Thursday, May 10, 2012

4115.txt

date: Thu, 01 Feb 2001 09:43:00 +0000
from: Phil Jones <p.jonesatXYZxyz.ac.uk>
subject: Re: trees & warming
to: wigley@ucar.edu,k.briffa@uea.ac.uk, Sarah Raper <sraperatXYZxyz-bremerhaven.de>

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Tom,
Two versions of the Science paper that we have recently submitted are
attached. One
is word and one pdf. In the word version the figures can't be seen on the
screen, but they
can in the pdf. Any comments would be appreciated. The paper discusses
the past
and doesn't attempt to explain the causes. Let me know if you can't read
either file.
With respect to your email, from Figure 1 it is possible to estimate
the temperature
change over the 1700-1780 period from the 4 series we plot. The Mann et
al and
Crowley and Lowery series warm roughly the same amount, about 0.1 to 0.2
C at most.
Our two 'summer' series warm more, between 0.3 and 0.4. Part of this greater
warming is because we get a clear cooling around 1700, possibly due to a
couple
of large volcanic eruptions in the late 1690s. This period has much lower
error bars
than earlier so I feel we can be more confident of the rise, but 0.4 C
seems the
maximum we can get. This might suggest your less sensitive (?) solar
proxy. Presumably
this is from Judith Lean.
Can you send a copy of what you're doing ? Also a reminder to send
reprints of
your couple of recent papers from GRL. These are needed for the RAE
exercise here.
UEA needs to have copies on hand in the unlikely event of requests being
made by
the panel.
Not seen the paper by D'Arrigo on Mongolia in GRL. We probably won't
get that for
a while. Can you fax a copy ?
Keith's paper in JGR should be out in their Feb 1 issue. This is the
one that
describes the green curve in the Science paper.

Cheers
Phil



At 16:06 31/01/01 -0700, Tom Wigley wrote:
>Dear Phil and Keith,
>
>Good to see you at AMS, Phil. I think I mentioned that I was working on
>a paper on the idea of a cosmic ray/cloud-induced enhancement of solar
>forcing. Part of this paper makes use of the Wigley-Raper climate model
>to estimate past temperature changes for different forcings. One thing I
>need for this is your new Science paper on the paleo record, for reasons
>given below. Could you possibly mail (or, better, fedex) me a copy of
>this?
>
>One thing enhanced solar does is imply a total warming (global-mean)
>over 1700-(approx)1780 of about 1.0degC or 0.5degC (depending on which
>solar proxy is used). I have stated in my paper (without yet checking
>the various paleo records -- I was planning to shortcut this by using
>your paper) that this is much more than could be possible based on the
>proxy data, even allowing for coverage/seasonality/regression
>uncertainties. Do you agree? With your expert judgement, what do you
>think the bounds on 1700-1780 global-mean warming are? My guess is about
>0.2-0.3degC.
>
>If you are interested in this paper, I could send you a copy. It may be
>useful in what you are doing for Science.
>
>Also, what do you think of the D'Arrigo paper in GRL (latest issue)? She
>shows an amazing cool period in the 1800s in Mongolia, that is utterly
>unique in the record. She says (in typical sloppy fashion) that this is
>the, or part of the LIA. The problem here is, if one assumes that there
>really was a LIA but that it is masked by other variability so not easy
>to see, then there has to be a cause. I cannot see any evidence that
>1800s cold could be due to volcanoes. The Sun (if one allows it to be
>cloud-enhanced, which I doubt) gives a cool blip from 1780-1830 (coldest
>in about 1810) that could be 0.3-0.6degC in the global mean. This is
>much shorter than in D'Arrigo, although the start point is right on.
>
>On the issue of the LIA masking, I keep reminding people about my paper
>with Sarah in the 1995 Martinson et al. (eds) book ("Natural Climate
>Variability on Decade-to Century Time Scales", NRC, see pp. 169-174.) I
>think this is a rather neat and quite important paper -- but every on
>(including you guys) keeps ignoring it.
>
>Cheers, Tom.

Prof. Phil Jones
Climatic Research Unit Telephone +44 (0) 1603 592090
School of Environmental Sciences Fax +44 (0) 1603 507784
University of East Anglia
Norwich Email p.jonesatXYZxyz.ac.uk
NR4 7TJ
UK
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