Here it is:

The ads will run on forty buses for one month, according to 350 Seattle. Metro's ad agency says the ads started running today. In March, the Seattle City Council unanimously declared in no uncertain terms that increasing numbers of oil trains puts the city at risk of a disaster—the trains have a history of exploding during derailments because they carry highly flammable crude in unsound tanker cars, and in Seattle they pass by two sports stadiums and directly under Pike Place Market. Plus, exploiting fossil fuels threatens the planetary climate.

You would think that'd be alarming enough, but this ad is clear and compelling (if a little text heavy) and should help the public—only 33% of which, as Charles notes, believes in man-made global warming—get more fired up (ahem) about the issue.