This design is intended to address a question I was surprised how often came up in the stages of my research: Does Global Warming even exist? Users are encouraged to distribute (legally!) the stickers in places they feel a reminder is necessary.
http://www.canada.com/nationalpost/story.html?id=156df7e6-d490-41c9-8b1f-106fef8763c6&k=0
http://answers.yahoo.com/question/index?qid=20070613110556AAjgROR