Controversy Chapter II
Tue Sep 09, 2003
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Hi, I'm Bryan Yeaton for the Weather Notebook's Climate Change series.
Well, the real problem in assessing climate change is that at any one time there can be very
large temperature anomalies, and unless you deal with those properly you can get a very
unrepresentative view of what's going on.
Dr. Kevin Trenbreth is head of the Climate Analysis Section at the National Center for
Atmospheric Research. He and other scientists have taken issue with a paper by Willie Soon and
Sallie Baliunas of the Harvard Smithsonian Center for Astrophysics, which we looked at last
Soon and Baliunas had raised the issue questioning the medieval warm period, and they had done
another assessment of the Little Ice Age and the Medieval Warm Period, using techniques which
we thought were really not up to snuff in many ways.
We understand that weather happens in waves; if one region is warm, another region around the
world is somewhat cooler than normal because we have northerlies in one place and southerlies
in another place. If you don't properly take that into account when you do the analysis, then
you can come up with a distorted view of what's going on and we think that's actually what
happened in the Soon and Bellunus case.
BRYAN: One thing that struck me about both these papers is it's just a tiny slice of
DR. T: The whole of civilization has sort of grown up in the last ten thousand years and so
the development of civilization has occurred in a relatively benign climate. So, there is
relevance to looking much more at the last thousand years and the last ten thousand years in
Next week, Dr. Soon responds to the criticism.
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