Time Magazine: Every successful social movement has its defining images. Think of the civil rights movement, and the photos of protesters being attacked by police dogs and pummeled by high-pressure fire hoses. Or the Vietnam anti-war movement, and the video of body bags being beamed back to America’s living rooms. Even environmentalism has its iconic images, like Cleveland’s heavily polluted Cuyahoga River catching fire in the 1960s, smog wreathing Los Angeles’s skyline during the next decade and even the …