In the insulated bubble of Hollywood, it can be easy to forget about the world outside—and its plethora of environmental woes. Yet, despite early morning call times, on-air appearances, and overseas commercials, some celebrities consistently find time to make a difference—miraculously, in 140 characters or less. Interspersed between teaser trailer links and movie stills promoting upcoming projects lies a wealth of inspiring, do-good tweets from Tinseltown’s most eco-savvy stars, who are (quite selflessly) using their popularity for a great (and green) cause. In honor of Earth Month, we’ve rounded up our favorite feeds you absolutely need to #follow.