There is a great deal of research claiming to verify AGW. I don't think it's valid, because the CO2 issue is far too complex to be modeled with validity. But claiming that science wasn't done that supported AGW is absolutely not true.
Is invalid science still science? If so, then was it science that told us the world was flat, and bleeding would cure the plague, and malaria was caused by "bad vapors"?
If it isn't true or valid, it just isn't science. AGW is an unfounded and unproven theory. Science requires the proof of a theory, not just the development of a theory.
Therefore, my original criticism remains. We are seeing an interesting dual standard in the debate. The pro-AGW factions are in fact asking the anti-AGW factions to prove a negative. The scientific burden of proof has always been to prove the theory. Forcing others to disprove an unfounded theory turns the entire scientific method on its head.
The complexity accrues to the modelling of anything termed 'global'. The CO2 issue isn't that complex. From 0 up to a certain point, CO2 has an increasing effect as a greenhouse gas. After a certain point, and we are quite close to that point, it has minimal additional effect.
Here's a tutorial on the subject. Enjoy: Part 1 Part 2 Part 3 Part 4