The below are part of a series of alleged emails from the Climate Research Unit at the University of East Anglia, released on 20 November 2009.
Original Filename: 986499438.txt | Return to the index page | Permalink | Earlier Emails | Later Emails
From: "Michael Mann" <memann00@xxxxxxxxx.xxx>
To: T.Osborn@xxxxxxxxx.xxx
Subject: RE: problem
Date: Thu, 05 Apr 2001 15:37:xxx xxxx xxxx
Reply-to: mann@xxxxxxxxx.xxx
Cc: k.briffa@xxxxxxxxx.xxx, mann@xxxxxxxxx.xxx, p.jones@xxxxxxxxx.xxx
<x-flowed>
HI Tim,
THanks for looking into this so quickly. I agree w/ your assessment. It is
probably just the fact that the signal of interest in SOI and NINO3 is
really the interannual signal, and this is not evident in the low-frequency
component shown, which emphasizes discrepancies that are actually small
compared to amplitude of the interannual signal present in both Stahle et al
and Mann et al. So I would urge showing the annual reconstructions in this
case, rather than smoothed for this reason...
In IPCC we only chose to show 1700 to present, which is a better
calibrated/verified interval than back to 1650, so I'd encourage you guys to
restrict it to 1700-present if you can. Other than that,
I think it is important to acknowledge that SOI and NINO3 have different
low-frequency trends over the 20th century, and might well have different
trends in the past. It is true that many of the proxies used are sensitive
to the SOI (e.g. mexican tree rings), but others are sensitive to Pacific
SST (e.g. corals from GBR, New Caledonia, Galapagos) and our claim is that
the calibration process will select out the best estimate of the temperature
patterns, rather than SLP patterns, associated w/ ENSO, from the multiproxy
network. In the future, we'll be going after SLP reconstruction too, and
it'll be interesting to see what the difference is.
I hope that clarifies. Please let me know if I can be of any further help,
provide further clarification, etc. Thanks again,
mike
>From: Tim Osborn <T.Osborn@xxxxxxxxx.xxx>
>To: "k.briffa" <k.briffa@xxxxxxxxx.xxx>, Michael Mann <memann00@xxxxxxxxx.xxx>,
> "p.jones" <p.jones@xxxxxxxxx.xxx>, "T.Osborn" <T.Osborn@xxxxxxxxx.xxx>,
> mann <mann@xxxxxxxxx.xxx>
>CC: rbradley <rbradley@xxxxxxxxx.xxx>
>Subject: RE: problem
>Date: Wed, 4 Apr 2001 23:02:35 +0100
>
> >Thanks for getting back to me so quickly. I could be wrong, but i just
> >want to make sure. The cold-season NINO3 is far more consistent w/ DJF
>SOI
> >and Stahle's recon, so I just want to be sure that is the one that
> >is shown.
>
> >> >Are you sure you have used the *cold-season* NINO3
> >> >reconstruction, as discussed (and available) in the Mann et al Earth
> >> >Interactions paper, and not the annual mean reconstruction!!
> >> >
> >> >http://www.ngdc.noaa.gov/paleo/ei/ei_reconsb.html
> >> >
> >> >I don't believe that has the trend that the series you show does. That
> >> >NINO3 series agrees closely (r=0.63) w/ the Stahle et al series (once
> >> >the sign has been flipped on that series, and the off-by-one-year date
> >> >convention is taken into account
>
>Dear all,
>
>I've found a machine with telnet and have been able to check my files &
>programs. The file I'm using matches the ninocold-recon.dat file
>downloadable
>from the ei_reconsb.html. It also correlates at r=0.63 with Stahle. I
>don't
>have access to plotting here, so I cannot investigate further the reason
>for
>the apparent mismatch, though I wonder whether it is due to the heavy
>(30-yr)
>smoothing used in the Science paper - much more smoothing than is typically
>used when looking at ENSO! These 30-yr differences are in fact quite small
>in
>comparison with some of the interannual variations, and perhaps the series
>would look very much more alike if unfiltered? Anyway, as far as I can
>tell,
>the figure is ok.
>
> >> >Moreover, it is inappropriate to refer (as you do) the Nino3
> >>reconstruction
> >> >as an SOI reconstruction, no matter whether it has been
> >> >renormalized, sign-switched, etc. There are fundamennal differences
> >>between
> >> >the low-frequency behavior of NINO3 and SOI, (consider
> >> >for example the 20th century!) and they aren't dynamically equivalent!
>To
> >> >say there is a "long-term trend" in our "SOI reconstruction"
> >> >is extremely misleading. There is a long-term trend in our *NINO3*
> >> >reconstruciton. Only Stahle produced an SOI reconstruction, and it is
> >>only
> >> >meaningful to correlate the two at annual timescales where they should
> >> >similarly reflect largely interannual ENSO variability.
>
>Phil/Keith - I've got a copy of our paper with me and I agree with what
>Mike
>says above, but on the other hand the lack of space constrains us. I
>wonder
>whether we can squeeze anything in at the proofs stage (have you had them
>yet
>Phil?). With a quick read I couldn't actually spot the phrase "long-term
>trend", but we could still add something about SOI and SST being coupled on
>interannual time scales and possibly doing somewhat different things on
>longer
>timescales. Mike - would you not agree, however, that your predictors
>(excluding corals) are mainly remote from the Nino 3 SST region and that
>they
>are likely responding via atmospheric teleconnection patterns and therefore
>perhaps should pick up the SOI even if calibrated against Nino 3 SST? Feel
>free to disagree - just wanted to get your reaction!
>
>Best regards
>
>Tim
>
>
_________________________________________________________________
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Original Filename: 988466058.txt | Return to the index page | Permalink | Earlier Emails | Later Emails
From: tom crowley <tom@xxxxxxxxx.xxx>
To: Chick Keller <ckeller@xxxxxxxxx.xxx>
Subject: Re: Low Frequency signals in Proxy temperatures:
Date: Sat, 28 Apr 2001 09:54:xxx xxxx xxxx
Cc: tom@xxxxxxxxx.xxx, p.jones@xxxxxxxxx.xxx, rbradley@xxxxxxxxx.xxx, k.briffa@xxxxxxxxx.xxx, mann@xxxxxxxxx.xxx, mhughes@xxxxxxxxx.xxx
Chick,
look at the instrumental record! there are huge differences between
different regions - Alaska has warmed substantially while eastern North
America cooled after the 1950s. locking onto local records, no matter how
beautiful, can lead to serious errors. If the ice cores are so infallible
why do they give substantially different stories for grip and gisp2 over
the last 1500 years?
the bottom line is that one cannot make a robust case that decadally
hemispheric temperatures over the last 1500 years were even as warm as the
late 20th century, much less warmer.
Tom
>
>Well said indeed! This helps me to slowly understand what's being
>done and why.
>
>My nagging problem remains however, and that's that there seem to be
>too many paleo records published that show much larger amplitude
>variations. Now many can be explained, but some look more robust.
>For example I think most people are wondering about the total
>disagreement between isotope temperatures from GISP II and borehole
>temperatures from GRIP and Dye 3. Here the usual land use caution
>doesn't apply since I don't think the ice above the boreholes has
>changed much?
>
>And if I understand Tom Crowley's note to me, his reconstruction
>averaged normalized records, thus missing large amplitude variations
>such as the Keigwin Sargasso one, which he used, but which shows a
>large amplitude signal tantalizingly similar to the GRIP/Dye 3
>records. (Tom used GISP II which essentially has no low frequency
>amplitude)
>
>So I read all the papers, and am impressed by the painstakingly
>careful work, but still wonder about a world in which the
>hemispherical low frequency temperature amplitude could be (see Jones
>et al Science this week) only about 0.4
Original Filename: 988831541.txt | Return to the index page | Permalink | Earlier Emails | Later Emails
From: Edward Cook <drdendro@xxxxxxxxx.xxx>
To: "Michael E. Mann" <mann@xxxxxxxxx.xxx>
Subject: Re: hockey stick
Date: Wed, 2 May 2001 15:25:xxx xxxx xxxx
Cc: tom crowley <tom@xxxxxxxxx.xxx>, esper@xxxxxxxxx.xxx, Jonathan Overpeck <jto@u.arizona.edu>, Keith Briffa <k.briffa@xxxxxxxxx.xxx>, mhughes@xxxxxxxxx.xxx, rbradley@xxxxxxxxx.xxx, p.jones@xxxxxxxxx.xxx, srutherford@xxxxxxxxx.xxx
Hi Mike,
No problem. I am quite happy to work this stuff through in a careful way
and am happy to discuss it all with you. I certainly don't want the work to
be viewed as an attack on previous work such as yours. Unfortunately, this
global change stuff is so politicized by both sides of the issue that it is
difficult to do the science in a dispassionate environment. I ran into the
same problem in the acid rain/forest decline debate that raged in the
1980s. At one point, I was simultaneous accused of being a raving tree
hugger and in the pocket of the coal industry. I have always said that I
don't care what answer is found as long as it is the truth or at least
bloody close to it.
Cheers,
Ed
>Hi Ed,
>
>This is fair enough, and I'm sorry if my spelling out my concerns
>sounded defensive to you. It wasn't meant to be that way.
>
>Lets figure this
>all out based on good, careful
>work and see what the data has to say in the end. We're working towards
>this ourselves, using revised methods and including borehole data, etc.
>and will keep everyone posted on this.
>
>I don't in any way doubt yours and Jan's integrity here.
>
>I'm just a bit concerned that the result is getting used publically, by
>some, before it has gone through the gauntlet of peer review.
>Especially because it is, whether you condone it or not, being used as
>we speak to discredit the work of us, and Phil et al, this is dangerous.
>I think there are some legitimate issues that need to be sorted out
>with regard to the standardization method, and would like to see
>this play out before we jump to conclusions regarding revised estimates
>of the northern hemisphere mean temperature record and the nature of
>the "MWP".
>
>I'd
>be interested to be kept posted on what the status of the manuscript is.
>
>Thanks,
>
>mike
>
>On Wed, 2 May 2001, Edward Cook wrote:
>
>> Hi Mike,
>>
>> >A few quick points Ed,
>> >
>> >These "Wally seminars" are self-promoting acts on Broecker's part, and I
>> >think the community has to reject them as having any broader significance.
>> >If Broecker had pulled this w/ Ray, Malcolm, Keith, Phil, and Tom around,
>> >he wouldn't get away w/ such a one-sided treatment of the issue. I've been
>> >extremely troubled by what I have heard here.
>>
>> It appears that you are responding in a way that is a bit overly defensive,
>> which I regret. I am not supporting Broecker per se and only explained in a
>> very detailed fashion the origin of the work by Esper and me and how it was
>> presented to refute a very unfair characterization of tree-ring data in
>> Wally's perspective piece. The fact that Esper compared his series with
>> Jones, Briffa, and Mann et al. should not be viewed as an attack on your
>> work. It was never intended to be so, but it is was a clearly legitimate
>> thing to do. As I said, I have no control over Broecker. But it is unfair
>> and indeed incorrect to start out by dismissing the "Special Wally
>> Seminars" as self-promoting acts. To say that is simply wrong. He doesn't
>> bring people in to only express support for his point of view or pet
>> theory, as you are implying. So, I suggest that you cool down a bit on this
>> matter. It detracts from the scientific issues that should properly be
>> debated here. This is the only point on which I will defend Broecker.
>>
>> >I'm also a bit troubled by your comparisons w/ glacial advances, etc. and
>> >how these correlate w/ your reconstruction. Malcolm, Ray, Phil, and others
>> >have been over this stuff time and again, and have pointed out that these
>> >data themselves don't support the notion of globally-synchronoous changes.
>> >You seem to be arguing otherwise? And with regard to association w/
>> >volcanic forcing, Tom has already shown that the major volcanic events are
>> >captured correctly in the existing reconstructions, whether or not the
>> >longer-term trends are correct or not...
>>
>> I am not arguing for "globally-synchronous changes" and never have. To
>> quote what I said about neo-glacial advances, some of the fluctuations in
>> Esper's series "correspond well with known histories of neo-glacial advance
>> in some parts of the NH". Note the use of the word "some" in that quote.
>> That is a fair statement and why shouldn't I say it if it is true,
>> coincidently or not. Whether or not it argues for "globally-synchronous
>> changes" is up to you. I would never argue that everything happening on
>> multi-decadal time scales is phase-locked across the NH. That would be a
>> silly thing to say. But it is perfectly valid to point out the degree to
>> which independent evidence for cold periods based on glacier advances
>> appears to agree with a larger-scale indicator of temperature variablity. I
>> thought this is how science to supposed to proceed. I also don't see your
>> point about volcanic forcing. I mentioned this purely in the spirit of the
>> work of Crowley and others to suggest that the Esper series is probably
>> capturing this kind of signal as well. It has nothing to do with the issue
>> of centennial trends in temperature. You are reading far more into what I
>> wrote than I ever intended or meant.
>>
>> >Re the boreholes. Actually, if Tom's estimates are correct, and it is also
>> >correct that the boreholes have the low-frequency signal correct over the
>> >past few centuries, we are forced to also accept Tom's result that the
>> >so-called "MWP", at the hemispheric scale, is actually even COOLER relative
>> >to present than our result shows! That was clear in Tom's presentation at
>> >the workshop. So lets be clear about that--Tom's work and the boreholes in
>> >no way support Broecker's conclusion that the MWP was warmer than we have
>> >it--it actually implies the MWP is colder than we have it!
>> >Tom, please speak up if I'm not correct in this regard!
>>
>> I am not saying that Tom's results are wrong. And, I am certainly not
>> saying that Broecker is right. I merely described the results of a new
>> analysis of a somewhat new set of long tree-ring records from the
>> extra-tropics. My statement that the MWP appeared to be comparable to the
>> 20th century does not imply, nor was it meant to imply, that somehow the
>> 20th century temperature is not truly anomalous and being driven by
>> greenhouse gases. To quote from my email, "I would not claim (and nor would
>> Jan) that it exceeded the warmth of the late 20th century. We simply do not
>> have the precision or the proxy replication to say that yet." Note the use
>> of the word "precision". This clearly relates to the issue of error
>> variance and confidence intervals, a point that you clearly emphasize in
>> describing your series. Also note the emphasis on "late 20th century". I
>> think that most researchers in global change research would agree that the
>> emergence of a clear greenhouse forcing signal has really only occurred
>> since after 1970. I am not debating this point, although I do think that
>> there still exists a signficant uncertainty as to the relative
>> contributions of natural and greenhouse forcing to warming during the past
>> xxx xxxx xxxxyears at least. Note that I also tried to emphasize the
>> extra-tropical nature of this series, and it may be that the tropics do not
>> show the same strength of warming. But I do argue strongly that we do not
>> have the high-resolution proxy data needed to test for a MWP in the
>> tropics. Please correct me if I am wrong here.
>>
>> >We are in the process of incorporating the borehole data into the
>> >low-frequency component of the reconstruction. The key difference will be
>> >that they are going to be calibrated against the instrumental record and
>> >weighted by the spatial coherence within the borehole data rather than what
>> >Pollack has done. I expect the results will be different, but in any case
>> >quite telling...
>>
>> Fine.
>>
>> >I'll let Malcolm and Keith respond to the issues related to the
>> >standardization of the Esper chronologies, though it immediately sounds to
>> >me quite clear that there is the likelihood of of having contaminated the
>> >century-scales w/ non-climatic info. Having now done some work w/
>> >chronologies in disturbed forests myself now (in collaboration w/ Dave
>> >Stahle), I know how easy it is to get lots of century-scale variability
>> >that has nothing to do w/ climate. I imagine the reviewers of the
>> >manuscript will have to be convinced that this is the case w/ what Esper
>> >has done. I'm very skeptical. I'm also bothered that Broecker has promoted
>> >this work prior to any formal peer review. There are some real issues w/
>> >the standardization approach and there is a real stretch in promoting this
>> >as a hemispheric temperature reconstruction.
>>
>> I appreciate your skepticism and I hope that Jan and I can convince you
>> otherwise. I also encourage you to continue getting your shoulders sore and
>> hands dirty on tree-ring sampling and analysis. Esper's analysis is not
>> perfect. Nor is anyone elses who works in this game. But if Esper's series
>> is wrong on century time scales, then Jones and Briffa are wrong too. If
>> Esper's series is also wrong on inter-decadal time scales, then your series
>> is wrong as well because on that time scale of variablity, his series
>> agrees very well with yours. So, I would be very cautious about declaring
>> that Esper's series is in some sense invalid. Finally, as I have said ad
>> nausem, I have no control over what Broecker thinks or does beyond
>> presenting to him a convincing case for the ability of certain tree-ring
>> series to preserve long-term temperature variability. And again, "I also
>> tried to emphasize the extra-tropical nature of this series." Please give
>> me a break here.
>>
>> >Finally, what is the exact spatial distribution of the sparse data he used.
>> >Scott R. drove home the point regarding the importance of taking into
>> >account spatial sampling in his talk at the workshop. A sparse
>> >extratratropical set of indicators, no matter how
>> >locally-temperature-sensitive they are, will not, unless you're *very*
>> >lucky w/ the locations, be an accurate indicator of true N. Hem temp. In
>> >general it will overestimate the variance at all timescales. The true N.Hem
>> >temperature (ie, weighted largely by tropical ocean SST) has much less
>> >variance than extratrpoical continents. There may be a large apples and
>> >oranges component to the comparisons you describe.
>>
>> I know your argument and I am sensitive to it, hence my emphasis on
>> "extra-tropical". So, don't look for disagreement on the importance of the
>> tropical SSTs to any estimate of NH temperatures. But let's be honest here.
>> Your reconstruction prior to roughly AD 1600 is dominated by extra-tropical
>> proxies. So, in a way, you are caught in the same dilemma as all other
>> people who have tried to do this.
>>
>> >We've shown that are reconstructions in continental extratropical regions
>> >have lots more variance and variability. It is, as we have all shown, the
>> >averaging over many regions that reduces the amplitude of variability. Our
>> >regional reconstructions show far more significant warm and cold periods.
>> >But they cancel out spatially!
>>
>> Understood, but it is still unclear how this all happens as your
>> reconstruction proceeds back in time with an increasingly limited and
>> spatially-restricted set of proxies. Confidence limits that you place on
>> your series is laudable and I agree, to first order, that the MWP in your
>> series could easily have been cooler than what you show. But it implicitly
>> assumes that the estimates are equally unbiased (or equally biased for that
>> matter) back in time. I don't know if that is an issue here, but I believe
>> that the issue of bias using an increasingly sparse number of predictors
>> scattered irregularly over space has not be investigated. Please correct me
>> if I am wrong here.
>>
>> >If a legitimate argument were to be made that we have significnatly
>> >understiamted, within the context of our uncertainty estimates, the
>> >amplitude of the MWP at the hemispheric scale, I'd be the first to accept
>> >it (note that, as Phil et al pointed out in their recent review article in
>> >Science, we do not dispute that temperatures eearly in the millennium,
>> >within the uncertainty estimates, may have been comparable to early/mid
>> >20th centurys--just not late 20th century temperatures).
>>
>> We are in agreement here. See my earlier comments.
>>
>> >Frankly though Ed, I really don't see it here. We may have to let the
>> >peer-review process decid this, but I think you might benefit from knowing
>> >the consensus of the very able group we have assembled in this email
>> >list, on what Esper/you have done?
>>
>> Of course, I know everyone in this "very able group" and respect their
>> opinions and scientific credentials. The same obviously goes for you. That
>> is not to say that we can't disagree. Afterall, consensus science can
>> impede progress as much as promote understanding.
>>
>> Cheers,
>>
>> Ed
>>
>> >Comments or thoughts?
>> >
>> >cheers,
>> >
>> >mike
>> >
>> >At 10:59 AM 5/2/xxx xxxx xxxx, Edward Cook wrote:
>> >> >Ed,
>> >> >
>> >> >heard some rumor that you are involved in a non-hockey stick
>>reconstruction
>> >> >of northern hemisphere temperatures. I am very intrigued to learn about
>> >> >this - are these results suggesting the so called Medieval Warm
>>Period may
>> >> >be warmer than the early/mid 20th century?
>> >> >
>> >> >any enlightenment on this would be most appreciated, Tom
>> >> >
>> >> >
>> >> >
>> >> >Thomas J. Crowley
>> >> >Dept. of Oceanography
>> >> >Texas A&M University
>> >> >College Station, TX 77xxx xxxx xxxx
>> >> >xxx xxxx xxxx
>> >> >xxx xxxx xxxx(fax)
>> >> >xxx xxxx xxxx(alternate fax)
>> >>
>> >>Hi Tom,
>> >>
>> >>As rumors often are, the one you heard is not entirely accurate. So, I
>>will
>> >>take some time here to explain for you, Mike, and others exactly what was
>> >>done and what the motivation was, in an effort to hopefully avoid any
>> >>misunderstanding. I especially want to avoid any suggestion that this work
>> >>was being done to specifically counter or refute the "hockey stick".
>> >>However, it does suggest (as do other results from your EBM, Peck's work,
>> >>the borehole data, and Briffa and Jones large-scale proxy estimates) that
>> >>there are unresolved (I think) inconsistencies in the low-frequency
>>aspects
>> >>of the hockey stick series compared to other results. So, any comparisons
>> >>with the hockey stick were made with that spirit in mind.
>> >>
>> >>What Jan Esper and I are working on (mostly Jan with me as second author)
>> >>is a paper that was in response to Broecker's Science Perspectives
>>piece on
>> >>the Medieval Warm Period. Specifically, we took strong exception to his
>> >>claim that tree rings are incapable of preserving century time scale
>> >>temperature variability. Of course, if Broecker had read the
>>literature, he
>> >>would have known that what he claimed was inaccurate. Be that as it may,
>> >>Jan had been working on a project, as part of his post-doc here, to
>>look at
>> >>large-scale, low-frequency patterns of tree growth and climate in long
>> >>tree-ring records provided to him by Fritz Schweingruber. With the
>>addition
>> >>of a couple of sites from foxtail pine in California, Jan amassed a
>> >>collection of 14 tree-ring sites scattered somewhat uniformly over the
>> >>xxx xxxx xxxxdegree NH latitude band, with most extending back 1xxx xxxx xxxxyears.
>> >>All of the sites are from temperature-sensitive locations (i.e. high
>> >>elevation or high northern latitude. It is, as far as I know, the largest,
>> >>longest, and most spatially representative set of such
>> >>temperature-sensitive tree-ring data yet put together for the NH
>> >>extra-tropics.
>> >>
>> >>In order to preserve maximum low-frequency variance, Jan used the Regional
>> >>Curve Standardization (RCS) method, used previously by Briffa and myself
>> >>with great success. Only here, Jan chose to do things in a somewhat
>>radical
>> >>fashion. Since the replication at each site was generally insufficient to
>> >>produce a robust RCS chronology back to, say, AD 1000, Jan pooled all of
>> >>the original measurement series into 2 classes of growth trends:
>>non-linear
>> >>(~700 ring-width series) and linear (~500 ring-width series). He than
>> >>performed independent RCS on the each of the pooled sets and produced
>>2 RCS
>> >>chronologies with remarkably similar multi-decadal and centennial
>> >>low-frequency characteristics. These chronologies are not good at
>> >>preserving high-frquency climate information because of the scattering of
>> >>sites and the mix of different species, but the low-frequency patterns are
>> >>probably reflecting the same long-term changes in temperature. Jan than
>> >>averaged the 2 RCS chronologies together to produce a single chronology
>> >>extending back to AD 800. It has a very well defined Medieval Warm
>>Period -
>> >>Little Ice Age - 20th Century Warming pattern, punctuated by strong
>>decadal
>> >>fluctuations of inferred cold that correspond well with known histories of
>> >>neo-glacial advance in some parts of the NH. The punctuations also appear,
>> >>in some cases, to be related to known major volcanic eruptions.
>> >>
>> >>Jan originally only wanted to show this NH extra-tropical RCS
>>chronology in
>> >>a form scaled to millimeters of growth to show how forest productivity and
>> >>carbon sequestration may be modified by climate variability and change
>>over
>> >>relatively long time scales. However, I encouraged him to compare his
>> >>series with NH instrumental temperature data and the proxy estimates
>> >>produced by Jones, Briffa, and Mann in order bolster the claim that his
>> >>unorthodox method of pooling the tree-ring data was producing a record
>>that
>> >>was indeed related to temperatures in some sense. This he did by linearly
>> >>rescaling his RCS chronology from mm of growth to temperature
>>anomalies. In
>> >>so doing, Jan demonstrated that his series, on inter-decadal time scales
>> >>only, was well correlated to the annual NH instrumental record. This
>>result
>> >>agreed extremely well with those of Jones and Briffa. Of course, some of
>> >>the same data were used by them, but probably not more than 40 percent
>> >>(Briffa in particular), so the comparison is based on mostly, but not
>> >>fully, independent data. The similarity indicated that Jan's approach was
>> >>valid for producing a useful reconstruction of multi-decadal temperature
>> >>variability (probably weighted towards the warm-season months, but it is
>> >>impossible to know by how much) over a larger region of the NH
>> >>extra-tropics than that produced before by Jones and Briffa. It also
>> >>revealed somewhat more intense cooling in the Little Ice Age that is more
>> >>consistent with what the borehole temperatures indicate back to AD 1600.
>> >>This result also bolsters the argument for a reasonably large-scale
>> >>Medieval Warm Period that may not be as warm as the late 20th century, but
>> >>is of much(?) greater significance than that produced previously.
>> >>
>> >>Of course, Jan also had to compare his record with the hockey stick since
>> >>that is the most prominent and oft-cited record of NH temperatures
>>covering
>> >>the past 1000 years. The results were consistent with the differences
>>shown
>> >>by others, mainly in the century-scale of variability. Again, the Esper
>> >>series shows a very strong, even canonical, Medieval Warm Period - Little
>> >>Ice Age - 20th Century Warming pattern, which is largely missing from the
>> >>hockey stick. Yet the two series agree reasonably well on inter-decadal
>> >>timescales, even though they may not be 1:1 expressions of the same
>> >>temperature window (i.e. annual vs. warm-season weighted). However, the
>> >>tree-ring series used in the hockey stick are warm-season weighted as
>>well,
>> >>so the difference between "annual" and "warm-season weighted" is probably
>> >>not as large as it might seem, especially before the period of
>>instrumental
>> >>data (e.g. pre-1700) in the hockey stick. So, they both share a
>>significant
>> >>degree of common interdecal temperature information (and some, but not
>> >>much, data), but do not co-vary well on century timescales. Again,
>>this has
>> >>all been shown before by others using different temperature
>> >>reconstructions, but Jan's result is probably the most comprehensive
>> >>expression (I believe) of extra-tropical NH temperatures back to AD 800 on
>> >>multi-decadal and century time scales.
>> >>
>> >>Now back to the Broecker perspectives piece. I felt compelled to refute
>> >>Broecker's erroneous claim that tree rings could not preserve long-term
>> >>temperature information. So, I organized a "Special Wally Seminar" in
>>which
>> >>I introduced the topic to him and the packed audience using Samuel
>> >>Johnson's famous "I refute it thus" statement in the form of "Jan
>>Esper and
>> >>I refute Broecker thus". Jan than presented, in a very detailed and well
>> >>espressed fashion, his story and Broecker became an instant convert. In
>> >>other words, Wally now believes that long tree-ring records, when properly
>> >>selected and processed, can preserve low-frequency temperature variability
>> >>on centennial time scales. Others in the audience came away with the same
>> >>understanding, one that we dendrochronologists always knew to be the case.
>> >>This was the entire purpose of Jan's work and the presentation of it to
>> >>Wally and others. Wally had expressed some doubts about the hockey stick
>> >>previously to me and did so again in his perspectives article. So, Jan's
>> >>presentation strongly re-enforced Wally's opinion about the hockey stick,
>> >>which he has expressed to others including several who attended a
>> >>subsequent NOAA meeting at Lamont. I have no control over what Wally says
>> >>and only hope that we can work together to reconcile, in a professional,
>> >>friendly manner, the differences between the hockey stick and other proxy
>> >>temperature records covering the past 1000 years. This I would like to do.
>> >>
>> >>I do think that the Medieval Warm Period was a far more significant event
>> >>than has been recognized previously, as much because the high-resolution
>> >>data to evaluate it had not been available before. That is much less
>>so the
>> >>case now. It is even showing up strongly now in long SH tree-ring series.
>> >>However, there is still the question of how strong this event was in the
>> >>tropics. I maintain that we do not have the proxies to tell us that now.
>> >>The tropical ice core data are very difficult to interpret as temperature
>> >>proxies (far worse than tree rings for sure and maybe even unrelated to
>> >>temperatures in any simple linear sense as is often assumed), so I do not
>> >>believe that they can be used alone as records to test for the
>>existence of
>> >>a Medieval Warm Period in the tropics. That being the case, there are
>> >>really no other high-resolution records from the tropics to use, and the
>> >>teleconnections between long extra-tropical proxies and the tropics are, I
>> >>believe, far too tenuous and probably unstable to use to sort out this
>> >>issue.
>> >>
>> >>So, at this stage I would argue that the Medieval Warm Period was probably
>> >>a global extra-tropical event, at the very least, with warmth that was
>> >>persistent and probably comparable to much of what we have experienced in
>> >>the 20th century. However, I would not claim (and nor would Jan) that it
>> >>exceeded the warmth of the late 20th century. We simply do not have the
>> >>precision or the proxy replication to say that yet. This being said, I do
>> >>find the dismissal of the Medieval Warm Period as a meaningful global
>>event
>> >>to be grossly premature and probably wrong. Kind of like Mark Twain's
>> >>commment that accounts of his death were greatly exaggerated. If, as some
>> >>people believe, a degree of symmetry in climate exists between the
>> >>hemispheres, which would appear to arise from the tropics, then the
>> >>existence of a Medieval Warm Period in the extra-tropics of the NH and SH
>> >>argues for its existence in the tropics as well. Only time and an enlarged
>> >>suite of proxies that extend into the tropics will tell if this is true.
>> >>
>> >>I hope that what I have written clarifies the rumor and expresses my views
>> >>more completely and accurately.
>> >>
>> >>Cheers,
>> >>
>> >>Ed
>> >>
>> >>==================================
>> >>Dr. Edward R. Cook
>> >>Doherty Senior Scholar
>> >>Tree-Ring Laboratory
>> >>Lamont-Doherty Earth Observatory
>> >>Palisades, New York 10964 USA
>> >>Phone: xxx xxxx xxxx
>> >>Fax: xxx xxxx xxxx
>> >>Email: drdendro@xxxxxxxxx.xxx
>> >>==================================
>> >
>> >_______________________________________________________________________
>> > Professor Michael E. Mann
>> > Department of Environmental Sciences, Clark Hall
>> > University of Virginia
>> > Charlottesville, VA 22903
>> >_______________________________________________________________________
>> >e-mail: mann@xxxxxxxxx.xxx Phone: (8xxx xxxx xxxxFAX: (8xxx xxxx xxxx
>> > http://www.evsc.virginia.edu/faculty/people/mann.shtml
>>
>>
>> ==================================
>> Dr. Edward R. Cook
>> Doherty Senior Scholar
>> Tree-Ring Laboratory
>> Lamont-Doherty Earth Observatory
>> Palisades, New York 10964 USA
>> Phone: xxx xxxx xxxx
>> Fax: xxx xxxx xxxx
>> Email: drdendro@xxxxxxxxx.xxx
>> ==================================
>>
>>
>>
>
>_______________________________________________________________________
> Professor Michael E. Mann
> Department of Environmental Sciences, Clark Hall
> University of Virginia
> Charlottesville, VA 22903
>_______________________________________________________________________
>e-mail: mann@xxxxxxxxx.xxx Phone: (8xxx xxxx xxxxFAX: (8xxx xxxx xxxx
> http://www.evsc.virginia.edu/faculty/people/mann.html
==================================
Dr. Edward R. Cook
Doherty Senior Scholar
Tree-Ring Laboratory
Lamont-Doherty Earth Observatory
Palisades, New York 10964 USA
Phone: xxx xxxx xxxx
Fax: xxx xxxx xxxx
Email: drdendro@xxxxxxxxx.xxx
==================================
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From: "Michael E. Mann" <mann@xxxxxxxxx.xxx>
To: Ed Cook <drdendro@xxxxxxxxx.xxx>
Subject: Re: Comments on "Extending NAO Reconstructions ..."
Date: Thu, 17 May 2001 13:15:xxx xxxx xxxx
Cc: Juerg Luterbacher <juerg@xxxxxxxxx.xxx>, Keith Briffa <k.briffa@xxxxxxxxx.xxx>, Phil Jones <p.jones@xxxxxxxxx.xxx>, "Michael E. Mann" <mann@xxxxxxxxx.xxx>, Scott Rutherford <srutherford@xxxxxxxxx.xxx>
<x-flowed>
Hi Ed,
On the road, but just had to chime into this debate briefly.
What you say is of course true, but we have to start somewhere. Step #1 is
producing a reconstruction. Without some reasonable estimate of
uncertainty, a reconstruction isn't
very useful in my opinion. Step #2 is producing some reasonable estimate of
uncertainty. In my mind, this is based on looking at the calibration
residuals, seeing if they pass some basic tests for whiteness, normality,
etc., looking at the verification statistics, and seeing if this continues
to hold up in an independent sample. It is important to use the longest
instrumental records we have for independent verification where possible.
Of course, there may be additional biases in the predictors that are
difficult to identify even in a relatively long verification interval
(e.g., ultra low-frequency problems w/ fidelity). Step #3 is trying to
evaluate this as best we can (looking at the frequency domain structure of
the predictors themselves, seeing if there is loss of variance at very long
timescales, looking at the robustness of long-term trends to
standardization issues, etc.), etc...I see this as a successive series of
diagnostics and self-consistency checks that iterate towards getting a
reasonable handle on the uncertainties. This is the approach
that we have taken, and I think it is the most appropriate...
I firmly believe that a reconstruction w/ out some reasonable estimate of
uncertainty is almost useless! If the community wants to use paleodata for
signal detection, model validation, etc. I believe that this is absolutely
essential to do, whether or not we can do a perfect job.
I would be very surprised if Hans would disagree w/ my statement above!
anyways, my two cents on the matter...
mike
At 09:50 AM 5/17/xxx xxxx xxxx, Ed Cook wrote:
>Hi Juerg,
>
>I've done an admittedly quick read of your paper "Extending NAO
>Reconstructions Back to AD 1500" and find it to be fine overall. One slight
>correction on pg. 3 concerning the Cook et al. (1998) recon. The tree-ring
>records used also included some from England, as well as the eastern US and
>northern Fennoscandia. On pg. 10, sentence 8-9 in Conclusions, the wording
>is a little confusing. You say "Including station pressure of Gibraltar and
>Reykjavik as predictors in 1821 lead to a decrease of the confidence
>estimates". This almost sounds like you are doing worse when adding in
>Gibraltar and Reykjavik, when I know you mean the opposite. So, a change in
>wording to something like "... lead to increased confidence in the
>estimates of monthly NAO". Also in Table 1, is the Cullen R4 NAO
>reconstruction the one with instrumental data in it? If so, it has used
>some of the same data as yours. I don't recall if R4 is the one with
>instrumental data. But if it is, you ought to mention that.
>
>
>On a thematic note that doesn't have much direct bearing on the paper as it
>stands now (but which may be of interest to Keith, Phil, and Mike as well),
>I have growing doubts about the validity and use of error estimates that
>are being applied to reconstructions, such as those you have applied in
>Fig. 3. First, as you say at the end of the paper, there is a clear
>frequency dependence in the strength of relationship between the actual and
>proxy-estimated data that is not being considered, i.e. "the SE ... become
>smaller when considering low-pass filtered time series" (pg. 10). The
>assumption of the error estimates as now estimated and applied is that the
>error variance is truly white noise, i.e. equally distributed across all
>frequencies. That is surely not the case. This is different from questions
>about autocorrelated residuals, which tell you nothing about the frequency
>dependence of the quality of the estimates. This is where classic
>regression theory falls down. It is based on the notion that each
>observation is a random sample with no time history or frequency domain
>structure. When we use long time series of observations (climate or proxy)
>to reconstruct some climate variable, we are also using predictors that
>have time series structure and history that cannot vary in a completely
>random fashion even if the data could be completely resampled. This is
>because they represent a series of prior "observations" of
>climatic/environmental conditions. This lack of randomness of the
>observations used for reconstructing past climate again causes me to doubt
>the validity of the error estimates being applied. The degree to which the
>reconstruction can actually vary from year to year within the prescribed
>error limits is itself constrained by the time history of the observations
>themselves used for reconstruction. In contrast, the 2SE limits in your
>Fig. 3 prior to 1821 contain almost all of the estimates. This result could
>be used to claim that there is effectively no useful time history of
>variation in the NAO reconstruction prior to 1821 because each estimate may
>fall with equal probability anywhere in the error envelop. I would regard
>this interpretation as completely wrong. Thus, I would say that the decadal
>period of above-average winter NAO in your reconstruction around AD 1700 is
>real, assuming that the predictors used are providing unbiased estimates,
>even though it is fully enclosed by the 2SE limits that intersect zero.
>This is getting towards the debate with Von Storch over "most probable"
>estimates. I am probably not explaining myself well here and undoubtedly
>need to think more about it. But I really think that error bars, as often
>presented, may potentially distort and unfairly degrade the interpreted
>quality of reconstructions. So, are the error bars better than nothing? I'm
>not so sure.
>
>Cheers,
>
>Ed
>
> >Hello Ed
> >
> >thanks very much for your nice mail. I hope these little
> >comments were useful for you and yes of course
> >we hope too that we can merge the data base sometime
> >later on. This would be great.
> >
> >Do you think that you could send me some comments
> >on our paper by tomorrow?
> >Is your paper for the Orense book?
> >
> >Many greetings and till later
> >
> >Juerg
>
>
>==================================
>Dr. Edward R. Cook
>Doherty Senior Scholar
>Tree-Ring Laboratory
>Lamont-Doherty Earth Observatory
>Palisades, New York 10964 USA
>Email: drdendro@xxxxxxxxx.xxx
>Phone: xxx xxxx xxxx
>Fax: xxx xxxx xxxx
>==================================
_______________________________________________________________________
Professor Michael E. Mann
Department of Environmental Sciences, Clark Hall
University of Virginia
Charlottesville, VA 22903
_______________________________________________________________________
e-mail: mann@xxxxxxxxx.xxx Phone: (8xxx xxxx xxxxFAX: (8xxx xxxx xxxx
http://www.evsc.virginia.edu/faculty/people/mann.shtml
</x-flowed>
Original Filename: 990718382.txt | Return to the index page | Permalink | Earlier Emails | Later Emails
From: "Michael E. Mann" <mann@xxxxxxxxx.xxx>
To: christy@xxxxxxxxx.xxx
Subject: Re: FYI: Fwd: Re: IPCC
Date: Thu, 24 May 2001 11:33:xxx xxxx xxxx
Cc: rbradley@xxxxxxxxx.xxx, tkarl@xxxxxxxxx.xxx, tom crowley <tom@xxxxxxxxx.xxx>, mhughes@xxxxxxxxx.xxx, jto@u.arizona.edu, rbradley@xxxxxxxxx.xxx, p.jones@xxxxxxxxx.xxx, k.briffa@xxxxxxxxx.xxx, "Folland, Chris" <ckfolland@xxxxxxxxx.xxx>, jouzel@xxxxxxxxx.xxx, trenbert@xxxxxxxxx.xxx, steig@xxxxxxxxx.xxx, mann@xxxxxxxxx.xxx
<x-flowed>
John:
For future reference, I think its also important to clarify for you what
the Dahl-Jensen, Clow et al borehole results actually show (see Dahl-Jensen
et al, "Past Temperatures Directly from the Greenland Ice Sheet", Science,
282, October 1998).
In fact, the results show that the amplitude of variability over the past
1000+ years differs by a factor of 2 between the GRIP and Dye 3 borehole
estimates (the latter only 865 km to the south). This is an example of
extreme regional-scale variability, which should give pause to those who
want to draw large-scale inferences.
However, even more importantly, they show in the case of Dye 3, the mid
20th century warm period in the record actually exceeds the Medieval warm
peak! (see Fig 4, lower panel, blue curve). So here we have two temperature
histories less than 1000 km apart in Greenland, which give different
stories regarding the level of Medieval warmth, with at least one of the
histories conforming precisely to the hemispheric trends presented in IPCC
chapter 2 (note that in the chapter, we actually discuss the evidence of
conflicting temperature trends in Greenland, though not specifically
referring to Dahl-Jensen et al).
So do I understand correctly that you are referring to the results of
Dahl-Jensen et al as conflicting with what we say in the chapter? At the
face of it, this argument has no merit whatsoever. I think we should all
use a better explanation from you, since you seem to be arguing publically
that the Dahl-Jensen et al record undermines what we've said in the chapter.
Thanks in advance,
mike
p.s. I've cc'd in Eric Steig, a collaborator of Clow's and a Greenland &
Antarctic Ice Core expert, to make sure my facts above have been presented
accurately. Perhaps Eric woudl be kind enough to forward my email to Gary
Clow, and Gary can let us know directly if he disagrees with any of my
remarks above.
At 03:30 PM 5/23/xxx xxxx xxxx, Michael E. Mann wrote:
>John,
>
>I appreciate your reply.
>
>However, I don't agree at all w/ your assessment. It was determined early
>on that the ice core borehole results would be discussed in the context of
>the millennial-scale variability section, as they arguably don't have the
>resolution to address the timescales relevant to the past 1000 years. So
>this was in Jean's domain, not mine, and if the cross-references between
>the sections aren't clear enough in that regard, that is indeed our fault.
>
>However, there is considerable discussion of the fact that the
>Arctic/North Atlantic regions are inappropriate for inferences into
>hemispheric-scale temperature patterns, and this remains fundamentally
>from any reasonable treatment of the underlying climate dynamics that
>influence that region.
>
>The various hemispheric temperature reconstructions discussed in our
>chapter (the emphasis was on the commonality between them), including Mann
>et al, Jones et al, Briffa et al, Crowley and Lowery, and others, make
>considerable use of just about all of the available reliable low-res and
>high-res paleo data available, and come to a clear concensus regarding the
>relative warmth of the Medieval period at the hemispheric/global scale.
>Crowley's modeling results come to the same conclusion, and it entirely
>independent of
>any empirical paleoclimate reconstructions.
>
>You misrepresent the Mann et al reconstruction--it is not based on "tree
>rings", but uses all high-resolution proxy information commonly available.
>We have shown, in fact, that our reconstruction is robust to the
>inclusion/disclusion of tree ring information. The Crowley and Lowery
>reconstruction, which is discussed in our chapter, makes use of almost no
>tree ring data, and employs lower-resolution proxy indicators, including
>the very records (Keigwin, Lamb's central england temperature record,
>GISP2 o18) that are often used to argue for a warmer MWP, and yet comes to
>the same conclusion. And Tom shows that when averaged across the
>hemisphere, a warmer-than-present-day MWP just doesn't hold up.
>
>Our treatment of this subject in the chapter was far more careful, far
>more inclusive and detailed, and far more nuanced than you give us credit
>for. Your comments below remain disturbingly selective and myopic, and we
>have dealt w/ similar comments many times over...
>
>If ABC is looking to do a hatchet job on IPCC so be it (this doesn't
>surprise me--Stossel has an abysmal record in his treatment of
>environmental issues, from what I had heard), but I'll be very disturbed
>if you turn out to have played into this in a way that is unfair to your
>co-authors on chapter 2, and your colleagues in general. This wouldn't
>have surprised me coming from certain individuals, but I honestly expected
>more from you...
>
>Mike
>
>>Date: Wed, 23 May 2001 13:50:xxx xxxx xxxx
>>From: John Christy <christy@xxxxxxxxx.xxx>
>>X-Mailer: Mozilla 4.04 (Macintosh; I; PPC)
>>To: "Michael E. Mann" <mann@xxxxxxxxx.xxx>
>>Subject: Re: IPCC
>>
>>Hi Mike:
>>
>>Here's what happened. ABC News 20/20 with Stossel wanted me to be part
>>of a segment that will air at the end of June on the climate change
>>issue. Specifically the piece will be dealing with the alarmist
>>rhetoric that tends to be found in the media. I am more than happy to
>>talk about that because I've been very disappointed with what has gone
>>on even with respect to some of the IPCC elders and their pronouncements
>>for forthcoming disasters.
>>
>>In one of the pre-interviews they asked about the "Hockey Stick". I
>>told them of my doubts about the intercentury precision of the record,
>>especially the early part, and that other records suggested the period
>>1000 years ago was warmer. I remember saying that "you must give the
>>author credit for including the large error bars for that time series in
>>the figure." I also specifically said that the most precise record of
>>century scale precision, Greenland Borehole temps, was very important to
>>note but that the figure was not in the IPCC. I then looked quickly at
>>the IPCC reference list and saw the citation of Dahl-Jensen and assumed
>>that it was at least commented on in the 1000 year time series material
>>and told ABC as much.
>>
>>ABC called back a few days later and said they couldn't find a reference
>>to the Greenland stuff in the IPCC discussion of the past 1000 years.
>>So I read the final version, and ABC was right. I said this was an
>>omission that should not have happened - and that I take part of the
>>blame because I had mentioned it at each of our Lead Author meetings.
>>
>>Last Thursday night, I was one of the guys flown to NY City for the
>>taping of the show. There was only one question on this particular
>>issue (it was even after Stossel had left the room) and I gave much the
>>same answer as I indicated above (as best as I can remember)- that the
>>"Hockey Stick" (I don't think I used the term "Hockey Stick", and I'm
>>almost positive I did not mention your name at any point) is one
>>realization of temperatures but that other data are not included and
>>that I had thought the "other" data were clearly mentioned in the IPCC,
>>but weren't. I mentioned the large error bars (as a credit to you) and
>>that I was partly to blame for this omission. If they use my remark,
>>they could slice and dice it to make it as provocative as possible.
>>
>>Four of us were taped for almost 2 hours, and from this they will select
>>about 8 minutes, so I doubt my remarks will make the show. When Stossel
>>came back in after all was said and done, he said to me that I might be
>>a good scientist but I didn't have the emotion and passion necessary to
>>excite the audience. In one way, that is a compliment I suppose. I
>>think Pat M. will have a good chunk of air time (I don't remember
>>whether he added any comments on the 1000-year time series, but he may
>>have).
>>
>>Whatever is shown, just keep it in context. There is no way a clear
>>scientific point with all the caveats and uncertainties can come across
>>in such venues. However, I do agree with Stossel's premise (though I
>>don't know what the piece will actually look like so I may be
>>disappointed) that the dose of climate change disasters that have been
>>dumped on the average citizen is designed to be overly alarmist and
>>could lead us to make some bad policy decisions. (I've got a good story
>>about the writers of the TIME cover piece a couple of months ago that
>>proves they were not out to discuss the issue but to ignore science and
>>influence government.)
>>
>>It is not bad science to look at arguably the most precise measure of a
>>point temperature (actually two boreholes) when that point shows a 600+
>>year period of greater warmth than today. On that time scale, the
>>equivalent spatial scale is much larger than any of the regional
>>oscillations we now identify. But, there are several other (admittedly
>>less robust) measures that suggest greater warmth 1000 years ago that
>>are outside the N. Atlantic area. I just don't think tree rings, if
>>averaged over a century, can tell us which century was warmest. We've
>>never had two complete, independent centuries of global instrumental
>>data (separated by more than one century) to even test this idea. (By
>>the way, I came to my own conclusions long before Broekers piece
>>appeared.) This is an area of further work that I promoted to the NRC
>>about 2 months ago (more funding for Paleo work to assess intercentury
>>precision of all proxy records.)
>>
>>Regarding the IPCC. The IPCC TAR is good, but it is not perfect nor
>>sacred and is open to criticism as any document should be. In some
>>cases it is already outdated. Some of the story lines used to generate
>>high temperature changes are simply ridiculous. The IPCC is us. We are
>>under no gag rule to keep our thoughts to ourselves. I thought our
>>chapter turned out pretty good overall, and I attribute that to the
>>open, working relationship we all had (some other chapter groups did not
>>experience this) and to the tireless efforts of our convening lead
>>authors.
>>
>>Good to hear from you.
>>
>>John C.
>>
>>
>>--
>>************************************************************
>>John R. Christy
>>Director, Earth System Science Center voice: xxx xxxx xxxx
>>Professor, Atmospheric Science fax: xxx xxxx xxxx
>>Alabama State Climatologist
>>University of Alabama in Huntsville
>>http://www.atmos.uah.edu/atmos/christy.html
>>
>>Mail: University of Alabama in Huntsville, Huntsville AL 35899
>>Express: NSSTC/ESSC 320 Sparkman Dr., Huntsville AL 35805
>
>_______________________________________________________________________
> Professor Michael E. Mann
> Department of Environmental Sciences, Clark Hall
> University of Virginia
> Charlottesville, VA 22903
>_______________________________________________________________________
>e-mail: mann@xxxxxxxxx.xxx Phone: (8xxx xxxx xxxxFAX: (8xxx xxxx xxxx
> http://www.evsc.virginia.edu/faculty/people/mann.shtml
>
_______________________________________________________________________
Professor Michael E. Mann
Department of Environmental Sciences, Clark Hall
University of Virginia
Charlottesville, VA 22903
_______________________________________________________________________
e-mail: mann@xxxxxxxxx.xxx Phone: (8xxx xxxx xxxxFAX: (8xxx xxxx xxxx
http://www.evsc.virginia.edu/faculty/people/mann.shtml
</x-flowed>
Original Filename: 990718506.txt | Return to the index page | Permalink | Earlier Emails | Later Emails
From: Kevin Trenberth <trenbert@xxxxxxxxx.xxx>
To: "Michael E. Mann" <mann@xxxxxxxxx.xxx>
Subject: Re: Fwd: Recent Paper from the Competitive Enterprise Institute
Date: Thu, 24 May 2001 11:35:xxx xxxx xxxx(MDT)
Reply-to: <trenbert@xxxxxxxxx.xxx>
Cc: <rbradley@xxxxxxxxx.xxx>, <tkarl@xxxxxxxxx.xxx>, tom crowley <tom@xxxxxxxxx.xxx>, <mhughes@xxxxxxxxx.xxx>, <jto@u.arizona.edu>, <rbradley@xxxxxxxxx.xxx>, <p.jones@xxxxxxxxx.xxx>, <k.briffa@xxxxxxxxx.xxx>, "Folland, Chris" <ckfolland@xxxxxxxxx.xxx>
Mike:
You are right: this is a disinformation campaign.
Some remarks
1) On the Christy et al grl paper, I sent the following to John following
the IPCC Shanghai mtg.:
Date: Mon, 22 Jan 2001 15:39:xxx xxxx xxxx(MST)
From: Kevin Trenberth <trenbert@xxxxxxxxx.xxx>
To: John Christy <christy@xxxxxxxxx.xxx>
Subject: your grl paper
John:
Just back from IPCC. One surprise was the strong Saudi delegation
distributed your recent grl paper and wanted it inserted into the SPM! In
spite of the fact that you are a lead author on Chapter 2 , the paper is
referenced, etc. In fact Simon Brown was there.
Chris Folland made a comment about his hypothesis for this: related to
changes/growth in ships. My hypothesis focusses on the buoy data.
See our recent paper submitted to jgr:
http://www.cgd.ucar.edu/cas/papers/jgr2001b/jgr2.html also
http://www.cgd.ucar.edu/cas/papers/jgr2001a/jgr_interann.html
This shows that during and following El Nino there is an anomalous flux of
heat out of ocean into atmosphere in the east Pacific of order 50 W m-2 over
many months: so ocean T warms relative to air. During La Lina flux goes
other way. i.e. air warms relative to ocean.
So your results must be affected by 1xxx xxxx xxxxevent at end of series and that
may explain trend differential.
Hope this helps
Regards
Kevin
i.e. the result is not as advertized.
=====================
2) wrt Lindzen's paper
Here is the text from my recent Senate testimony
The determination of the climatic response to the changes in heating and
cooling is complicated by feedbacks. Some of these can amplify the original
warming (positive feedback) while others serve to reduce it (negative
feedback). If, for instance, the amount of carbon dioxide in the atmosphere
were suddenly doubled, but with other things remaining the same, the outgoing
long-wave radiation would be reduced and instead trapped in the atmosphere.
To restore the radiative balance, the atmosphere must warm up and, in the
absence of other changes, the warming at the surface and throughout the
troposphere would be about 1.2dg C. In reality, many other factors will
change, and various feedbacks come into play, so that the best IPCC estimate
of the average global warming for doubled carbon dioxide is 2.5dg C. In
other words, the net effect of the feedbacks is positive and roughly doubles
the response otherwise expected. The main positive feedback comes from
increases in water vapor with warming.
In 2001, the IPCC gave special attention to this topic. The many issues with
water vapor and clouds were addressed at some length in Chapter 7 (of which I
was a lead author, along with Professor Richard Lindzen (M.I.T.), and
others). Recent possibilities that might nullify global warming (Lindzen
2001) were considered but not accepted because they run counter to the
prevailing evidence, and the IPCC (Stocker et al., 2001) concluded that ``the
balance of evidence favours a positive clear sky water vapour feedback of the
magnitude comparable to that found in the simulations."
===
Here is a more complete rebuttal, written March 23 to MacCracken.
Subject: Re: Recent Lindzen paper
Kevin Trenberth
1) The paper is based on very simple conceptual ideas that do not mesh with
reality. Fig. 2 is simply not correct. For a more correct view of the
overturning see:
Trenberth, K. E., D. P. Stepaniak and J. M. Caron, 2000: The global monsoon
as seen through the divergent atmospheric circulation. {J. Climate},
13, 3xxx xxxx xxxx.
This paper also shows that the flow in the tropics is dominated by transients
(and thus mixing) of all kinds. The mean overturning is only about a third
of the daily mean variance for a month and much less if the intra diurnal
variations and interannual variations are included.
2) The "observations" analysis makes absolutely no sense to me at all. There
is a totally inadequate description of what is done and no way to decipher
what a dot in Fig 5 or Fig 6 is. Given 20 months, and daily values (how
was that done?) why are there only about 330 points? Why isn't Fig 6 part
of Fig. 5?
In any event the results are totally at odds with other evidence. Here I
refer to the Goes Precipitation Index which uses 3 hourly data on OLR, and
thus on high cloud, as an index of rainfall, and it is clear from many
studies that OLR generally decreases (convection and high cloud increase)
with SST, the reverse of the relationship in Fig. 5.
Moreover the whole conceptual basis for anything here is surely flawed. As
stated, on short time scales SST is not changing. But clouds are NOT caused
by local SST, rather they arise from either transients, like the MJO, or for
the ITCZ and SPCZ (which are major operators in this region), they come from
moisture convergence (P>>E) and so it is the patterns of SST (gradients) as
well as where the warmest water is that determines where the convergence and
clouds occur. Now in the warm pool, the convergence is focussed more on the
edges, as that is where the pressure gradients are greater, and so the
convergence is not where SST is necessarily highest.
In any case, moisture is not equal to cloudy air. Many analyses show that
moisture is much more extensive, see for example
Trenberth, K. E., and C. J. Guillemot, 1998: Evaluation of the atmospheric
moisture and hydrological cycle in the NCEP/NCAR reanalyses. {Climate
Dyn.}, {14}, xxx xxxx xxxx.
Even with such results, other factors need to be considered.
One process might be
High SST => convergence => rainfall and cloud
OR
Less cloud => more solar radiation => higher SST
Those give opposite relations and both operate. The latter is more important
in the Indian Ocean where subsidence (from the Pacific) dominates.
However, it also operates over the oceans in the region in question in
northern summer, because that is the monsoon season, and the main convection
is over land, meaning subsidence over the ocean.
None of this is sorted out in any way in this paper.
In fact it is so bad in this regard I do not know how it got published.
In Fig 5 etc, no correlations are given, nor are their significance levels.
My rough estimate is that the correlation is about 0.2 to 0.3 and that is
significant if the 330 or so points are independent. But why should I have
to guess at that.
Again I would question the editorial and review process.
3) Finally, I refer you to chapter 7 of IPCC which is a more balanced
assessment. Lindzen was a coauthor of that with me and others. Lindzen
wrote 7.2.1 and the same figure 1 in the BAMS article was included as 7.1 in
chapter 7 along with similar ones from models, showing that these things are
fully simulated in good models, although better with higher resolution.
Anyway, his arguments were fully considered in chapter 7 and you can read it
to see the result. The whole of 7.2.1, including 7.2.1.1. 7.2.1.2 and
7.2.1.3 was put together originally by Lindzen, Pierrehumbert and Le Treut,
but basically the final version was rewritten by me to provide better
balance. Pierrehumbert is an agnostic of sorts: disbelieves everything
including models but seems to have faith in simple theories. Le Treut was
sound on the modeling. I did not change the substance of what they prepared,
I did reshape it and polish and it ended up in a form they accepted.
Note at the end it clearly states:
"the balance of evidence favours a positive clear sky water vapour feedback of
the magnitude comparable to that found in the simulations."
The 4 subsections together are quite long and throughly air the issue, much
moreso than any previous IPCC report. For those of you who do not have it:
7.2.1 "Physics of the water vapour and cloud feedbacks" (draft written by
Lindzen) is 1.3 pages, 7.2.1.1 (I think Pierrehumbert) "Water vapour
feedback", is 1 page, 7.2.1.2 "Representation of watre vapour in models" is
1.5 pages (Le Treut) and 7.2.1.3 "Summary on water vapour feedbacks" is half
a page or so.
---------------
Kevin E. Trenberth e-mail: trenbert@xxxxxxxxx.xxx
Climate Analysis Section, NCAR, ML www.cgd.ucar.edu/cas/
P. O. Box 3000, [1850 Table Mesa Drive] (3xxx xxxx xxxx
Boulder, CO 80307 [80305] (3xxx xxxx xxxx(fax)
*******************************
On Thu, 24 May 2001, Michael E. Mann wrote:
> FYI. I received this from a colleague. This gives you some idea of who is
> behind this latest disinformation push.
>
> A note to all regarding the Broecker piece, which has been heavily referred
> to in this and other similar recent pieces (though it is an opinion piece,
> and not peer-reviewed).
> A response by Bradley, Briffa, Crowley, Hughes, Jones, and Mann appears in
> tomorrows issue of "Science". This response simply points out that old
> fallacies that are simply reiterated in Broecker's piece...
>
> mike
>
>
>
>
>
> > COMPETITIVE ENTERPRISE INSTITUTE
> >
> >
> > Advancing the principles of free enterprise and
> > limited government
> >
> >
> > 5/16/01
> >
> > Latest Global Warming Report Already Obsolete
> >
> > By Paul J. Georgia
> >
> >
> >
> > The United Nations Intergovernmental Panel on Climate Change
> >(IPCC) is
> > conducting a campaign of fear to convince us that energy
> >suppression is
> > our only salvation. The "Summary for Policymakers" of the
> >group's latest
> > report ? the report itself has not been officially released ?
> >paints a horrific
> > picture of a climate system gone mad.
> >
> > The new report, known as the "Third Assessment Report" (TAR),
> >is
> > expected to be the focal point for policymakers for the next
> >five years as
> > they decide what to do about global warming, just as the 1995
> >Second
> > Assessment Report has guided policymakers for the last five
> >years.
> > Indeed, the bureaucrats driving the global warming process
> >are using the
> > IPCC to justify their anti-energy policies. Klaus Toepfer,
> >executive
> > director of the United Nations Environment Programme, said,
> >"The
> > scientific consensus presented in this comprehensive report
> >about
> > human induced climate change should sound alarm bells in
> >every
> > national capital and in every local community."[1]
> >
> > In the midst of this campaign, however, the science continues
> >to move
> > apace, leaving many of the IPCC's underlying assumptions and
> > subsequent conclusions in shambles. A sampling of scientific
> >studies
> > published after the completion of the final drafts of the TAR
> >is presented
> > here to give the reader a taste of the constant flux of
> >scientific inquiry and
> > our rapidly changing understanding of the climate system.
> >Indeed, if
> > recent studies are correct there would be little
> >justification for Kyoto-style
> > policies that would ultimately impede humanity's ability to
> >provide itself
> > with the wealth- and health-enhancing benefits of modern
> >civilization.
> >
> > Water Vapor Feedback. The biggest uncertainty in climate
> >science
> > remains "feedback" effects on the climate. The conventional
> >explanation
> > by proponents of global warming theory always assumes that
> > human-induced increases in atmospheric concentrations of
> >greenhouse
> > gases, primarily carbon dioxide, could lead to catastrophic
> >warming of
> > the planet. Man-made greenhouse gas emissions, however, are
> >only an
> > indirect cause of the forecasted warming. A doubling of
> >carbon dioxide
> > concentrations alone would lead to slight warming of about
> >one degree
> > Celsius (1.8 degrees Fahrenheit) over the next 100 years.
> >This small
> > amount of warming, according to standard global warming
> >theory, speeds
> > up evaporation, thereby increasing the amount of water vapor
> >(a major
> > greenhouse gas) in the atmosphere. This "positive water
> >vapor feedback"
> > effect is where most of the predicted warming comes from.
> >This
> > assumption has never been tested.
> >
> > A recent study in the Bulletin of the American Meteorological
> >Society
> > suggests that the reverse is true.[2] The authors find a
> >negative water
> > vapor feedback effect that is powerful enough to offset all
> >other positive
> > feedbacks. Using detailed daily observations of cloud cover
> >from
> > satellites in the tropics and comparing them to sea surface
> >temperatures,
> > the researchers found that there is an "iris effect" in which
> >higher
> > temperatures reduce the warming effect of clouds.
> >
> > According to a NASA statement about the study, "Clouds play a
> >critical
> > and complicated role in regulating the temperature of the
> >Earth. Thick,
> > bright, watery clouds like cumulus shield the atmosphere from
> >incoming
> > solar radiation by reflecting much of it back into space.
> >Thin, icy cirrus
> > clouds are poor sunshields but very efficient insulators that
> >trap energy
> > rising from the Earth's warmed surface. A decrease in cirrus
> >cloud area
> > would have a cooling effect by allowing more heat energy, or
> >infrared
> > radiation, to leave the planet."[3]
> >
> > The researchers found that a one degree Celsius rise in ocean
> >surface
> > temperature decreased the ratio of cirrus cloud area to
> >cumulus cloud
> > area by 17 to 27 percent, allowing more heat to escape.
> >
> > In an interview, lead author Dr. Richard S. Lindzen said the
> >climate
> > models used in the IPCC have the cloud physics wrong. "We
> >found that
> > there were terrible errors about clouds in all the models,
> >and that that will
> > make it impossible to predict the climate sensitivity because
> >the
> > sensitivity of the models depends primarily on water vapor
> >and clouds.
> > Moreover, if clouds are wrong, there's no way you can get
> >water vapor
> > right. They're both intimately tied to each other." Lindzen
> >argues that
> > due to this new finding he doesn't expect "much more than a
> >degree
> > warming and probably a lot less by 2100."[4]
> >
> > The study is the best empirical confirmation to date of the
> >negative
> > feedback hypothesis proposed by Lindzen early on in the
> >global warming
> > debate. It builds on earlier empirical work by Drs. Roy
> >Spencer of NASA
> > and William Braswell of Nichols Research Corporation. Their
> >1997 study
> > also cast doubt on the assumption of a positive water vapor
> >feedback
> > effect.[5] They found that the tropical troposphere, the
> >layer of air
> > between 25,000 and 50,000 feet, is much dryer than climate
> >modelers
> > previously thought. Further empirical work will no doubt
> >confirm whether
> > this phenomenon is common throughout the tropics, which act
> >as the
> > Earth's exhaust vents for escaping heat.
> >
> >
> > Black Carbon. In 1995, the IPCC had to explain in its Second
> > Assessment Report why its previous predictions of global
> >temperature
> > change were nearly three times larger than observed in the
> >actual
> > temperature record. The SAR concluded that emissions of
> >sulfate
> > aerosols from burning coal were offsetting the warming that
> >should be
> > caused by carbon dioxide levels in the atmosphere. Sulfate
> >aerosols,
> > according to this explanation, reflect incoming solar
> >radiation back to
> > space, thereby cooling the planet.
> >
> >
> > The TAR takes the sulfate aerosol idea even further. The SAR
> >had
> > predicted a temperature rise of 1 to 3.5 degrees C (1.8 to
> >6.3 degrees F)
> > over the next 100 years. The TAR goes even further,
> >anticipating a 1.4 to
> > 5.8 degrees C (2.52 to 10.44 degrees F) rise in temperature.
> >The
> > extreme case scenario of a 5.8 degrees C of warming, for
> >instance, is
> > based partly on assumptions that the whole world will raise
> >its level of
> > economic activity to that of the U.S., will equal U.S. per
> >capita energy
> > use, and energy use will be carbon intensive. The primary
> >assumption
> > behind the new scenario, however, is that sulfate aerosol
> >emissions will
> > be eliminated by government regulation, giving carbon dioxide
> >free
> > reign.[6]
> >
> > Sulfate aerosols, then, are a key component of catastrophic
> >global
> > warming scenarios. Without them, the IPCC cannot explain why
> >the
> > earth is not warming according to their forecasts, nor can
> >they
> > reasonably claim that global warming will lead to
> >catastrophes of biblical
> > proportions.
> >
> > A new study in Nature eliminates sulfate aerosols as a
> >corrective for the
> > models. [7] The author, Mark Jacobson, a professor with the
> >Department
> > of Civil & Environmental Engineering at Stanford University,
> >examines
> > how black carbon aerosols affect the Earth's climate. Unlike
> >other
> > aerosols that reflect solar radiation back into space, black
> >carbon (soot)
> > absorbs solar radiation, thereby raising atmospheric
> >temperatures.
> >
> > Until now the warming influence of black carbon was thought
> >to be minor,
> > leading researchers to ignore it. James Hansen, with the
> >Goddard
> > Institute for Space Studies, in a paper published in August
> >2000, first
> > suggested that black carbon plays an important role in global
> > warming.[8] Jacobson found "a higher positive forcing from
> >black carbon
> > than previously thought, suggesting that the warming effect
> >from black
> > carbon may nearly balance the net cooling effect of other
> >anthropogenic
> > aerosol constituents."
> >
> > There you have it. Soot offsets the cooling effect of other
> >aerosols,
> > meaning we are back at square one. Scientists still do not
> >have a
> > plausible explanation for why the Earth has failed to warm in
> >line with
> > climate model results. Indeed, all the prognostications of
> >the IPCC are
> > wrong if the Nature study is right.
> >
> >
> > Natural Cycles. The main propaganda device of the TAR is the
> >"hockey
> > stick graph." The graph is a temperature record derived from
> >tree rings
> > dating back to 1000 AD and running through 1900, with the
> >20th century
> > thermometer-based temperature data attached at the end.[9]
> >It claims to
> > show that global temperatures have remained steady or even
> >decreased
> > during the last millennium until the industrial age, when
> >there was an
> > anomalous warming represented by the blade of the hockey
> >stick. The
> > hockey stick is largely bogus, however. The margin of error
> >is so large
> > that nearly any temperature trend could be drawn to fit
> >within it.
> >
> >
> >
> > The hockey stick features prominently in all of IPCC Chairman
> >Robert
> > Watson's speeches, and to the uninitiated it is very
> >persuasive. Senator
> > John McCain (R-AZ), for example, expressed alarm when he saw
> >the
> > graph at Commerce Committee hearings last May.
> >
> >
> > Watson uses the hockey stick to claim that current warming is
> >greater
> > than at any other time in the last 1,000 years. The Medieval
> >Warm
> > Period (MWP) and the Little Ice Age (LIA) were two naturally
> >occurring
> > events during the last millennium where the range of global
> >temperature
> > change exceeded that of the 20th century. During the MWP,
> >global
> > temperatures were higher than they are today. The MWP,
> >however, does
> > not show up in the hockey stick graph.
> >
> > The hockey stick has effectively been dismantled in a recent
> >study in
> > Science, however.[10] Wallace Broecker, of the
> >Lamont-Doherty Earth
> > Observatory, argues that the MWP and the LIA were indeed
> >global
> > phenomena. Referring to the hockey stick, Broecker notes, "A
> >recent,
> > widely cited reconstruction leaves the impression that the
> >20th century
> > warming was unique during the last millennium. It shows no
> >hint of the
> > Medieval Warm Period (from around 800 to 1200 A.D.) during
> >which the
> > Vikings colonized Greenland, suggesting that this warm event
> >was
> > regional rather than global. It also remains unclear why just
> >at the dawn
> > of the Industrial Revolution and before the emission of
> >substantial
> > amounts of anthropogenic [manmade] greenhouse gases, Earth's
> > temperature began to rise steeply."
> >
> >
> > Broecker reviewed several scientific studies which
> >reconstruct the Earth's
> > temperature history into the distant past using various
> >proxies. He
> > concludes, "The post-1860 natural warming was the most recent
> >in a
> > series of similar warmings spaced at roughly 1500-year
> >intervals
> > throughout the present interglacial, the Holocene."[11] In
> >other words,
> > the current warm period may just be attributable to natural
> >cycles.
> >
> >
> > Flawed Temperature Data. The National Oceanic and
> >Atmospheric
> > Administration (NOAA) claimed that the year 2000 was the
> >sixth
> > warmest since 1880. Other temperature records find less
> >warming.[12]
> > Last year was only the 14th warmest, or 9th coolest, year
> >since 1979
> > according to the satellite temperature record,[13] and only
> >the 9th
> > warmest, according to records that include only measurements
> >from
> > meteorological stations.[14]
> >
> > The NOAA data, which is cited by government officials and the
> >news
> > media, may be the least accurate, according to a study that
> >recently
> > appeared in Geophysical Research Letters.[15] The NOAA
> >datasets "are
> > a mixture of near-surface air temperatures over land and sea
> >water
> > temperatures over oceans," according to lead author Dr. John
> >Christy,
> > professor of atmospheric science and director of the Earth
> >System
> > Science Center at the University of Alabama in Huntsville.
> >
> > Since actual air temperature data over many large ocean areas
> >are
> > nonexistent, the NOAA uses sea surface temperatures as a
> >"proxy,"
> > assuming that sea surface temperatures and air temperatures
> >move in
> > lock step. This is not the case, according to the data
> >compiled by
> > Christy and his colleagues at the Hadley Centre of the United
> >Kingdom's
> > Meteorological Office, who worked on the study. The
> >researchers used
> > buoy data in the tropical Pacific Ocean to compare "long-term
> >xxx xxxx xxxxyear)
> > trends for temperatures recorded one meter below the sea
> >surface and
> > three meters above it."
> >
> > What they found was a significant discrepancy. "For each
> >buoy in the
> > Eastern Pacific, the air temperatures measured at the three
> >meter height
> > showed less of a warming trend than did the same buoy's water
> > temperatures at one meter depth," the study said. The
> >difference is a
> > near-surface seawater warming trend of 0.37 degrees C per
> >decade and
> > an air temperature trend of only 0.25 degrees C per decade
> >during the
> > 20-year period tested. Replacing the sea surface
> >temperatures with the
> > air temperature data reduces the Earth's global warming trend
> >by a third,
> > from 0.19 to 0.13 degree C per decade.
> >
> > This is significant due to difficulties with reconciling the
> >various global
> > temperature data sets, particularly the discrepancy between
> >tropospheric
> > temperatures measured by satellites that show little to no
> >warming, and
> > the surface-based temperature data that show slightly more
> >warming.
> > Last year, the National Research Council stated that both
> >temperature
> > records are correct and speculated about an explanation.[16]
> >
> > This brings up another problem, however. The standard
> >explanation of
> > the greenhouse effect suggests warming occurs first five
> >kilometers
> > above the earth's surface in the atmospheric layer known as
> >the
> > troposphere. How events at the surface are connected to what
> >happens
> > high in the atmosphere is not clear, but it is believed that
> >surface
> > warming would follow tropospheric warming through climatic
> >processes
> > such as air circulation.[17] If both temperature records are
> >correct, then
> > this explanation of the greenhouse effect is wrong. Christy
> >et al. brings
> > the surface temperature data into closer agreement with the
> >satellite
> > data, suggesting that a better explanation for the
> >discrepancy is flawed
> > surface data.
> >
> > Progressive Science. At a press conference at the National
> >Press
> > Club on April 18, Mr. Jan Pronk, chairman of the Sixth
> >Conference of the
> > Parties of the United Nations Framework Convention on Climate
> >Change
> > said most issues were still on the table in the ongoing Kyoto
> >negotiations
> > but the scientific basis of catastrophic global warming could
> >not be
> > questioned. That would be like going back ten years, he
> >said. This is a
> > myopic and erroneous view of science. Science is not static
> >but
> > dynamic. It reaches tentative conclusions at best, and those
> > conclusions constantly give way to new data. The IPCC is a
> >static
> > process, however. The Third Assessment Report is already
> >obsolete and
> > it has not even been released yet. With these four recent
> >studies, it may
> > be time to bid catastrophic global warming theory a warm
> >farewell.
> >
> >
> >
> >
> >
> > [1] "Evidence of Rapid Global Warming Accepted by 99 Nations,"
> >Environment News Service, January 22,
> > 2001.
> > [2] Richard S. Lindzen, Ming-Dah Chou, and Arthur Y. Hou, "Does the
> >Earth Have an Adaptive Infrared Iris?,
> > Bulletin of the American Meteorological Society, 82:417-32, March
> >2001.
> > [3] ftp://www.gsfc.nasa.gov/pub/PAO/Releases/2001/01-18.htm
> > [4] "Is Globe Warming? Sure, But Far Less than Alarmists Say,"
> >Tech Central Station
> > (http://www.techcentralstation.com/BigShotFriday.asp), March 5,
> >2001.
> > [5] Roy W. Spencer and William D. Braswell, "How Dry is the
> >Tropical Free Troposphere? Implications for
> > Global Warming Theory," Bulletin of the American Meteorological
> >Society, 78:1xxx xxxx xxxx.
> > [6] In correspondence with Nature magazine, one of the IPCC's
> >coordinating lead authors, Thomas Stocker of
> > the Physics Institute at the University of Bern in Switzerland,
> >wrote, "First, although climate modeling has
> > advanced during the past five years, this is not the main reason
> >for the revised range of temperature
> > projections. The higher estimates of maximum warming by the year
> >2100 stem from a more realistic view of
> > sulphate aerosol emissions. The new scenarios assume emissions
> >will be reduced substantially in the coming
> > decades, as this becomes technically and economically feasible, to
> >avoid acid rain. Sulphate emissions have
> > a cooling effect, so reducing them leads to higher estimates of
> >warming." See "Climate panel looked at all
> > the evidence," Nature, 410: 299, March 15, 2001.
> > [7] Mark Z. Jacobson, "Strong radiative heating due to the mixing
> >state of black carbon in atmospheric
> > aerosols," Nature, 409: 695-72, February 8, 2001.
> > [8] James D. Hansen, Makiko Sato, Reto Ruedy, Andrew Lacis, and
> >Valdir Oinas, "Global Warming in the
> > twenty-first century: An alternative scenario," Proceedings of the
> >National Academy of Sciences,
> > 97:9xxx xxxx xxxx.
> > [9] The tree ring data originated with Michael E. Mann, Raymond S.
> >Bradley and Malcolm K. Hughes,
> > "Northern Hemisphere Temperatures During the Past Millennium:
> >Inferences, Uncertainties, and Limitations,"
> > Geophysical Research Letters, 26: 759, March 15, 1999.
> > [10] Wallace S. Broecker, "Was the Medieval Warm Period Global?"
> >Science, 291: 1497-99, February 23,
> > 2001.
> > [11] Also see H.H. Lamb, Climate History and the Modern World, (New
> >York: Routledge, 1985), and Brian
> > Fagan, The Little Ice Age: How Climate Made History, 1xxx xxxx xxxx,
> >(New York: Basic Books, 2000).
> > [12] http://www.ncdc.noaa.gov/ol/climate/research/2000/ann/ann.html
> > [13] http://www.ghcc.msfc.nasa.gov/MSU/msusci.html
> > [14] http://www.john-daly.com/press/press-01.htm#Phil
> > [15] John R. Christy, David E. Parker, Simon J. Brown, Ian Macadam,
> >Martin Stendal, and William B. Norris,
> > "Differential Trends in Tropical Sea Surface and Atmospheric
> >Temperatures since 1979," Geophysical
> > Research Letters, 28:183.
> > [16] Reconciling Observations of Global Temperature Change,
> >National Academy Press: Washington, D.C.,
> > 2000.
> > [17] Richard S. Lindzen, "Climate Forecasting: When Models are
> >Qualitatively Wrong," George C. Marshall
> > Institute, Washington, D.C., 2000.
> >
> >
> >
> >
Original Filename: 992021888.txt | Return to the index page | Permalink | Earlier Emails | Later Emails
From: Keith Briffa <k.briffa@xxxxxxxxx.xxx>
To: Stepan Shiyatov <stepan@xxxxxxxxx.xxx>
Subject: Re: Article and money
Date: Fri Jun 8 13:38:xxx xxxx xxxx
Stepan
it is just pressure of work. I am afraid the final report did not go to INTAS . I will do
it this week! I still expect we will get the money outstanding - just late . Sorry.
Keith
At 02:22 PM 5/31/01 +0600, you wrote:
Dear Keith,
Thank you for the print of collaborative article published in the J.
of Geophysical Research I have received some days ago. The article is
very interesting and, I think, these reconstructions will be used by
many researchers of different disciplines.
At the end of the last year Janet asked me to send the account of the
bank to transfer the rest money of the INTAS project (737 Euros). I have
sent you the necessary form to transfer the money for my name, but
the Ekaterinburg Branch of Bank for Foreing Trade did not receive the
money until now. Do you know the reason?
This summer I am very busy. Along with Fritz Schweingruber and his team
(four persons)we will visit many sites (using helicopter) on the North of
European and Siberian Arctic and Subarctic (from the Lower of Pechora
river in the west to the Lover of Khatanga river in the East). We will
try to find a new sources of subfossil wood material between the Yamal
Peninsula and Taimyr Peninsula, on the one hand, and between the Yamal
Peninsula and Kola Peninsula, on the other hand. The second aim is to
collect samples from living trees of different ages for estimating
biomas changes.
After this trip I and my post-graduate student will be working in the
Polar Urals (large-scale mapping of forest-tundra ecosystems over the
forest-tundra ecotone for three time intervals: the beginning of the
XXth century, the 1960ties and the 2000ties.
At the end of September I intend to be in Davos.
Best Regards,
Stepan
stepan@xxxxxxxxx.xxx
--
Dr. Keith Briffa, Climatic Research Unit, University of East Anglia,
Norwich, NR4 7TJ, United Kingdom
Phone: xxx xxxx xxxx Fax: xxx xxxx xxxx
Original Filename: 992349996.txt | Return to the index page | Permalink | Earlier Emails | Later Emails
From: Phil Jones <p.jones@xxxxxxxxx.xxx>
To: "Michael E. Mann" <mann@xxxxxxxxx.xxx>, Thomas R Karl <Thomas.R.Karl@xxxxxxxxx.xxx>
Subject: Re: NRC report on climate change
Date: Tue, 12 Jun 2001 08:46:36 +0100
Cc: trenbert@xxxxxxxxx.xxx,"Michael E. Mann" <mann@xxxxxxxxx.xxx>, rbradley@xxxxxxxxx.xxx,tom crowley <tom@xxxxxxxxx.xxx>, mhughes@xxxxxxxxx.xxx,k.briffa@xxxxxxxxx.xxx, Folland Chris <ckfolland@xxxxxxxxx.xxx>
<x-flowed>
Dear All,
I'd just like to echo all the points made by Mike and Kevin. The
logic behind saying that
there isn't enough paleo data before 1600 yet there may have been even
early millennia which
experienced warming of almost 2 C per millennium escapes me. As Kevin
points out they have
mixed up all the various factors that force climate on interannual to
intermillennial timescales.
One of the main points of IPCC is to synthesize the science, with
particular reference to
potential future changes. Changes in the distant past (glacial and
deglaciation) are of less
relevance to the 21st century because of differences in boundary
conditions. The last few hundred
to a thousand years are clearly more important to the near future. At
least from my quick
reading there seems no explicit reference to changes in the thermohaline
circulation.
Perhaps the paleo people on this list need to redouble their efforts
to empahasize the
importance of the last few thousand years, stressing absolute dating,
calibration and
verification. Another issue that is mixed up in the report (apart from
the forcing) is spatial
scales. I will try and address these at the Chicago meeting. What are the
4 useful sites ?
I just hope in the US that people read the full IPCC reports and the
summaries, rather
than this hastily cobbled together document. I also hope that Europeans
don't read it. It has
already got some air time here and may get some more with Bush here this
week. Issues
like star wars and capital punishment were commented upon whilst I came
to work. Kyoto
wasn't mentioned.
Cheers
Phil
At 10:45 11/06/xxx xxxx xxxx, Michael E. Mann wrote:
>Hi Tom,
>
>Thanks for your message. I know how hard you worked to make the report as
>balanced as possible, and realize this experience must have been a bit
>frustrating for you, after all the careful and hard work you and Chris put
>into our IPCC chapter. While the idea that the limited panel involved in
>the NAS report can provide an improved or more objective assessment of the
>science relative to IPCC seems, of course, ridiculous to a lot of us. But
>I'm very thankful you were on the panel. Needless to say, my criticism
>below is in no way directed towards you, but rather some of the other
>panel members whom I think did a real injustice to the science.
>
>Having seen the list of authors and reviewers of the report, I think I
>have a pretty good idea what the source of a good deal of that skepticism
>is and I think much of it is spurious and unfair. There are legitimate
>caveats and uncertainties--I think we've been very honest about these in
>our publication, and we (as Phil, Keith, and others) are working earnestly
>to improve the reconstructions. But the claims we make (e.g. the
>anomalousness of recent warmth) are guided by the substantial
>uncertainties in the reconstructions, which of course take into account
>uncertainty due to increasingly sparse information back in time, and I
>have yet to see any legitimate argument that our reconstruction (or Phils,
>Toms, Keiths, etc.) is "wrong" within the context of the diagnosed
>uncertainties. Unfortunately, much of the criticsm that has been advanced
>recently is knee-jerk and unsubstantiated, particularly with regard to
>dendroclimatological issues (which Malcolm and Keith can comment on best).
>Much of this has to do w/ a lack of understanding of tree ring information
>(to be honest Tom, I didn't see one name in the list of authors or
>reviewers of the NAS report whom I think is qualified to comment on
>dendroclimatological climate reconstruction and its strengths and
>weaknesses, and that is a real problem. In such a vaccum it is easy, for
>example, for Wally to wave around some highly non-standard, un
>peer-reviewed tree-ring analysis that he has been promoting (which Ed Cook
>himself, a co-author on this, admits makes use of a questionable
>standardization approach), in an attempt to dismiss all other climate
>reconstructions which use tree ring information.
>
>The criticism that there are only "4 useful sites" for reconstructing
>climate over the past 1000 years is especially irksome and ignorant. Does
>Tom C. agree that there are only 4 meaningful records that contribute to
>his reconstruction? Does Phil, or Keith? Where does that number come from?
>The same source as R.L.'s GHG sensitivity factor of 1.0 (i.e., the ether)
>I suspect.
>
>The discussion of paleo in the report (which I realize you had very
>limited control over) is disturbingly misleading and flawed to many of us
>who actually work in this area. There are throwaway statements about
>millennial trends of 2 C in global temperatures being typical during the
>early Holocene that have no basis in fact. They are again probably based
>on this increasingly disturbing notion that Arctic ice core borehole
>thermometry or other ice core information tells us anything at all about
>the hemisphere let alone globe. A small number of scientists are really
>misleading the scientific community in this regard. How odd that the panel
>was happy to claim that there were millennial periods with 2 degree C
>warming in global temperature during the holocene (for which there is no
>reliable empirical evidence whatsoever) and yet focuses its skepticism on
>much more detailed and careful assessments of the most recent millennium.
>I think you can see why some of us are frustrated by this type of
>inconsistency, and suspect some degree of bias or agenda at work. There
>was a clear bias in the panel in the promotion of ice cores (which sample
>a very limited portion of the globe and are very questionable in their
>ability to say *anything* about hemispheric or global temperature
>variations). I am disturbed by this because the NAS report shouldn't have
>been promoting a particular specific area of funding. It seems to have.
>
>Finally, with regard to one of the primary supposed discrepancies in the
>paleo record of the past 1000 years, temperature reconstructions from
>boreholes vs. other proxies, I'll be presenting some results in Chicago
>which I think you'll all find quite elucidating. Turns out there is no
>discrepancy after all. More on that soon. I'll also try to confront both
>the "real" and "imagined" sources of uncertainty and bias in
>paleoreconstructions in my presentation there, and we should all be able
>to have a very healthy discussion of this.
>
>I really think that there was a bias in this panel which cannot be
>considered representative of the community as a whole. So I vote that we
>not over-react. I'm anxious to see Lindzen, Broecker, or Mike Wallace
>publish a peer-reviewed critical analysis of proxy data over the past 1000
>years. Until that day, I take their comments w/ a shaker of salt...
>
>mike
>
>At 09:41 AM 6/11/xxx xxxx xxxx, Thomas R Karl wrote:
>>Kevin,
>>
>>I agree with most of your points. It was a very interesting Panel. I should
>>emphasize however, that the Paleo record (at least the last 1000 years)
>>has many
>>critics, and we really need to show how the data prior to 1600 stands
>>up. Some
>>contend there are only 4 good sites in the first part of the record. I
>>am not sure
>>of this, perhaps Mike and others will explain this in Chicago.
>>
>>Regards, Tom
>>
>>Kevin Trenberth wrote:
>>
>> > FYI
>> >
>> > Some comments on the NRC/NAS report on the IPCC and global warming
>> >
>> > Kevin Trenberth
>> > 6/7/2001
>> >
>> > While the report overall is an endorsement of the IPCC report and the
>> > process, it has a lot of "buts" in it, and the overall tone is to somewhat
>> > downplay the problem. It does not focus on policy relevant issues. The
>> > report was done in a very hurried fashion and perhaps as a result,
>> there are
>> > several factual errors or misstatements and there are errors of
>> omission. My
>> > impression is that it tends to overstate the caveats and need for
>> questioning
>> > of results and understate the certainties and likelihoods.
>> >
>> > 1. In dealing with natural variability, there are two aspects that are
>> > mixed in this report. There is natural variability of climate
>> > that is tied to external forcings, such as variations in the sun,
>> > volcanoes, and the orbital variations of the Earth around the sun. The
>> > latter is the driver for the major ice ages and interglacials. The
>> second
>> > kind of natural variability is that internal to the climate system
>> arising
>> > from interactions between the atmosphere and ocean, such as El
>> Nino, for
>> > instance. This variability occurs even in an unchanging climate.
>> >
>> > In the section dealing with this and in the summary, both kinds of
>> > variability are discussed as if they are the second kind. Glacial to
>> > interglacial differences are discussed without any mention of the known
>> > causes and as if these can happen without a cause. This is
>> misleading at
>> > best. A consequence is that there is no clear statement that the
>> > recent warming is outside the realm of natural variability - and that a
>> > cause is needed. And the cause is human induced changes in the
>> > atmospheric composition.
>> >
>> > 2. The report does not clearly address issues in attribution of recent
>> > climate change to human activities. At the end of p 3 in the
>> summary it
>> > makes an equivocal statement. It avoids the issue that the recent
>> > temperature increase is outside any estimates of natural variability
>> > without any forcings. What else is the warming due to?
>> >
>> > On p 14, it does not sum up the forcings and make a clear statement
>> about
>> > the total. Nowhere does it say that the recent warming has to be
>> because
>> > of an increase in heating. This reasoning also put limits on how large
>> > aerosol cooling can be.
>> >
>> > On p 17, the ambiguity over the term "natural forcing" is used to
>> say that
>> > a causal link can not be unequivocally established. It does not mention
>> > estimates of variability from the paleo record and how well they
>> agree (or
>> > not) with model estimates.
>> >
>> > It does not note on p 17 that many models show the signal of
>> greenhouse gas
>> > effects emerging from the noise of natural variability about 1980. The
>> > attribution statement is weak.
>> >
>> > 3. Several statements about the hydrological cycle, rainfall, and
>> warming are
>> > misleading and even wrong. One direct consequence of this is that
>> > statements about changes in extremes are missing, understated and
>> incorrect.
>> > Another is to understate the threats in the tropics and subtropics.
>> >
>> > It begins in the first sentence of the summary: "Greenhouse gases are
>> > accumulating as a result of human activities, causing surface air
>> > temperatures and subsurface temperatures to rise." Later in the
>> paragraph
>> > it states "Secondary effects are suggested by computer model
>> simulations
>> > and basic physical reasoning. These include increases in rainfall
>> rates
>> > and increased susceptibility of semi-arid regions to drought."
>> > While the first statement is true, is is misleading. The increased
>> > greenhouse gases cause increased heating (also called radiative
>> forcing in
>> > this report). It is also referred to as "warming". The latter term is
>> > ambiguous and misused in this report, by confusing where it should mean
>> > "heating" versus where it should mean "increased temperature". So
>> while
>> > some of the increased heating does in fact cause an increase in surface
>> > temperature, much of the heating goes into evaporation of surface
>> > moisture. This changes the moisture content of the atmosphere and
>> > rainfall. This increase in the hydrological cycle is NOT a secondary
>> > effect, it is a primary one.
>> >
>> > Moreover, the increase in atmospheric moisture content is much
>> greater than
>> > the increase in evaporation, because it is controlled by the
>> temperature
>> > (which determines the water holding capacity of the atmosphere
>> through the
>> > so-called Clausius Clapeyron effect) while the evaporation is
>> controlled
>> > by the surface heating. For doubled CO2, evaporation and the overall
>> > hydrological cycle speeds up by about 3%, but the moisture in the
>> > atmosphere increases by about 6% per degree C, or about 15% for a
>> doubling
>> > of CO2.
>> >
>> > The rainfall intensity is determined by the available moisture, and
>> so it
>> > increases at about the latter rate. But the total precipitation
>> increases
>> > only at the former rate, and so the frequency of precipitation must
>> > decrease in some way. This also means that the residence time for
>> water
>> > vapor increases in a world with increased heating. The increased
>> drying
>> > means increased risk of drought everywhere, not just semi-arid
>> locations,
>> > and increased intensity increases risk of floods. These increases
>> in risk
>> > of extremes are direct consequences and are not adequately
>> mentioned. In
>> > the section on "Future climate change", p 19, one statement is
>> wrong: "An
>> > increase in the recycling rate of water in the hydrological cycle is
>> > anticipated in response to higher global average temperatures." The
>> > increased hydrological cycle is in response to increased heating, not
>> > increased temperatures (and may not occur if only the temperature is
>> > increased). The term "recycling" is normally used to refer to
>> moisture that
>> > evaporates and precipitates in the same catchment, and is
>> misleading here.
>> >
>> > A consequence of all this is that in the summary on p 4 in
>> addressing the
>> > question "What will be the consequences of global warming (e.g.,
>> extreme
>> > weather, ...)...", there is no statement about increased risks of
>> extremes
>> > of floods and droughts, and heat waves. It also underplays the
>> risks of
>> > increases in pests and diseases (like fungal diseases) in agriculture.
>> >
>> > 4) The report contends that emissions in the last decade have averaged
>> less
>> > than in IPCC predictions, notably for CO2 and methane. However, the
>> IS92c
>> > scenario had flat CO2 emissions till 2020 and then declining
>> emissions to
>> > 2100, and for methane values projected are quite close to those
>> observed.
>> > In any case they are not forecasts but scenarios, to be used for
>> planning
>> > purposes. Statements in the summary on p 4 and on p19 are misleading.
>> > Also, the claim that CO2 emissions will accelerate for mid-range
>> estimates
>> > is not true: those have emissions increasing at a close to constant
>> rate.
>> >
>> > 5) The report dodges the issue of what is a "safe" level of
>> concentration of
>> > greenhouse gases, and has a strong US bias. It does not list on p
>> 21, for
>> > instance, the vulnerability of small island States to sea level
>> rise and
>> > of poorer countries to all aspects of climate change. Again it avoids
>> > discussion of changes in extremes. It is also incorrect in stating
>> "The
>> > largest changes occur consistently in the regions of the middle to high
>> > latitudes." This is true only for temperature and NOT for
>> precipitation
>> > (also p 8) perhaps because of the issues raised in item 2).
>> > Therefore it understates the threats to tropical countries.
>> >
>> > Some details:
>> >
>> > p 6: The accepted value of forcing for doubled CO2 with a stratosphere in
>> > adjustment (which occurs rapidly) is 3.5 W m-2, not 4.
>> >
>> > p 11: sheep are just as much a source of methane as cows and cattle.
>> >
>> > p 24: the list of variables needed for an observing system should include
>> > those for the ocean.
>> >
>> > ---------------
>> > Kevin E. Trenberth e-mail: trenbert@xxxxxxxxx.xxx
>> > Climate Analysis Section, NCAR, ML www.cgd.ucar.edu/cas/
>> > P. O. Box 3000, [1850 Table Mesa Drive] (3xxx xxxx xxxx
>> > Boulder, CO 80307 [80305] (3xxx xxxx xxxx(fax)
>> > *******************************
>
>_______________________________________________________________________
> Professor Michael E. Mann
> Department of Environmental Sciences, Clark Hall
> University of Virginia
> Charlottesville, VA 22903
>_______________________________________________________________________
>e-mail: mann@xxxxxxxxx.xxx Phone: (8xxx xxxx xxxxFAX: (8xxx xxxx xxxx
> http://www.evsc.virginia.edu/faculty/people/mann.shtml
Prof. Phil Jones
Climatic Research Unit Telephone +44 xxx xxxx xxxx
School of Environmental Sciences Fax +44 xxx xxxx xxxx
University of East Anglia
Norwich Email p.jones@xxxxxxxxx.xxx
NR4 7TJ
UK
----------------------------------------------------------------------------
</x-flowed>
Original Filename: 992879415.txt | Return to the index page | Permalink | Earlier Emails | Later Emails
From: "Michael E. Mann" <mann@xxxxxxxxx.xxx>
To: "Dr. Nanne Weber" <weber@xxxxxxxxx.xxx>
Subject: Re: workshop report
Date: Mon, 18 Jun 2001 11:50:xxx xxxx xxxx
Cc: "Michael E. Mann" <mann@xxxxxxxxx.xxx>, Julia Cole <jcole@xxxxxxxxx.xxx>, rbradley@xxxxxxxxx.xxx, jto@u.arizona.edu, storch@xxxxxxxxx.xxx, wanner@xxxxxxxxx.xxx, tom crowley <tom@xxxxxxxxx.xxx>, k.briffa@xxxxxxxxx.xxx
<x-flowed>
Hi Nanne,
Thanks for your comments. I've asked Julie Cole, who is attempting a
revised draft, to incorporate your suggestions. Hans or you should also
provide a revised paragraph 7 that is more to your liking than what I wrote.
I'm requesting that Julie wait until the end of this week (Friday, Jun 22)
to give the others time to get their comments in also. Then, after Julie
provides me w/ her revised draft, I'll try to make a few more small changes
and sent that onto the group for suggested final changes.
I hope this sounds acceptable to all concerned?
thanks,
mike
At 03:22 PM 6/18/01 +0000, Dr. Nanne Weber wrote:
>Hi Mike (and others),
>
>Below follow some comments on the draft report for EOS that you send
>around. The
>general outline is fine for me. Responding to Julie's comment on the
>large-scale/regional
>reconstruction issue: I guess that the three different approaches
>mentioned are not
>necessarily restricted to large-scale. Especially (1) can be for all
>scales, (2) will work
>better for large scales, but (3) could be very well applied to regional
>scales
>like African monssoon or NAO. However, I do think that this 'scales
>issue'
>should be addressed explicitly in the text (as indicated in my
>comments).
>
>We can not cover all of the workshop in a small EOS report, but I do
>think
>that there should be more emphasis on the different model strategies
>presented,
>process-based proxy modeling and some more mention of historical
>documentary data.
>
>I am willing to take my share in the rewriting task. Just let me know
>what is most
>convenient for you.
>
>
>One practical point: the Netherlands funding agency is called National
>Research Program (NRP) of the Netherlands (KNMI is my affiliation, but
>it
>did not pay the bill)
>
>Thanks,
>
>Nanne
>===================================================
>
>
>First para, first sentence: name all boundary conditions relevant
>for geological timescales (astronomical forcing, orography, GHG
>concentrations)
>or none.
>
>First para, fifth sentence: Three distinct approaches have .... in
>reconstructing
>the LARGE-SCALE AND REGIONAL climate history of past centuries and
>millenia.
>
>First para, point (3): the assimilation of paleoclimatic proxy data
>directly
>into (leave out 'forced') climate model integrations (using statistical
>models to upscale the proxy data to large-scale climatic patterns), in a
>manner
>conceptually etc,.
>
>
>
>Second para: can be written in a more condense manner. One ore two
>sentences
>discussing the large-scale versus regional climate issue should be
>added. For example:
>(i) add after the second sentence ('The first method...'): This holds
>for
>spatial scales ranging from local (in the case of site-by-site
>calibration) to
>large scale (in the case of pattern calibration, e.g. ENSO and NAO) and
>up to hemispheric/global.
>(ii) add just before 'It was our belief that a meeting': The second and
>third
>approaches are more suitable for reconstructing the actual large-scale
>climatic
>state, as the local climate is inherently noisy and only to a limited
>amount determined by external forcing or related to large-scale patterns
>
>like e.g. the NAO.
>
>Second para, modify the description of the third approach as follows:
>The third approach can be thought of......, but it is nudged
>toward the actual observed large-scale climatic state at the time
>resolution provided by the proxy data. This method is more resistant to
>the potential biases......model-based approaches, but it is relatively
>untested to the application of proxy data.
>
>
>
>Fourth para: leave out second sentence "A frequency-domain...' (too much
>
>technical detail, in a too condensed form to be understandable to a
>general
>reader of EOS).
>
>
>
>Fifth para: very much biased toward the modeling of large-scale, forced
>signal.
>My go at modelling paragraph(s):
>Three types of modelling experiments were distinguished: free
>simulations without
>any external forcing, giving insight into the patterns and timescales of
>
>internally-generated variability, forced simulations and simulations
>constrained
>by the assimilation of proxy data. Examples were presented, where models
>used ranged
>from an energy balance model (EBM), an intermediate-complexity climate
>model (EMIC) to
>atmospheric and coupled General Circulation Models (GCM). Simulations
>with an
>EBM as well as a GCM appear to explain variations over
>century-to-decadal timescales
>in proxy-based reconstructions of the Northern Hemisphere temperature
>over the past millenium, using estimated changes in radiative forcing
>(solar
>irradiance changes, volcanic activity, GHG and aerosol concentrations).
>Discrepancies,
>however, etc.... (a bit long as it is now).
>
>Process-based models of glaciers and sea level were used to generate
>synthetic
>records of these low-frequency proxies on the basis of EMIC and GCM
>simulations,
>using unforced runs as well as orbital and solar-forced runs.
>Over longer timescales simulated glacier lengths and sea level
>variations
>can be used to validate the models response in climatic parameters
>which are not well constrained by existing proxy data, like the
>hydrological cycle.
>In addition, model-data intercomparisons can be carried
>out on the level of the proxy itself rather than on the level of
>reconstructed
>climatic variables. Such process-based models require an understanding
>of local meteorological processes as well as the complicated (physical,
>biological or
>chemical) processes determining the proxy itself. A promising new model
>of
>tree-ring growth was presented.
>
>A new data-assimilation approach to paleoclimatic reconstruction DATUN
>(..)
>was discussed at length....
>This paragraph is not very clear as it is. I can have a go at it,
>but maybe Hans should.
>
>
>
>Para seven: This could be much shorter. Several points are mentioned
>here
>for the first time--> move up te earlier paragraphs (as indicated above)
>
>....currently emphasized high-resolution proxies such as tree rings,
>HISTORICAL
>DOCUMENTARY DATA, corals and ice cores. In addition, low-frequency
>climate
>variability may be reconstructed from low-resolution proxies such as
>borehole
>records, glaciers, foraminifera in marsh cores indicative of sea level
>as well
>as lake and ocean sediments which are not necessarily laminated.
>Process-based proxy models would enable to better exploit the
>information
>contained in proxy records and help to resolve the origin of apparent
>discrepancies between the different data sources. It is also important
>to
>better constrain the histories of radiative forcings prior to AD 1600.
>It was
>strongly felt that there should be an emphasis on developing
>projects....
_______________________________________________________________________
Professor Michael E. Mann
Department of Environmental Sciences, Clark Hall
University of Virginia
Charlottesville, VA 22903
_______________________________________________________________________
e-mail: mann@xxxxxxxxx.xxx Phone: (8xxx xxxx xxxxFAX: (8xxx xxxx xxxx
http://www.evsc.virginia.edu/faculty/people/mann.shtml
</x-flowed>
Original Filename: 993768960.txt | Return to the index page | Permalink | Earlier Emails | Later Emails
From: Martin Welp <Martin.Welp@xxxxxxxxx.xxx>
To: gberz@xxxxxxxxx.xxx, tloster@xxxxxxxxx.xxx, ccarraro@xxxxxxxxx.xxx, juergen.engelhard@xxxxxxxxx.xxx, guentherr@xxxxxxxxx.xxx, bhare@xxxxxxxxx.xxx, klaus.hasselmann@xxxxxxxxx.xxx, m.hulme@xxxxxxxxx.xxx, carlo.jaeger@xxxxxxxxx.xxx, martin.welp@xxxxxxxxx.xxx
Subject: ECF: Agenda of the telephone conference 2 July 2001
Date: Thu, 28 Jun 2001 18:56:00 +0200
Dear member of the ECF steering committee,
The next telephone conference takes place on Monday, 2 July 2001 at
17.00-18.00 CET. The agenda is as follows (it may be modified at the
beginning of the meeting):
1. Minutes of previous telephone conference (Draft sent by email on
14.6.2001) (5 Min.)
2. ECF preparatory meeting in Brussels (15 Min.)
(Agenda, Inputs: project descriptions, Outputs: workplan, sketch of a
position paper)
3. ECF as an Association and/or Foundation (15 Min.)
4. Three priority projects (15 Min.)
5. Varia (10 Min.)
Important!! Please check that the telephone number where you want to be
called is correct.
Gerhard Berz xxx xxxx xxxx
Carlo Carraro xxx xxxx xxxx
J
Original Filename: 993841811.txt | Return to the index page | Permalink | Earlier Emails | Later Emails
From: Keith Briffa <k.briffa@xxxxxxxxx.xxx>
To: "Dr. Reinhard B
Original Filename: 994083845.txt | Return to the index page | Permalink | Earlier Emails | Later Emails
From: "Ian Harris (Harry)" <harryharris@xxxxxxxxx.xxx>
To: list@xxxxxxxxx.xxx
Subject: Re: [ngp-list] Press Release 'Global Warning' talk establishes West Norfolk Green Party
Date: Mon, 2 Jul 2001 10:24:05 +0100
Reply-to: list@xxxxxxxxx.xxx
<x-flowed>*sigh*
At 9:43 am +0100 2/7/01, Williams, Derek wrote:
>No, it's very dangerous to make predictions like this and IMO doesn't
>help the cause. Even without human activities, natural things like big
>volcanoes can easily disrupt the climate in such a way as to swamp the
>signs of global warming and indeed produce severe weather conditions as
>a casual glance at met records for the past couple of hundred years
>quickly shows (frozen Thames etc)
>
>One example of how this could work: A big volcanoe errupting a massive
~~~~~~~~ hello Dan :-)
>amount of ash could change the albedo of the earth by enough to counter
>the warming effect of the increased CO2 (albedo - and sorry if the
>selling is wrong - measures the reflectivity of the earth, more smoke in
~~~~~~~ *grin*
>the atmoshere reflects more radiation back to space). Cutting the
>forrests down has the same effect, both because of the smoke from the
>burning trees and the resulting cleared ground, which is why on photos
>of building sites the bare earth looks white.
>
>Over simplification does no-one any good.
You're hardly any better, Derek: this is hardly a 'Nature' paper, is it?
You're talking about volcanic events that have a very different
duration than the warming effects we're talking about. Major
eruptions show up very clearly in the tree ring records going back
centuries, but that's because you can pick out a one-to-three year
spike rather than a prolonged cooling effect.
A rudimentary understanding of albedo is all very well, but since the
radiative heat input from the Sun is still poorly understood
(surprisingly) we can't deduce too much. In any case relying on mass
deforestation or a prolonged series of major volcanic eruptions is
hardly an attractive alternative to giving up burning what are finite
resources anyway.
Have a look at http://www.cru.uea.ac.uk/ - particularly
http://www.cru.uea.ac.uk:80/cru/info/warming/. We're looking at an
*unprecedented* acceleration in temperature, and it's not due to a
sudden lack of volvanic eruptions. Even if it turns out to be
naturally-occurring, who's willing to take that chance? We should be
trying to wean ourselves off of unsustainable energy generation and
use anyway.
Cheers
Harry
--
Ian Harris - "Harry" Telephone: xxx xxxx xxxx
Climatic Research Unit Email: i.harris@xxxxxxxxx.xxx
University of East Anglia
Norwich NR4 7TJ
The content of this email should not be construed to represent the
views of the Climatic Research Unit as a whole, nor of any other
member of the Unit. If in doubt, please seek clarification before
attribution.
</x-flowed>
Original Filename: 994186877.txt | Return to the index page | Permalink | Earlier Emails | Later Emails
From: Phil Jones <p.jones@xxxxxxxxx.xxx>
To: Keith Briffa <k.briffa@xxxxxxxxx.xxx>, "Dr. Reinhard B
Original Filename: 994187098.txt | Return to the index page | Permalink | Earlier Emails | Later Emails
From: "Michael E. Mann" <mann@xxxxxxxxx.xxx>
To: Hans von Storch <Hans.von.Storch@xxxxxxxxx.xxx>
Subject: Re: EOS report
Date: Tue, 03 Jul 2001 15:04:xxx xxxx xxxx
Cc: "Michael E. Mann" <mann@xxxxxxxxx.xxx>, Julie Jones <jones@xxxxxxxxx.xxx>, Julia Cole <jcole@xxxxxxxxx.xxx>, rbradley@xxxxxxxxx.xxx, jto@u.arizona.edu, weber@xxxxxxxxx.xxx, wanner@xxxxxxxxx.xxx, tom crowley <tom@xxxxxxxxx.xxx>, k.briffa@xxxxxxxxx.xxx, Martin Widmann <Martin.Widmann@xxxxxxxxx.xxx>
<x-flowed>
HI Hans,
Yes--it was the discussion of this in the De Bilt meeting report that led
me to think this was envisioned in a broadened version of the DATUN
approach. I thought the idea was that you would eventually use a forward
biological/physical model to scale up from a given proxy an estimate of say
precipitation or temperature for an atmospheric model gridpoint and use
that to nudge say the slp or 500 mb field into a particular
configuration. This is clearly more ambitious than what you are doing now,
and I suppose I was blurring the distinct efforts of Nanne and colleagues
with that of yours and colleagues. I makes much more sense at present to
only use a statistically-based upscaling of the proxy data. The other
possibility remains intriguing, but we are certainly far off from doing
that in my opinion as well. I'm actually quite relieved to find out that I
was wrong in assuming that this is the direction the DATUN approach was going.
thanks for the clarification,
mike
At 08:32 PM 7/3/01 +0200, you wrote:
>Hi folks,
>"forward models" can only deal with "weather -> proxy", but we need "proxy
>-> circulation". If we had forward models, and we should certainly strive
>to develop such models, we could generate large data sets of consistent
>pairs "weather, proxy" and then derive empirically (neural nets?) the
>needed inverse relationship. (Actually, this method is used at our lab to
>evaluate the informational value of remotely sensed data about water
>quality in coastal seas.) But the inverse relationship is not
>process-based but necessarily phenomenological.
>
>I think the need for forward models was spelled out in the report about he
>De Bilt meeting in 1999 (see EOS paper by Weber and me).
>
>Regards
>
>Hans
>
>At 13:52 03.07.xxx xxxx xxxx, Michael E. Mann wrote:
>>Dear Julie et al,
>>
>>Then I apologize--I thought the idea in DATUN was to at leat eventually
>>incorporate physical or biologically-based models of proxies into the
>>upscaling effort in addition to/in place of statistical upscaling. There
>>was lots of discussion of this, and I recall Hans early on having
>>described to me plans to use physical models of proxies in the process
>>(though I could be mistaken), so I thought that was a planned component
>>of DATUN, and the work that you described (ie, using empirical CCA
>>techniques) was just a preliminary empirical approach. But from what
>>Martin and you have told me, this is not the case, and there is no plan
>>in DATUM to use physical/biological forward models of proxies. If someone
>>out there still believes this is *not* the case please let me know!
>>Otherwise, the wording will be clarified to indicate that it is a
>>"statistical" and not physical/biological model that is used to upscale
>>the proxy information.
>>
>>That simplifies things quite a bit...
>>
>>mike
>>
>>At 07:18 PM 7/3/01 +0200, Julie Jones wrote:
>>
>>>Hi Mike
>>>
>>>I'm getting very confused now!
>>>
>>>If you mean 'forward modelling', by what I term upscaling, this is done
>>>in exactly the same way as most other climate reconstructions,
>>>i.e. calibrating proxy data against climate data using linear multivariate
>>>statistical methods (in this case I use CCA), so has the same errors
>>>inherent in it as other reconstructions where proxy data has been
>>>calibrated against large-scale climate, or climate indices.
>>>
>>>If your idea is that such large-scale climate reconstructions may have
>>>additional uncertainties compared to local empirical models, where proxy
>>>data are calibrated against local climate records, I agree that this is
>>>so - but I think this applies to all such non-local reconstructions, so
>>>should maybe go in the paragraph which discusses reconstructions of
>>>regional climate variability to keep things consistent.
>>>
>>>The additional potential source of error specific to the DATUN method
>>>compared to the other climate reconstructions, whether local or
>>>large-scale, is in the 'nudging' to assimilate the climate reconstructions
>>>obtained as above into the GCM, which should probably go into the text, so
>>>we could perhaps change the end of the paragraph to read:
>>>
>>>......This method is more resistant to biases specific to
>>>purely empirical or model-based approaches but it is relatively untested
>>>using proxy data, and prone to additional uncertainties in the nudging
>>>method used to assimilate the proxy data.
>>>
>>>
>>>Am I on the right track, or have I missed something?
>>>
>>>
>>>cheers
>>>
>>>Julie
>>>
>>>************************************
>>>Dr. Julie M. Jones
>>>Institute for Coastal Research
>>>GKSS Forschungszentrum
>>>Max-Planck-Strasse
>>>D-21502 Geesthacht
>>>Germany
>>>
>>>e-mail: jones@xxxxxxxxx.xxx
>>>phone: +49 (0)4xxx xxxx xxxx
>>>fax: +49 (0)4xxx xxxx xxxx
>>>************************************
>>>
>>>On Tue, 3 Jul 2001, Michael E. Mann wrote:
>>>
>>> > Dear All,
>>> >
>>> > I am working on preparing a final version of the workshop report based on
>>> > Julie (C)'s revisions, and comments thusfar recieved.
>>> >
>>> > There is one instance below in which it seems especially important
>>> that we
>>> > agree on the wording, so I wanted to give you my revised wording now and
>>> > let you comment on it if you see any problem:
>>> >
>>> > The third approach represents a hybrid of the first two; it
>>> prescribes the
>>> > dynamics of the system using model physics, but aims to reproduce the
>>> > historical climate evolution by "nudging" the model towards reconstructed
>>> > climate estimates. This method is more resistant to biases specific to
>>> > purely empirical or model-based approaches but it is relatively untested
>>> > using proxy data, and prone to additional uncertainties in the forward
>>> > models employed to describe proxy-climate relationships.
>>> >
>>> > I think the latter statement is important because the assumption in the
>>> > forward model is *not* the same assumption as in empirical
>>> reconstructions
>>> > (I take a slight issue w/ Julie J in this regard). The forward modeling
>>> > makes some universal assumptions regarding e.g. tree growth patterns. The
>>> > empirical calibration approach calibrates the individual trees against
>>> > local meteorological/climate records. It doesn't make any universal
>>> > assumptions, though the local calibration may be flawed! In other words,
>>> > we're not saying that one method is better than the other, but the
>>> > potential pitfalls are definitely different! I think this needs to be
>>> > expressed, hence my revised wording. Julie J should let me know if
>>> there is
>>> > a problem w/ this, since she and Julie C spent some time parsing the
>>> > wording on the paragraph in question.
>>> >
>>> > Thanks,
>>> >
>>> > mike
>>> >
>>> > At 07:43 PM 6/28/01 +0200, Julie Jones wrote:
>>> >
>>> > >Hi Julie
>>> > >
>>> > >Yes, that works, although if I could ask for one extra word -
>>> > >
>>> > >...but it is also limited by potential....
>>> > >
>>> > >cheers
>>> > >
>>> > >Julie
>>> > >
>>> > >
>>> > >************************************
>>> > >Dr. Julie M. Jones
>>> > >Institute for Coastal Research
>>> > >GKSS Forschungszentrum
>>> > >Max-Planck-Strasse
>>> > >D-21502 Geesthacht
>>> > >Germany
>>> > >
>>> > >e-mail: jones@xxxxxxxxx.xxx
>>> > >phone: +49 (0)4xxx xxxx xxxx
>>> > >fax: +49 (0)4xxx xxxx xxxx
>>> > >************************************
>>> > >
>>> > >On Thu, 28 Jun 2001, Julia Cole wrote:
>>> > >
>>> > > > Hi Julie,
>>> > > >
>>> > > > First, sorry for the author oversight! I did not change that from
>>> > > > Mikes original, which did not have you on it, but he told me you
>>> > > > should be added.
>>> > > >
>>> > > > I like all your suggestions. I would alter the wording of the last
>>> > > > one a bit maybe, to use somewhat fewer words. Does this work? (68
>>> > > > words instead of 78). We are tight on space.
>>> > > >
>>> > > > The third approach represents a hybrid of the first two; it
>>> > > > prescribes the dynamics of the system using model physics, but aims
>>> > > > to reproduce the historical climate evolution by "nudging" the model
>>> > > > towards reconstructed climate estimates. This method is more
>>> > > > resistant to biases specific to purely empirical or model-based
>>> > > > approaches, but it is limited by potential instabilities in the
>>> > > > proxy-climate relationships and is relatively untested using proxy
>>> > > > data.
>>> > > >
>>> > > > cheers, Julie
>>> > > >
>>> > > >
>>> > > >
>>> > > > >Dear All,
>>> > > > >
>>> > > > >Thanks Julie and Mike for your work on the paper. I have just a few
>>> > > > >sentences where I suggest alterations.
>>> > > > >
>>> > > > >1. First paragraph:
>>> > > > >
>>> > > > >'State-of-the-art climate models are also being applied to
>>> analyze late
>>> > > > >Holocene climate sensitivity, upscale paleodata to large-scale
>>> > > > >reconstructions, and simulate proxies themselves'
>>> > > > >
>>> > > > >I suggest changing to
>>> > > > >
>>> > > > >'State-of-the-art climate models are also being applied to
>>> analyze late
>>> > > > >Holocene climate sensitivity, assimilate large-scale climate
>>> > > > >reconstructions from palaeodata, and simulate proxies themselves.'
>>> > > > >
>>> > > > >
>>> > > > >2. Paragraph2, last sentence:
>>> > > > >
>>> > > > >'....patterns of atmospheric circulation, just as meteorological
>>> > > > >information is assimilated into numerical weather forecasting
>>> models (von
>>> > > > >Storch et al. 2000).'
>>> > > > >
>>> > > > >I suggest changing to
>>> > > > >
>>> > > > >....patterns of atmospheric circulation, in a conceptually
>>> similar way to
>>> > > > >the assimilation of meteorological information into numerical
>>> weather
>>> > > > >forecasting models (Weber and von Storch 1999; von Storch et al.
>>> 2000)
>>> > > > >
>>> > > > > - the Weber and von Storch reference is already in the
>>> reference
>>> > > list.
>>> > > > >
>>> > > > >3. Paragraph 3,
>>> > > > >
>>> > > > >'The third approach represents a hybrid of the first two; it
>>> prescribes
>>> > > > >the dynamical evolution of the system from climate physics but
>>> > > > >is "nudged" toward the observed climate by the proxy data. This
>>> method
>>> > > > >is more resistant to the biases specific to purely empirical or
>>> purely
>>> > > > >model-based approaches, but it is limited by potential instabilities
>>> > > > >in the proxy-climate relationships and by imperfections in the
>>> upscaling
>>> > > > >models, and it is relatively untested using proxy data.'
>>> > > > >
>>> > > > >I would suggest changing to the following (As the upscaling
>>> models are
>>> > > > >produced in exactly the same way as other
>>> > > > >climate reconstructions, so there are no extra imperfections in the
>>> > > > >upscaling models than in other climate reconstructions).
>>> > > > >
>>> > > > >'The third approach represents a hybrid of the first two; it
>>> prescribes
>>> > > > >the dynamics of the system using model physics, but is aimed
>>> > > > >at reproducing the historical climate evolution by "nudging" the
>>> model
>>> > > > >states towards towards climate estimates obtained by the first
>>> > > > >approach. Although this approach also requires the stability
>>> > > > >assumption in the statistical models, it is hoped that it is more
>>> > > > >resistant to the biases specific to purely empirical or purely
>>> model-based
>>> > > > >approaches; it is however relatively untested.'
>>> > > > >
>>> > > > >
>>> > > > >Finally, I've been missed off the list of authors! - and the
>>> address for
>>> > > > >Hans and myself should be GKSS Research Centre, Geesthacht.
>>> > > > >
>>> > > > >Best regards
>>> > > > >
>>> > > > >Julie
>>> > > > >
>>> > > > >
>>> > > > >
>>> > > > >************************************
>>> > > > >Dr. Julie M. Jones
>>> > > > >Institute for Coastal Research
>>> > > > >GKSS Forschungszentrum
>>> > > > >Max-Planck-Strasse
>>> > > > >D-21502 Geesthacht
>>> > > > >Germany
>>> > > > >
>>> > > > >e-mail: jones@xxxxxxxxx.xxx
>>> > > > >phone: +49 (0)4xxx xxxx xxxx
>>> > > > >fax: +49 (0)4xxx xxxx xxxx
>>> > > > >************************************
>>> > > >
>>> > > >
>>> > > > __________________________________
>>> > > > Dr. Julia Cole
>>> > > > Dept. of Geosciences
>>> > > > Gould-Simpson Bldg.
>>> > > > 1040 E. 4th St.
>>> > > > University of Arizona
>>> > > > Tucson AZ 85721
>>> > > >
>>> > > > phone xxx xxxx xxxx
>>> > > > fax xxx xxxx xxxx
>>> > > > __________________________________
>>> > > >
>>> >
>>> > _______________________________________________________________________
>>> > Professor Michael E. Mann
>>> > Department of Environmental Sciences, Clark Hall
>>> > University of Virginia
>>> > Charlottesville, VA 22903
>>> > _______________________________________________________________________
>>> > e-mail: mann@xxxxxxxxx.xxx Phone: (8xxx xxxx xxxxFAX: (8xxx xxxx xxxx
>>> > http://www.evsc.virginia.edu/faculty/people/mann.shtml
>>> >
>>
>>_______________________________________________________________________
>> Professor Michael E. Mann
>> Department of Environmental Sciences, Clark Hall
>> University of Virginia
>> Charlottesville, VA 22903
>>_______________________________________________________________________
>>e-mail: mann@xxxxxxxxx.xxx Phone: (8xxx xxxx xxxxFAX: (8xxx xxxx xxxx
>> http://www.evsc.virginia.edu/faculty/people/mann.shtml
>
_______________________________________________________________________
Professor Michael E. Mann
Department of Environmental Sciences, Clark Hall
University of Virginia
Charlottesville, VA 22903
_______________________________________________________________________
e-mail: mann@xxxxxxxxx.xxx Phone: (8xxx xxxx xxxxFAX: (8xxx xxxx xxxx
http://www.evsc.virginia.edu/faculty/people/mann.shtml
</x-flowed>
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From: Jean-Charles HOURCADE <hourcade@xxxxxxxxx.xxx>
To: roger.harrabin@xxxxxxxxx.xxx, klaus.hasselmann@xxxxxxxxx.xxx, stephan.herbst@xxxxxxxxx.xxx, nhohne@xxxxxxxxx.xxx, David.C.Hone@xxxxxxxxx.xxx, m.hulme@xxxxxxxxx.xxx, saleemul.huq@xxxxxxxxx.xxx, siegfried.jacke@xxxxxxxxx.xxx, carlo.jaeger@xxxxxxxxx.xxx, ffu@xxxxxxxxx.xxx, ola.johannessen@xxxxxxxxx.xxx, e.l.jones@xxxxxxxxx.xxx, p.kabat@xxxxxxxxx.xxx, bernd_kasemir@xxxxxxxxx.xxx, kemfert@xxxxxxxxx.xxx, kohl.harald@xxxxxxxxx.xxx, julia-maria.kundermann@xxxxxxxxx.xxx, tloster@xxxxxxxxx.xxx, prbuero@xxxxxxxxx.xxx, mccaffi@xxxxxxxxx.xxx, G.Meran@xxxxxxxxx.xxx, a-michaelowa@xxxxxxxxx.xxx, jane.milne@xxxxxxxxx.xxx, horst.minte@xxxxxxxxx.xxx, eckard.minx@xxxxxxxxx.xxx, annette.muenzenberger@xxxxxxxxx.xxx, adelbert.niemeyer@xxxxxxxxx.xxx, t.oriordan@xxxxxxxxx.xxx, ccarraro@xxxxxxxxx.xxx, tol@xxxxxxxxx.xxx
Subject: No Subject
Date: Wed, 11 Jul 2001 09:58:13 +0200
Dear Friends,
A few remarks before the meeting of tonight and tomorrow,
I am sure that our meeting will make clearer the different objectives of
ECF, in particular regarding the articulation between the scientific agenda
and activities in direction to stakeholders and policy-makers.
I would like to stress that I will attend the ECF meeting not only in the
name of the Cired, but also in view of preparing the involvment of the
Institut Laplace in ECF, namely the community of climate modellers, with
which we develop a long term research program. I would like to explain
hereafter in a few words what should be, in my view the priorities of ECF,
in terms of scientific agenda:
Given recent Ipcc experience, the first priority would be to progress in
direction to integrated models. Indeed the lessons of the Ipcc are twofold:
- first the Sress scenarios confirm the possibility of generating very
different emissions growth scenarios over the long run, but the consistency
between the Storylines and the numerical scenarios remain uncertain; this
uncertainty and vagueness reveals a more fundamental limitation of the
state of the art of economic modelling over the long run, in particular to
provide an explicit picture of linkages between structural changes
(infrastructure transportation, urban forms that govern the energy content
of final consumption, industrial structure and the so-called
dematerialisation), innovation and both macro and micro economic drivers
(productivity, growth and price-signals). This makes very difficult to
detect where are the real bifurcations, the real policy-parameters and to
make much progress in the understanding of the timing of policy responses,
- second the sections on 'damages ' have make some progress but remain
weak in terms of the social and economic implications. More precisely they
deal mostly with impacts on physical parameters (sea-level rise), in a few
cases adress impacts on humans (tropical diseases), but all this does not
give a comprehensive picture of social and economic damages (once
discounted the effect of adapatation),
One of the scientific objective of ECF should be to be prepared to provide
in a few years for a convincing contribution in future exercises like the
SRES and in the future Ipcc rounds. This passes first through two parallel
efforts:
- on long term economic modelling where the limitations of existing tools
are obvious depiste real progress; this relates basically to three
challenges:
- a macroeconomic framework insuring the consistency between prices and
quantities at any point in time without necessarily resorting to the
modelling tricks relying on the conventional neo-classical growth theory;
these 'tricks' assume indeed perfect foresight, efficient markets and the
absence of strategic or routine behaviours; New conceptual frameworks about
endogenous growth theory allow for such a move, but there is a gap between
advances in pure theory and empirical modelling,
- the endogeneisation of technical change and more precisely to develop
this endogeneisation in such a way that the information coming from
sectoral models in energy, transportation or agriculture is not lost (this
comes back to the bottom-up/top-down controversy); note that one key
challenge here is to progress in direction to transportation and agriculture
- an explicit treatment of expectations and uncertainty; one key issue
indeed is that the stabilisation of expectations over the long run is the
main driver of technical change, consumption patterns and structural
adaptation.
- on 'coupling' economic and climate models: here there are two routes,
either to develop coupling methods between large-scale models or to develop
interface compact modules, reduced forms of large scale models. Both routes
are valid, however, in the following years, to develop integrated models
made up with reduced forms of larger models seems more promising; thanks to
tractable and numerically controlable models, in will be easier to reveal
the key mechanisms at work and to introduce uncertainties. This will pass
through progress in the representation of carbon cycle (including
sequestration) in such models and, more importantly in the representation
of damages and adaptation, which rises rather fundamental conceptual issues
that explain what seems to be the second priority in my view.
The second prority relates to the joint question of damages and
precautionary principle:
- part of the agenda is covered by Mike Hulme's paper and I will not
elaborate here on other dimensions I would link to include and how to
assess a cost. I will simply insist of the fact that we need to set up a
taxonomy of damages in economic terms, this means as resulting not of the
climate transformation per se but from the joint effect of inertia and
uncertainty (to pass to Riviera to the beaches of Normandy in not a cost in
itself in a world restabilized around a new climate equilibrium; what
matter are the transition costs and the generated variability of climate).
Moreover I would insist for adopting deliberately a worldview because,
fundamentally, climate change will generate a new human geography, and not
to be restricted to the European subcontinent,
- this should lead to develop in parallel stochastic decision modelling
tools to disentangle the many dimensions and views about the precautionary
principle and, I take some risks in saying that, in a symmetric treatment
of climate damages and nuclear risks (we cannot avoid to try and put some
rationale in this discussion which is one of the reason for the failure of
the EU tax in 1992 and of COP6, and which will be an 'hidden' division line
within the EU)
The third priority should be the topic 1 made by Klaus. For me the two
first modelling efforts I described briefly are outmostly important to
bring new insights for responding the question of the instruments. However,
we have, before waiting for the acheivement of a new generation of models
(which will respond to point 2 and 3 of Klaus's paper), it matters to
develop in parallel a specific programm on international coordination
architecture given the failure of COP6 and the lack of understanding of
economic and social implications of the selection of this architecture
(coordination through prices or quantities, full agreement or partial
expanding coalition, issue linkages, perceived equity etc ....). This
workprogramm should build on advances on the role of economic and non
economic instruments in fostering innovation, and on the distributive
static and dynamic implications of such instruments.
These are very brief remarks, simply to give you some ideas about my
current perspectives.
Original Filename: 995978954.txt | Return to the index page | Permalink | Earlier Emails | Later Emails
From: Edward Cook <drdendro@xxxxxxxxx.xxx>
To: Tim Osborn <t.osborn@xxxxxxxxx.xxx>
Subject: Re: N(eff) and practicality
Date: Tue, 24 Jul 2001 08:49:xxx xxxx xxxx
Cc: Phil Jones <p.jones@xxxxxxxxx.xxx>, Keith Briffa <k.briffa@xxxxxxxxx.xxx>
Hi Tim,
Thanks for the remarks. We can certainly spend some time talking through
some of the points raised. I guess I am still finding it difficult to
believe that an rbar of 0.05 has any operational significance in estimating
Neff. It is kind of like doing correlations between tree rings and climate:
a correlation of 0.10 may be statistically significant, but have no
practical value at all for reconstruction. The same goes for an rbar of
0.05 in my mind. I agree that what I suggested (i.e. testing the individual
correlations for significance and only using those above the some
significance level for estimating rbar) is somewhat ad hoc and not
theoretically pleasing. However, it is also true that correlations below
the chosen significance threshold are "not significantly different from
zero" and could be ignored in principle, just as we would do in testing
variables for entry into a regression model. This would clearly muddy (a
nice choice of words!) the rbar waters, I admit.
In terms of the problem I am working on (computing bootstrap confidence
limits on annual values of 1205 RCS-detrended tree-ring series from 14
sites), it is hard to know what to do. Certainly, using Neff will result in
almost none of the annual means being statistically significant over the
past 1200 years. I don't believe that this is "true". Other highly
conservative methods of testing significance result in a very high
frequency of similarly negative results, i.e. the test of significance in
spectral analysis that takes into account the multiplicity effect of
testing all frequencies in an a posteriori way (see Mitchell et al. 1966,
Climatic Change, pg. 41). If you use this correction, virtually no
"significant" band-limited signals will ever be identified in
paleoclimatological spectra. So, this test has very low statistical power.
I think that this is the crux issue: Type-1 vs. Type-2 error in statistical
hypothesis testing. The Neff correction greatly increases the probability
of Type-2 error, while virtually eliminating Type-1 error. So, truth or
dare.
Consider one last "thought experiment". Suppose you came to Earth from
another planet to study its climate. You put out 1,000 randomly distributed
recording thermometers and measure daily temperatures for 1 Earth year. You
then pick up the thermometers and return to your planet where you estimate
the mean annual temperature of the Earth for that one year. How many
degrees of freedom do you have? Presumably, 999. Now, suppose that you
leave those same recording thermometers in place for 20 years and calculate
20 annual means. From these 20-year records, you also calculate an rbar of
0.10. How many degrees of freedom per year do you have now? 999 or 9.9?
What has changed? Certainly not the observation network. Does this mean
that we can just as accurately measure the Earth's mean annual temperature
with only 10 randomly placed thermometers if they provide temperature
records with an rbar of 0.00 over a 20 year period? I wouldn't bet on it,
but your theory implies it to be so. Surely, one would have more confidence
(i.e. smaller confidence intervals) in mean annual tempertures estimated
from a 1000-station network.
Cheers,
Ed
>Ed,
>
>re. your recent questions about Neff and rbar etc...
>
>I've thought a bit about these kind of questions over the past few years,
>but have never completely got my head around it all in a satisfactory way.
>I agree with what Phil said in his reply to you. Also, your idea of
>subsamping 40% of the cores at a time sounds reasonable, though I don't
>think it would be possible to write a very elegant statistical
>justification! Anyway, I just wanted to add a couple of points to what
>Phil said:
>
>(1) Even for very low rbar, the formula certainly works for
>idealised/synthetic cases (i.e. with similar standard deviations and
>inter-series correlations etc.). For example, I just generated 1000 random
>time series (each 500 elements long) with a very weak common signal,
>resulting in rbar=0.047. n=1000 was the closest I could get to n=infinity
>without waiting for ages for the correlation matrix to be computed! The
>formula:
>
>neff = n / ( 1 + [n-1]rbar )
>
>which reduces to neff = 1 / rbar for n=infinity gives neff = 20.83. For
>such a low rbar, neff seems rather few? The mean of the variances of the
>1000 series was 1.04677. If I took the "global-mean" timeseries (i.e. the
>mean of the 1000 series, then it's variance was 0.05041. The ratio of
>these variances is 20.77 - almost the same as neff! If our expectation
>that neff should be higher than 20.83 was true, then the variance of the
>mean series should have been much lower than it was. It should be easy to
>try out similar synthetic tests with various options (e.g. shorter time
>series, sets of series with differing variances, subsets with higher common
>signal (within-site) combined with subsets with weaker common signal
>(distant sites) etc.) to test the formula further.
>
>(2) I agree that rbar is computed from sample correlations rather than true
>(population) correlations.
>(a) For short overlaps, the individual correlations will rarely be
>significant. But the true correlations could be higher as well as lower,
>so rbar could be an underestimate and neff could be an overestimate! Maybe
>you have even fewer than 20 degrees of freedom!
>(b) I did wonder whether the sample rbar might be a biased estimate of the
>population rbar, given that the uncertainty ranges surrounding individual
>correlations are asymmetric (with a wider range on the lower side than the
>higher side). But I've checked this out with synthetic data and the rbar
>computed from short samples is uncertain but not biased.
>(c) Just because rbar is only 0.05 does not mean that you need series 1500
>elements long to be significant - that would be the case for testing a
>single correlation coefficient. But rbar is the mean of many coefficients
>(not all independent though!) so it is much easier to obtain significance.
>Not sure how you'd test for this theoretically, but a Monte Carlo test
>would work, given some assumptions about the core data. For 100 cores,
>each just 20 years long, a quick Monte Carlo test indicates that an rbar of
>0.05 is indeed significant - therefore rbar=0.05 in your case with > 100
>cores, many of which will be > 20 years long, should certainly be significant.
>
>Looking forward to your visit! We can discuss this some more.
>
>Tim
>
>
>Dr Timothy J Osborn | phone: xxx xxxx xxxx
>Senior Research Associate | fax: xxx xxxx xxxx
>Climatic Research Unit | e-mail: t.osborn@xxxxxxxxx.xxx
>School of Environmental Sciences | web-site:
>University of East Anglia __________| http://www.cru.uea.ac.uk/~timo/
>Norwich NR4 7TJ | sunclock:
>UK | http://www.cru.uea.ac.uk/~timo/sunclock.htm
==================================
Dr. Edward R. Cook
Doherty Senior Scholar
Tree-Ring Laboratory
Lamont-Doherty Earth Observatory
Palisades, New York 10964 USA
Phone: xxx xxxx xxxx
Fax: xxx xxxx xxxx
Email: drdendro@xxxxxxxxx.xxx
==================================
Original Filename: 998078193.txt | Return to the index page | Permalink | Earlier Emails | Later Emails
From: "Stephan Singer" <SSinger@xxxxxxxxx.xxx>
To: <bill.hare@xxxxxxxxx.xxx>,<baldur.eliasson@xxxxxxxxx.xxx>, <klaus.hasselmann@xxxxxxxxx.xxx>, <tol@xxxxxxxxx.xxx>, <ccarraro@xxxxxxxxx.xxx>, <gretz@xxxxxxxxx.xxx>, <hourcade@xxxxxxxxx.xxx>, <GBerz@xxxxxxxxx.xxx>, <ola.johannessen@xxxxxxxxx.xxx>, <Carlo.Jaeger@xxxxxxxxx.xxx>, <Martin.Welp@xxxxxxxxx.xxx>, <Ottmar.Edenhofer@xxxxxxxxx.xxx>, <schellnhuber@xxxxxxxxx.xxx>, <juergen.engelhard@xxxxxxxxx.xxx>, <m.hulme@xxxxxxxxx.xxx>, <ccarraro@xxxxxxxxx.xxx>
Subject: response
Date: Fri, 17 Aug 2001 15:56:33 +0200
Dear Mr Hasselmann,
thanks for the draft position of the ECF. I do believe it is very good first approach to position the needs of a science-based climate policy in the future. I do particularly like the quasi-goal of a long-term 0-emission target supported by the scientific community.
However, there are a few amendments I like to propose:
a) I do not agree at all that the focus on the short term "dictared by the 10 year Kyoto horizon has tended to obscure longer term issues".
In the contrary, if we were to agree on longer-term and deeper targets - what we all want I suppose - there must be a starting point somewhere in the next years. I do agree that the 1 CP targets are moderate and will be diluted by all kinds of loopholes. But given the economic and political nature of this treaty, more is/was not reachable by the international community. I prefer an unperfect agreement coevering the globe (almost!) as a starter over an perfect agreement that will never be agreed upon.
And - probably more important - the recent Bonn agreement will give the signal to the main polluters that the atmosphere is not a free sewer any more. At best, they won some time - but the ultimate message is, that the train towards deeper targets has started. This may impact future industrial investment and legislative decision making much deeper than the targets of the 1 CP itself as it provides some basic certainty.
Having said this, the next important discussion round on a political level will resume about "adequacy of commitments" of the next CPs. that is the build-in logic of both the treaty and the Convention. Here countries will start to address targets for 2xxx xxxx xxxx. Thus, there is an approach to the long-term issues. It is a transient process over time. And, please believe me, almost everyone I talked to in the past who complained about the "short-term" focus of the treaty as opposed to a long-term global strategy had not in mind to strengthen environmental effectiveness - these voices mostly reflected the desire to fully delay any early action after all. And without early action and without short term focus we will never get to the longer-term targets.
In short, I believe, a scientific approach should foster the architecture of the KP and that of the Convention and the need for further target-setting processes in the future by all parties - and that is intrinsincally embedded in the process.
In that respect, it is probably scientifically correct to state that the "Kyoto reductions have negligible impacts on global warming" but it would be politically naive to conclude that this means Kyoto is only "symbolic". It is much more.
b) I have problems with the focus on solar as the sole beneficiary of a 0-emission society. Still, I still like to focus on those measures that are not implemented yet and can provide the bulk of future emissions reductions mostly cost-effectively - that is energy efficiency in its various forms and various applications. And renewables are those who benefit most from energy efficiency as each renewable kWh provides more service, km or goods.
Generally, I like a broader approach to renewables. It is not "one takes it all" solar what will save the world from climate change. We need many forms of renewables according to the cultural, political and economical circumstances in the various regions. In some it may be solar thermal power or PV, in others it is off-shore wind, and in many rural areas it may be biomass or geo-thermal energy. And let us not forget the challenge of producing hydrogen from renewable sources as another ultimate fuel.
c) How dow we deal with equity? I believe it has to be addressed in one way or the other - and I mean much more than the usual GHG emissions per capita approach. This would include compensation/adaptation funding for poor and vulnerable developing countries - but also how to deal with targets for (certain) developing countries in the next CPs.
best regards
Stephan Singer
WWF International
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From: Klaus Hasselmann <klaus.hasselmann@xxxxxxxxx.xxx>
To: "Stephan Singer" <SSinger@xxxxxxxxx.xxx>, <bill.hare@xxxxxxxxx.xxx>, <baldur.eliasson@xxxxxxxxx.xxx>, <tol@xxxxxxxxx.xxx>, <ccarraro@xxxxxxxxx.xxx>, <gretz@xxxxxxxxx.xxx>, <hourcade@xxxxxxxxx.xxx>, <GBerz@xxxxxxxxx.xxx>, <ola.johannessen@xxxxxxxxx.xxx>, <Carlo.Jaeger@xxxxxxxxx.xxx>, <Martin.Welp@xxxxxxxxx.xxx>, <Ottmar.Edenhofer@xxxxxxxxx.xxx>, <schellnhuber@xxxxxxxxx.xxx>, <juergen.engelhard@xxxxxxxxx.xxx>, <m.hulme@xxxxxxxxx.xxx>, <ccarraro@xxxxxxxxx.xxx>
Subject: Re: response to response
Date: Sat, 18 Aug 2001 13:39:00 +0200
<x-flowed>
>Dear Stephan (I suggest we use the anglo-saxon first-name form, coupled
>with "Sie" if we slip into German)
I agree with all of your points and hope you will contribute to finding the
right language in our position paper to reflect both the need for long-term
goals and the value of at least starting off with something one can build
upon. One of my motives was to help keep the door open for those who wish
to join the process later without too much embarassment. I also agree that
we need to investigate all technological options. I am certainly not an
expert in this field and am willing to learn from those who see more Global
Mitigation Potential in some of the currently proposed technologies than I do.
With best regards
Klaus
Prof. Dr. Klaus Hasselmann
work: Max Planck Institute of Meteorology,
Bundestrasse 55, D21046 Hamburg, Germany
Tel. (+49) (0xxx xxxx xxxxFax. (+49) (0xxx xxxx xxxx
home: Schulstr. 79, D 25368 Kiebitzreihe
Tel. (+49) (0)4xxx xxxx xxxx, Fax. (+49) (0)4xxx xxxx xxxx
e-mail: klaus.hasselmann@xxxxxxxxx.xxx
</x-flowed>
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From: Mike Hulme <m.hulme@xxxxxxxxx.xxx>
To: "Matilda Lee" <matildalee1@xxxxxxxxx.xxx>
Subject: Re: Request from The Ecologist magazine
Date: Tue Aug 21 09:41:xxx xxxx xxxx
See comments embedded from me below ............ I would appreciate receiving a copy of the
magazine when published. Thank you.
My affiliation is provided below.
Mike
At 15:15 14/08/01 +0000, you wrote:
Yes-very much so! Your response would be greatly appreciated. Thanks!
From: Mike Hulme <m.hulme@xxxxxxxxx.xxx>
To: "Matilda Lee" <matildalee1@xxxxxxxxx.xxx>
Subject: Re: Request from The Ecologist magazine
Date: Tue, 14 Aug 2001 16:08:55 +0100
Been away on holiday - is this still relevant?
Mike
At 10:10 03/08/01 +0000, you wrote:
Dear Sirs:
The Ecologist, a London-based internationally recognized environmental
magazine, will be publishing a Special Edition on Climate Change in
September. For this edition, we believe it would be extremely useful to
gather the opinions of the top climatologists on an issue for which there
is growing interest by those concerned with climate change.
This issue is addressed in Article II of the United Nations Framework
Convention on Climate Change, which states:
"The ultimate objective of this Convention and any related legal
instruments that the Conference of the Parties may adopt is to achieve, in
accordance with the relevant provisions of the Convention, stabilization
of greenhouse gas concentrations in the atmosphere at a level that would
prevent dangerous anthropogenic interference with the climate
system. Such a level should be achieved within a time-frame sufficient to
allow ecosystems of adapt naturally to climate change, to ensure that food
production is not threatened and to enable economic development to proceed
in a sustainable manner."
Furthermore, the need to address the issue of atmospheric concentrations
was recently reaffirmed by Michael Zammit Cutajar, Executive Secretary of
the UNFCCC, who stated at the closing session of the IGBP in Amsterdam on
13 July 2001,
"I believe that the political process on climate change would be greatly
assisted by agreement on a target for atmospheric concentrations, at least
an intermediate target. This would give a sense of where the whole
international community should be heading and a basis for apportioning
responsibility for getting there."
We would be very appreciative if you would send a return email with your
response to the following questions for publication in The Ecologist
Special Edition on Climate Change.
-At what levels do you think we should aim to stabilize carbon dioxide
concentrations in the atmosphere and why?
I do not believe we have any sure basis for establishing what a 'non-dangerous' level
should be. This is so for several reasons:
- what is 'dangerous' depends on what measures are taken to adapt to climate change.
550ppm may be 'safe' in one assumed future world but 'dangerous' in another.
- the concept of 'danger' is not one that science can pronounce on. Such a level has to be
negotiated via a social and political process. This negotiation has also to take place in
the context of other risks that society is exposed to, i.e., we may be prepared to run a
higher risk with climate change if it means we can divert greater resources to reducing
global poverty.
- the basis for establishing 'danger' is contested. One could argue that 'dangerous'
climate change is change in climate that leads to the death of just *one* person; or argue
that some benefit/cost ratio should be used; or argue that if a sovereign state is
extinguished (e.g. a Pacific atoll nation) then that is the definition of 'dangerous'.
Thus you can see that I do not believe we can arbitrarily choose 550ppm or 650ppm, as done
by many scientific pronouncements (including the IPCC and others), and claim that is our
target. This can only be done by using the instruments of social and political discourse
on an international scale.
What we can say is that the higher the concentration of CO2 reached the greater the likely
risks associated with that concentration will be. But this is a relative argument, not an
absolute one.
-What does that level equate to in terms of percentages of emissions
reductions and by what date should we aim to reach that level?
So you see this second question I cannot answer. What we need to be doing, while we debate
the first question, is to put in place measures/mechanisms/processes that will now, and in
the future, give us greater flexibility of choice about different energy systems that have
different carbon ratings. The process is more important that the targets, as the Kyoto
negotiations have amply demonstrated.
In 10 years times, what we regard as 'dangerous' climate change will be very different from
today - and different again in the year 2020. We therefore need an emissions reduction
strategy that is flexible and reflexive to the changing demands of society.
We are aware that there is currently no consensus within the scientific
community on what an appropriate level for atmospheric concentrations is.
Indeed not - and there never can be. This question is not appropriately answered by
science - it has to be answered by society! This is a very important point to get across.
Our aim in this endeavour is to share with our readers the values
considered relevant to this debate to illustrate why a consensus is
difficult to achieve.
Exactly so - and in the end it is a matter of risk assessment and risk management. And
with most matters of risk, it is the perception by different individuals that matters more
than any quasi-objective estimate of risk. Temperamentally I take more risks than does my
wife - my concept of dangerous climate change is likely therefore to be quite different
from hers. Writ large and across the nations of the world, this is the problem of climate
change management.
Thank you in advance for your consideration.
Sincerely,
Matilda Lee
The Ecologist
_________________________________________________________________
Get your FREE download of MSN Explorer at [1]http://explorer.msn.com/intl.asp
_________________________________________________________________
Get your FREE download of MSN Explorer at [2]http://explorer.msn.com/intl.asp
References
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2. http://explorer.msn.com/intl.asp
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From: Rob Swart <Rob.Swart@xxxxxxxxx.xxx>
To: wigley@xxxxxxxxx.xxx
Subject: Re: TGCIA scenario recommendations
Date: Mon, 27 Aug 2001 11:39:11 +0200
Cc: m.hulme@xxxxxxxxx.xxx, parryml@xxxxxxxxx.xxx, Rob Swart <Rob.Swart@xxxxxxxxx.xxx>, steve smith <ssmith@xxxxxxxxx.xxx>, s.raper@xxxxxxxxx.xxx, Tsuneyuki MORITA <t-morita@xxxxxxxxx.xxx>, tim.carter@xxxxxxxxx.xxx
Dear Tom,
Thanks for your message and papers. The problem is clearly one of the
science-policy interface. If science cannot demonstrate that it makes a
difference in terms of avoided climate change and impacts if GHG
concentrations are stabilised, why bother? Currently a Danish guy, Bj
Original Filename: 999293834.txt | Return to the index page | Permalink | Earlier Emails | Later Emails
From: Mike Hulme <m.hulme@xxxxxxxxx.xxx>
To: Klaus Hasselmann <klaus.hasselmann@xxxxxxxxx.xxx>, Carlo.Jaeger@xxxxxxxxx.xxx, Martin Welp <Martin.Welp@xxxxxxxxx.xxx>, schellnhuber@xxxxxxxxx.xxx, Ottmar.Edenhofer@xxxxxxxxx.xxx, tol@xxxxxxxxx.xxx, ccarraro@xxxxxxxxx.xxx, ccarraro@xxxxxxxxx.xxx, juergen.engelhard@xxxxxxxxx.xxx, baldur.eliasson@xxxxxxxxx.xxx, hourcade@xxxxxxxxx.xxx, ola.johannessen@xxxxxxxxx.xxx, gretz@xxxxxxxxx.xxx, bill.hare@xxxxxxxxx.xxx, SSinger@xxxxxxxxx.xxx, guentherr@xxxxxxxxx.xxx, gberz@xxxxxxxxx.xxx
Subject: Re: ECF position paper
Date: Fri Aug 31 17:37:xxx xxxx xxxx
Klaus,
A few belated comments on your 1st draft ...... which is looking promising:
a. we need to be careful about using concepts/terms such as 'unacceptable' global warming.
As I think Richard Tol says, we do not have any sound basis for determining what
constitutes 'dangerous' climate change. Is it one life lost? a nation-state inundated?
or some more utilitarian exceedance of a benefit/cost ratio? Does every citizen on the
planet have a vote or just each government? We should draw attention to the rather flimsy
basis upon which notions of safe or dangerous, tolerable or unacceptable climate change are
debated. In the end of course there are lots of things we may view as 'unacceptable' (war
for example), yet they happen and we survive. I think this is an area rich for research
and we could draw out some of the dimensions.
b. later on you use the idea of balancing abatements costs vs. the risks of climate
change. I think we need to use the language of risk here and to draw upon insights
developed by risk analysts (academic and professionals) about how we frame the climate
change problem in risk terms. The differential perceptions of risks, inc. climate ones,
therefore becomes central in addressing point a.
c. the proposed ECF project on changes in extreme weather is of course a necessary first
step towards the quantification of climate risks. This should be one of the justifications
for work in this area. It is also the case that better understanding of these changes will
yield insights into how adaptation does or should proceed, at both environmental systems
and institutional systems levels.
d. re. nuclear energy in a climate protection portfolio, the ECF should be bold and should
question and expose assumptions made on both sides of the debate about the up and
down-sides of this technology. It is rising higher on the UK agenda and there will be some
challenging times ahead in this country about its rightful place and role.
I look forward to seeing the second draft,
Mike
At 14:24 11/08/01 +0200, Klaus Hasselmann wrote:
Dear colleague:
I was requested on the 6.August telephone conference by the ECF skeleton board and the
members of the former ECF steering committe to coordinate the writing of an ECF position
paper, as agreed upon at the ECF meeting in Brussels on July 12.
It was proposed that we complete the position paper and present it to the press about a
week in advance of the Marrakech COP 7 meeting in November this year.
I suggest the following timetable:
1) preliminary agreement on the structure and contents of the paper by the end of this
month,
2) production of first draft in September,
3) detailed discussion of first draft on 2nd October in Potsdam (an additional day ahead
of the 3-4.October ECF meeting, which was proposed on 6.August to discuss the details of
the various projects agreed upon at the Brussels meeting)
4) completion of the paper in October.
5) November: presentation of the paper
I would hope that apart from the 2nd October meeting we can achieve our task by e-mail.
But a meeting may be necessary in September. If so, we should try to combine it with one
of the other project meetings that will be taking place in September.
Everybody is invited to participate. Please feel free to copy this mail to other ECF
members or potential members who I may have missed.
It has been suggested that the position paper should be short, about 5 pages, plus some
appendices if necessary.To get the discussion going, I propose the attached structure as
straw man. Please note that many of the points I have listed are my own views, and I
will by happy to - and expect to - modify them based on your responses.
With best regards
Klaus
Prof. Dr. Klaus Hasselmann
work: Max Planck Institute of Meteorology,
Bundestrasse 55, D21046 Hamburg, Germany
Tel. (+49) (0xxx xxxx xxxxFax. (+49) (0xxx xxxx xxxx
home: Schulstr. 79, D 25368 Kiebitzreihe
Tel. (+49) (0)4xxx xxxx xxxx, Fax. (+49) (0)4xxx xxxx xxxx
e-mail: klaus.hasselmann@xxxxxxxxx.xxx
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From: "Michael E. Mann" <mann@xxxxxxxxx.xxx>
To: Ed Cook <drdendro@xxxxxxxxx.xxx>
Subject: Re: Esper/Cook paper
Date: Mon, 10 Sep 2001 10:35:xxx xxxx xxxx
Cc: "Malcolm K. Hughes" <mhughes@xxxxxxxxx.xxx>, "Michael E. Mann" <mann@xxxxxxxxx.xxx>, Crowley_Hegerl <tcrowley@xxxxxxxxx.xxx>, jto@u.arizona.edu, rbradley@xxxxxxxxx.xxx, Jan Esper <esper@xxxxxxxxx.xxx>, srutherford@xxxxxxxxx.xxx, p.jones@xxxxxxxxx.xxx, k.briffa@xxxxxxxxx.xxx
<x-flowed>
Hi Ed,
Just to reiterate one more key point---Superimposing the two series and
their uncertainties is not the whole story (although it is a definite
improvement over just showing the two reconstructions on top of each other
w/ know assessment of uncertainty). However, doing the above still only
poses the question:
apple +/- [uncertainty in apple] =? orange +/- [uncertainty in orange]
As we discussed in a previous email exchange (based on the correlations you
calculated between instrumental series w/ the trend removed) , the two
reconstructions should probably only share about 60% or so variance in
common in the best case scenario, where there is no uncertainty at all,
owing simply to the differing target regions/season...
So we need to be very careful w/ the following statement which you made in
your previous email:
"If so, this would not mean that the series are not significantly different
from each
other. One can't dismiss the highly systematic differences at
multi-centennial timescales quite so easily."
I'm not sure you can justify that statement based on sound statistical
reasoning!
I agree w/ your following statement "Why these differences are there is the
crux question."
However,I hope the discussion will accurately reflect the fact that the
leading hypotheses to be rejected in answering that question are 1) random
uncertainty in the two series owing to differing data quality and sampling,
etc. can explain the difference and 2) systematic differences owing to
differing target region and seasonality can explain any residual
differences after (1).
That may be a tough standard to beat, but it *is* the approach that Tom,
Phil, Keith, and I have all been taking in addressing the issue of whether
our different reconstructions are or are not inconsistent and the
conclusion has in general been (see e.g. IPCC which was really a consensus
of many of us, though admittedly only I was a lead author) that, despite
notable differences in the low-frequency variability, the different
reconstructions probably cannot be considered inconsistent given the
uncertainties and differences in seasonality/spatial sampling. I have a
hard time understanding why the same standard should not be applied to
comparisons w/ your current reconstruction?
Does your RCS reconstruction really not fall in the mix of all the other
reconstructions? Is it truly an outlier w/ respect to Phil's, Tom's, MBH,
and other existing N. hem reconstructions that are based on different
seasonality and regional sampling???
We've probably had enough discussion now on this point, so I'll leave it to
you to discuss the results in the way you see most fit, but I really hope
you take the above points into account, in fairness to the previous work...
I look forward to seeing the final manuscript in one form or another, in
any case,
cheers,
mike
At 08:10 AM 9/10/xxx xxxx xxxx, Ed Cook wrote:
>I do intend to put in a new Fig. 5 that will compare the mean RCS with MBH,
>including each series' confidence limits. This will be done on low-pass
>filtered data (probably 40 year because of what Mike has sent me). I am
>sure that there will be significant overlap of confidence limits,
>especially prior to AD 1600, when they are quite wide in MBH. If so, this
>would not mean that the series are not significantly different from each
>other. One can't dismiss the highly systematic differences at
>multi-centennial timescales quite so easily. Why these differences are
>there is the crux question.
>
>Cheers,
>
>Ed
>
> >Dear Ed and Jan,
> >I have a couple of general comments, and then some specific little things
> >that
> >may be helpful. It is possible that some of the answers to my questions
> >may be
> >in the two manuscripts in review or in press (TRR and Dendrochronologia) to
> >which you refer.
> > It seems that your results are consistent with the general shape and
> >some of the detail of the MBH99 series, apart from departures before 1200
> >and in
> >the 19th century. As the two datasets are largely, but not completely,
> >independent, this is an important result. At the time when your
> >replication is
> >weakest, there appear to be differences between the linear and
> non-linear RCS
> >curves and the MBH series. Before about 1200 your dataset is dominated by
> >material from four sites, I think - Polar Urals, Mongolia, Quebec and the
> >Taimyr
> >Peninsula. It therefore seems to me that it is important to make the
> >kinds of
> >direct graphical comparisons that Mike suggests of both your series and
> >the MBH
> >series (superimposed and with their confidence limits shown). Perhaps the
> >differences you note are not robust, and then there would seem to be little
> >reason to seek climatological explanations. I suggest that the graphical
> >comparison Mike suggests will be important since it should allow some
> >assessment
> >of the extent to which MBH and others have or have not underestimated
> >temperature in the AD 1xxx xxxx xxxxperiod, if your arguments hold up.
> > I think that a reasonable reader would have some questions about this
> >particular application of the RCS approach. Maybe an expansion of the
> >footnote
> >might help. How does the determination of the form of the regional
> >standardization curve itself depend on replication within each sampled
> >population? Do we know that the regional standardization curve does not vary
> >with time? Or, do we know that the regional standardization curve does
> >not vary
> >with climate on multicentennial timescales? If so, how? Is it not quite
> >possible
> >that the level of the part of the curve for, say, trees between ages 100
> >and 300
> >is set by climate in the early life of the tree, or that it is itself
> >directly
> >determined by contemporaneous temperatures? A number of these questions
> >occur to
> >me because I have been struggling with RCS in the Yakutia material I have
> >been
> >working on with Gene Vaganov. We have a very good situation for the
> >application
> >of the method, with a couple of hundred samples for which we have pith - no
> >estimate needed. Even so, the resulting chronology, once calibrated, gives
> >impossible temperatures in the early part of the millennium. They imply mean
> >early summer temperatures of up to 18 degrees Celsius, which, at 70 degrees
> >north would have led to massive ecological and geomorphological change.
> I can
> >find no evidence for this. I would not be at all surprised if an
> >examination of
> >the Taimyr material you used were to show the same thing. I say this
> >because I
> >know Mukhtar Nuarzbaev's RCS chronology from the Taimyr shows these very
> high
> >levels at precisely the same time as the Yakutia material. Perhaps Mukhtar
> >and I
> >are misapplying the RCS method - a real possibility at least as far as I am
> >concerned. Alternatively, there is some problem with RCS that we have yet to
> >identify.
> >We are all stuck with a more fundamental problem, which is that we have no
> >way
> >to calibrate multicentennial variations. You have used one method of
> >producing
> >chronologies with greater low frequency variability, one that has some very
> >appealing characteristics. There are other ways the same objective could be
> >reached, but we do not have a simple way to choose between them in most
> >cases. I
> >do think it would be interesting to compare the RCS for the Sierra Nevada
> >material you used, if it contains enough samples to do that, with the Great
> >Basin upper forest border network, as highgraded to only contain samples
> with
> >minimum segment length of 500 years, and very conservatively detrended.
> >
> >Here are some specific points:
> >In the penultimate line on page 2 you refer to 1,205 tree ring series
> from 14
> >locations. Some readers will for sure be confused by the word "series" in
> >this
> >case - how about "core samples" or "radii" or "trees"?
> >Page 3 - I need to check this, but I think the segment lengths in the
> >relevant
> >series in the MBH99 analyses are much longer than 400 years.
> >Page 5 - The differences of timing in high values between the linear and
> >non-linear chronologies are actually quite striking. I think if you and I
> >were
> >looking at a couple of subsamples from a single site we would put these
> >differences down to inadequate sample depth.
> >Page 6 - you talk about the two series (RCS and MBH) disagreeing strongly,
> >but
> >at the moment there is no basis available to the reader to see how strongly.
> >This comes back to Mike's suggestion of a direct graphical comparison with
> >confidence limits, etc.
> >
> >Hope this helps, Cheers, Malcolm
> >
>
>
>==================================
>Dr. Edward R. Cook
>Doherty Senior Scholar
>Tree-Ring Laboratory
>Lamont-Doherty Earth Observatory
>Palisades, New York 10964 USA
>Email: drdendro@xxxxxxxxx.xxx
>Phone: xxx xxxx xxxx
>Fax: xxx xxxx xxxx
>==================================
_______________________________________________________________________
Professor Michael E. Mann
Department of Environmental Sciences, Clark Hall
University of Virginia
Charlottesville, VA 22903
_______________________________________________________________________
e-mail: mann@xxxxxxxxx.xxx Phone: (4xxx xxxx xxxxFAX: (4xxx xxxx xxxx
http://www.evsc.virginia.edu/faculty/people/mann.shtml
</x-flowed>
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From: "Malcolm Hughes" <mhughes@xxxxxxxxx.xxx>
To: "Michael E. Mann" <mann@xxxxxxxxx.xxx>, Ed Cook <drdendro@xxxxxxxxx.xxx>
Subject: Re: Esper/Cook paper
Date: Mon, 10 Sep 2001 12:40:xxx xxxx xxxx
Cc: "Malcolm K. Hughes" <mhughes@xxxxxxxxx.xxx>, Crowley_Hegerl <tcrowley@xxxxxxxxx.xxx>, jto@u.arizona.edu, rbradley@xxxxxxxxx.xxx, Jan Esper <esper@xxxxxxxxx.xxx>, srutherford@xxxxxxxxx.xxx, p.jones@xxxxxxxxx.xxx, k.briffa@xxxxxxxxx.xxx
Dear Ed - Didn't Keith Briffa also come up with a more marked LIA
than MBH99 in his age-band work? If this turns out to be right, it
should eventually be easier to find the sources of the differences
between the reconstructions, just by virtue of there being not only
many more tree-ring data for that period, but also more other, data,
such as documentary. Cheers, Malcolm
Malcolm Hughes
Professor of Dendrochronology
Laboratory of Tree-Ring Research
University of Arizona
Tucson, AZ 85721
xxx xxxx xxxx
fax xxx xxxx xxxx
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From: Ed Cook <drdendro@xxxxxxxxx.xxx>
To: Keith Briffa <k.briffa@xxxxxxxxx.xxx>
Subject: Re: the real message
Date: Mon, 10 Sep 2001 16:45:xxx xxxx xxxx
Hi Keith,
You probably haven't seen the newest version, which has not yet been
submitted, but I CLEARLY state that several of the data sets/sites used in
the paper have been used before and I reference all of the relevant papers.
I never implied anywhere that this was the first successful use of RCS. I
also reference your Quat. Sci. Rev. paper and your Age Banding paper. I
also state in the concluding section that what has been shown is not new,
but it is somewhat novel (the separation of the data into RC curve classes
and the regionalization of the data on the scale described) and
informative. I stand by that completely. So, the version I am working on
covers (hopefully) some of your concerns/complaints. I will do my best to
be "fair" before I finally submit it. However, this is a Report to Science
(~2500 word limit), so I can't do the kind of review of the literature and
detailed discussiion of results that would be possible in more normal size
papers.
Sorry for sounding a bit testy here. I've been fielding a whole raft of
questions, comments, and criticisms from Mike Mann, Tom Crowley, and
Malcolm Hughes. Some of them useful, many of them tiresome or besides the
point. I never wanted to get involved in this quixotic game of producing
the next great NH temperature reconstruction because of the professional
politics and sensitivities involved. All I wanted to do was demonstate with
Jan that Broecker was wrong, something that you have obviously done a few
times before but in journals that Broecker and others don't follow closely
(I guess. I should also say that the amount of ignorance about tree rings
in the global change/paleo/modeling community is staggering given what has
been published. Like it or not, they simply don't read our papers.). In so
doing, it seemed reasonable to compare the RCS chronology against the
hockey stick because that is the series that Broecker was railing against.
That is why I didn't bother to compare the series against all the other
records produced by you, Phil, and others. Jan originally did that, but I
chose to restrict the comparison to tighten the focus of the paper. More
reference to your results is clearly justified, so maybe I was wrong here.
This all reinforces my determination to leave this NH/global temperature
reconstruction junk behind me once I get this paper submitted. It's not
worth the aggravation. However, the paper is something that I need to do
for Jan. And I still think it is a good paper.
Cheers,
Ed
>What I really mean is that you have written this paper implying that you
>are getting low-frequency NH temperatures out of tree-ring data for the
>first time- using the RCS. You set up this question then use a lot of data
>in your analysis and the RCS as though they have not been analysed like
>this before and then show you get more of a LIA than Mann , while
>ignoring the fact that I have already produced calibrated summer
>temperature curves (in the Science Perspective piece) from RCS ring width
>data in Sweden , Urals , Taimyr and (in the JGR paper) using banded
>density - which both show more low frequency than MBH. The real question is
>whether MBH use data in tropical and mid latitudes that supress what is
>really a high latitude summer signal in their northen predictors ? I just
>don't think you are being very fair here- despite how many times you cite
>me ( perhaps the citations should anyway reflect the useful contributions
>to a particular area even if they number more than a token couple)
>that's off my chest now
>cheers
>Keith
>
>--
>Professor Keith Briffa,
>Climatic Research Unit
>University of East Anglia
>Norwich, NR4 7TJ, U.K.
>
>Phone: xxx xxxx xxxx
>Fax: xxx xxxx xxxx
>
>http://www.cru.uea.ac.uk/cru/people/briffa/
==================================
Dr. Edward R. Cook
Doherty Senior Scholar
Tree-Ring Laboratory
Lamont-Doherty Earth Observatory
Palisades, New York 10964 USA
Email: drdendro@xxxxxxxxx.xxx
Phone: xxx xxxx xxxx
Fax: xxx xxxx xxxx
==================================
Original Filename: 1000168453.txt | Return to the index page | Permalink | Earlier Emails | Later Emails
From: Keith Briffa <k.briffa@xxxxxxxxx.xxx>
To: Ed Cook <drdendro@xxxxxxxxx.xxx>, "Michael E. Mann" <mann@xxxxxxxxx.xxx>
Subject: Re: Esper/Cook paper
Date: Mon Sep 10 20:34:xxx xxxx xxxx
Cc: "Malcolm K. Hughes" <mhughes@xxxxxxxxx.xxx>, Crowley_Hegerl <tcrowley@xxxxxxxxx.xxx>, jto@u.arizona.edu, rbradley@xxxxxxxxx.xxx, Jan Esper <esper@xxxxxxxxx.xxx>, srutherford@xxxxxxxxx.xxx, p.jones@xxxxxxxxx.xxx
Ed
I still believe you are not showing sufficient comparisons with series
besides the MBH ; necessary to demonstrate the true extent of "new" information in this
work. At the very least this needs to acknowledge that other (and other tree-ring-based )
series are out there , that use at least some of the data you employ , and use the RCS
method to process may of their constituent series - i.e. the Northern chronology series
shown in my QSR paper. What is similar and what is different in your series and this one?
You give the impression here that you are using the RCS and new data to demonstrate the
possibility of getting more low frequency signal from tree-ring data - but then you base
this on a comparison with MBH only. Surely what is needed here is to establish WHY MBH
don't get as much LIA for example . By not showing that other tree-ring data that have also
shown a LIA , and not exploring why MBH does not (despite using some of the same -and note
-already RCS standardised data) is perhaps confusing rather than clarifying the issue.
When we discussed this here, I also suggested the need to show separate "north" and more
"south" curves ,separated in your data set, to try to get at least some handle on the
independent expression of the centennial trends in a region south of the over-exploited
northern network . At the very least it should be clearly stated that many of the site data
used here and in previous work (see our Science perspectives piece) are common and other
series already produce more low-frequency signal than is implied in MBH .
Sorry for this rushed comment but I wanted to get this point over as we had talked about it
before but you don't seem to have taken it on board.
cheers
Keith
At 02:51 PM 9/10/xxx xxxx xxxx, Ed Cook wrote:
Hi Mike et al.,
Okay, here is an overlay plot of MBH vs. RCS, with RCS scaled to the
1xxx xxxx xxxxperiod of MBH, and with 95% confidence limits. This has been done
for the 40-yr low-pass RCS data to be consistent with the low-pass MBH
series you sent me. The 95% confidence limits of the RCS are also scaled
appropriately. Since correlations with both instrumental and MBH are
O(0.95) after even 20-year smoothing because of the trend, the RCS limits
are effectively based on the bootstrap 95% limits of the 14 chronologies.
Assuming that the original RCS C.I.s are reasonably accurate (which I think
they are), what is apparent (to me anyway) is that the confidence limits of
MBH are uniformly narrower after AD 1600. Prior to that, they are
comparable to RCS back to ca. AD 1200 where RCS C.I.s get bigger. Of course
this is an odd comparison because the confidence limits are not derived the
same way. However, I do think that they are somewhat informative
nonetheless. What is also apparent is the much great amplitude of
variability in the RCS estimates. This is consistent with the understanding
that extratropical temperatures are more variable than tropical
tempertures, which supports the idea that the MBH record does have more
tropical temperature information in it. The other interesting thing about
expressing the RCS data this way and overlaying it on MBH is the appearance
that MBH is missing the LIA rather than the MWP, at least on
multi-centennial timescales. This turns some of Broecker's criticism of the
"hockey stick" on its head. I'm not sure where all this leads.
Any comments and further suggestions are welcome as long as they come in by
tomorrow. I am definately submitting the paper within a day or two.
Cheers,
Ed
==================================
Dr. Edward R. Cook
Doherty Senior Scholar
Tree-Ring Laboratory
Lamont-Doherty Earth Observatory
Palisades, New York 10964 USA
Email: drdendro@xxxxxxxxx.xxx
Phone: xxx xxxx xxxx
Fax: xxx xxxx xxxx
==================================
--
Professor Keith Briffa,
Climatic Research Unit
University of East Anglia
Norwich, NR4 7TJ, U.K.
Phone: xxx xxxx xxxx
Fax: xxx xxxx xxxx
[1]http://www.cru.uea.ac.uk/cru/people/briffa[2]/
References
1. http://www.cru.uea.ac.uk/cru/people/briffa/
2. http://www.cru.uea.ac.uk/cru/people/briffa/