Wednesday, December 21, 2011

1158324958.txt

From: Jonathan Overpeck <jto@u.arizona.edu>
To: Keith Briffa <k.briffa@uea.ac.uk>
Subject: Re: 1988/2005
Date: Fri, 15 Sep 2006 08:55:58 -0600
Cc: David Rind <drind@giss.nasa.gov>, rahmstorf@ozean-klima.de, Bette Otto-Bleisner <ottobli@ncar.ucar.edu>, cddhr@giss.nasa.gov, Ricardo Villalba <ricardo@lab.cricyt.edu.ar>, t.osborn@uea.ac.uk, joos <joos@climate.unibe.ch>, Eystein Jansen <eystein.jansen@geo.uib.no>, <oyvind.paasche@bjerknes.uib.no>

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Thanks Keith, Tim and Fortunat for your input.
We'll go with what we have then - Eystein's
suggestion minus the second "individual".

Eystein and �yvind - just want to double check
that you've deleted that 2nd "individual" in the
all important 1998 sentence??

Thanks, Peck

>I do not disagree either - in fact I preferred
>not to make the "too clever" second statement in
>my "straw man" as I said at the time. If this is
>the consensus (and I believe it is the
>scientifically correct one) then I would be
>happy with Eystein's sentence. The worry is that
>we have inserted this late with no refereeing
>and no justification in the text. I would also
>suggest dropping the second "!individual" in the
>sentence.
>
>At 10:50 15/09/2006, Fortunat Joos wrote:
>>Hi,
>>
>>I support Eystein's suggestion and agree with David.
>>
>>If there is not sufficient evidence to support
>>or dismis claims whether 1998 or
>>2005 was the warmest year of the millennium than we should indeed say so.
>>It is the nature and the strenght of the IPCC
>>process that points from the TAR
>>and earlier reports get reconsidered and
>>reassessed. It is normal that earlier
>>statements get revised. Often statements can be strenghtened, but sometimes
>>statements can not be supported anymore. Our job is to present the current
>>understanding of science as balanced as possible.
>>
>>With best wishes,
>>
>>Fortunat
>>
>>Quoting Eystein Jansen <Eystein.Jansen@geo.uib.no>:
>>
>>> Hi all,
>>> My take on this is similar to what Peck wrote. My suggestion is to write:
>>>
>>> Greater uncertainty associated with proxy-based
>>> temperature estimates for individual years means
>>> that it is more difficult to gauge the
>>> significance, or precedence, of the extreme warm
>>> individual years observed in the recent
>>> instrumental record, such as 1998 and 2005, in
>>> the context of the last millennium.
>>>
>>> I think this is scientifically correct, and in
>>> essence means that we, as did the NAS panel say,
>>> feel the TAR statement was not what we would have
>>> said. I sympatise with those who say that it is
>>> not likely that any individual years were
>>> warmer, as Stefan has stated, but I don�t think
>>> we have enough data to qualify this on the
>>> hemispheric mean.
>>>
>>> Best wishes,
>>> Eystein
>>>
>>>
>>> If this is interpreted as a critisim of the TAR, then I think we
>>> At 14:09 -0600 13-09-06, Jonathan Overpeck wrote:
>>> >thanks David - lets see what others think. I
>>> >agree, that we don't want to be seen as being
>>> >too clever or defensive. Note however, that all
>>> >the TAR said was "likely" the warmest in the
>>> >last 1000 years. Our chapter and figs (including
>>> >6.10) make it clear that it is unlikely any
>>> >multi-decadal period was as warm as the last 50
>>> >years. But, that said, I do feel your are right
>>> >that our team would not have said what the TAR
>>> >said about 1998, and thus, we should delete that
>>> >second sentence.
>>> >
>>> >any other thoughts team?
>>> >
>>> >thx, peck
>>> >
>>> >
>>> >>Leaving aside for the moment the resolution
>>> >>issue, the statement should at least be
>>> >>consistent with our figures. Fig. 6-10 looks
>>> >>like there were years around 1000 AD that could
>>> >>have been just as warm - if one wants to make
>>> >>this statement, one needs to expand the
>>> >>vertical scale in Fig. 6-10 to show that the
>>> >>current warm period is 'warmer'.
>>> >>
>>> >>Now getting back to the resolution issue: given
>>> >>what we know about the ability to reconstruct
>>> >>global or NH temperatures in the past - could
>>> >>we really in good conscience say we have the
>>> >>precision from tree rings and the very sparse
>>> >>other data to make any definitive statement of
>>> >>this nature (let alone accuracy)? While I
>>> >>appreciate the cleverness of the second
>>> >>sentence, the problem is everybody will
>>> >>recognize that we are 'being clever' - at what
>> > >>point does one come out looking aggressively
>>> >>defensive?
>>> >>
>>> >> I agree that leaving the first sentence as the
>>> >>only sentence suggests that one is somehow
>>> >>doubting the significance of the recent warm
>>> >>years, which is probably not something we want
>>> >>to do. What I would suggest is to forget about
>>> >>making 'one year' assessments; what Fig. 6-10
>>> >>shows is that the recent warm period is highly
>>> >>anomalous with respect to the record of the
>>> >>last 1000 years. That would be what I think we
>>> >>can safely conclude the last 1000 years really
>>> >>tells us.
>>> >>
>>> >>David
>>> >>
>>> >>At 9:10 AM -0600 9/13/06, Jonathan Overpeck wrote:
>>> >>>Keith - thanks for this and the earlier
>>> >>>updates. Stefan is not around this week, but
>>> >>>hopefully the others on this email can weight
>>> >>>in. My thoughts...
>>> >>>
>>> >>>1) We MUST say something about individual
>>> >>>years (and by extension the 1998 TAR
>>> >>>statement) - do we support it, or not, and why.
>>> >>>
>>> >>>2) a paragraph would be nice, but I doubt we can do that, so..
>>> >>>
>>> >>>3) I suggest putting the first sentence that
>>> >>>Keith provides below as the last sentence, in
>>> >>>the last (summary) para of 6.6.1.1. To make a
>>> >>>stand alone para seems like a bad way to end
>>> >>>the very meaty section.
>>> >>>
>>> >>>4) I think the second sentence could be more
>>> >>>controversial - I don't think our team feels
>>> >>>it is valid to say, as they did in TAR, that
>>> >>>"It is also likely that, in the Northern
>>> >>>Hemisphere,... 1998 was the warmest year" in
>>> >>>the last 1000 years. But, it you think about
>>> >>>it for a while, Keith has come up with a
>>> >>>clever 2nd sentence (when you insert "Northern
>>> >>>Hemisphere" language as I suggest below). At
>>> >>>first, my reaction was leave it out, but it
>>> >>>grows on you, especially if you acknowledge
>>> >>>that many readers will want more explicit
>>> >>>prose on the 1998 (2005) issue.
>>> >>>
>>> >>>Greater uncertainty associated with
>>> >>>proxy-based temperature estimates for
>>> >>>individual years means that it is more
>>> >>>difficult to gauge the significance, or
>>> >>>precedence, of the extreme warm years observed
>>> >>>in the recent instrumental record. However,
>>> >>>there is no new evidence to challenge the
>>> >>>statement made in the TAR that 1998 (or the
>>> >>>subsequent near-equivalent 2005) was likely
>>> >>>the warmest of Northern Hemisphere year over
>>> >>>the last 1000 years.
>>> >>>
>>> >>>5) I strongly agree we can't add anything to the Exec Summary.
>>> >>>
>>> >>>6) so, if no one disagrees or edits, I suggest
>>> >>>we insert the above 2 sentences to end the
>>> >>>last (summary) para of 6.6.1.1. Or should we
>>> >>>make it a separate, last para - see point #3
>>> >>>above why I don't favor that idea as much.
>>> >>>But, it's not a clear cut issue.
>>> >>>
>>> >>>Thoughts? Thanks all, Peck
>>> >>>
>>> >>>
>>> >>>>Eystein and Peck
>>> >>>>I have thought about this and spent some time
>>> >>>>discussing it with Tim. I have come up with
>>> >>>>the following
>>> >>>>
>>> >>>>Greater uncertainty associated with
>>> >>>>proxy-based temperature estimates for
>>> >>>>individual years means that it is more
>>> >>>>difficult to gauge the significance, or
>>> >>>>precedence, of the extreme warm years
>>> >>>>observed in the recent instrumental record.
>>> >>>>However, there is no new evidence to
>>> >>>>challenge the statement made in the TAR that
>>> >>>>1998 (or the subsequent near-equivalent 2005)
>>> >>>>was likely the warmest in the last 1000 years.
>>> >>>>
>>> >>>>This should best go after the paragraph that concludes section 6.6.1.1
>>> >>>>
>>> >>>>I believe we might best omit the second
>>> >>>>sentence of the suggested new paragraph - but
>>> >>>>you might consider this too subtle (or
>>> >>>>negative) then. I think the second sentence
>>> >>>>is very subtle also though - because it does
>>> >>>>not exclude the possibility that the same old
>>> >>>>evidence that challenges the veracity of the
>>> >>>>TAR statement exists now , as then!
>>> >>>>I think this could go in the text where
>>> >>>>suggested , but I think it best NOT to have a
>>> >>>>bullet about this point.We need to check
>>> >>>>exactly what was saidin the TAR . Perhaps a
>> > >>>>reference to the Academy Report could also be
>>> >>>>inserted here?
>>> >>>>
>>> >>>>Anyway, you asked for a straw-man statement
>>> >>>>for all to argue about so I suggest we send
>>> >>>>this to Stefan, David , Betty and whoever
>>> >>>>else you think.
>>> >>>>cheers
>>> >>>>Keith
>>> >>>>
>>> >>>>--
>>> >>>>Professor Keith Briffa,
>>> >>>>Climatic Research Unit
>>> >>>>University of East Anglia
>>> >>>>Norwich, NR4 7TJ, U.K.
>>> >>>>
>>> >>>>Phone: +44-1603-593909
>>> >>>>Fax: +44-1603-507784
>>> >>>>
>>> >>>> http://www.cru.uea.ac.uk/cru/people/briffa/
>>> >>>
>>> >>>
>>> >>>--
>>> >>>Jonathan T. Overpeck
>>> >>>Director, Institute for the Study of Planet Earth
>>> >>>Professor, Department of Geosciences
>>> >>>Professor, Department of Atmospheric Sciences
>>> >>>
>>> >>>Mail and Fedex Address:
>>> >>>
>>> >>>Institute for the Study of Planet Earth
>>> >>>715 N. Park Ave. 2nd Floor
>>> >>>University of Arizona
>>> >>>Tucson, AZ 85721
>>> >>>direct tel: +1 520 622-9065
>>> >>>fax: +1 520 792-8795
>>> >>>http://www.geo.arizona.edu/
>>> >>>http://www.ispe.arizona.edu/
>>> >>
>>> >>
>>> >>--
>>> >>////////////////////////////////////////////
>>>///////////////////////////////
>>> >>
>>> >>////////////////////////////////////////////
>>>///////////////////////////////
>>> >
>>> >
>>> >--
>>> >Jonathan T. Overpeck
>>> >Director, Institute for the Study of Planet Earth
>>> >Professor, Department of Geosciences
>>> >Professor, Department of Atmospheric Sciences
>>> >
>>> >Mail and Fedex Address:
>>> >
>>> >Institute for the Study of Planet Earth
>>> >715 N. Park Ave. 2nd Floor
>>> >University of Arizona
>>> >Tucson, AZ 85721
>>> >direct tel: +1 520 622-9065
>>> >fax: +1 520 792-8795
>>> >http://www.geo.arizona.edu/
>>> >http://www.ispe.arizona.edu/
>>>
>>>
>>> --
>>> ______________________________________________________________
>>> Eystein Jansen
>>> Professor/Director
>>> Bjerknes Centre for Climate Research and
>>> Dep. of Earth Science, Univ. of Bergen
>>> All�gaten 55
>>> N-5007 Bergen
>>> NORWAY
>>> e-mail: eystein.jansen@geo.uib.no
>>> Phone: +47-55-583491 - Home: +47-55-910661
>>> Fax: +47-55-584330
>>
>>
>>--
>> Climate and Environmental Physics
>> Sidlerstr. 5, CH-3012 Bern
>> Phone: ++41(0)31 631 44 61 Fax: ++41(0)31 631 87 42
>> Internet: http://www.climate.unibe.ch/~joos/
>
>--
>Professor Keith Briffa,
>Climatic Research Unit
>University of East Anglia
>Norwich, NR4 7TJ, U.K.
>
>Phone: +44-1603-593909
>Fax: +44-1603-507784
>
>http://www.cru.uea.ac.uk/cru/people/briffa/


--
Jonathan T. Overpeck
Director, Institute for the Study of Planet Earth
Professor, Department of Geosciences
Professor, Department of Atmospheric Sciences

Mail and Fedex Address:

Institute for the Study of Planet Earth
715 N. Park Ave. 2nd Floor
University of Arizona
Tucson, AZ 85721
direct tel: +1 520 622-9065
fax: +1 520 792-8795
http://www.geo.arizona.edu/
http://www.ispe.arizona.edu/
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