Re: The green house effect - one of Thatcher's lies?

Thus spake AJH <news@xxxxxxxxxxxxxxxxxxxx>
On Fri, 23 Mar 2007 09:24:09 +0000, Oh No
<NotI@xxxxxxxxxxxxxxxxxxxxxxxxxxxx> wrote:

Thus spake AJH <news@xxxxxxxxxxxxxxxxxxxx>
On Thu, 22 Mar 2007 17:22:17 +0000, Oh No
<NotI@xxxxxxxxxxxxxxxxxxxxxxxxxxxx> wrote:

Thus spake Oz <Oz@xxxxxxxxxxxxxxxxxxxx>


Worth remembering, however, that H2O vapour is a potent greenhouse gas.


Indeed, by all accounts much more potent than CO2,

Yes it has the ability to absorb a lot of re radiated energy but check
out the spectrum it absorbs and how much of those frequencies are
absorbed at any low level of water vapour in the atmosphere. I'm told
the absorption for H2O was already saturated, those for CO2 had far
less chance of being intercepted, hence doubling Co2 doubled the
effect, doubling water vapour has no effect.

This probably applies to water vapour,

Yes because with radiation incident at the surface and then re
radiated the effect is about when the atmosphere is transparent to the
eye, but obviously not transparent to bands of radiation being
captured. Clouds both prevent incoming radiation, by reflecting the
bulk back and similarly trap outgoing radiation below them. The
greenhouse effect is about how an apparently clear sky can trap
outgoing radiation because it is a different wavelength from the
incident radiation that got to the surface. I saw someone said that
even UK has clear skies 52% of the time, which seemed high but I
suppose can be easily checked.

My comments were because it was easy to draw the wrong inference from
the statement that water vapour is a strong GHG (ie. absorbs re
radiated energy), because it is opaque to only some bands and these
were never escaping even before anthropogenic changes to the
atmospheric composition.

but not to the effect of clouds
which is much more complex. Clouds both trap heat and prevent solar
warming, depending on when and where they form. We don't seem to be able
to model cloud formation at all well. It seems to me that they are
likely to have much more effect on climate than the man made level of
changes in CO2.

Note water vapour is a gas below its critical temperature, clouds are
a sol of water droplets.

I don't know it is more complex that the other proposed mechanisms but
we are certainly beyond accurately modeling it.

Another factet disturbed me recently but I haven't had time to think
about it. This was the assertion that you could tell all the extra 50%
of CO2 in the atmosphere (and the implication is not recycled by life
forms) is fossil derived by carbon dating.

An extra 50% seems an over estimate. There was already a significant
upswing in CO2 before the industrial revolution, following on from the
last ice age. This upswing has outstripped previous ones, but the amount
potentially attributable to our activity looks to be nearer 25%, if I
can read the graphs in Wiki. This is a lot higher than some figures that
have been bandied about.

Now I can see that the C14:C12 from biomass decomposition can be dated
and that fossil derived CO2 will have no measurable C14 left but once
they're mixed???

I would think that a computation can be done from the alteration in the
mix to determine the proportions going into the mix.

Also C14 formation is assumed to be a constant from cosmic radiation,
if sun activity changes won't this change?

I should think it must.

Also of cause if CO2 in the
atmosphere doubles the ratio of C14 to C12 must half given a constant
formation of C14, or have I missed something obvious?



All irrelevant is CO2 isn't causal but that doesn't alter the fact
that we are dumping enough CO2 into the atmosphere to cause a
dramatic change in composition and in doing so using up a resource
with no good plan for the future, and associated pollution is reducing
the earth's ability to recycle the products of fossil fuel use.

From my interest in combustion and especially in relation to third
world cooking I can see that 2billion smoky fires can have a
considerable effect on atmospheric conditions.

Wiki thinks indonesian peat fires released 13%-40% as much carbon as the
burning of fossil fuels.


Regards

--
Charles Francis
moderator sci.physics.foundations.
substitute charles for NotI to email

--
Posted via a free Usenet account from http://www.teranews.com

.

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