date: Wed, 16 Apr 2003 21:05:09 +0100
from: "Max Beran" <maxberan@oldboot.demon.co.uk>
subject: RE: The Alexander technique
to: "Keith Briffa" <k.briffa@uea.ac.uk>

Keith

Yes but what about the substantive dendro queries.

Max

-----Original Message-----
From: Keith Briffa [mailto:k.briffa@uea.ac.uk]
Sent: 16 April 2003 10:10
To: Max Beran
Subject: The Alexander technique


Dear Max
nice to hear from you and thanks for taking the trouble to get in touch
with that advice. It so happens that I am booked for a session sponsored by
the University in June , and ironically my wife Sarah , on reading a book
someone else lent me with the same advice, has become a devotee. I have
still to read it! I am having physio once a fortnight , but I have to say I
am a little disappointed that I am being to get more frequent back aches
and some pain again , particularly when I sit for a while. Anyway , I will
go to that course and perhaps even find time to read the book. Thanks again
Keith

At 03:03 AM 4/16/03 +0100, you wrote:
>Keith
>
>Did you have an opportunity to ponder the following.
>
>I hope your back is fully mended. You ought to take up the Alexander
>technique. I mention it because my wife is an Alexander technique teacher
>and our principal breadwinner now that I'm retired.
>
>All the best
>
>Max
>
>-----Original Message-----
>From: Max Beran [mailto:maxberan@oldboot.demon.co.uk]
>Sent: 25 February 2003 15:10
>To: k.briffa@uea.ac.uk
>Subject: Tree rings and the Mann hockey stick
>
>
>Dear Keith
>
>I deliver courses on global change in Oxford and area and one of the
matters
>that comes up is the Mann hockey stick and its implications (Mann-made
>climate change:-). It has been given enormous prominence both in terms of
>its message about the recent and "deep" past, and in terms of its portents.
>Its use as the take-home message from the policymakers summary of the
>IPCC-TAR demonstrates this clearly.
>
>I am aware that the detailed form of the curve conflicts with what is known
>about well attested features of the millennial climate (weak, if any,
>signatures of medieval warming and the little ice age), but what is
>exercising me more is what it says about trees themselves (I know it is
>multi-proxy but as I understand it, dendrochronology rules).
>
>That tree-ring contribution to the temperature reconstruction obviously
uses
>a numerical expression of the sensitivity between temperature and tree ring
>width/density. I don't have any numbers but if these are anything like the
>ones you show in Figure 2 of your 1998 Nature paper, then there is an
>approximate one-to-one between the standardised departures of
>April-September temperature and tree ring width or density.
>
>Two areas of concern are (a) the situation up to the present, and (b) the
>future.
>
>                                 The present
>
>Given that the standard deviation of the yearly values of summer average
>temperature is of the order of 0.5 degree, this is coincidentally about the
>same difference as between pre-industrial times and now. This implies that
>there ought to have been a similar one standard deviation growth in tree
>rings. (Again I've no access to real numbers but I guess we are talking a
mm
>or 3). At an individual site and year this is doubtless well within the
>noise level, but would be expected to shine through when maintained over a
>number of years and sites. I tried to compare this with Figure 7 of your
>1998 Royal Society paper but got mixed up with whether this shows the
annual
>values of the BAI (as implied by the text) or the annual values of the
>year-on-year "change-in-BAI" as in the caption. If the former, one might
>have expected some sort of compound interest pattern, if the latter an even
>faster growing pattern (compound compound). Perhaps the modesty of the rise
>is indicative of the reversal of the sensitivity between tree rings and
>temperature that is visible in the post-1940 data on Figure 6 of the Royal
>Society paper.
>
>How do you reconcile this reversal in the sign of the relationship between
>tree growth and temperature, and Figure 6 in general, with the statements
>elsewhere in the paper saying there has been a non-climatic "enhancement"
of
>tree growth?
>
>If there has indeed been a reversal in the sign of the sensitivity this
>would imply a very large reduction in NPP as a result of the conspiracy
>between ring width and wood density. One might then ask why this post-1940
>sensitivity is not a more reliable basis for backward reconstruction? I
know
>you tend towards non-climatic explanations (notwithstanding my confusion
>over the direction) but for my money this explanation could be at least as
>legitimately aimed at the period from 1880 to 1940. Huge proportional
>changes in land use and industrial pollution in that era make current
>incursions look relatively speaking benign. Just look at population,
>agricultural area, industrial outputs and emissions data to see this.
>
>                                         The future
>The climate models, bless'em, indicate a temperature increase of the order
>of less than 5 to more than 10 standard deviations by the 2080s. Accepting
>the robustness of the sensitivities implicit in the Hockey stick
>reconstruction (much used to tune and confirm GCM behaviour), that suggests
>to me that we can anticipate a similar order of growth in tree ring width
>and density? I can't picture what the standard deviation of the density
>series might be in relation to the mean, but I would hazard a guess that
>applying this to the tree ring width alone would lead to a more than
>doubling of today's BAI. The overall effect on NPP of such a dramatic shift
>in growth behaviour would surely turn the current 60-ish Gt to well over
100
>Gt. If only a modest fraction was turned into NBU this could make a mighty
>hole in emissions and would be good news at least over the lifetimes of the
>trees. And all this is would put the benefit of CO2 fertilisation
completely
>in the shade.
>
>Seems to me we have a classic checks-and-balances situation here. The
>climate modellers (and the policy makers) implicitly accept the tree-ring
to
>climate sensitivity as far as the past is concerned. This bolsters their
>belief in the forward projections of temperature with all that that implies
>for impacts and policy. By their own logic, they should then also accept
>that trees (far and away the dominant living carbon pool) would continue in
>their positive temperature-driven response and provide a hefty negative
>feedback acting via the land carbon cycle. In all seriousness though, does
>anyone really believe trees would respond so dramatically. We'd know about
>it from physiology and see some signal in latitude clines - as far as I
know
>they don't exist, but you'd know for sure.
>
>So at what point does the tree ring to temperature sensitivity break down?
>And what might its impacts be on the hockey stick and through that the GCM
>tuning? Have there been other periods when your post-1940 reversal occurred
>perhaps due to macroclimatic forces? Could these also account for the
>discrepancy between the hockey stick and what we thought we used to know
>about the climate since 1000 AD?
>
>Any thoughts on any of the above would be delightedly received. You may
even
>save a soul from falling into the embrace of the sainted Lomborg!
>
>Max Beran
>
>1 The Croft
>East Hagbourne
>Didcot OX11 9LS
>Tel: 01235 812493
>Fax: 0870 054 7384

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

Phone: +44-1603-593909
Fax: +44-1603-507784

http://www.cru.uea.ac.uk/cru/people/briffa/


