cc: "Jan Esper" <esper@wsl.ch>, "Keith Briffa" <k.briffa@uea.ac.uk>
date: Thu, 21 Mar 2002 08:09:06 -0500
from: Edward Cook <drdendro@ldeo.columbia.edu>
subject: Re: Roger Highfield/The Daily Telegraph
to: "Science" <science@telegraph.co.uk>

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Getting better!

>Hi All
>I made such a steaming mess of my last draft that I have put together a Mk 2
>version - apologies for this. Once again, if there is anything that
>horrifies or offends, mark comments, insults and so on IN CAPS and email
>back to me by mid PM (around 3pm UK time) today. Best, Roger H
>
>By Roger Highfield, Science Editor
>EVIDENCE that  1000 years ago the Northern Hemisphere may have been as warm
>as  today has been revealed by a study of tree rings, showing that the
>Earth's  temperature has a greater ability to rise on its own accord than
>scientists had thought.
>  Today's find does not necessarily undermine evidence of global warming
>caused by the burning of fossil fuels, though it does show that the
>Intergovernmental Panel on Climate Change, IPCC, HAS PROBABLY 
>underestimated the extent of historical global warming that is free 
>of any human influence.
>  While its executive summary found that conditions during the 20th century
>were warmer than at any other time since AD 1000, the new work, combined
>with other studies, now suggests  that the ''Medieval Warm Period'' one
>thousand years ago may have been just as warm as recent decades in the
>Northern Hemisphere and perhaps even farther afield.
>  The finding has come from a study of records at 14 locations in the
>Northern Hemisphere to help establish that tree rings can preserve records
>of climate change spanning centuries, published today in the journal Science
>by Dr Jan Esper of  the Swiss Federal institute in Birmensdorf and Dr Edward
>Cook of  the Lamont-Doherty Earth Observatory in Palisades, New York.
>  Trees grow an additional layer of wood every year, forming ANNUAL rings whose
>width varies, depending on environmental conditions. Scientists can use THESE
>overlapping ANNUAL RING-WIDTH SERIES to piece together year-to-year- 
>climate changes based on ring thickness.
>   This gets tricky for older trees, however, because age also make 
>rings BECOME INCREASINGLY NARROW, THUS complicating the detection of 
>long term trends DUE TO CLIMATE. The new work, an extension of a 
>method used by Prof Keith Briffa at the Climatic Research Unit, 
>University of East Anglia, shows that it is possible to get around 
>this problem to create a record of climate change over the past one 
>thousand years, which corresponds well to known climate events.
>   ''There is no escaping the fact that the climate swings and potential
>natural long term variability is greater than portrayed by the IPCC,'' said
>Prof Briffa.
>  "The idea that Medieval warmth was restricted to Europe is now looking far
>less likely as evidence for warmth at about AD 1000 from much farther afield
>is coming to light" said Professor Briffa , though he warned that "the
>oldest data , statistically speaking, are prone to large uncertainty"
>  Crucial work to understand the details of how tree rings related to climate
>by comparing ring features with very recent, well documented, climatic
>change, are not as well advanced as they should be.
>  "We need to see how well these records perform during the time of greatest
>directly recorded warmth - that of the last 20 years. Surprisingly, we do
>not have enough tree-ring and other indirect climate evidence for this
>period.
>"Many of the records were developed in the1970s and early 1980s and a huge
>international effort is required to resample at many sites around the world"
>ENDS
>
>----- Original Message -----
>From: "Edward Cook" <drdendro@ldeo.columbia.edu>
>To: "Science" <science@telegraph.co.uk>
>Cc: "Jan Esper" <esper@wsl.ch>; "Keith Briffa" <k.briffa@uea.ac.uk>
>Sent: Thursday, March 21, 2002 12:08 PM
>Subject: Re: Roger Highfield/The Daily Telegraph
>
>
>>  Hi Roger,
>>
>>  Here are my editorial comments (in brackets) and changes (in CAPS).
>>
>>  Ed
>>
>>  >Dear Dr Cook
>>  >I am interested in writing up your Science paper for Friday's Daily
>>  >Telegraph. To speed things along, I have drafted a story and wondered
>  > >whether you think I have got the gist right. Just mark comments, insults
>and
>>  >suggestions IN CAPS on offending parts and email back to me by 2pm LATEST
>on
>>  >Thur. All the best, and hope that you can help. Best, Roger Highfield,
>>  >Science Editor
>>  >
>>  >By Roger Highfield, Science Editor
>>  >EVIDENCE that temperatures 1000 years ago MAY HAVE BEEN AS WARM AS
>>  >today has been found by a tree ring study, showing that the Earth's
>>  >temperature has a
>>  >greater ability to rise on its own accord than scientists had thought.
>>
>>  [I must say that I am not too happy with the way that you begin your
>>  article. I never stated nor implied that "temperatures 1000 years ago
>>  were warmer than today". It is reasonable to claim that temperatures
>>  1000 years ago may have been comparable to today's temperatures in
>>  the Northern Hemisphere extratropics (30-70 degrees north), which is
>>  the regional focus of the study. However, one can not legitimately
>>  expand this claim to the tropics using the tree-ring data that was
>>  used in the paper.]
>>
>>  >  Today's find does not necessarily undermine evidence of global warming
>>  >caused by the burning of fossil fuels, though it does question one
>>  >conclusion of the the International Panel on Climate Change, IPCC, in its
>>  >assessment of global warming.
>>  >  While its executive summary found that conditions during the 20th
>century
>>  >were warmer than at any other time since AD 1000, the new work now
>suggests
>>  >that the ''Medieval Warm Period'' may have been just as warm as recent
>>  >decades IN THE NORTHERN HEMISPHERE EXTRATROPICS.
>>
>>  [It is impossible to claim from the evidence provided that
>>  temperatures during the ''Medieval Warm Period'' may have been warmer
>>  than today even for the region that the study addresses.]
>>
>>  >  The finding has come from a study of records at 14 locations to help
>>  >establish that tree rings can preserve records of climate change spanning
>>  >centuries, published today in the journal Science by DR JAN ESPER OF
>>  >THE SWISS FEDERAL INSTITUTE WSL IN BIRMENSDORF AND Dr Edward Cook of
>>  >the
>>  >Lamont-Doherty Earth Observatory in Palisades, NEW YORK.
>>
>>  [I am the second author. Jan Esper should be listed first.]
>>
>>  >  Trees grow an additional layer of wood every year, forming rings whose
>>  >width varies, depending on environmental conditions. Scientists can use
>>  >overlapping ring sets to piece together year-to-year- climate changes
>based
>>  >on ring thickness.
>>  >  This gets tricky for older trees, however, because age also make rings
>>  >relatively narrow, complicating the detection of long term trends. The
>new
>>  >work, an extension of a method used by Prof Keith Briffa at the Climatic
>>  >Research Unit, University of East Anglia, shows that it is possible to
>get
>>  >around this problem to create a record of climate change over the past
>one
>>  >thousand years, which corresponds well to known climate events.
>>  >  ''There is no escaping the fact that the climate swings and potential
>>  >natural long term variability is greater than portrayed by the IPCC,''
>said
>>  >Prof Briffa.
>>  >  A consensus is building that it was as warm a millennium ago as in
>recent
>>  >decades is now correct, said Prof Briffa, though he said that the oldest
>>  >data, statistically speaking, are the most error prone.
>>  >  Crucial work to understand the details of how tree rings related to
>climate
>>  >by comparing ring features with very recent, well documented, climatic
>>  >change, are not as well advanced as they should be.
>>  >  ''We need to see how well these records perform - they may
>underestimate
>>  >the magnitude of the warming,'' he said, adding that the sensitivity of
>the
>>  >tree ring record seems to change over time for reasons that are not fully
>>  >understood.
>>  ><NO>ends<RO>
>>  >
>>  >CONTACT DETAILS: Science Desk, The Daily Telegraph, 1 Canada Square,
>London
>>  >E14 5DT, Tel 44 207 538 6478/7, (note, voice mail can take more than an
>hour
>>  >to log a call), Fax 44 207 538 6883, Editorial email (text only, no
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>>  >(news), photo@telegraph.co.uk, pls copy to dtpicdsk@telegraph.co.uk,
>  > >Features: spillarm@telegraph.co.uk (note jpeg preferred, DPI 200-300,
>each
>>  >file sent separately), Editorial graphics, graphics@telegraph.co.uk,
>>  >Electronic Telegraph,  www.telegraph.co.uk
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>>  >-------------------
>>
>>
>>  --
>>  =================================
>>  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
>>  =================================
>>


-- 
=================================
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
=================================
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