Al Gore seemed to be successfully fulfilling this role for a while, but recently he has largely disappeared from the public eye - largely because of his sex scandals in 2010.
The disappointing climate summit in Cancun was under attended and underreported by the media.
From the report at the link below:
Climate researchers confirm a noticeable decline in interest.
Global warming as an issue is a "loser" in media terms.
Let's face it - global warming is no longer cool (pun intended) - it's yesterdays story.
Hippies are going back to saving whales and attacking the fur industry.