date: Wed, 3 Jan 2007 21:19:07 -0700 (MST)
from: "Kevin E Trenberth" <trenbertatXYZxyzr.edu>
subject: Re: Science presentation for Paris
to: "Susan Solomon" <ssolomonatXYZxyznoaa.gov>
Dear Susan and Martin
Thanks for the prompt feedback. I wonder if I lost some other email (I
asked about news conferences)?
I am not happy with some of your comments and wish to respond.
All of the slides I included were designed to address misunderstandings in
the comments on the SPM. You criticized slide 16 yet if there was just 1
slide to show, that would be my choice. There are so many comments in
changes in precipitation that are quite WRONG! In particular, comments
230, 232, 357, 360, 379 (twice) and it also addresses 377, 382 and 383.
This relates to misunderstandings among many LAs as well, as I addressed
at one of the plenary talks where I cautioned about use of the term
"intensification of the hydrological cycle" as being quite wrong and
misused. In 352 it claims no trends in global precip. Well precip does
not and should not refer to just amount, but also to type, intensity,
frequency, duration, patterns etc. It is an incorrect and misinformed
comment and fails to recognize that we don't know what is happening over
the oceans. 232 makes the error related to intensification of the
hydrological cycle. It does not relate to runoff or drought. 357 is
wrong in its characterization of trends, and confused by variability. 362
is quite wrong, as temperature changes must have circulation changes
associated with them (they can not be uniform. 379 is wrong about
precipitation vs water vapor and that relates to characteristics and
intensity, and then is very wrong later when it relates heavy
precipitation to evaporation. Nothing could be further from the truth.
Many other comments indicate an absence of understanding of fundamental
issues related to how precipitation changes. It is not helped by having
mean amounts treated separately from extremes, by the way. But that is in
I hope you mistated your point 2. No figures not in the chapter even
though the material is extensively written about in the chapter? Does
this mean I can't use polar bears on the opening slide? On tropical
cyclones I included 4 slides, 3 of which are not in the chapter. The
first was on where TCs occur: very educational. But not usable according
to you? BTW you call out slides 35 and 38 but there are only 35 in the
whole presentation so I am not sure what they are.
You call out slide 6 but there are direct queries 256 and 259 asking what
the ranking of the top 12 years are. We are not going to put this in the
chapter but surely it is a good slide to show?
You ask about DTR and dimming and in section 184.108.40.206 the links between DTR
and cloud are well spelled out. There is nothing new here. But it is
evident from the comments on DTR that a lot of people are confused about
this. The fact that DTR went down so much previously was related to cloud
and not greenhouse effects. This needs to be made clear.
I am not sure what to say about Tropical cyclones. I did not find any
comments worth responding to except for 2 from the US govt which are quite
wrong. These are 391 and 424. They refer to some work by Kossin that was
featured in an AMS seminar on Capitol Hill and unfortunately reported on
by Dick Kerr in Science. The work is not published and has been rejected.
It is flawed. It failed to take account different sizes of storms in
different basins and applied an algorithm trained in the N Atlatic to
global. It failed to show improved agreement over time, but instead
suggested the whol ]record was wrong! Well the paper was wrong. So how
should one respond to comments like this?
Similarly the comment 333 by the US govt on the Walker Circulation cites
Vecchi et al which was published in Nature 6 May 2006, after our deadline.
Also I think it is partly wrong and relates to the 1976/77 climate shift.
I would not include it even now.
You also query slide 19 and this deals with issues of snow pack and how it
relates to drought, something not covered in our chapter as it is a cross
cutting issue. I did highlight in my slides the issue of the link between
precipitation and temperature which relates to evapotranspiration and
drought. Slide 22 is discussed in detail in our chapter although that
figure is not presented. Does that make it invalid?
Please consider what the briefings are intended to do. Is it to clear up
misunderstandings as seen through the comments? Or is it to present a
small subset of material from the chapter? Obviously what is presented
should not be at odds with the chapter, and none of my material is. My
assessment was that a tutorial was needed on precipitation and circulation
changes and drought associated with climate change. Let me know if this
is no correct.
Sorry for sounding off a bit here, but better to clear the air. Perhaps
my impression of what the comments say and how to deal with them is
different than yours. All the more reason for a telecon. I thought
most of the comments were minor suggestions that I assume you have in
hand. The others mostly do not involve changes but rather require
refuting the erroneous siggestions and comments.
Let me know how to proceed, given the above.
Thanks for the cc on this. It's generally looking very good. Martin
Manning and I wanted to make a few specific comments and suggestions:
1) Please try to make these rather less detailed whereever practical.
This is an audience that is quite diverse, and for many of them material
that is too technical will not work well. Please help to present
material that addresses the comments we got on the SPM but it would be
better not to raise new points or give more detail on points that didn't
get a lot of concerns. Slide 16 is an example of one that seems too
detailed - we didn't get many comments expressing concerns on those
points. Slide 19 is another one that is more detailed than what we have
in the text, and there are others with material more detailed or with a
rather different emphasis than we need. It's always tempting to do more
but time is limited.
2) Please don't include any figures or statements that were not actually
in the chapters. It will only raise concerns as to why they were not
included, and we have a large amount to deal with already -- so please
let's not create new areas for questions. Both the delegates and we are
going to have to work with what we have at this point, as tempting as it
always is to add stuff. Slides 7, 22, 35, and 38 are among the figures
that don't appear in the report, so I suggest dropping those - you can put
in text that covers the points. If you show a slide like 6, you will be
provoking somebody to suggest adding such a table to the report. That
would be tough - we have a lot of other stuff to cover and I don't think
we should invite such changes. Similarly please check over all the
statements - e.g., are your statements about dimming and DTR changes in
the report? Here and a few other places seemed to me (Susan) to be saying
things rather differently to the chapter text.
3) Please ensure that you do cover the key queries raised - the basis for
drought and tropical cyclones are two key ones and I think these could be
4) Don't try to cover CO2 or other material on forcing - Ramawamy's
presentation will do that.
Again, many thanks for this - and thanks for being so prompt and
circulating it. I hope these comments are helpful.
Susan and Martin
> Hi all
> Please find attached the slides I have prepared for Paris. Please note
> that several are "hidden" and will not show on a slide show, but please
> look at them all. There are still far too many, even with the hidden
> ones, and based on the comments I would be inclined not to include the
> ones on hurricanes. I have not included ones on the ice and oceans or
> SLR, presuming those are to be done and added by Peter and Jurgen. One
> hidden one is a version of the combined figure from the SPM.
> Phil has approved these, but Phil, note I upgraded some of the slides.
> Please provide your votes on what to include and what to not include.
> Best regards
> Martin Manning wrote:
>> Dear Kevin
>> Here is the follow up message as just mentioned.
>>> Date: Mon, 18 Dec 2006 19:13:46 -0700
>>> To: trenbertatXYZxyzr.edu, plemkeatXYZxyz-bremerhaven.de,
>>> From: Martin Manning <mmanningatXYZxyznoaa.gov>
>>> Subject: Science presentation for Paris
>>> Cc: ssolomonatXYZxyznoaa.gov
>>> Bcc: f\IPCC4\WG1-AR4\FinalSession
>>> Dear Kevin, Peter and Juergen
>>> You will probably have just seen our email with a copy of the
>>> comments on the SPM. This one is to follow up and ask if you would
>>> please start to prepare a joint science presentation for Paris that
>>> would help us to address the comments on the Observations section
>>> that are related to chapters 3, 4 and 5 (we are separately asking
>>> Nathan, Richard and Jonathan to prepare something on sea level
>>> projections and the connection to ice sheets and it may be useful to
>>> compare notes with them on SLR). Please feel free to go through the
>>> comments yourself and draw your own conclusions as to what can be
>>> helpful in this regard. You will see the ones that we have
>>> highlighted. Our summary of the main issues that we think will help
>>> the delegates is:
>>> 1. Choices of temperature baselines and trends
>>> 2. Urban heat island effect and how treated
>>> 3. Arctic temperature variability; what is known and to what
>>> degree current warming is larger/different in character?
>>> 4. Where extremes data comes from
>>> 5. How drought assessed
>>> 6. robustness of precipitation trends in various regions
>>> 7. Basis for tropical cyclone statement
>>> 8. Basis for DTR statement
>>> 9. how uncertainties in SPM-3 constructed
>>> 10. snow cover/ice flow data (including basis for figure
>>> SPM-3 and its error bars, and the available spatial range
>>> in information on ice flow changes, e.g., WAIS vs
>>> 11. what can be said about Larsen B (is there a summary
>>> sentence from the chapter that could be brought forward
>>> in a balanced way?)
>>> 12. explain / show data on ocean warming (e.g. occurs below
>>> the thermocline!)
>>> 13. tide gauge vs satellite data -- availability &
>>> 14. why can't use "accelerating" word for SLR
>>> It will be useful if this science presentation can implicitly deal
>>> with misunderstandings, but not at the level of addressing specific
>>> comments or governments obviously. We would also advise against
>>> getting into discussion of actual wording in the SPM or detailed
>>> discussion on figures etc - as that is better left to the plenary
>>> session and to contact groups where necessary.
>>> Please bring a completed presentation to Paris so that we can discuss
>>> it as necessary on Saturday Jan 27. Feel free to call on your
>>> colleagues to assist with the preparation of this but we are asking
>>> that you give the presentation jointly and that you can coordinate
>>> this among yourselves as regards best use of the time etc. The timing
>>> is still not decided but we intend to go through the SPM in order so
>>> it would likely be either at lunch time of the first day (Jan 29) or
>>> in the morning of the second day (Jan 30). Suggested length is total
>>> of 30 minutes = 20 minutes presentation + 10 minutes for questions.
>>> Please let me know if you have any questions, concerns or if we can
>>> Best wishes for the holiday season
>>> Susan and Martin
>>> *Recommended Email address: mmanningatXYZxyznoaa.gov
>>> *Dr Martin R Manning, Director, IPCC WG I Support Unit
>>> NOAA, Earth System Research Laboratory Phone: +1 303 497 4479
>>> 325 Broadway, R/CSD 2 Fax: +1 303 497 5628
>>> Boulder, CO 80305, USA
> Kevin E. Trenberth e-mail: trenbertatXYZxyzr.edu
> Climate Analysis Section, NCAR www.cgd.ucar.edu/cas/
> P. O. Box 3000, (303) 497 1318
> Boulder, CO 80307 (303) 497 1333 (fax)
> Street address: 1850 Table Mesa Drive, Boulder, CO 80305
Dr. Kevin. E. Trenberth
Climate Analysis Section
PO Box 3000
Boulder CO 80307
ph: (303) 497 1318