date: Thu Oct  2 16:44:13 2008
from: Keith Briffa <k.briffa@uea.ac.uk>
subject: Re: recognize this?!
to: Edward Cook <drdendro@ldeo.columbia.edu>

   Ed
   I truly hope for this also - and that you may eventually end up as a lead author or
   convening lead author on the hoped-for palaeo chapter. I would certainly promote this to
   the best of my ability.
   Keith
   At 16:20 02/10/2008, you wrote:

     Hi Keith,
     I think we are all in basic agreement here. My beef with IPCC is
     perhaps a bit unfair. It is probably more so an issue with the way the
     debate over past and present warming has been conducted, as you also
     suggest. The science is indeed moving past the point where the only
     issue to discuss and debate was one related to temperature change, and
     IPCC is responding to it as you say. Hopefully, IPCC will still
     include an explicit paleo chapter in the next report to enable a more
     complete synthesis to be made concerning past and present
     hydroclimatic variability. There will be a tremendous amount of
     exciting new results coming out over the next couple of years in that
     regard. I certainly hope you and Tim can work with me on some of this
     stuff. It will be fun to do.
     Cheers,
     Ed
     ==================================
     Dr. Edward R. Cook
     Doherty Senior Scholar and
     Director, Tree-Ring Laboratory
     Lamont-Doherty Earth Observatory
     Palisades, New York 10964  USA
     Email: drdendro@ldeo.columbia.edu
     Phone: 845-365-8618
     Fax: 845-365-8152
     ==================================
     On Oct 2, 2008, at 10:58 AM, Keith Briffa wrote:

     Dear Ed
     Thanks for these comments - and while I agree with them , I do not
     necessarily concur on the "fashionable" opinion these days that IPCC
     has made a mistake in stressing the temperature issue and the rank
     magnitudes  of late Holocene warm periods. It is undeniable that
     hydroclimatic variability , past and future, is of enormous
     scientific and societal importance. However, the IPCC must follow
     the published literature and  to a large extent the assessment must
     maintain a reasonable degree of continuity. Just as it is vital to
     understand spatial variability  and mechanisms concerning
     temperature (and precipitation) changes, the extent of published
     knowledge has not, as yet, supported a strong emphasis on these
     topics. The focus on the MWP was perhaps to some degree a response
     to the misinformation peddled by certain climate warming sceptics,
     but I believe it was justified to devote the amount of limited space
     allotted to this section to the area of large-scale temperature
     reconstructions, especially considering the extent of the recent
     literature and the attacks on the TAR hockey stick. I hope we did a
     reasonable job in assessing the evidence honestly. I am in no doubt
     that  future IPCC reports will reflect a growing body of evidence
     for the existence of large natural variability in moisture
     conditions and , hopefully, the dynamic mechanisms whereby
     temperature and moisture have varied over space in recent millennia.
     In our defence I would also say that the AR4 clearly pointed to the
     importance of the issue of natural drought occurence and cited the
     best relevant work demonstrating this -  ie your own.
     My beef with Esper is not because his conclusion is wrong - merely
     that his piece wrongly impugns the IPCC. Through a subtle
     combination of selective focus, blatant misrepresentation of the
     text, and a complete failure to acknowledge the circumspect language
     and explicit caveats therein, he builds a straw man and succeeds in
     publishing a trivial, unoriginal idea.
     cheers
     Keith
        At 14:48 01/10/2008, you wrote:

     Hi Keith and Tim,
     I have quickly read through the Esper paper and have the following
     comments to make. First, I hadn't seen it before, so it is all new
     to me. It is certainly true that Jan did not do a proper job citing
     Briffa et al. (1992). That was a clear mistake, especially given
     that Douglass (1929) was cited for crossdating. I also note that
     Jan did not cite Osborn et al. (1997) on adjusting the variance in
     series for sample size changes. That too was an clear oversight
     given that Frank et al. (2007) was cited. Hopefully, neither was
     done intentionally. I tend to give people the benefit of a doubt on
     that unless it is a chronic problem in their publications. The
     latter issue of variance adjustment is also relevant to the
     discussion concerning spatial homogeneity or lack thereof. Am I
     correct in assuming that some form of variance adjustment was made
     to the series used in the AR4 report? I haven't read the report
     closely enough to recall if that was done. If it was done, that
     would tend to force the data towards an appearance of greater
     homogeneity, I would guess, hence the relative stability of the
     bootstrap intervals, etc.. In any case, I do tend to agree with Jan
     that nothing very definitive can be said about the spatial
     homogeneity of the putative MWP until we get more records to look
     at that truly express temperature and not something else.
     The whole issue of whether or not the MWP was more spatially
     heterogeneous or not is a huge "red herring" in my opinion anyway.
     A growing body of evidence clearly shows that hydroclimatic
     variability during the putative MWP (more appropriately and
     inclusively called the "Medieval Climate Anomaly" or MCA period)
     was more regionally extreme (mainly in terms of the frequency and
     duration of megadroughts) than anything we have seen in the 20th
     century, except perhaps for the Sahel. So in certain ways the MCA
     period may have been more climatically extreme than in modern
     times. The problem is that we have been too fixated on temperature,
     especially hemispheric and global average temperature, and IPCC is
     enormously guilty of that. So the fact that evidence for "warming"
     in tree-ring records during the putative MWP is not as strong and
     spatially homogeneous as one would like might simply be due to the
     fact that it was bloody dry too in certain regions, with more
     spatial variability imposed on growth due to regional drought
     variability even if it were truly as warm as today. The Calvin
     cycle and evapotranspiration demand surely prevail here:  warm-dry
     means less tree growth and a reduced expression of what the true
     warmth was during the MWP.
     That is my take on the Esper and Frank paper, with obvious
     editorial comments included as well.
     Cheers,
     Ed
     ==================================
     Dr. Edward R. Cook
     Doherty Senior Scholar and
     Director, Tree-Ring Laboratory
     Lamont-Doherty Earth Observatory
     Palisades, New York 10964  USA
     Email: <[1]mailto:drdendro@ldeo.columbia.edu>drdendro@ldeo.columbia.edu
     Phone: 845-365-8618
     Fax: 845-365-8152
     ==================================
     On Sep 29, 2008, at 11:06 AM, Keith Briffa wrote:

     X-Mailer: QUALCOMM Windows Eudora Version 7.1.0.9
     Date: Mon, 29 Sep 2008 09:50:59 +0100
     To: Keith Briffa <<[2]mailto:k.briffa@uea.ac.uk>k.briffa@uea.ac.uk>
     From: Tim Osborn <<[3]mailto:t.osborn@uea.ac.uk>t.osborn@uea.ac.uk>
     Subject: recognize this?!
     Dr Timothy J Osborn, Academic Fellow
     Climatic Research Unit
     School of Environmental Sciences
     University of East Anglia
     Norwich  NR4 7TJ, UK
     e-mail:   <[4]mailto:t.osborn@uea.ac.uk>t.osborn@uea.ac.uk
     phone:    +44 1603 592089
     fax:      +44 1603 507784
     web:      <[5]http://www.cru.uea.ac.uk/~timo/>[6]http://www.cru.uea.ac.uk/~timo/
     sunclock:
     <[7]http://www.cru.uea.ac.uk/~timo/sunclock.htm>[8]http://www.cru.uea.ac.uk/~timo/sunclo
     ck.htm

     --
     Professor Keith Briffa,
     Climatic Research Unit
     University of East Anglia
     Norwich, NR4 7TJ, U.K.
     Phone: +44-1603-593909
     Fax: +44-1603-507784
     <[9]http://www.cru.uea.ac.uk/cru/people/briffa/>[10]http://www.cru.uea.ac.uk/cru/people/
     briffa/ <esper frank IPCC on MWP hetero 2008.pdf>

     --
     Professor Keith Briffa,
     Climatic Research Unit
     University of East Anglia
     Norwich, NR4 7TJ, U.K.
     Phone: +44-1603-593909
     Fax: +44-1603-507784
     [11]http://www.cru.uea.ac.uk/cru/people/briffa/

   --
   Professor Keith Briffa,
   Climatic Research Unit
   University of East Anglia
   Norwich, NR4 7TJ, U.K.

   Phone: +44-1603-593909
   Fax: +44-1603-507784
   [12]http://www.cru.uea.ac.uk/cru/people/briffa/

