC conclusions? In my response I want to argue that these guys from the Bundesanstalt fur Geowissenschaften do not represent paleoclimatology, but rather are completely marginal in the paleoclimatology community. (Or have you heard much of them? The most prominent guy is Ulrich Berner.)
Specifically, they challenge Mann et al. data based on the argument that tree rings are unreliable for long-term trends. They claim that icecore records show climate shifts within the past 2,000 years that are much larger than what happened in the 20th C. Any ideas how to counter this? I thought that a catchy example that politicians might understand is Lonnie's problems with vanishing ice on Kilimandjaro. What other clear examples do we have for the 20th C being beyond normal variability? Hope that now before your baby is there you might still have a few minutes to give me some advice.
Overpeck responds, copying the rest of the Hockey Team, whose contributions appear later in the thread:
Hi Stefan (and other friends of coal companies) - urn, this does sound familiar, and the only good thing about this kind of attack is that it forces us to be really clear about what we know and don't know. In the US, that has meant refuting the biased attacks on the various paleo proxy-based records (e.g., Mann et all, at the same time working to improve what we know about the same proxies. Unfortunately, we don't know anything for sure, but that's science. We do know that lots of the attacks are biased and poorly justified.
We never got around to doing any PAGES/CLIVAR resolution - the WG support one way or the other was not strong, so it was easier not to do anything. Of course, you make a good case why we should have tried harder. But that's behind us. It might be possible for us to do it now - IF we had a hero to lead the effort - right now, I'm maxed out (but would be happy to help).
I've cc'd your msg to a host of colleagues who have been in this debate for some time over here. Some on the list are on the PAGES/CLIVAR working group - now smaller and more focused thanks to CLIVAR's pushing. But, for a paleo "resolution" to be drafted, I think we'd want at least this group - some "neo" guys, but also so card-carrying dirt-digging paleo guys. We could easily get more.
But we need a hero - probably from this group - to take the lead. I'm hoping Mike Mann might be that person. He's on the pic working group, knows the issues as well as (understatement) anyone, and seems to be the most productive person this side of the mid-Atlantic ridge. But, as you say, we'd need good buy in from more traditional paleo folk - e.g., dendro, borehole, ice-core, coral, sediments.
What do you all think?
Does this make sense Jean-Claude and Keith? (I can't speak for pic alone) .
This elicits a response from Henry Pollack, a borehole expert:
Hello Stefan and others,
While there are differences that remain between the northern hemisphere temperature reconstructions that emerge from the borehole temperatures versus those that derive from the multi-proxies, both techniques tell essentially the same story for the 20th century: it has been a century of rapid warming, both in the magnitude and rate of warming. The boreholes and the multiproxies independently say that it has been the warmest and the most rapidly warming century of the past five and past ten centuries, respectively.
Skeptics have a very difficult time sidestepping these fundamental observations about the 20th century. The boreholes, however, suggest that the 20th century warming is an acceleration of warming that began earlier, whereas the multiproxies show a long slow cooling prior to the 20th century warming. I am among those who have wondered whether the dendroclimatologic data has fully retained the long borehole thing. period people variability of the climate signal. Were it only the who are in need of persuasion here, it would be one But this perspective is shared to varying degrees by others in the paleoclimate community, and I do not think it is a dead issue.
I have not been persuaded by Mike's arguments to the effect that the long term cooling trend prior to the 20th century warming can be seen in the other proxies independently of the dendro data. This is not the place to argue that point, but I concur with Peck that we must be really clear about what we know with high confidence, and what issues still have some scientific play associated with them. To that end, I repeat my opening statement recommending that we continue to emphasize the strong 20th century agreement between the instrumental record, the borehole record, the multi-proxies, and a host of other indirect indications that the 20th century was a very unusual century. Add to that the strong correlation of the 20th century surface temperature history with the radiative forcing history (but only if the anthropogenic forcings are included), and you essentially make the IPCC case. The disagreements that we may have amongst ourselves are small compared to that common view of the 20th century.
To address some of Stefan's particular questions: That there is evidence that natural forcings played a central role in climate prior to when humans became big influences on climate is no surprise. But the question is not whether the sun has played an important role in the climate system thousands of year ago. The question is whether it is the central player in the 20th century. All efforts to model 20th century climate using only natural forcings have failed. Anthropogenic forcings are a necessary and increasingly important ingredient in reproducing the global temperature over the 20th century with climate models. As for the argument that C02 plays a minor role in climate, one can simply point to the Vostok and Grip cores which show strong correlations of C02, CH4 and temperature. If nothing else these observations argue for strong coupling between the carbon cycle and temperature. The "lead or lag" arguments sometimes put out are to my mind irrelevant; the essential point is that when one changes, the other does too. In the 20th century it is the C02 that is driving, and temperature is tracking closely. Not even the skeptics argue with the observation that anthropogenic greenhouse gases increased dramatically in the 20th century. As for the past 2000 years, I don't know which cores they are referring to, and Lonnie is the obvious person to help with the details. But if it is the Greeenland cores the German skeptics are emphasizing, one can point out that what happens locally in Greenland does not necessarily paint a global picture. It may be a good indicator for the North Atlantic, but is it a representative record for the entire hemisphere or globe? This is one argument frequently used in addressing the question of whether the Medieval Warm Period or the Little Ice Age were global or regional events. A hemispheric or global picture requires hemispheric or global data. In summary, my experience with the skeptics (and I have had quite a bit) leads me to recommend that you turn the argument back to the 20th century at every possible opportunity. They always want to exploit the uncertainties of the past, whereas the more current information is more strongly based on instrumental observations, is much more diverse, and much more geographically widespread.
Cheers, Henry Pollack
I have to run off to teach but will reply a bit later on.
As Peck mentions, there are still some legitimate uncertainties in what we do, and we're all working to address that and introduce the appropriate caveats in our current conclusions. If that's what this was all about, there would be no problem. Unfortunately, the skeptics aren't interested in a balanced or honest discussion, but rather in delivering a one-sided and deeply flawed attack that disinforms a relatively ignorant the lay public who is their target ... There are a few key points that address the most serious flaws in their line of reasoning and attack. Got to run, but will outline these in an email later on this afternoon.
Thanks for getting in touch w/ us about this. More in a bit,
I think such a resolution is a good medium-term idea, but not the solution to my short-term problem - I need to write a few sentences over the weekend basically, and will be grateful for any suggestions. Is it true that the Mann et al. compilation shows similar unusual warming in the last hundred years even with the tree data not included? (I apologise to Mike for only vaguely remembering his talks about this, I'm afraid I didn't take notes.) That would be an important point, as the written sceptics statement that I'm trying to refute speficically attacks the tree ring data.
Dear Stefan (and others) :
Here are two typical related erroneous claims by the skeptics, and appropriate responses:
l) "Proxies such as that used by MBH (Mann/Bradley/Hughes) don't show late 20th warming"
The warming trend in the proxy-reconstructed Northern Hemisphere temperature reconstruction closely matches that in the actual 20th century Northern Hemisphere temperature series, with no evidence of any significant trend in the residuals. The calibration interval terminates in 1980 because relatively few proxy records extend into the most recent decades a (many terminate in the 1970s and early 1980s) . It is thus a deliberately misleading statement to say that the reconstruction "doesn't reproduce the post 1980 warming". We don't attempt to reconstruct the post 1980 warming w/ the network at hand.
The skeptics often confuse this (intentionally?) with a largely independent observation (Briffa et aI, 1998; see also followup by Vaganov, Hughes et all of a decline in the strength of the relationship between certain types of (mostly high latitude) tree ring density records and temperature in the latter 20th century. This decline is largeey evident in only tree ring latewood density and not annual ring width data (very few of the former are used by MBH), and only appears to be a problem in the most recent decades.
2) "Problems w/ tree-ring data compromise the reliability of MBH (Mann/Bradley/Hughes)
It is indeed the case (as you correctly recall) that we have shown that our reconstruction of the century-scale trends over the past few centuries is robust to the inclusion/disclusion of tree ring data from our proxy network (there is enough coral, ice core, and long historical data to attempt a multiproxy reconstruction wlout tree ring data over the past few centuries--such a comparison shows that the basic trends are not sensitive to using tree ring data anyways. This is shown in the following article:
Mann, M.E., Gille, E., Bradley, R.S., Hughes, M.K., Overpeck, J.T., Keimig, F.T., Gross, W., Global Temperature Patterns in Past Centuries: An interactive presentation, Earth Interactions, 4-4, 1-29, 2000.
which is available electronically here: http://www.ngdc.noaa.gov/paleo/ei/ei cover.html
In this regard, I must take some exception to one of the statements in Henry's otherwise very informative and helpful email (which I just received now as I was ready to send this out!). We *have* shown in the above peer-reviewed manuscript (of which Peck is, incidentally, a co-author) that the basic trends in our Northern Hemisphere temperature reconstruction are insensitive to whether or not tree ring data are used at all In fact, in unpublished work (hopefully soon to be published) we believe we show reasonably convincingly that a reconstruction using borehole data (based an alternative approach from that used by Henry which makes use of spatial covariance information and explicit calibration) yields again more or less the same trend! But, I agree with Henry, this is not the place for that particular deba te ...
I hope the above is helpful. Please let me know if I can be of further help.
I agree with you that we need to take position. This implies writing some scientific paper and obviously we need a hero to push it, M. Mann could be the right guy, together with people from corals, ice core, etc ..
As editor of CLIMATE DYNAMICS, a journal which is well read on both sides of the Atlantic, and in particular in Europe with the EGS support,I suggest this review being submitted to CLIMATE DYNAMICS. Obviously, it will experience a large review process, but I could ensure to sped it up. Then it would be nice to have it printed and published in Germany. I think that a review in an international journal would have more impact than any grey literature coming out as IGBP report.
The currents events transpiring in the U.S. make this all seem so trivial in comparison, but a few comments:
I'm flattered by Peck and Jean-Claude's support for me to head this particular effort ... However, I'm not sure if this is likely to be most effective. The problem is that I in particular have been the focal point of many of the ad hominem attacks by the skeptics, even though it is clear that the basic message the skeptics don't like (ie, that recent temperatures are unprecedented at the hemispheric/global level over the past several centuries/millennium) follows from many of our efforts.
The "skeptics" (as Malcolm points out, we need a new word for them--suggestions?) like to single me out (e.g., the "Mann reconstruction", etc.), as if my work is isolated from my collaborators and other colleagues doing similar work (Tom, Phil, Keith, Ed, Henry, etc.). I think this effort would be more successful if a few of our more august senior colleagues were to lead this sort of effort. I know that Ray and Henry have been particularly active in trying to counter act "skeptic" disinformation campaigns here in the states. I think Peck, Tom, and Phil would be very helpful here too. It isn't just the paleo record but the observational surface temperature record which is often under attack. I think that anything that we right had to have broad uthorship and representation . ..
I'm happy to help out, but I think its actually best if I'm not seen as the "leader" of the effort,
I agree that a high profile peer reviewed publication rather than grey literature is best. It may be that (some) of the worries that Mike expresses could be alleviated by having the pUblication somehow appear as an 'official' CLIVAR/PAGES product, thereby removing some of the with any particular author's perceived personal agenda and distinguishing this from a review paper coming from an individual or small group of collaborators.
Should a leader nominate him/herself, and should a group of people (such as the email recipients of these emails or a similar one) wish to collaborate on such a paper oriented around debating the points of the un-skeptical greenhouse deniers as an official CLIVAR/PAGES product, I am confident that PAGES would be able to support this effort both in name and with a ( small amount) of funding should it be required. I guess that CLIVAR would also be supportive.
Note that the recently published PAGES glossy brochure "Environmental Variability and Climate Change" which serves as the executive summary of our (in prep) synthesis book, is in part oriented around discussing a series of questions often raised by these deniers (if you have not received a copy yet please request it). The glossy is of course aimed at a much different audience than a paper in the peer reviewed literature would be.
I've been bogged down with meetings and proposal writings to respond sooner, and today doesn't seem appropriate but here goes.
Mike raised the issue of the observational record and with this no matter what I write or say will alter the skeptic view. CRU has had several emails thanking us for the information pages on our web site urging us to do more to counter the view. Questions I get at talks on the surface record generally cite the satellite record as showing no warming. I have a prepared answer, which I think is good, but in Britain at least there is a partial belief that scientists (and governments for some) are not to be believed (because of CJD, foot and mouth, nuclear research etc) area the view permeates and Even though we are working in a different we get tarred with the same brush. Responding to people who say we are the greenhouse industry and we say what we say to get more grants is difficult. If only they knew how difficult is to get some grants Mike and a few of you may have been on a skeptic email list. I was until recently and it has taken me about a month to get off. I used to respond and possibly changed a few minds - noticing that when I got these emails they were to me personally and not to the group. When I responded the issues changed and a month or two later it was back to the first issue again. It was just self defeating and time wasting. I've left it Mike MacCracken and a few others to keep replying but he's probably realising it is a lost cause.
As a result of the responses I am working on a paper (not really started) with Dave Easterling at NCDC on the surface record pointing to a few facts about the surface record - Russia is warming, getting lake/river freeze dates and the like. Lonnie writing something about the demise of tropical ice caps - great talk last time we met, by the way - would be useful. Maybe it's done, but the literature is enormous now. My big hope is a paper I know is being written with a new MSU2 series, with different corrections.
The new series shows more warming, but it means the sonde record is wrong. Obviously it is important for the authors to get it right (with Christy and Spencer as reviewers) but it all relates (for the MSU and the sondes) to diurnal cycles not being correctly accounted One point the skeptics have been getting at me about is this - briefly to illustrate their lack of logic. Christy et al have a paper in GRL (VoI28, 183-186) which shows that since 1979 air temperatures measured by ships and buoys in the tropics (mainly Pacific) have not warmed as much as SSTs. I was asked by several of the skeptics when I would be taking this into account in the gridded data. When I said I wouldn't because of the assumptions I make (these are that SST is a surrogate for air temperature) I was slammed on the email list. I said I would need to have the corrections to apply spatially and by month and it was just the tropics (20N-20S, OK a large part of the Earth's surface).
I do know that a paper will be submitted soon that shows that SSTs in the South Pacific agree better with island air temperatures than marine temperatures (MATs). Also the paper will show that MATs in the Pacific are being affected by the now dominance of larger container ships as we don't get access to Korean, Japanese and Taiwanese fishing fleet data until decades later.
So, to writing a paper. I have written a review in Reviews of Geophysics in 1999 and there was a Science paper (with Keith and Tim) in April 2001. Both were high profile, yet seem to have little effect. They are well cited but they haven't changed any skeptics. In my opinion the satellite record is the key to all this. The millennial record got attention because it was one more thing that needed to be explained away by the skeptics, take away the satellite record and they will melt away like the tropical ice caps.
Mike is right that he isn't right person. They'll just say he got all his pals to agree that his curve is right. Whether anyone else would be better is doubtful. Mike has experienced most of the verbal and web-site attacks, but there isn't much between the curves I've produced, or Keith, Tom and now Ed. Basically the LIA wasn't as cold or the as warm as people believed and we are warmer now that we've been for a millennium. What the temperatures were in the 10th century may be an issue but this wasn't in the last millennium. My belief is that another paper, even with a CLIVAR/PAGES product name, will do little good to allay the skeptical view. It would be good to work together but to it won't achieve the
particular aim. The vital piece of evidence that will be listened is the tropical ice caps - if they are not producing layers now and have nice medieval layers, this is pretty damning. Knowing why it is happening is something else. The scanty local records near the ice caps, don't show enough warming, but the ice is clearly going, even if the MSU2LT/MSU2 show little warming at these elevations.
The skeptics are skeptical of everything, not just in the climate field. I have met a couple and been told this by a few others over email. They are mostly right wing but I guess we all knew that. As for a new name for them - those I can think of today aren't appropriate. Any term needs to secular and not suggesting belief etc. As I said at the beginning this type of email doesn't seem relevant today, but life should go on - I hope it does.
All the best to all of you
We have discussed a published response to the "skeptics", in particular the web-based type of critic, but I wonder if Jean-Claude had something else in mind. As I understand it, the concern has arisen that a part of "established" or "official" science in Germany is planning an active campaign within the German governmental and political scene. Their intent is to question the main IPCC findings, with, in their eyes, the high-resolution paleo component as a weak point of the IPCC TAR. Because the critics are geologists, they will have credibility in these circles, and a journal article, appropriately distributed, could be a useful tool. As in the US, those with power and influence (even within our National Academy of Science) seem not to understand the difference between the scientific approaches needed to study decade to century variability as distinct from longer-term phenomena.
If my understanding is correct,I think Jean-Claude's suggestion should Be followed. If we are only talking about the general problem Phil discussed, then Phil is right.
I have read with interest the latest round of exchanges suggesting an authoritative review article on the paleoclimate of the past millennium or perhaps longer time interval.
At risk of seeming contrarian, I do not think that is what is needed. The IPCC TAR is an excellent review and summary of the entire issue; a more detailed paleoclimate review would hardly be more persuasive to those who are unwilling to accept the IPCC science. The "ideologues" (thank you Malcolm, I am no longer referring to them as skeptics) are hardly open to persuasion). Another review article would be something akin to preaching to the choir.
We need to spend time reaching out to the public through their media, not ours. We need an educated public who believes what the science is saying, and who will reach decision-makers with no fear of being called self-serving. That is a label that the ideologues try to pin on us, when it is they who should be wearing the scarlet letter of self-service.
Whenever the issue arises of scientists arguments being self serving, I turn the argument around immediately, pointing to the fossil fuel industry's obvious self-interest. I never let such a charge go unanswered. We probably spend more time than is necessary talking to each other, and much less than is necessary in engaging an interested but somewhat puzzled public. But we are making headway: in the USA there are now appearing articles in non-scientific magazines on how to argue with the ideologues, and how to persuade the puzzled public. The League of Conservation Voters magazine recently had such a presentation; the Union of Concerned Scientists as well. The County Planning Commission of one of the Florida coastal counties featured in a newsletter a summary of the possible consequences of sea level rise due to 21st century warming.
The public is moving to accept the science, because of dramatic consequences that they can see: the melting of the ice on Kilimanjaro, an ice-free passage through t he Northwest passage in 2000, the t hinning of Arctic sea-ice by 40%, an iceberg the size of Belgium breaking out of the Larsen ice shelf. These are the images that need to be put before the public at every opportunity. And there are many opportunities: community service clubs such as Rotary, Kiwanis; University alumni groups, legislative public hearings, radio and television interviews, trips with eco-tourists, etc. etc. We can argue until doomsday with each other whether the temperature over the past thousand years was ever warmer than today, and the public will yawn.
So Stefan, how can we help you win the hearts and minds of the decision-makers in Germany? What specific questions do you think you will face and need to answer with short, conci se, easy to understand responses? Let us all share with Stefan our experiences of teaching this material to non-scientific audiences.
I am emerging from the recent dark days fighting mad.
And lastly, Rahmstorf
Dear Henry and everyone else,
let me first thank all of you who have wri tten supportive and helpful mails and my apologies for not responding immediately. I did spend late nights last weekend drafting a response with the help of your input - in German, so sending it around is probably useless for most of you. It is now being worked over by Martin Claussen and others from our institute and next week we plan to finalise it.
Of course we are also very shocked and stunned by the attack on the US. We had a five-minute work stoppage and silence in Germany this morning, including at PIK, where staff gathered outside our main building. In Berlin people are queing up outside the US embassy to bring flowers and write their names in a book. We feel that not only do we have many friends in New York and other parts of the US, but also this is really an attack on us as well , on all of modern democratic society. I personally hope for a determined, united and wise response that will fight terrorism without harming innocent people and will not cause more hatred and an escalation of violence.
Back to the climate contras. What struck me from your responses is that these people of the BGR are using exactly the same arguments, down to citing the same references, as you mention from your experience. I wonder whether there is some sinister connection or orchestrated campaign here, the german coal industry connected with their US counterparts? Do you have access to any materials (pamphlets etc.) that the US "sceptics" have produced? This is not really something for me to follow up but I'm thinking of passing information to a friendly journalist - I think it's a job for a journalist to research some of the background of where the ideas and funding for this recent campaing over here actually come from. I think in either case - whether the BGR is using taxpayers money to produce disinformation leaflets or whether they are sponsored by coal money - it is something the public should know about.