Earth Day arrives only once a year, but Hollywood has a way of reminding us to care for our planet far more often. While some stars prefer to take their environmental efforts off-screen, crusading behind the scenes in high-level diplomatic meetings (see: Leonardo DiCaprio), others take their crusades on the road, hiking big mountains (Jessica Biel, Emile Hirsch) or staging sit-ins (Darryl Hannah) to make a point.

Despite the feel-good activism and high-profile efforts, ultimately, Hollywood knows that it's not altruism that spurs love for one's planet -- it's mortal fear. With that in mind, Moviefone is celebrating Earth Day by highlighting the films that make the scariest cases for taking care of our home turf while we still have a chance. We've rounded up 10 films that not-so-subtly demand we save the planet.
categories Features, Hot Topic