Carbon Dioxide and Global Warming

This 2007 article on global warming and carbon dioxide looks interesting. It talks about lots of things, including plant use of carbon dioxide.

It has seemed to me that the strongest evidence for a linke between carbon dioxide and warming was the higher amount of warming in cold dry regions. Such regions have less water vapor, so the same absolute increase in carbon dioxide would generate more of a marginal greenhouse effect. I thought of a problem with that, though. If warming in general-- for some other reason such as sunspots-- occurred, then there would be an increase in water vapor, and *that* increase would have more effect in cold dry regions.