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The run-away greenhouse is impossible



 
 
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  #1  
Old June 23rd 08, 12:00 AM posted to soc.men,sci.chem,sci.physics,sci.astro
Andrew Usher
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Posts: 586
Default The run-away greenhouse is impossible

The conventional explanation of the run-away greenhouse effect,
which produced the conditions we see on Venus today, is that
the evaporation of water vapor caused the temperature to rise so
high that the atmosphere became unbound.

I have seen a journal article that says the temperature would reach
'several thousand degrees' until the surface could 'radiate in the
visible'.
This is absurd and impossible. In fact I am sure the temperature on
Venus has never been significantly hotter than today.

First of all, even if the surface did reach such temperatures, it
could
not 'radiate in the visible' to space, as the H2O atmosphere would
be completely opaque at all wavelengths. Even if there were no clouds,
it would be nearly opaque in the visible due to Rayleigh scattering.

Second, where does the heat come from? No sunlight will reach the
surface, so the only source of surface heating is internal heat. On
Earth today internal heating of the surface is roughly 1/5,000 of
solar
heating; on Venus it must be much closer. But regardless of the heat
source, convection limits the surface temperature to a value that
increases only logarithmically with pressure, and is proportional to
the adiabatic lapse rate. In an atmosphere saturated with H2O at
high temperatures ( 100 C), the lapse rate is very small; therefore,
even though the atmosphere is think, the temperature will surely
remain below the critical point of water as long as the atmosphere
is mostly water.

When, however, the planet has lost most of its water to
photo-dissociation, the base of the cloud layer will lift off the
ground and the surface temperature rise because of the increase
in the lapse rate (the amount of sunlight getting through is
irrelevant
as long as the atmosphere is in convective equilibrium). This
results in the conditions observed on Venus. What happens when
the last of the water is lost? The cloud layer then disappears, but
the surface temperature won't decrease unless the amount it can
now radiate to space exceeds solar input, which seems unlikely
unless the CO2 atmosphere is so thick as to be opaque in the
visible from Rayleigh scattering (several times Venus).

Andrew Usher
  #2  
Old June 23rd 08, 12:06 AM posted to soc.men,sci.chem,sci.physics,sci.astro
Andrew Usher
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Posts: 586
Default The run-away greenhouse is impossible

This wasn't supposed to go to soc.men actually.

My point (I didn't quite finish) was that there can be no such
thing as a true 'run-away greenhouse', that there can be no
abrupt tipping point but only a gradual change. It is
nonetheless irreversible, though.

Also, this has no effect on projections of man-made global
warming, as it can't occur unless solar input is considerably
higher than today.

Andrew Usher
  #3  
Old June 23rd 08, 01:18 AM posted to soc.men,sci.chem,sci.physics,sci.astro
Yousuf Khan
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Posts: 594
Default The run-away greenhouse is impossible

Andrew Usher wrote:
This wasn't supposed to go to soc.men actually.

My point (I didn't quite finish) was that there can be no such
thing as a true 'run-away greenhouse', that there can be no
abrupt tipping point but only a gradual change. It is
nonetheless irreversible, though.

Also, this has no effect on projections of man-made global
warming, as it can't occur unless solar input is considerably
higher than today.

Andrew Usher


And according to the Gaia Hypothesis, life on Earth itself will evolve
to absorb and subsume any climate conditions that will lead to runaway
greenhouse effects.

Yousuf Khan
  #4  
Old June 23rd 08, 02:42 AM posted to soc.men,sci.chem,sci.physics,sci.astro
Robert J. Kolker[_2_]
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Posts: 51
Default The run-away greenhouse is impossible

Yousuf Khan wrote:


And according to the Gaia Hypothesis, life on Earth itself will evolve
to absorb and subsume any climate conditions that will lead to runaway
greenhouse effects.


The planet is not a living organism. Organism live on the planet.

Bob Kolker

  #5  
Old June 23rd 08, 03:53 AM posted to soc.men,sci.chem,sci.physics,sci.astro
Benj
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Posts: 267
Default The run-away greenhouse is impossible

On Jun 22, 9:42 pm, "Robert J. Kolker" wrote:

And according to the Gaia Hypothesis, life on Earth itself will evolve
to absorb and subsume any climate conditions that will lead to runaway
greenhouse effects.


The planet is not a living organism. Organism live on the planet.


And the way you know this for such a certainty is? Oh that's right.
FAITH!

I love faith-based science, don't you?

I especially love those who have such unquestioned authority that they
can simply answer all questions with unshakable assertion that is
obviously so authoritative that none dare question it! Love, ya,
Bob!

  #6  
Old June 23rd 08, 08:41 AM posted to soc.men,sci.chem,sci.physics,sci.astro
Mike Dworetsky
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Posts: 715
Default The run-away greenhouse is impossible

"Benj" wrote in message
...
On Jun 22, 9:42 pm, "Robert J. Kolker" wrote:

And according to the Gaia Hypothesis, life on Earth itself will evolve
to absorb and subsume any climate conditions that will lead to runaway
greenhouse effects.


The planet is not a living organism. Organism live on the planet.


And the way you know this for such a certainty is? Oh that's right.
FAITH!

I love faith-based science, don't you?

I especially love those who have such unquestioned authority that they
can simply answer all questions with unshakable assertion that is
obviously so authoritative that none dare question it! Love, ya,
Bob!


Well, unless you know of some life form that can survive without liquid
water and can breath "live" steam, I'd say that Bob is right.

The runaway greenhouse predicted for Earth would be the result of solar
luminosity increase giving rise to extra CO2 and water vapour, hence
greenhouse feedback into yet higher temperatures.

By the way, the Gaia Hypothesis is just that, a hypothesis, or conjecture,
proposed as an explanation of certain observations in the fossil record. It
hasn't reached the status of a theory, yet.

--
Mike Dworetsky

(Remove pants sp*mbl*ck to reply)

  #7  
Old June 23rd 08, 06:00 PM posted to soc.men,sci.chem,sci.physics,sci.astro
[email protected]
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Posts: 134
Default The run-away greenhouse is impossible

On Jun 22, 10:53*pm, Benj wrote:
On Jun 22, 9:42 pm, "Robert J. Kolker" wrote:

And according to the Gaia Hypothesis, life on Earth itself will evolve
to absorb and subsume any climate conditions that will lead to runaway
greenhouse effects.


The planet is not a living organism. Organism live on the planet.


And the way you know this for such a certainty is? *Oh that's right.
FAITH!

I love faith-based science, don't you?

I especially love those who have such unquestioned authority that they
can simply answer all questions with unshakable assertion that is
obviously so authoritative that none dare question it! Love, ya,
Bob!


Well, faith based science has its merits by avoiding the brain strain
that comes as a reult of serious thinking!
Hence, without the brain strain, empty headed believers in faith based
science tend live longer than those that actually contribute to the
physical sciences, but fortunatly for the human race, don't reproduce
very often.

This is why we see so many 80 year old Bible thumpers, but not very
many historically productive sceintist over the age of roughly 70.

Harry C.

p.s., On a more serious note, during their college years, most
physical science majors burn the midnight oil studying, sometimes
pulling all-nighters simply to stay ahead, and in other cases, to pay
for their education. I've noticed that this takes years off of one's
lifespan. I'm 70, and a vast majority of my physics classmates are
already dead. Still, the business and theology majors are still going
strong! I have to tell you this: Classical and Theoretical Mechanics
courses are the real killers, having seen several physics majors taken
away the those nice men in the white lab coats, while still muttering
bable about Euler's equations and the nunation and precession of a
gyroscope. (I only use Euler as as example, because an equal level of
brain strain can result when one thinks about the physical
implications of any transform, and it is clearly better for your
health to simply accept that these devices work on face value alone.
Not ponder them. and why they work. This is how faith simplies life.)

Harry C.









  #8  
Old June 23rd 08, 06:35 PM posted to soc.men,sci.chem,sci.physics,sci.astro
Uncle Al
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Posts: 697
Default The run-away greenhouse is impossible

Andrew Usher wrote:

The conventional explanation of the run-away greenhouse effect,
which produced the conditions we see on Venus today, is that
the evaporation of water vapor caused the temperature to rise so
high that the atmosphere became unbound.

I have seen a journal article that says the temperature would reach
'several thousand degrees' until the surface could 'radiate in the
visible'.
This is absurd and impossible. In fact I am sure the temperature on
Venus has never been significantly hotter than today.

[snip cogent analysis]

The following sends the wrong message, doesn't it? It's factual.

http://wattsupwiththat.wordpress.com/2008/06/21/a-window-on-water-vapor-and-planetary-temperature-part-2/

Sunspots and such,

Graphics
========
http://upload.wikimedia.org/wikipedia/commons/2/28/Sunspot_Numbers.png
The most recent minimum, to the right, has averaged about 10
sunspots/month.
http://www.dxlc.com/solar/images/solar.gif
local solar flux is dropping
http://www.skepticalscience.com/images/tsi_composite.gif
local solar flux is dropping
http://www.swpc.noaa.gov/SolarCycle/Ap.gif
local solar flux is dropping to 10-year lows
http://www.swpc.noaa.gov/SolarCycle/sunspot.gif
projected sunspot number. All we need do is wait and see. The
third unmentioned red curve would be more interesting - stays flat.

COMMENTARY
==========
Global Cooling is nothing new. Click on graphics to enlarge.
http://smarteconomy.typepad.com/smart_economy/2006/09/global_warming_.html

http://www.newrivervalleynews.com/content/view/12742/261/
http://www.climatescienceinternational.org/index.php?option=com_content&task=view&id=31&Itemi d=1
http://ff.org/centers/csspp/library/co2weekly/20060920/20060920_13.html
layman reference
http://www.sciencedaily.com/releases/2004/06/040602061025.htm
slightly better
http://www.grisda.org/origins/10051.htm
data

Weather is always extreme compared to climate. One can play the
GLOBAL WARNING game with anything, earthquakes to

http://thepoorman.net/2008/06/18/gregg-easterbrook-is-wait-for-it-an-idiot/

Proximity is not causality. More hurricanes than any other time in
history were predicted post-Katrina! What does the highly anomalous
*absence* of Caribbean hurricanes portend? Extreme hurricane
disasters! Eventually a pulse will appear. So?

--
Uncle Al
http://www.mazepath.com/uncleal/
(Toxic URL! Unsafe for children and most mammals)
http://www.mazepath.com/uncleal/lajos.htm#a2
  #9  
Old June 23rd 08, 08:12 PM posted to soc.men,sci.chem,sci.physics,sci.astro
Puppet_Sock
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Posts: 60
Default The run-away greenhouse is impossible

On Jun 22, 10:53*pm, Benj wrote:
On Jun 22, 9:42 pm, "Robert J. Kolker" wrote:

And according to the Gaia Hypothesis, life on Earth itself will evolve
to absorb and subsume any climate conditions that will lead to runaway
greenhouse effects.


The planet is not a living organism. Organism live on the planet.


And the way you know this for such a certainty is? *Oh that's right.
FAITH!


Science does not deal in "know this for such a certainty." Science
deals in valid theories that make predictions and can be falsified.

The "Gaia hypothesis" isn't such a thing. The "Gaia hypothesis"
is bad poetry.

We know that the planet isn't alive because we go out and observe it
and it does not have any of the properties of a living thing.

I love faith-based science, don't you?


No, I don't. And the "Gaia hypothesis" is one such chunk of trash
that we really would be better off putting in the dustbin. It can keep
company with alchemy and phlogisten.

I especially love those who have such unquestioned authority that they
can simply answer all questions with unshakable assertion that is
obviously so authoritative that none dare question it! Love, ya,
Bob!


Um. Where do you see these unshakable assertions? Other than
in the pronouncements of the Gaia enthusiasts that is.
Socks
  #10  
Old June 23rd 08, 09:22 PM posted to soc.men,sci.chem,sci.physics,sci.astro
tadchem[_1_]
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Posts: 235
Default The run-away greenhouse is impossible

On Jun 22, 9:42*pm, "Robert J. Kolker" wrote:
Yousuf Khan wrote:

And according to the Gaia Hypothesis, life on Earth itself will evolve
to absorb and subsume any climate conditions that will lead to runaway
greenhouse effects.


The planet is not a living organism. Organism live on the planet.


Not that he said that...

I read Yousef's comment as discussing the effect of "life on Earth"
collectively. not that the earth itself is alive, nor that he
personally endorses the Gaia 'Hypothesis' (really a New-Age neo-
religion).

The consequence of non-equilibrium thermodynamics (see Prigogene, for
example) is that 'dissipative systems' (such as 'organic life') that
absorb absorb energy and reduce entropy are almost inevitable wherever
a system has a net energy influx, a solvent which can affect the
constituents of the system, and a potential for a phase transition in
the solvent. The temperature and phase changes will differentiate and
segregate the constituents,
producing 'organized' structures and reducing entropy locally.

Bob Kolker


Tom Davidson
Richmond, VA
 




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