Thursday, January 19, 2012

2072.txt

cc: "Michael E. Mann" <mannatXYZxyzginia.edu>, "Phil Jones" <p.jonesatXYZxyz.ac.uk>, "Keith Briffa" <k.briffaatXYZxyz.ac.uk>, <ckfollandatXYZxyzo.gov.uk>, <peter.stottatXYZxyzoffice.com>, <d.vineratXYZxyz.ac.uk>, <m.hulmeatXYZxyz.ac.uk>
date: Fri Oct 3 10:59:16 2003
from: Tim Osborn <t.osbornatXYZxyz.ac.uk>
subject: Re: Mann and Jones, climate of the last two millennia
to: "Robert Matthews" <r.matthewsatXYZxyzsics.org>

At 10:35 03/10/2003, you wrote:

Many thanks for this; it's much appreciated.
Could you comment on why only the NH temperature graph shows that the
current warming is unprecedented ?
thanks
Robert

The number (and possibly the quality of some) of proxy records is lower in the SH than the
NH. Thus there is greater uncertainty when using those records to reconstruct past SH
temperature.
Also, warming during recent decades has been greater in the NH than the SH (e.g. 1976-2000
trends quoted by the latest IPCC report are 0.6 degrees C for the NH, and 0.3 degrees C for
the SH).
Combining weaker recent warming with greater uncertainty in previous temperatures means
that the SH warming cannot be concluded to be unprecedented compared with the last 2000
years or so.
Regards
Tim

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