I've just come across a British psychology blog (new to me) that talks about a Berkley climate change-related study that was widely reported and chewed over in the U.S. This latest post has a good summary of the study's methodology and also provides some larger context:
This is the latest in a string of studies that suggest fear-based messages can backfire if they clash with people's underlying beliefs. For example, morbid anti-smoking messages can actually encourage smoking in those for whom the habit is tied to their self-esteem. In relation to climate change, there's evidence that framing environmentalism as patriotic can be more effective than playing on people's fears.