Mark & Juanita writes:

On Mon, 26 Feb 2007 04:24:23 GMT, Lobby Dosser
wrote:

J. Clarke wrote:

On Mon, 26 Feb 2007 02:49:02 GMT, Lobby Dosser
wrote:

Mark & Juanita wrote:

So, given that everything observed is evidence of global warming,
the
thing to ask the proponents of this theory, is "what evidence would
be required to refute this theory?" When everything is cited as
evidence of a theory and nothing as evidence to dispute it, then one
needs to start questioning the person postulating the theory.


Facts:

1. CO2 reflects infrared radiation.

2. The earth gives off infrared radiation.

3. When infrared radiation reflects back to earth, the global
temperature rises

4. Human produced CO2 can be distinguished from that produced by other
sources.

How?

Determining the carbon isotope ratios.

http://www.realclimate.org/index.php?p=87



From your link, "CO2 produced from burning fossil fuels or burning
forests has quite a different isotopic composition from CO2 in the
atmosphere."

How, pray tell, is this capable of distinguishing between CO2 from
human-caused burning forests and CO2 produced by forest fires induced by
natural causes?

I don't think it is... but the CO2 released from burning forests was
originally removed (by photosynthesis) from the atmosphere fairly recently
- in the lifetime of the tree. (Carbon in the trees from uptake of soil
carbon through roots is small, and also of fairly recent origin -
probbaly a few generations of trees.)

It's the carbon from fossil fuels that hasn't take part in the cycle
for millions of years that is the problem. The natural system is used to
taking out the CO2 added from forest fires and plant, animal, and soil
respiration, and has been in rough balance for centuries. It's not
succeeding in adjusting to the extra CO2 from fossil fuels, though.

And by the way: humans also fight forest fires. I don't know offhand
whether Smokey the Bear or the careless smoker is winning, but globally
forest fires are not a large flux - general plant respiration, soil
respiration, and plant decay dominate, I think.

Other questions to ask:
"Furthermore, the 13C/12C ratios begin to decline dramatically just as the
CO2 starts to increase -- around 1850 AD."
OK, when and where? Is this a local phenomena, or is this paper making
the claim that starting around 1850, the entire world experienced this
increase?

CO2 is well-mixed. Measurements from pole-to-pole and at many locations
show the same trends. Geography does play a minor role is some local
phenomena, but the trends discussed there are global. There is VERY little
wiggle room to argue that the current rise in atmopspheric CO2 is due to
something other than burning fossil fuels.