BCE Romantics: Muir, Ruskin, Thoreau: late 19th C Scientists: Brandeis, Pinchot, Leopold: 19th-20th 20th C disasters: Minamata, Torrey Canyon, Chernobyl: 60s-80s Scientists: Carson, Meadows, Commoner, Ehrlich: 60s, 70s Green ideologues: Kelly, Bahro, Porritt: 80s