Friday, March 30, 2012


date: Wed, 05 Jan 2000 11:21:09 +0200
from: Timothy Carter <>
subject: Canberra decisions

Dear colleagues,

I set a 4 January cut-off for your comments on the annotated comments and
on the general decisions reached in Canberra. This was primarily to ensure
that we are all working with the same set of agreed actions when revising
the text.

The annotated comments will eventually have to be sent to the TSU, but we
don't need to do this yet. I haven't received any suggestions for revisions
on these (yet). However, Serguei has made some suggestions concerning the
general decisions, which you should all have received yesterday.

This is by means of a reply to Serguei and for all of you to note (so I
don't have to send out a revised set of comments at this stage):

Serguei's first point concerns palaeoclimatic analogues:

< The proposed response: We will add a few references to illustrate cases
< palaeoanalogues have been developed for impact assessment, but we feel
that the use of
< analogues is more relevant for considering climate model validation (WG
I) than for
< constructing detailed climate scenarios for use in policy-related impact
assessment ( cf.
< F. Oldfield general comment and further justification below). Moreover,
the use of
< analogues is described at more length in Chapter 13/WG I report, which is
< exclusively to climate scenarios.

< My comment: I disagree. As I definitely said in Canberra, there are two
< solid and usable approaches at the moment: analogue and model ones (with
< respect to modelers). IPCC is not a proper place to judge which approach is
< more solid, this should be decided through scientific discussions at
< conferences, in articles in leading scientific periodicals, etc. Professor
< Andrew Velichko has just given me very interesting and detailed scenarios
< on future changes in vegetation in Europe. No principle differences with
< predictions were found be me. I think that interaction of these two
< will be mutually beneficial, and there is no need to vote within IPCC for
< of these approaches. I will strongly stay for methodological diversity.

< Let me propose the following compromise version of our response: We will
add a
< short paragraph and few references to illustrate cases where
< have been used for developing climate scenarios as well as respective
< assessments. A reference to Chapter 13/WG I report, which is devoted
< exclusively to climate scenarios, will be also made.

I can live with this compromise decision as it sidesteps the contentious
issue of the validity of the approach.

However, we probably still have to address this issue somewhere (possibly
in Chapter 13/WG I) since it is raised forcibly by Oldfield and less
directly by Anisimov and Borzenkova (and Velichko). We may have to annotate
relevant general reviewers' comments on the whole TAR (where the Oldfield
comments appear), which we haven't yet done.

I am still uncomfortable with the idea of using past reconstructed climate
for "prediction", where the mechanisms for past changes (e.g. altered solar
insolation) may be quite different from anticipated future changes (i.e.
greenhouse gas forcing). I use the term "prediction" here to imply that
they should offer plausible scenarios of the future. Can we accept that
they are plausible simply on the grounds that they have occurred in the past?

I concur with Oldfield that there are numerous examples of rapid warming
events in the past that are difficult to explain and may be relevant as
plausible scenarios for a future unstable climate response to rapid
forcing. However, to my knowledge, I don't believe that past rapid warming
events have been applied as scenarios in impact assessment. IPCC cannot
easily review and evaluate scenarios that have not been developed and applied.

On the other hand, I recognise that other palaoeanalogues have been widely
applied in impact assessments and (appear) to give similar patterns of
change as some AOGCMs in some regions (though I don't see that this is a
sufficient argument for using them for prediction!) We can reference some
of this work. However, perhaps we don't need to raise the issue of the
validity (or otherwise) of paleaoanalogues here in the chapter, as this
will be covered in Chapter 13/WG I. Note that we may include a Table from
Chapter 13/WG I showing attributes of various scenario construction
techniques, where there is some evaluation of the different methods.

Serguei's second point:

< Decision: The section on water resources will be revised to read marine
and freshwater
< scenarios. A new paragraph will be required on marine scenarios (we need
to identify
< someone to draft this). The section on freshwater could be shortened and
reference made to
< Chapter 4. Nigel Arnell, CLA for Ch 4, has been contacted to discuss this.

< My comment: Basically I agree. However, let me finally clarify the point.
I suggest to
< retain a structure of the subsection as it is (Reference conditions,
Methods of scenario
< development, Application and interpretation�), but in addition to water
resource scenarios
< write something on marine scenarios and freshwater scenarios emphasizing
< aspects (e. g., pollution, acidification).

OK, but we must try to keep this section concise!

< Professor Alla Tsyban (CH6 CLA) can drafted 0.5 page on marine issues
and Anne Koukhta
< (who is already our CA) can take care on freshwater environmental issues
(also 0.5 page).
< Tim, please, respond, whether you are agreeable.

This would be useful - can Prof Tsyban and Dr Koukhta take a global view on
these issues? Again, we should be looking for a very brief mention of the

< In addition to Tim's contacts with Nigel Arnell I think I shall contact
(if you do not
< mind) with Igor Shiklomanov to get his opinion on our freshwater resource
subsection (as
< he is respective CLA in WGII).

That's a good idea, as the tables that we currently have in the text are
based on his work. I think that Arnell may also have contacted Prof.

Finally, please remember that we have set ourselves a 21 January deadline
for revised sections. Let's see if we can keep to this ambitious schedule.

Best wishes and a Happy New Year to you all,



Dr. Timothy Carter
Finnish Environment Institute
Box 140, Kes�katu 6, FIN-00251 Helsinki, FINLAND

Tel: +358-9-40300-315; GSM +358-40-740-5403
Fax: +358-9-40300-390


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