EMA Missions in Music Award winner and environmental activist Morissette narrates several global warming documentaries including "Global Warming: The Signs and The Science" by PBS and "The Great Warming" with Keanu Reeves. She has spoken out against drilling in the Arctic National Wildlife Refuge and encouraged fans to learn about and become more involved in political issues involving energy. She also practices basic green habits like using solar panels to power her home, cutting down on air conditioning, turning lights off and recycling.

Grammy-winning Crow got busy publicizing her eco-friendly record in 2007. She promoted Stop Global Warming with founder and activist Laurie David, advocating "one square per restroom visit" in addition to raising environmental awareness by touring the country in a biodiesel-powered bus. Crow also threw an eco-friendly baby shower featured in InStyle magazine. (Find out how to throw one like it here.)

TV comedy star Louis-Dreyfus has helped raise millions for the Natural Resources Defense Council, the Waterkeeper Alliance and the Trust for Public Land. She also joined the board of Heal the Bay in the '90s. And yes, she too drives a hybrid and lives in an environmentally sound house.

"The Closer" star, who has been photographed toting eco-friendly, reusable shopping bags, is also a member of the Natural Resources Defense Council and a supporter of the socially conscious social network SixDegrees.org, started by husband Kevin Bacon in partnership with Network for Good.

The famed author of the Harry Potter series received the Order of the Forest award from Canadian group Markets Initiative for insisting that 16 publishers worldwide print her novels on recycled paper that didn't come from ancient or endangered forests.