cc: Steve Colman <scolman@d.umn.edu>, Eystein Jansen <Eystein.Jansen@geo.uib.no>, Jonathan Overpeck <jto@u.arizona.edu>, Tim Osborn <t.osborn@uea.ac.uk>, David Rind <drind@giss.nasa.gov>, Stefan Rahmstorf <rahmstorf@ozean-klima.de>, Bette Otto-Bleisner <ottobli@ncar.ucar.edu>, cddhr@giss.nasa.gov, Ricardo Villalba <ricardo@lab.cricyt.edu.ar>, Jouzel@dsm-mail.extra.cea.fr, Valerie Masson-Delmotte <Valerie.Masson@cea.fr>, Dominique Raynaud <raynaud@lgge.obs.ujf-grenoble.fr>, Keith Briffa <k.briffa@uea.ac.uk>, Phil Jones <p.jones@uea.ac.uk>, jean-claude.duplessy@lsce.cnrs-gif.fr, dolago@uonbi.ac.ke, peltier@atmosp.physics.utoronto.ca, rramesh@prl.res.in, olgasolomina@yandex.ru, derzhang@msn.com, Heinz Wanner <wanner@giub.unibe.ch>, Thorsten Kiefer <thorsten.kiefer@pages.unibe.ch>, Eric W Wolff <ewwo@bas.ac.uk>, fatima.abrantes@ineti.pt, j.dearing@soton.ac.uk, jose_carriquiry@uabc.mx, moha_umero@yahoo.com, Michael Schulz <mschulz@uni-bremen.de>, nakatsuka.takeshi@f.mbox.nagoya-u.ac.jp, Bette Otto-Bliesner <ottobli@ucar.edu>, peter.kershaw@arts.monash.edu.au, pfrancus@ete.inrs.ca, Whitlock Cathy <whitlock@montana.edu>, zlding@mail.iggcas.ac.cn, Laurent Labeyrie <Laurent.Labeyrie@lsce.ipsl.fr>, Gavin Schmidt <gschmidt@giss.nasa.gov>
date: Wed, 22 Apr 2009 08:42:20 +0200
from: Fortunat Joos <joos@climate.unibe.ch>
subject: Re: Key new IPCC relevant paleo-science
to: Jonathan Overpeck <jto@email.arizona.edu>

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Dear colleagues

The question is not whether it is useful for the paloecommunity to have 
a chapter in AR5, but rather whether it is useful for IPCC to have a 
chapter on paleo again in AR5.

We are competing here with space constraints. For example, there have 
not been separate chapters on sea level or on carbon cycle. There are 
thoughts around that these important topics need again be presented in a 
dedicated chapters as in the TAR.

I believe that we need to make the case that paleoscience can indeed 
contribute highly (policy) relevant information to IPCC AR5. We need to 
make sure that this information is properly addressed in AR5. Whether 
this will be done in a dedicated chapter or in a few chapters with a 
strong paleocomponent is perhaps not so important.

It is a bit early to assess new material as there are only 2 years since 
the last assessement.


Here a few topics:

a) What is the role of anthropogenic and natural forcings for Holocene 
climate?

There is new work on the role of solar variability in the 	 Holocene 
(e.g. by the groups of Beer, Bard and others)

New 13C measurements (manuscript will be submitted in the next two 
weeks) allow for a sound quantification of the processes responsible for 
the Holocenen CO2 variations. Anthropogenic land use plays a minor role

Land use studies now extend over the past 1200 years with AOGCM 
(Pongratz et al.) or the entire Holocene (in prep)

There are new manuscripts on fire histories (e.g. Marlon et al., 
NatGeoscience)

The rates of change in radiative forcing from GHGs and other components 
have been evaluated (attached)

b) Can paleo data constrain climate sensitivity and the carbon cycle 
feedback?

There are manuscript emergings on constraining the carbon cycle-climate 
feedback and climate sensitivity from paleo data that complement earlier 
studies presented in AR4:
Koehler et al., submitted to QSR
Frank et al., in preparation

Obviously there are many more such as sea level, abrupt changes, ...

With best wishes

Fortunat
-- 

   Climate and Environmental Physics,
   Physics Institute, University of Bern
   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/


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