"Christy btw, is a global warming denialist. "

You don't understand how funny that is, do you?

Btw Wikipedia uses the word "skeptical".

Wikipedia says
"Some people think he should no longer be considered skeptical of the global warming hypothesis, because of an interview with National Public Radio about the new AGU statement:

Christy said:"It is scientifically inconceivable that after changing forests into cities, turning millions of acres into farmland, putting massive quantities of soot and dust into the atmosphere and sending quantities of greenhouse gases into the air, that the natural course of climate change hasn't been increased in the past century." "
http://en.wikipedia.org/wiki/John_Christy

Btw, I would tend to somewhat agree with this statement. But the question is how much and is the increase even measurable. Afterall we know that urban areas increase local temperatures by a very significant amount. But when you limit the effect to just human CO2 emissions you are dealing with an even smaller increase.
But I don't like his choice of the phrase "scientifically inconceivable", it's such an seemingly absolute phrase [I'm nitpicking more on style than substance]. I would say it's extremely unlikely from all we scientifically know that human activity has had a net affect of cooling the planet. But considering the political pressure he might be experiencing it's understandable that he say this.

I would say that if for some reason [say it appeared that we starting to head into a ice age] we wanted to increase the global temperature by 1 C, releasing massive amounts of CO2 won't be a workable solution, I would think it's possible that the air would become unbreathable before achieving a significant increase in global temperature.