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). 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)

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