Re: Cosmic rays and global warming

In article <5NednbNj95ITuj_bnZ2dnUVZ_oesnZ2d@xxxxxxxxxxx>,
dkomo <dkomo871@xxxxxxxxxxx> wrote:
Robert Grumbine wrote:
In article <G8adnXvBP4hIzAPbnZ2dnUVZ_vOlnZ2d@xxxxxxxxxxx>,
dkomo <dkomo871@xxxxxxxxxxx> wrote:

Robert Grumbine wrote:

In article <NPidnc-A6cI-AwDbnZ2dnUVZ_r23nZ2d@xxxxxxxxxxx>,
dkomo <dkomo871@xxxxxxxxxxx> wrote:


[trim]

[snip some good information]

Why snip that, when we're talking about that, and not the preceding,
which I just trimmed, which you didn't continue with?

Anyhow:

Do you know of any web sites that have a comprehensive list of
objections to the AGW hypothesis, with good responses to those
objections? The realclimate.org site does this but is somewhat
disorganized and sprawling.

The Coby Beck link realclimate mentions, and I mentioned in
your snippage, comes closest to Mark Isaak's Counter-Creationism
Handbook, for climate. It does, at least, organize the denialist
claims into some reasonable groupings.

Also, I'd like to mention the article "The Physical Science behind
Climate Change" in the August 2007 issue (current issue) of Scientific
American. The authors of the article were lead authors in the 2007 IPCC
assessment. There is some supplementary material to the article here:

http://www.sciam.com/ontheweb/

Right now my major skepticism of the climate modeling predictions for
global warming has to do with cloud cover. The authors of the SciAm
article say:

"Some important uncertainties remain, of course. For example, the
precise way in which clouds will respond as temperatures increase is a
critical factor governong the overall size of the projected warming.
The complexity of clouds, however, means that their response has been
frustratingly difficult to pin down, and, again, much research remains
to be done in this area."

Let us back up a step before you tire yourself running off to
conclusions. "All models are wrong. Some models are useful."
It's a sentiment I've heard from a number of modellers, including
in the climate change area. The question has never been, to the
science, one of whether the models were perfect. They never have
been, and never will be. We already know that.

The question is whether they can be useful. If by 'useful' you
mean 'all models must agree in all details for every day of the next
100 years', then no climate model will ever be useful -- the details
are weather, and weather is chaotic. But, then, this requirement is
rather like the creationists who want birth certificates for every
ancestor of every species.

Instead, one can examine the spread of the different models'
outcomes for same scenarios. This has been a fair sized industry
for over a decade, starting with the AMIP (Atmospheric Model
Intercomparison Project) (which has since spawned batches of other
MIPs). Regardless of cloud scheme, radiation scheme, turbulence
treatment, ocean model, ice model, land surface model, ... all
the climate models (see CMIP results) show warming (currently the
range is, iirc, 1.5 to 4.5 C for CO2 doubling see IPCC 4 for latest
summary). On the one hand, it may be a large range (depending on what
you mean by large). On the other hand, it's remarkable that will all
the tremendous differences in cloud treatments (et al.) _no_ model
shows a cooling. More striking is that with 20 years advance in
computing technology, and in understanding clouds, and in understanding
the rest of the system, the current range is still inside the range
of 20 years ago for CO2 doubling (1.0 to 5.5 iirc). Clouds do matter,
and uncertainties about them are a significant fraction of the range
(not all, on the other hand).

But the uncertainty is not large enough to include 'no change',
much less 'cooling' as a result of doubled CO2. Recall that, as
with creationists claiming that we're suppressing the evidence
against evolution, the surest route to a Crafoord prize (they don't
give Nobels in this area) would be to show that regardless of what
humans do to the atmosphere, climate doesn't respond.


As a personal anecdote, I have two wireless digital thermometers out in
the back yard at different locations. It is quite hot this time of
year. I have observed on a number of occasions that if the sky is clear
and the day is hot, as soon as clouds come in and obscure the sun, the
temperature can drop 5 to 10 degrees within an hour. I think if cloud
formation in the climate models is not handled accurately, the
predictions of how much warming will take place in the rest of this
century could be invalid.

Mostly what you discovered is why it is meteorological recording
stations are not placed in unshaded sites in back yards. Certain
times of day, my equally-poorly sited thermometer will show a jump
of 20 F in a few minutes, and later an equal drop, as the sun moves
past certain trees.

For global concerns, your patch of ground got shaded by the cloud's
motion, true. But it is equally the case that some other patch of ground
got exposed to the sun after previously being shaded. Net of zero.


There are some extremely powerful integral constraints on the
climate system. The sun continues to radiate strongly, and in a
certain part of the spectrum. That it makes small variations over
time is certainly interesting. But those variations are indeed small,
0.25 W/m^2 (in the climate sense, recognizing the earth is a sphere,
1 if you treat the earth as a disk). And the portion of the spectrum
involved does not change (a bit of increase in UV doesn't change the
basics).

Inside the atmosphere, more greenhouse gas in the atmosphere
means more warming. One can try to dodge around, and wave hands
mightily about how clouds will magically cancel out all the radiation
changes from the greenhouse gases. But the thing that greenhouse
gases _do_ is capture terrestrial radiation. When they do, they
warm the earth. You'd have to violate conservation of energy to avoid
this fact.

You could try to argue that a small warming, say, 0.5 C, would
lead to enough changes in clouds to prevent any further warming.
It's been attempted, and a mechanism proposed. The mechanism was
promptly disproven. But you're still stuck with some warming even
in that most hopeful of situtations. If there were no temperature
changes, there's no reason for the clouds to do anything any different
than before. CO2 and other anthropogenic greenhouse gases do
nothing directly to clouds. They're not cloud forming nuclei,
nor do they directly affect the precipitation process. The only
thing they do is change heating and cooling rates.
--
Robert Grumbine http://www.radix.net/~bobg/ Science faqs and amateur activities notes and links.
Sagredo (Galileo Galilei) "You present these recondite matters with too much
evidence and ease; this great facility makes them less appreciated than they
would be had they been presented in a more abstruse manner." Two New Sciences

.

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