On Mar 7, 9:25 am, wrote:
On Mar 6, 1:58 pm, wrote:



On Mar 6, 12:10 am, Just Wondering wrote:

wrote:

Note that the highest CO2 concentration over the last half
million years is a bit over 300 ppm. The current concentration
is 380 ppm.

IF that is true, it's also true that the earth is far from the hottest
it's been during that same time frame. Which would seem to indicate
that CO2 concentration is not the cause of global temperature levels.

Sure, if you ignore Physics and rely on blind correlation instead.

You seem to under appreciate the distinction between 'the'
and 'a'. Changes in atmospheric composition must be a
cause of changes in global temperature. That is basic
Physics. To claim there can be no other causes is absurd
to the point that it suggests an effort to avoid meaningful
discussion.

That's true only if, by 'global temperature', you include geothermal
energy (that's probably where your often repeated 'conservation of
energy' non-sequitur came from). To his credit, even Al Gore doesn't
take the argument to that level of absurdity (although it wouldn't
surprise me if that was the Ace up his sleeve).

Sadly, you canno tmake that same claim.

In the context of the
controversy of global warming (man's contribution to the causes of
*atmospheric* warming), one must acknowledge that periods of increased
volcanic activity and the resulting increase in atmospheric greenhouse
gases - the likes of which would put our best efforts to pollute to
shame - are neither the result of human activity, nor the result of
atmospheric composition. Would you agree?

And I'm confused as to why you dismiss increased solar output as a
contributor to the observed increase in global temps. (Actually, I'm
not confused by your dismissal, at all. I'm just trying to keep the
discussion lively)

It is apparent that you came late to this discussion, and therefor do
not understand some of what I say. There are two valid ways to
inform yourself that are immediately obvious. The first, would be
to review the thread. The other would be to ask me. That you
eschew either method and instead chose the invalid approach
of assuming I am a crackpot leads me to certainly conclusions
about yourself that I prefer to not articulate in order to reduce the
liveliness of the discussion.

I use the addmitedly ill-defined term 'global temperature' in much
the same way as everyone else, meaning some sort of ground
level 'average' air temperature.

I did refer to radioactive decay and tidal friction when pointing out
the role of the conservation of energy, and lest you be confused,
I did so only for the sake of completeness and do not contend that
either plays a role in short-term climate change though either or
both may have dominated long-term change at other times.

Conservation of energy requires that the temperature of a body
change whenever the energy absorbed by that body plus the
energy generated within does not equal the energy emitted
by it.

Regarding the present effects of volcanism on climate change:

http://volcano.und.edu/vwdocs/Gases/man.html

"Present-day carbon dioxide (CO2) emissions from
subaerial and submarine volcanoes are uncertain at
the present time. Gerlach (1991) estimated a total
global release of 3-4 x 10E12 mol/yr from volcanoes. T
his is a conservative estimate. Man-made (anthropogenic)
CO2 emissions overwhelm this estimate by at least 150
times."

and, courtesy of the minions of the Bush administration who
are routinely accused of 'suppressing' real science:

http://www.osti.gov/energycitations/...sti_id=5271302

"Volcanic CO{sub 2} presently represents only 0.22% of anthropogenic
emissions but may have contributed to significant greenhouse` effects
at times in Earth history"

Would you agree that volcanic eruptions in the distant past are
non-sequitur as they have no effect on future short-term climate
changes?

I dismiss increased solar irradiance as a factor in the recent global
warming on _Mars_ because solar irradiance has decreased over the
three Martian years during which that temperature increase has been
observed. Pleas try to maintain an awareness of what planet you
are on.

I've also noted that studies of variation in solar irradiance over
more than
one solar cycle establish an upper limit on any increase that
corresponds
to a a forcing of about 0.1 W/sqm, about one quarter of the forcing
attributed to increasing CO2 over the same period of time.


Other factors forcing temperatures down, at the same time that
an increase in Greenhouse gases is forcing it up, are well-
established--see Global dimming.


FF