On Thu, 10 Dec 2009 18:24:56 +0100, Tom P wrote:

I M @ good guy wrote:
On Thu, 10 Dec 2009 05:14:41 -0800 (PST), Dawlish
wrote:

On Dec 10, 1:00 pm, "Stan" wrote:
"I M @ good guy" wrote in messagenewsfq1i5taabqfsl4nrlcst0bjh907pc1tpe@4ax .com...
On Thu, 10 Dec 2009 03:57:22 -0800 (PST), Dawlish
wrote:
On Dec 10, 10:56 am, "I M @ good guy" wrote:
AGW has to be
based on more than the simplistic assumption
that CO2 increases causes temperature increases.
Obviously it is. CO2 increases will cause temperature increases
unless other (natural) factors override the increase which is being
caused by increasing CO2. The physics behind that was settled over a
century ago. Pumping more CO2 in the earth's atmosphere *will*
increase absorption of outgoing IR radiation and it will cause
warming. That is accepted by almost all climate scientists and
physicists and whether you like it, or not, it is. The greenhouse
effect is well understood and the physics behind it really are
settled. The degree of warming that will be caused caused by
increasing the atmospheric concentration of CO2 is also settled,
unless you wish to change those physical laws.
GHGs are what cool the atmosphere, and
all the scientists think the minor trace gas is
what warms the atmosphere?
Scientists I know don't seem to think this, although they do say that some
of the minor gases have a potential greater green house effect. Can you
please give me some links so I can read up? (Not that I doubt you but I know
several people can read same article and all come up with different
conclusions due to selective reading, and may not realise they are doing it,
see my reply to article on greenhouse effect on Mars)

Also my earlier point regarding graph is that the time scale at bottom is
not even but they are evenly spaced. But I agree about your point regarding
too small to catch the peaks and troughs etc.

That brings me to the point of my original post. Given that the
physics is settled, why isn't the earth cooler than it presently is,
given that two of the major natural varients (PDO and Solar output)
are in a state that ought to mean that they are having a negative
effect on temperatures - which they clearly aren't? They should be
causing cooling and we should not be experiencing some of the warmest
conditions in 130 years - unless the natural effects are *not*
managing to override the effects of CO2; which logically leaves CO2 as
the main driver of global temperature increase. Unless I (and also the
vast majority of climate scientists) see something else affecting
global temperatures in a greater way than the physics shows the
increases in CO2 should, I'm more likely to strengthen my views on CO2
being the cause of GW, than not.
Why isn't it cooler? Maybe if the methods
and weather stations used 50 years ago would
show more cooling, but if you are cock-sure,
no sense in exploring any possible explanations.
I agree with Dawlish here, the sun is at a solar Minimum and global climate
should be showing, even with global warming, global average temperature
heading towards a trough, although with global warming I would expect the
min of the trough to be slightly higher than last trough.

However with 1998 as starting point there was a slight dip followed by
rising i.e. almost steady Taking out the 1998 blip, temperatures have only
slowed down in the general rising, and look like they are starting to speed
up again.

Note to Dawlish and good.guy try and keep tone friendly even if you disagree
on this. Debate can be fun even if you think other guy is talking a load of
rubbish.

I agree entirely with your remarks on keeping the tone reasonable,
Stan, even when so many scientists are tarred with a "nucase" brush
they simply don't deserve.

I don't even believe fully that CO2 is the main driver for GW; I just
think, on the basis of evidence, that it is likely to be - unlike guy,
who even denies the science and says that GHGs *cool* the atmosphere.
Well, I'll just point out again that the vast majority (and I make no
apology for using that term again, as it is true) of climate
scientists and physicists would regard that as twaddle. Not just me,
guy, but almost everyone else.


You're joking aren't you?

If not, state what you (and the scientists
and physicists) think cools the atmosphere
after the sun warms it, the outgoing energy
has to equal the incoming.

[[Please note: I do not call rational scientists
names, it is the foul mouthed idiots posting
in alt.global-warming nonsense about absolute
certainty in AGW]]


Ok, here we go - the temperature at which the earth is in radiative
equilibrium with the incoming solar energy is around -20°c.

How is the facts of that statement derived,
is that minus 20 C?


This is the
temperature of the atmosphere at an altitude of around 6km - I have to
say "around", because this varies by latitude, but for the sake of
simplicity if we are going to get anywhere in the discussion, we have to
stick to averages and approximations.

To get anywhere in the science, specifics
are needed, not estimates of averages and guess
approximations.


So, at this altitude, we can say for simplicities sake that the LWR is
being emitted by the GHGs in the atmosphere at this altitude.


Sorry, LWIR can be leaving the Earth from
a lot of different levels at the same time.


(There is
also a component that gets through from the surface directly in certain
spectral bands, which we leave aside).


It is between 10 and 20 percent, a little too
much to leave aside.


That means that in a very
strange sense of the word, GHGs "cool" the atmosphere.


Not a strange sense at all, without GHGs,
the N2 and O2 could not cool much at all.



It's an
expression that denialists (sorry, sceptics) are fond of using even if
it doesn't really mean anything.


No, it is the basic physics, the only thing
that cools the atmosphere.

It's like saying that if I wear an
anorak, the anorak "cools" me because my body heat ultimately can only
escape from the surface of the anorak...


If your anorak had the properties of nitrogen,
you would have to open it up or have a heat stroke.


That aside, the next thing to note is that the temperature at the
surface is always higher than the temperature at the -20°c level as a
result of the Lapse Rate.


Not as a result of the Lapse Rate, partly
because of the sun and partly because heat
is migrating from the center of the Earth.
And gravity and the mass of the atmosphere
is what causes the Lapse Rate.

While using an equivalent temperature
level may have a use in approximations, it
has no bearing on reality and the physics.


The Lapse Rate is a consequence of the hydrostatic equation and the
gas laws. This is basic physics. The exact amount depends on the amount
of water vapour in the atmosphere, but this again is limited by the
Clausius-Clapeyron equation, which in turn is derived from the
fundamental physics of thermodynamics.


A lapse rate can exist without water vapor,
I assume you meant the amount or rate of LWIR
depends mostly on water vapor.


Now, the important thing to note is that the composition of GHGs at
this altitude is not the same as the surface. At the surface, the higher
temperature allows water vapour to exist in large quantities measurable
in percentages. As we go up higher in the atmosphere, the temperature
drop (lapse rate) causes the maximum water vapour content to drop
dramatically. Again, the relationship between temperature and saturation
vapour pressure is determined by Clausius-Clapeyron. That means that at
6km altitude, instead of being the overwhelming GHG ,water vapour is
less than 10 times the concentration of CO2 - still higher than CO2, but
with the result that changes in the CO2 concentration are by no means
negligible, but have a direct effect on the overall greenhouse gas
effect.


And I will admit not much LWIR makes it
to space from exactly that altitude.


Note we are talking about the MAXIMUM concentration possible of
water vapour - at any moment, the actual concentration can be even lower.


I suppose the lower in the atmosphere,
the more strict the Local Temperature Equilibrium.

I submit that the GHGs alone could not
hold enough heat to prevent the temperature
from dropping more at night.

At higher altitudes the GHGs radiate more
to space than reaches low altitudes, trying to deny
that GHGs cool the atmosphere does not help the
AGW premise in the least.

Regardless of how these processes result
in retention of heat in the atmosphere, cooling
of the atmosphere is done totally and only
by the GreenHouse Gases.