(Tangential suggestion: normally I don't approve of messing around with author's books in bookstores, but Swift Boat Liar Jerome Corsi is shilling his book, "Where's the Birth Certificate?" Bookstores selling that book deserve to have people leave copies of Obama's certificate in and near the books.)
There's been a mini-boomlet in coverage of how the Birthers' support for their Obama-is-Kenyan-born got cut in half in recent days. And contrary to some incorrect statements, the poll was done before bin Laden's death was announced, so the numbers aren't due to unrelated good news.
The interesting thing is that it's hard to see this is a result of people simply reacting to evidence and logic, or else they wouldn't be Birthers to begin with. I see two overlapping possibilities. The first is Allahpundit's view (at the first link above), that the soft-core Birthers just went with the flow of their companions and information fragments that they disinterestedly absorb. The long-form birth certificate got through their defensive shields and they defected on the basis of actually paying attention for once, leaving only the hardcores behind.
My alternative is that the change comes from the loss of soft-core advocates of Birtherism, not the soft-core believers. The single-issue advocates didn't shut up, but the politicians and wanna-be presidents who dallied at it, all went silent when Obama released his certificate. If one side pushes a victory and the other side loses its major voices, then you'll see results.
So I think that's what we need to have happen on climate change. Conspiracy-centered environment haters like Morano, Michaels, Lindzen etc won't be convinced about anything, but if their political overseers stop talking a big game, then we could then see a change in acceptance of reality.