On Tue, 16 Sep 2008 21:19:05 +0100 someone who may be Roger
wrote this:-

I believe that 17000 scientists work on 'global warming', but the case
for it is made by about a tenth of that number.

If that is the case then 15000 or more of the non supporters have been
incredibly quiet.

Indeed. They must all be part of the grand conspiracy to promote
false knowledge about climate change we hear so much about from the
antis. Subsequent postings in the thread did not provided a
convincing argument about the "silence" of these "15000 scientists".
It would be a most remarkable feat if the IPCC had managed to get
just the 2000 scientists involved in the "conspiracy" and at the
same time muzzle the 15000 not involved in the conspiracy. A most
remarkable feat.

On the "science" point in this sub-thread the article at
http://www.realclimate.org/index.php/archives/2008/09/simple-question-simple-answer-no/#more-595
is worth reading, this is the first few paragraphs

"I often get emails from scientifically trained people who are
looking for a straightforward calculation of the global warming that
greenhouse gas emissions will bring. What are the physics equations
and data on gases that predict just how far the temperature will
rise? A natural question, when public expositions of the greenhouse
effect usually present it as a matter of elementary physics. These
people, typically senior engineers, get suspicious when experts seem
to evade their question. Some try to work out the answer themselves
(Lord Monckton for example) and complain that the experts dismiss
their beautiful logic.

"The engineers' demand that the case for dangerous global warming be
proved with a page or so of equations does sound reasonable, and it
has a long history. The history reveals how the nature of the
climate system inevitably betrays a lover of simple answers.

"The simplest approach to calculating the Earth's surface
temperature would be to treat the atmosphere as a single uniform
slab, like a pane of glass suspended above the surface (much as we
see in elementary explanations of the 'greenhouse' effect). But the
equations do not yield a number for global warming that is even
remotely plausible. You can't work with an average, squashing
together the way heat radiation goes through the dense, warm, humid
lower atmosphere with the way it goes through the thin, cold, dry
upper atmosphere. Already in the 19th century, physicists moved on
to a 'one-dimensional' model. That is, they pretended that the
atmosphere was the same everywhere around the planet, and studied
how radiation was transmitted or absorbed as it went up or down
through a column of air stretching from ground level to the top of
the atmosphere. This is the study of 'radiative transfer,' an
elegant and difficult branch of theory. You would figure how
sunlight passed through each layer of the atmosphere to the surface,
and how the heat energy that was radiated back up from the surface
heated up each layer, and was shuttled back and forth among the
layers, or escaped into space.

"When students learn physics, they are taught about many simple
systems that bow to the power of a few laws, yielding wonderfully
precise answers: a page or so of equations and you're done. Teachers
rarely point out that these systems are plucked from a far larger
set of systems that are mostly nowhere near so tractable. The
one-dimensional atmospheric model can't be solved with a page of
mathematics. You have to divide the column of air into a set of
levels, get out your pencil or computer, and calculate what happens
at each level. Worse, carbon dioxide and water vapor (the two main
greenhouse gases) absorb and scatter differently at different
wavelengths. So you have to make the same long set of calculations
repeatedly, once for each section of the radiation spectrum."

The rest of the article is worth reading too.


--
David Hansen, Edinburgh
I will *always* explain revoked encryption keys, unless RIP prevents me
http://www.opsi.gov.uk/acts/acts2000/00023--e.htm#54