Wednesday, June 20, 2012

5339.txt

date: Tue, 14 Feb 2006 08:28:03 +0100
from: P�l Svensson <paal.svenssonatXYZxyznopec.no>
subject: RE: SUMMER TEMPERATURE VARIABILITY IN CENTRAL SCANDINAVIA DURING
to: "Keith Briffa" <k.briffaatXYZxyz.ac.uk>

Hi back

Thanks for taking time to answer.

My feeling is that the greatest contributor to worldwide temperature changes is the variation in solar influx on earth.
You have both long and short timed circles. I am sure that you have taken all that into account,
but I found this article today showing that not everybody does.
http://sciencenow.sciencemag.org/cgi/content/full/2006/213/1

Best

Paal





-----Original Message-----
From: Keith Briffa [mailto:k.briffa@uea.ac.uk]
Sent: 10 February 2006 14:57
To: P�l Svensson
Subject: Re: SUMMER TEMPERATURE VARIABILITY IN CENTRAL SCANDINAVIA
DURING THE LAST 3600 YEARS


Hi Paal
the quick answer is that we do wish to longer
timescales - but this analysis tried to capture
the spatial extent of warming over the whole
Hemisphere - so we have to compromise between as
wide a coverage as possible but going back as far
as possible. Hence we settled on a compromise
between coverage and length. Other analyses based
on much fewer series do however indicate that
these findings are probably still relevant for a
longer period, though at present not based on
sufficient coverage to justify publication. Cheers
Keith

At 13:24 10/02/2006, you wrote:

>Hi Keith
>
>The article below was published today in a
>norwegian newspaper saying that todays global
>warming is the worst in the last 1200 years.
>
>My question is why just the last 1200 years? Why
>don't you take the last 3.600 years?
>
>Best regards
>
>Paal Svensson
>
>Global oppvarming verre enn p� 1.200 �r
>NTB <<mailto:dn.no@dn.no>mailto:dn.no@dn.no>
>V�ret er varmere over hele verden i dag enn i noen annen periode p� 1.200 �r.
>Det heter det i en artikkel i tidsskriftet Science.
>Studien har unders�kt endringer i �rringer,
>fossiler og iskjerner fra 14 steder p� den
>nordlige halvkule for � fastsl� hvordan
>temperaturendringene har artet seg siden �ret 800.
>
>Uvanlig h�ye temperaturer
>Forskerne kom frem til at det 20. �rhundre
>utmerket seg med uvanlig h�ye temperaturer. Den
>n�v�rende varme perioden som ble innledet mot
>slutten av det 20. �rhundret, er den lengste og
>mest utbredte perioden med unormale temperaturer
>siden det 9. �rhundret, skriver Timothy Osborn
>og Keith Briffa ved East Anglia-universitetet i artikkelen.
>
>For � unders�ke om varmeperioden er i
>overensstemmelse med naturlige
>temperatursvingninger, sammenlignet de den med
>andre perioder i de siste 1.200 �rene.
>
>�rringer
>For � fastlegge klimasvingningene s� forskerne
>p� �rringene til gran- og furutr�r i
>Skandinavia, Sibir og Nord-Amerika, der brede
>�rringer indikerer varme �r, og de unders�kte
>kjerner som er boret ut av innlandsisen p�
>Gr�nland som viser hvilke �r som er varmere enn andre.
>
>De benyttet seg ogs� av kilder som dagb�ker og
>andre nedskrevne �yenvitneskildringer fra
>middelalderen om uvanlige fenomener som
>gjenfrosne kanaler i Belgia og Nederland.
>
>SUMMER TEMPERATURE VARIABILITY IN CENTRAL
>SCANDINAVIA DURING THE LAST 3600 YEARS
>HANS W. LINDERHOLM1,
><javascript:popRef('a1')><javascript:popRef('a3')>
>AND BJ�RN E. GUNNARSON<javascript:popRef('a2')>
>
>ABSTRACT. A Scots pine (Pinus sylvestris L.)
>tree-ring width chronology from J�mtland, in the
>central Scandinavian Mountains, built from
>living and sub-fossil wood, covering the period
>1632 BC to AD 2002, with a minor gap during AD
>887-907, is presented. This is the first
>multi-millennial tree-ring chronology from the
>central parts of Fennoscandia. Pine growth in
>this tree line environment is mainly limited by
>summer temperatures, and hence the record can be
>viewed as a temperature proxy. Using the
>regional curve standardization (RCS) technique,
>pine-growth variability on short and long time
>scales was retained and subsequently summer
>(June-August) temperatures were reconstructed
>yielding information on temperature variability
>during the last 3600 years. Several periods with
>anomalously warm or cold summers were found:
>450-550 BC (warm), AD 300-400 (cold), AD
>900-1000 (the Medieval Warm Period, warm) and AD
>1550-1900 (Little Ice Age, cold). The coldest
>period was encountered in the fourth century AD
>and the warmest period 450 to 550 BC. However,
>the magnitude of these anomalies is uncertain
>since the replication of trees in the J�mtland
>record is low during those periods. The
>twentieth century warming does not stand out as
>an anomalous feature in the last 3600 years. Two
>multi-millennial tree-ring chronologies from
>Swedish and Finnish Lapland, which have
>previously been used as summer temperature
>proxies, agree well with the J�mtland record,
>indicating that the latter is a good proxy of
>local, but also regional, summer temperature variability.

--
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/

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