At the first Earth Day protest in 1970, Margaret Mead, the American Anthropologist and proto-environmentalist, issued a call to action: “We have to learn to cherish this earth and cherish it as something that’s fragile, that’s only one, it’s all we have. We have to use our scientific knowledge to correct the dangers that have come from science and technology.” Back in those early days—long before we began driving hybrid cars and politicians started using words like “sustainability” and “carbon footprint” to win elections—Mead and her Earth Day comrades were on the fringe. Would she be surprised to see how mainstream the green movement is today? Probably not. After all, she once said, “Never doubt that a small group of thoughtful, committed citizens can change the world.” All it takes is a great idea. Here we’ve gathered 10 of those, along with the stories of the thoughtful citizens who are trying to make them a reality.