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Re: [Phys-l] Mike Mann _The hockey stick and the climate wars_



On 02/18/2012 10:41 AM, David Marx wrote:
The description of the book doesn't make me want to read it. His
argument is that all "deniers" are funded by powerful interests or
simply naively helping those powerful interests.

My, aren't we quick to condemn things we haven't read.

What he actually says in the Guardian interview is:
"true scepticism is two-sided.
One-sided scepticism is no scepticism at all."

which seems entirely correct and reasonable.

I wonder if he actually addresses the short-comings of his methods in
the book.

It's cheap to wonder about a book that hasn't come out yet. As
for his scientific integrity in general, the answer is yes, he
does discuss the state of the art and its limitations. For example,
in the colloquium I cited, he points out greater confidence and
accuracy in predicting global temperatures versus lesser confidence
and accuracy in predicting regional and local temperatures. He
points out that we would really like to know the latter better.

The trouble with the hockey stick is that both the historic and
modern temperatures are not consistent with most other data
available in the peer-reviewed literature (for historic data) and for
satellite data for global temperatures (available since 1979).

Nonsense.

For
example, the midieval warming period seems to be absent from the
data. A literature review finds 200 peer-reviewed articles that
discuss the MWP by 660 different scientists from 385 separate
institutions. Of those, 66 articles give quantitative data: 56
indicate MWP temeratures greater than today, 8 equalling today's
temps, and only 2 indicating less than today's temperatures (this is
consistent with Mann's work).

This is one of the standard lies that climate deniers have been
telling for many years. In fact both the medieval warm period and
the little ice age are visible in the hockey stick graph and have
been all along.

They also failed to explain why in their methods that they included
a weighting scheme that heavily weighted tree ring data that showed
a substantial warming trend over data that did not.

Hogwash. Most importantly, none of the tree-ring data is "heavily"
weighted. The conclusions are the same whether you include all of
it or none of it.

Secondly and less importantly, there are reasonable reasons for
de-weighting some of it. This is a catch-22: We know by *other*
means that the trees are under unprecedented stress, and this
changes the tree-ring-versus-temperature relationship. Of course
if you deny the other data, it makes it easier to deny the tree-ring
data ... but why bother? Why not just deny it all from the get-go?