Believe It Or Not: Briffa Believes In The Mediæval Warm Period!
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unprecedented warming in a thousand years or more in the proxy data' but in
reality the situation is not quite so simple. . I believe that the recent
warmth was probably matched about 1,000 years ago."
Keith Briffa, Hadley Centre
Warmest Regards
B0n oz
"It is a remarkable fact that despite the worldwide expenditure of perhaps
US$50 billion since 1990, and the efforts of tens of thousands of scientists
worldwide, no human climate signal has yet been detected that is distinct
from natural variation."
Bob Carter, Research Professor of Geology, James Cook University, Townsville
Surfer
>
>"I know there is pressure to present a nice tidy story as regards 'apparent
>unprecedented warming in a thousand years or more in the proxy data' but in
>reality the situation is not quite so simple. . I believe that the recent
>warmth was probably matched about 1,000 years ago."
>
>Keith Briffa, Hadley Centre
>
too!
(Now why on earth would you think otherwise?)
Description of the Medieval Warm Period and Little Ice Age in IPCC
reports
http://en.wikipedia.org/wiki/Description_of_the_Medieval_Warm_Period_and_Little_Ice_Age_in_IPCC_reports
<Start extract>
The description of the Medieval Warm Period and Little Ice Age in IPCC
reports has changed since the first report in 1990 as scientific
understanding of the temperature record of the past 1000 years has
improved. The Medieval Warm Period (MWP) and Little Ice Age (LIA) are
the best-known temperature fluctuations in the last millennium.
Critics of the "hockey stick graph" of later reports have claimed that
the record of the MWP and LIA were suppressed in the IPCC Third
Assessment Report, although every report has discussed the phenomena.
<End extract>
And here is how it appears on graphs. (See images at right)
http://en.wikipedia.org/wiki/File:1000_Year_Temperature_Comparison.png
<Start extract>
This image is a comparison of 10 different published reconstructions
of mean temperature changes during the last 1000 years. More recent
reconstructions are plotted towards the front and in redder colors,
older reconstructions appear towards the back and in bluer colors. An
instrumental history of temperature is also shown in black. The
medieval warm period and little ice age are labeled at roughly the
times when they are historically believed to occur, though it is still
disputed whether these were truly global or only regional events. The
single, unsmoothed annual value for 2004 is also shown for comparison.
(Image:Instrumental Temperature Record.png shows how 2004 relates to
other recent years).
It is unknown which, if any, of these reconstructions is an accurate
representation of climate history; however, these curves are a fair
representation of the range of results appearing in the published
scientific literature. Hence, it is likely that such reconstructions,
accurate or not, will play a significant role in the ongoing
discussions of global climate change and global warming.
For each reconstruction, the raw data has been decadally smoothed with
a sigma = 5 yr Gaussian weighted moving average. Also, each
reconstruction was adjusted so that its mean matched the mean of the
instrumental record during the period of overlap. The variance (i.e.
the scale of fluctuations) was not adjusted (except in one case noted
below).
Except as noted below, all original data for this comparison comes
from [1] and links therein. It should also be noted that many
reconstructions of past climate report substantial error bars, which
are not represented on this figure.
<End extract>