Even if warming observed to date is entirely due to changes in received solar energy, that does not invalidate worries about greenhouse climate change. I'm not too concerned about the next 25 years, but look 100 to 200 out, and there are real issues.

Unless anyone here has a different explanation for the climate on Venus, we know that CO2-based greenhouse warming works. Indeed, the Earth itself would be frozen if not for greenhouse warming from CO2 and H2O. I think we all agree on that.

So, at _some_ value greater than zero, increased concentrations of CO2, methane, fluorocarbons, etc., will change the climate. The question is, what is the point at which those concentrations will cause undesirable changes in climate?

Since the dawn of the industrial age, we've burned about 1/10th of presently known coal, oil, and gas resources. CO2 concentrations have gone up by about 25%. Pre-industrial levels were about as high as any seen in the Pleistocene, so we're already above that historical dataset.

I don't think anyone disagrees so far(acknowleding that the atmospheric increase doesn't fully account for emissions -- there is an extra sink somewhere).

By 2100, CO2 concentrations are likely to be 100% to 200% greater than pre-industrial levels. At the high end, that's comparable to the highest known concentrations in the past, specifically, during the hgh-volcanism Cretacteous, when there were no ice caps, widespread innudation of the continents, and a dramatically warmer climate, like subtropical right to the poles.

By 2200, CO2 concentrations would be more like double the levels seen during the Cretaceous, with god knows what effect.

Kyoto has all sorts of problems, I grant that. But I'd like the Kyoto bashers to give me their own long term scenario. Why isn't tripling or more of CO2 going to do anything, or, why aren't we going to see those sorts of emissions?