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 11/06/01 -0400, 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 6/11/01 -0400, 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@ucar.edu
>> > Climate Analysis Section, NCAR, ML           www.cgd.ucar.edu/cas/
>> > P. O. Box 3000, [1850 Table Mesa Drive]      (303) 497 1318
>> > Boulder, CO 80307  [80305]                   (303) 497 1333 (fax)
>> > *******************************
>
>_______________________________________________________________________
>                     Professor Michael E. Mann
>            Department of Environmental Sciences, Clark Hall
>                       University of Virginia
>                      Charlottesville, VA 22903
>_______________________________________________________________________
>e-mail: mann@virginia.edu   Phone: (804) 924-7770   FAX: (804) 982-2137
>
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.jones@uea.ac.uk
NR4 7TJ
UK
----------------------------------------------------------------------------


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@virginia.edu   Phone: (804) 924-7770   FAX: (804) 982-2137


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 089-3891 5290
Carlo Carraro +39-335-6170775
Jürgen Engelhard 02235-77268
Regine Günther 069-79144177
Bill Hare 030-44678765
Klaus Hasselmann 0170-9101601
Mike Hulme (excused)
Carlo Jaeger 0331-288 2601
Martin Welp 0331-288 2619
Reminder:
General information about the ECF can be found at the ECF website:

Background documents and internal information (e.g. the programme of the
Brussels meeting):

Your feedback on these sites is more than welcome!
The ECF Flyer is available now! I will send all members of the steering
committee 20 copies. If you need more of them please let me know.
Best regards,
Martin Welp
--
Dr. Martin Welp
Potsdam Institute for Climate Impact Research (PIK)
P.O. Box 601203, 14412 Potsdam, Germany
Tel. +49 (0)331 288 2619
Fax +49 (0)331 288 2620
E-mail: martin.welp@pik-potsdam.de
Internet:
~welp/index.html


Hi everyone
I have been through the ideas and offer a few (aptly non organised) comments. First Phil is
away and will not be able to comment until later.
First, the project needs more explicit focus. The call will focused on natural variability
. We are offering a detailed analysis of the variability of climate in the Alpine Region
that focuses on CLIVAR timescales - basically very high resolution and not extending much
beyond a few centuries. The project incorporates instrumental , model and palaeodata . The
inter-relationships between these will be studied to gain an understanding of the nature
and mechanisms of the climate variability - but is this enough. I feel it needs to be
linked with a strong element of understanding the range of social/economic impacts of this
variability.
Perhaps looking at aspects such as avalanches, forest damage, floods, tourism etc.? I
merely put this out as a straw man . I feel the EC are putting a lot of emphasis on this
aspect of research and incorporating research and researchers in these or similar areas
will be a big plus.
As for the specific points in the brainstorming document -
The Dendro aspect :
I think it is essential to update the Alpine tree-ring chronologies that are available .
This is because they are a proven asset but many questions regarding tree-productivity (in
relation to observed 20th century climate variability) simply can not be addressed without
doing this. Many were collected over 20 years ago. The additional data would then allow new
processing techniques to be employed and vital questions concerning the changing responses
of tree-growth to explored. The most efficient way to do this is to involve several groups
working in the Alps , (Thank you for sending the Thesis by Giorgio Strumia which is
certainly a very impressive piece of work) I would think Rupert Wimmer's group and the
Birmensdorf group would be ideal (Fritz Schweingruber has retired but Jan Esper has joined
them in his place - I can ask them to be involved but this depends on what the group here
think are the priorities and how much we see as the overall budget and institutional
allocations). I should say here that I think we would require money for a single person who
could , if it is  agreed, work on aspects of tree-ring processing and relationships with
climate in association with the other tree-ring groups, but also work with the climate and
model data , especially with a view to exploring the statistical inter-relationships and
dynamical associations between the different climate data sets. There is also the French
tree-ring group at Marseille? Perhaps though not all need to partners - ALSO I am thinking
of putting together a European Tree-ring project (or suggesting it as part of a large
European integrated proxy study of Holocene variability) so if this happened there could be
a link between it (involving some of the groups mentioned) and this proposal. The Swiss
might be interested to produce selected site tree-ring density/updating which I think would
be very valuable and I will speak to them without commitment as you ask.
As for some of the climate analysis possibilities mentioned, I very much like the ideas of
detailed ,local climate comparisons with the larger CRU (and CRUder!) data. We are very
interested in the association between time dependence in the relationships between
circulation changes and changes in Temp. and Prec. Also changes in the nature of climate
seasonality , and also extreme events (frost frequency , drought, intense rainfall). The
detailed analyses of these characteristics also compliments the interpretational work on
the tree-ring and glacier mass balance (and socio economic foci) data.
As for the glacier work - is not a huge effort already going into this? I think it is
important but does it fit as well ? The work proposed would have to be distinguished from
other ongoing efforts - though I do like the idea of linking the geomorphological evidence
of past glacier change (moraines , pro-glacial sediment data?) with reconstructed glacier
volume changes , where the reconstructions are based on new long instrumental data , and
palaeodata (temp. and precip.) used to drive a model of the glacier volume.  Our German (or
Julie) colleagues can point to such work based on GCM output . My colleague here (Sarah
Raper) has also done this sort of work but using a very simple model to estimate past
Storglaciaren (in Sweden) volume changes  and her results imply that these models must be
forward driven and not based on simple regression analysis using temperature and
precipitation to estimate past mass balance.
The future aspects of the discussion are important - and it is true that the previous EC
call dealt with modelling and scenarios of future changes. Here, I believe the use of
models should be strictly limited to understanding natural /current variability and change.
There is no benefit in going for a 2 year project - I strongly urge 3. I also would find a
meeting difficult. I am away from 17-29 July, and 11-25 August, and in meetings during
7-10th July and 26-31st August.
Phil will be back here next week and will no doubt comment in more detail on the
instrumental analysis aspects then.
Very best wishes to all
Keith
At 05:13 PM 6/25/01 +0200, Dr. Reinhard Böhm wrote:
Friends,
As announced last Friday, we want to open a first round of brainstorming about the
contents of our project. We have collected what we have received from You so far and
have it mixed with our own ideas (file Brainstorming-1.doc). It does not have a nice
structure and there are still a number of question marks, as You will see.
Please add things where you think something is missing and please feel free to tell us
which points make no sense, or are too ambitious or simply too much work.
Please consider also the "how to do it" (state of the art methods, new approaches to
solve problems, other data than those mentioned, other topics.....).
Please try also to find Your position in the project, tell us what You would prefer to
do....
Please try to consider whether we would have to include other groups in terms of
scientific potential and/or in terms of data (For example: Keith Briffa you mentioned
Fritz Schweingruber as the leading data holder of Alpine tree-ring data. Do you think we
should ask him to join us, or could You use his data also without him being a contractor
of the project? In case You want him in the project could we kindly ask you to contact
him, being much more familiar with him and with the tree-ring topic than we are?)
We would be glad to receive a very short answer from everybody within this week, because
from June 30th to July 15th all the three of us will not be at the institute.
For more detailed considerations and answers You have more time, it would be nice to be
able to study them after our return by mid of July. But please use also the
possibilities to contact  the other groups - the sooner we integrate to a group the
better it is.
Our time-table for the rest of the time until October:
July 16th to August 14th: We are at the institute, hoping to bring the project into a
near to final version what concerns the scientific content
August 15th to August 28th: Ice core conference at Kangerlussuaq (Greenland)
August 29th to September 17th: We are at the institute most of the time. We hope this
will be the time to elaborate the EU-shaped complete version.
September 18th to September 22nd: Big events going on in Vienna which may cut down our
time for the project (150th anniversary of our institute, Climate conference DACH-2001
(in German))
September 24th to October: Time reserved for all the things that could not be done yet
in spite of our time table
Could each of You please inform us about Your time table during summer and autumn?
A question to all of You: How do You think about one 2-days meeting this Summer or in
early September? What place do You prefer? If it is Austria we would have two low cost
possibilities: 1): at our institute  and 2) (more adventurous): At the
Sonnblick-observatory (You do not have to have Alpinistic experience, we have a private
cable car going up)
Some remaining questions:
Should we try a 2-years or a 3-years project?
Can everybody live with roughly 300.000 Euro (This would result into somewhere between
1.5 and two millions, which we heard is a magnitude preferred by the commission). Please
consider not only the sum of money but also how to spend it and how to fill it with a
reasonable equivalent in work amount.
What is your feeling about the "Climate variability atlas of the Alps"? Is it good to
have one main deliverable like that or should we better produce a number of smaller
things?
One last technical remark:  Please send your comments and mails not only to Vienna, but
also to the other groups (or at least to those You believe would be interested in what
You write). I do not think this would spoil too much our mail boxes and it has the
advantage to include the whole intellectual power of our group into the construction
phase of the proposal.
Looking forward to Your replies, ideas, time tables and anything else
With best regards
Reinhard
--
Dr. Keith Briffa, Climatic Research Unit, University of East Anglia,
Norwich, NR4 7TJ, United Kingdom
Phone: +44-1603-593909    Fax: +44-1603-507784


*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  - particularly
  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: +44 1603 593818
Climatic Research Unit                            Email: i.harris@uea.ac.uk
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.


Dear All,
Here are a few more comments on ALPIPMOD.
Ideas are probably not very well ordered.  First, you should try for a 3 year
project
and second, although here for most of the next three months (apart from odd days) I
probably
couldn't justify a meeting. I am intending on resubmitting another proposal to the October
EU round. This one will involve some of the group from ADVICE. It's aim will be to develop
a daily MSLP dataset for Europe and the Atlantic (30-70N by 70W-50E). After the dataset
is produced in the first year, the second and third year will see various analyses
performed
and comparisons of several GCM runs performed at the Hadley Centre. This new project
will probably go to 2.4.1 which will be a different area from yours which will be 2.1.4.
Thus I
would hope that your proposal could be developed over email.
The above dataset would go back to 1850. This is the period which from the IMPROVE
project
is just beyond how far we think we can reliably go back with daily data. Several papers
from
the IMPROVE poject (Moberg et al., 2000 in JGR and several others in press in a special
issue
of Climatic Change) have come to the about 1870 date. We have much earlier data for the 8
sites but ensuring strict homogeneity of the daily series seems doubtful for some types of
extreme measures prior to about 1870. Pressure seems better than temperature. Some sites
are better than others. Monthly is fine for all.
All the IMPROVE and ADVICE data can be used by the ALPIPMOD project. I have a summer
student updating the 51 monthly MSLP sites from ADVICE, amongst other things.
As for your ideas, I think you need some overarching theme. The atlas and CD of all
the data may be one, but it also needs to address some scientific issues which can be
shown to have relevance to the public.
I like the idea of making use of the Alpine orography looking at changes in lapse
rates and
the use of high and low elevation air pressures. The latter is a totally independent
method of
looking at the warming and can be used back to the late 18th century. The Alps have the
longest records of any mountaineous records of any region of the world.  Also I am a
strong
advocate of changes in the influence of features such as the NAO (and other circulation
indicators) on surface climate. You can clearly look at these changes over the last 200
years with all the data you have.
Another important issue to a lot of climatologists is the relative surface warming
compared
to the MSU2LT data in the lower troposphere. Although this is hemispheric in extent, we
can
look with the longer Alpine records as to changes in lower level lapse rates over 200+
years.
Related to this tropical ice caps are disappearing at alarming rates in Peru, Tanzania and
in Tibet (Lonnie Thompson's work). Lonnie has calculated that the ice cap on Kilimanjaro
will not be there by 2015 at its present rate of retreat. Lonnie has some local
temperature
series for about 40 years which show a small warming yet the ice caps are going fast. Why?
These ice caps have all been cored and have ice during the MWP times yet some aren't
producing layers now !
My idea is to use the better known histories of the Alpine glaciers to see if they
are
also melting at accelerated rates than simple temperature averages would imply. Keith
mentioned the forward modelling approaches to determine positions in the past (and then
relate these to moraine termini). Do these models still function in the last 20 years?
Lonnie
thinks a lot of the tropical melting is due to sublimation, which isn't accounted for by
the
degree day models. The elevational sunshine records may be important here and with
temperature a particular season may be much more important than the other three.
All the above is just ideas, but getting all the data together (instrumental and tree
ring
as well glacier termini and mass balance) allows us to be able to model the glaciers
better than
anywhere else. All Europeans will be interested in whether Alpine glaciers are going to
disappear and there will be clear impacts on biodiversity at the high elevations and
tourism.
Another impact area is on the use of glacier meltwater and runoff in hydropower
generation.
These are all good issues to use in the social and economic pages that need to be written.
Cheers
Phil
At 15:10 29/06/01 +0100, Keith Briffa wrote:
Hi everyone
I have been through the ideas and offer a few (aptly non organised) comments. First Phil
is away and will not be able to comment until later.
First, the project needs more explicit focus. The call will focused on natural
variability . We are offering a detailed analysis of the variability of climate in the
Alpine Region that focuses on CLIVAR timescales - basically very high resolution and not
extending much beyond a few centuries. The project incorporates instrumental , model and
palaeodata . The inter-relationships between these will be studied to gain an
understanding of the nature and mechanisms of the climate variability - but is this
enough. I feel it needs to be linked with a strong element of understanding the range of
social/economic impacts of this variability.
Perhaps looking at aspects such as avalanches, forest damage, floods, tourism etc.? I
merely put this out as a straw man . I feel the EC are putting a lot of emphasis on this
aspect of research and incorporating research and researchers in these or similar areas
will be a big plus.
As for the specific points in the brainstorming document -
The Dendro aspect :
I think it is essential to update the Alpine tree-ring chronologies that are available .
This is because they are a proven asset but many questions regarding tree-productivity
(in relation to observed 20th century climate variability) simply can not be addressed
without doing this. Many were collected over 20 years ago. The additional data would
then allow new processing techniques to be employed and vital questions concerning the
changing responses of tree-growth to explored. The most efficient way to do this is to
involve several groups working in the Alps , (Thank you for sending the Thesis by
Giorgio Strumia which is certainly a very impressive piece of work) I would think Rupert
Wimmer's group and the Birmensdorf group would be ideal (Fritz Schweingruber has retired
but Jan Esper has joined them in his place - I can ask them to be involved but this
depends on what the group here think are the priorities and how much we see as the
overall budget and institutional allocations). I should say here that I think we would
require money for a single person who could , if it is  agreed, work on aspects of
tree-ring processing and relationships with climate in association with the other
tree-ring groups, but also work with the climate and model data , especially with a view
to exploring the statistical inter-relationships and dynamical associations between the
different climate data sets. There is also the French tree-ring group at Marseille?
Perhaps though not all need to partners - ALSO I am thinking of putting together a
European Tree-ring project (or suggesting it as part of a large European integrated
proxy study of Holocene variability) so if this happened there could be a link between
it (involving some of the groups mentioned) and this proposal. The Swiss might be
interested to produce selected site tree-ring density/updating which I think would be
very valuable and I will speak to them without commitment as you ask.
As for some of the climate analysis possibilities mentioned, I very much like the ideas
of detailed ,local climate comparisons with the larger CRU (and CRUder!) data. We are
very interested in the association between time dependence in the relationships between
circulation changes and changes in Temp. and Prec. Also changes in the nature of climate
seasonality , and also extreme events (frost frequency , drought, intense rainfall). The
detailed analyses of these characteristics also compliments the interpretational work on
the tree-ring and glacier mass balance (and socio economic foci) data.
As for the glacier work - is not a huge effort already going into this? I think it is
important but does it fit as well ? The work proposed would have to be distinguished
from other ongoing efforts - though I do like the idea of linking the geomorphological
evidence of past glacier change (moraines , pro-glacial sediment data?) with
reconstructed glacier volume changes , where the reconstructions are based on new long
instrumental data , and palaeodata (temp. and precip.) used to drive a model of the
glacier volume.  Our German (or Julie) colleagues can point to such work based on GCM
output . My colleague here (Sarah Raper) has also done this sort of work but using a
very simple model to estimate past Storglaciaren (in Sweden) volume changes  and her
results imply that these models must be forward driven and not based on simple
regression analysis using temperature and precipitation to estimate past mass balance.
The future aspects of the discussion are important - and it is true that the previous EC
call dealt with modelling and scenarios of future changes. Here, I believe the use of
models should be strictly limited to understanding natural /current variability and
change. There is no benefit in going for a 2 year project - I strongly urge 3. I also
would find a meeting difficult. I am away from 17-29 July, and 11-25 August, and in
meetings during 7-10th July and 26-31st August.
Phil will be back here next week and will no doubt comment in more detail on the
instrumental analysis aspects then.
Very best wishes to all
Keith
At 05:13 PM 6/25/01 +0200, Dr. Reinhard Böhm wrote:
Friends,
As announced last Friday, we want to open a first round of brainstorming about the
contents of our project. We have collected what we have received from You so far and
have it mixed with our own ideas (file Brainstorming-1.doc). It does not have a nice
structure and there are still a number of question marks, as You will see.
Please add things where you think something is missing and please feel free to tell us
which points make no sense, or are too ambitious or simply too much work.
Please consider also the "how to do it" (state of the art methods, new approaches to
solve problems, other data than those mentioned, other topics.....).
Please try also to find Your position in the project, tell us what You would prefer to
do....
Please try to consider whether we would have to include other groups in terms of
scientific potential and/or in terms of data (For example: Keith Briffa you mentioned
Fritz Schweingruber as the leading data holder of Alpine tree-ring data. Do you think we
should ask him to join us, or could You use his data also without him being a contractor
of the project? In case You want him in the project could we kindly ask you to contact
him, being much more familiar with him and with the tree-ring topic than we are?)
We would be glad to receive a very short answer from everybody within this week, because
from June 30th to July 15th all the three of us will not be at the institute.
For more detailed considerations and answers You have more time, it would be nice to be
able to study them after our return by mid of July. But please use also the
possibilities to contact  the other groups - the sooner we integrate to a group the
better it is.
Our time-table for the rest of the time until October:
July 16th to August 14th: We are at the institute, hoping to bring the project into a
near to final version what concerns the scientific content
August 15th to August 28th: Ice core conference at Kangerlussuaq (Greenland)
August 29th to September 17th: We are at the institute most of the time. We hope this
will be the time to elaborate the EU-shaped complete version.
September 18th to September 22nd: Big events going on in Vienna which may cut down our
time for the project (150th anniversary of our institute, Climate conference DACH-2001
(in German))
September 24th to October: Time reserved for all the things that could not be done yet
in spite of our time table
Could each of You please inform us about Your time table during summer and autumn?
A question to all of You: How do You think about one 2-days meeting this Summer or in
early September? What place do You prefer? If it is Austria we would have two low cost
possibilities: 1): at our institute  and 2) (more adventurous): At the
Sonnblick-observatory (You do not have to have Alpinistic experience, we have a private
cable car going up)
Some remaining questions:
Should we try a 2-years or a 3-years project?
Can everybody live with roughly 300.000 Euro (This would result into somewhere between
1.5 and two millions, which we heard is a magnitude preferred by the commission). Please
consider not only the sum of money but also how to spend it and how to fill it with a
reasonable equivalent in work amount.
What is your feeling about the "Climate variability atlas of the Alps"? Is it good to
have one main deliverable like that or should we better produce a number of smaller
things?
One last technical remark:  Please send your comments and mails not only to Vienna, but
also to the other groups (or at least to those You believe would be interested in what
You write). I do not think this would spoil too much our mail boxes and it has the
advantage to include the whole intellectual power of our group into the construction
phase of the proposal.
Looking forward to Your replies, ideas, time tables and anything else
With best regards
Reinhard
--
Dr. Keith Briffa, Climatic Research Unit, University of East Anglia,
Norwich, NR4 7TJ, United Kingdom
Phone: +44-1603-593909    Fax: +44-1603-507784
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.jones@uea.ac.uk
NR4 7TJ
UK
----------------------------------------------------------------------------


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 03.07.01 -0400, 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@gkss.de
>>>phone: +49 (0)4152 871845
>>>fax: +49 (0)4152 871888
>>>************************************
>>>
>>>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@gkss.de
>>> > >phone: +49 (0)4152 871845
>>> > >fax: +49 (0)4152 871888
>>> > >************************************
>>> > >
>>> > >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@gkss.de
>>> > > > >phone: +49 (0)4152 871845
>>> > > > >fax: +49 (0)4152 871888
>>> > > > >************************************
>>> > > >
>>> > > >
>>> > > > __________________________________
>>> > > > Dr. Julia Cole
>>> > > > Dept. of Geosciences
>>> > > > Gould-Simpson Bldg.
>>> > > > 1040 E. 4th St.
>>> > > > University of Arizona
>>> > > > Tucson AZ   85721
>>> > > >
>>> > > > phone 520-626-2341
>>> > > > fax 520-621-2672
>>> > > > __________________________________
>>> > > >
>>> >
>>> > _______________________________________________________________________
>>> >                      Professor Michael E. Mann
>>> >             Department of Environmental Sciences, Clark Hall
>>> >                        University of Virginia
>>> >                       Charlottesville, VA 22903
>>> > _______________________________________________________________________
>>> > e-mail: mann@virginia.edu   Phone: (804) 924-7770   FAX: (804) 982-2137
>>> >
>>> >
>>
>>_______________________________________________________________________
>>                     Professor Michael E. Mann
>>            Department of Environmental Sciences, Clark Hall
>>                       University of Virginia
>>                      Charlottesville, VA 22903
>>_______________________________________________________________________
>>e-mail: mann@virginia.edu   Phone: (804) 924-7770   FAX: (804) 982-2137
>>
>
_______________________________________________________________________
Professor Michael E. Mann
Department of Environmental Sciences, Clark Hall
University of Virginia
Charlottesville, VA 22903
_______________________________________________________________________
e-mail: mann@virginia.edu   Phone: (804) 924-7770   FAX: (804) 982-2137


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.


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:    +44 1603 592089
>Senior Research Associate           | fax:      +44 1603 507784
>Climatic Research Unit              | e-mail:   t.osborn@uea.ac.uk
>School of Environmental Sciences    | web-site:
>University of East Anglia __________|   ~timo/
>Norwich  NR4 7TJ         | sunclock:
>UK                       |   ~timo/sunclock.htm
==================================
Dr. Edward R. Cook
Doherty Senior Scholar
Tree-Ring Laboratory
Lamont-Doherty Earth Observatory
Palisades, New York  10964  USA
Phone:  1-845-365-8618
Fax:    1-845-365-8152
Email:  drdendro@ldeo.columbia.edu
==================================


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 2013-2018. 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


>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) (0)40-41173-237 Fax. (+49) (0)40-41173-250
home: Schulstr. 79, D 25368 Kiebitzreihe
Tel. (+49) (0)4121-508849,  Fax. (+49) (0)4121-508850
e-mail: klaus.hasselmann@dkrz.de


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
To: "Matilda Lee"
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
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