Re: [asa] Back to evidence for human activity producing climate problems

From: Janice Matchett <>
Date: Sun Aug 26 2007 - 18:49:17 EDT

Just got back into town and while catching up on
the posts on this list, noticed your request. Comments below.

>"...our daughter, not a scientist, asks me for a
>short and simple, easily understandable overview
>of the evidence that it is human activity which
>produces problems for earth's climate and global
>warming there a short, simple few-pages
>article giving some basic understanding to a
>non-specialist? It should indicate the relative
>relevance of the various influences considered.
>.." ~ Peter Ruest - 11:31 AM 8/22/2007

>Peter, Perhaps the best readable analysis that
>interested non- scientists are likely to
>understand is by K*rryEmmanuel, an MIT
>meteorologist. ..~ Randy Isaac -Thu, 23 Aug 2007 10:35:47

@ Your daughter may find this short simple,
easily understandable overview helpful [Note - if
links don't work, copy and paste them into your browser manually]:

Randy's source: "The evolution of the scientific
debate about anthropogenic climate change
illustrates both the value of skepticism and the
pitfalls of partisanship." " Scientists are most
effective when they provide sound, impartial
advice, but their reputation for impartiality is
severely compromised by the shocking lack of
p*litical diversity among American academics, who
suffer from the kind of group-think that develops
in cloistered cultures. Until this profound and
well documented intellectual homogeneity changes,
scientists will be suspected of constituting a
leftist think tank." "On the left, an argument
emerged urging fellow scientists to deliberately
exaggerate their findings so as to galvanize an
apathetic public..." "Conservatives have
usually been strong supporters of nuclear power.
.. Had it not been for green opposition, the
United States today might derive most of its
electricity from nuclear power, as does France;
thus the environmentalists must accept a large
measure of responsibility for today’s most
critical environmental problem." ~ K*rryEmanuel

Then there's K. Emmanuel's colleague, Richard S.
Lindzed - the Alfred P. Sloan Professor of Meteorology at MIT.

Janice's source: "Recently many people have said
that the earth is facing a crisis requiring
urgent action. This statement has nothing to do
with science. Frankly, the very idea of
consensus in such an immature and multi- faceted
subject as climate change should be suspicious ab
initio. Consensus is largely a propaganda claim
designed to relieve ordinary people of the need
to understand the issue. This is neither good for
science nor for public policy. . " ~ Richard S.
Lindzed Global Warming: The Origin and Nature
of the Alleged Scientific

Here's the view on global warming of the paramount living physicist:

"... all the fuss about global warming is grossly
exaggerated. Here I am opposing the holy
brotherhood of climate model experts and the
crowd of deluded citizens who believe the numbers
predicted by the computer models. Of course, they
say, I have no degree in meteorology and I am
therefore not qualified to speak. But I have
studied the climate models and I know what they
can do. The models solve the equations of fluid
dynamics, and they do a very good job of
describing the fluid motions of the atmosphere
and the oceans. They do a very poor job of
describing the clouds, the dust, the chemistry
and the biology of fields and farms and forests.
They do not begin to describe the real world that
we live in. The real world is muddy and messy and
full of things that we do not yet understand. It
is much easier for a scientist to sit in an
air-conditioned building and run computer models,
than to put on winter clothes and measure what is
really happening outside in the swamps and the
clouds. That is why the climate model experts end
up believing their own models.".... Freeman

Randy's source admits as much: "Computer modeling
of global climate is perhaps the most complex
endeavor ever undertaken by mankind. A typical
climate model consists of millions of lines of
computer instructions designed to simulate an
enormous range of physical phenomena, including
the flow of the atmosphere and oceans,
condensation and precipitation of water inside
clouds, the transfer of solar and terrestrial
radiation through the atmosphere, including its
partial absorption and reflection by the surface,
by clouds and by the atmosphere itself, the
convective transport of heat, water, and
atmospheric constituents by turbulent convection
currents, and vast numbers of other processes.

There are by now a few dozen such models in the
world, but they are not entirely independent of
one another, often sharing common pieces of
computer code and common ancestors.

Although the equations representing the physical
and chemical processes in the climate system are
well known, they cannot be solved exactly.

It is computationally impossible to keep track of
every molecule of air and ocean, and to make the
task viable, the two fluids must be divided up
into manageable chunks. The smaller and more
numerous these chunks, the more accurate the
result, but with today’s computers the smallest
we can make these chunks in the atmosphere is
around 100 miles in the horizontal and a few
hundred yards in the vertical, and a bit smaller
in the ocean. The problem here is that many
important processes are much smaller than these scales.

For example, cumulus clouds in the atmosphere are
critical for transferring heat and water upward
and downward, but they are typically only a few
miles across and so cannot be simulated by the climate models.

Instead, their effects must be represented in
terms of the quantities like wind and temperature
that pertain to the whole computational chunk in question.

The representation of these important but
unresolved processes is an art form known by the
awful term parameterization, and it involves
numbers, or parameters, that must be tuned to get
the parameterizations to work in an optimal way.

Because of the need for such artifices, a typical
climate model has many tunable parameters, and
this is one of many reasons that such models are
only approximations to reality. Changing the
values of the parameters or the way the various
processes are parameterized can change not only
the climate simulated by the model, but the
sensitivity of the model’s climate to, say, greenhouse-gas increases.

  How, then, can we go about tuning the
parameters of a climate model in such a way as to
make it a reasonable facsimile of reality? Here
important lessons can be learned from our
experience with those close cousins of climate
models, weather-prediction models. These are
almost as complicated and must also parameterize
key physical processes, but because the
atmosphere is measured in many places and quite
frequently, we can test the model against reality
several times per day and keep adjusting its
parameters (that is, tuning it) until it performs as well as it can.

But with climate, there are precious few tests.
One obvious hurdle the model must pass is to be
able to replicate the current climate, including
key aspects of its variability, such as weather
systems and El Niņo. It must also be able to
simulate the seasons in a reasonable way: the
summers must not be too hot or the winters too cold, for example.

Beyond a few simple checks such as these, there
are not too many ways to test the model, and
projections of future climates must necessarily involve a degree of faith.

The amount of uncertainty in such projections can
be estimated to some extent by comparing
forecasts made by many different models, with
their different parameterizations (and, very
likely, different sets of coding errors). We
operate under the faith that the real climate
will fall among the projections made with the various models.." ~ K. E.

~ Janice ... Here's more: August 20, 2007
New Peer-Reviewed Scientific Studies Chill Global
Warming Fears

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Received on Sun Aug 26 18:49:36 2007

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