Greenhouse Gases Part of Urbanization

This Yahoo News article about a recent climatology study by NASA has raised a fuss on Digg. But here is the original NASA news release, posted to BBSnews. The scientists do not say there is no global warming, as the guy who originally dugg' the story posits. Nor do they say that greenhouse gases do not contribute to it. They are talking about the piece of puzzle of global climate change specific to California. They are saying for CALIFORNIA that both greenhouse gases and urbanization are contributing.

But I have to wonder what measures they used because - as anyone whose ever studied planetary heat and water cycles knows - increased urbanization increases paving which increases vehicle use and exhaust, which increases greenhouse gases -> the two are hopelessly intertwined! I guess I'll have to get a copy of the study and give it a read.