cc: "Jan Esper" , "Keith Briffa" date: Thu, 21 Mar 2002 08:09:06 -0500 from: Edward Cook subject: Re: Roger Highfield/The Daily Telegraph to: "Science" 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" >To: "Science" >Cc: "Jan Esper" ; "Keith Briffa" >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. >> >ends >> > >> >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 >> >attachments, for general use), dtnews@telegraph.co.uk, Editorial pictures >> >(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 >> >--------------------------------------------------- >> >LEGAL DISCLAIMER: This message, its contents and any attachments to it, >are >> >private and confidential. Any unauthorised disclosure, use or >dissemination >> >of the whole or any part of this message, without prior consent in >writing, >> >is prohibited. If you are not the intended recipient, please inform us >> >immediately. No contracts may be concluded on behalf of Telegraph Group >> >Limited by means of email. >> >------------------- >> >> >> -- >> ================================= >> 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 =================================