>Michael Plante <michael.plante@gmail.com> wrote:
>(snip)
>
>(snip)
>> The words "climate change", as opposed to "global warming", have the
>> interesting interpretation of being untestable: no one in their righ
mind
>> should expect the climate to stay the same, whether man exists or not.
I
>> should also point out that one of the key scientific debates (and mos
of
>> the typical banter you hear is not) is about positive versus negative
>> feedback, where the "input" to the model is primarily man-made CO2,
>> something that, in itself, is not enough to significantly affec
climate.
>
>Why do you say that? Have you considered how much CO2 we put
>into the atmosphere every day, where it goes, and how fast?

Because CO2 levels have been considerably higher in the distant past, an
over that "region of operation", CO2 levels still lagged temperature. T
answer your other question, one number I've seen is 10ppm every 5 years
with levels in the last decade at about 380ppm. The current level may b
about 40% over pre-industrial levels. It's still a trace gas. That said
my statement was not made solely on that basis.


>If not, what basis do you have for your statement?

Again, those who promote global warming state that CO2 leads to increase
water vapor, not that CO2 in itself changes temperatures much.

With no feedback (which no one claims), positive or negative, doubling CO
levels may increase temperatures by about 1 deg F, theoretically. Th
single preceding sentence is fairly neutral. What is controversial (i
actual scientific discussion) is the sign of feedback.

Those who claim positive feedback would predict 4-10 deg F by the end o
this century, although the models vary a lot.