Slate: Hollywood celebrities have long prided themselves as the social conscience of America. Now, it seems, they've widened their reach to the entire Earth.
"Climate change is real, it is happening right now,' DiCaprio said in his Oscar acceptance speech in February. "Let us not take this planet for granted.'
With those words, DiCaprio did more for climate change advocacy than any other individual effort, ever, according to a new study. Compared to the Paris climate summit last December--in which...