Well, look at that: a vast majority of "undecided likely voters" believe in climate change. And many say that each candidates' take on the issue will influence their vote next month. That's the finding from the latest Yale Project on Climate Change Communication research (a press release for which had been foundering in my inbox for a week or so now; hat tip to Grist), which finds that:
Most undecided likely voters (80%) believe that global warming is happening, while only 3% say it is not happening – which is very similar to likely Obama voters (86% and 4%, respectively).
Undecideds are markedly different than likely Romney voters, fewer than half of whom believe global warming is happening (45%). In fact, one in three likely Romney voters say it is not happening.
So, theoretically, a candidate's ideas about climate change — or lack thereof — could indeed sway the crucial group of undecided voters, who overwhelmingly believe that global warming is real and should be addressed. The Yale report also bluntly relays this telling finding: "The issue is of notably less importance to likely Romney voters."
Note that the "importance" of the climate issue breaks both ways for conservatives. Some elements of the rabid rightwing will disavow candidates if they believe in climate change, but they are a thinning herd, and amount to statistical noise in this report. That means Romney is more or less free to pivot back to the center on climate, as we've seen him make hints at doing, if he thinks it will help him snag some of those undecided moderates.
Making a play for the climate-concerned undecideds would break the climate silence, however; it's unclear whether either is willing to do so.