He's one of the surviving first wave environmentalists, whose book, The Closing Circle was particularly influential in the 1970s. Born the same year as JFK, Barry Commoner was recently interviewed by the New York Times. There's a new book and a big conference about him upcoming.
In the Times interview, the 90 year old Commoner describes himself as still an optimist, although he is also famous for saying, "When you fully understand the situation, it is worse than you think."
In particular, his Four Laws of Ecology became deeply embedded in the ecological consciousness of activists, and to some extent have become bedrock knowledge for the Boomer generation. They are (from his Wikipedia article)
1.. Everything is Connected to Everything Else. There is one ecosphere for all living organisms and what affects one, affects all.
2. Everything Must Go Somewhere. There is no "waste" in nature and there is no “away” to which things can be thrown.
3. Nature Knows Best. Humankind has fashioned technology to improve upon nature, but such change in a natural system is, says Commoner, “likely to be detrimental to that system.”
4. There Is No Such Thing as a Free Lunch. In nature, both sides of the equation must balance, for every gain there is a cost, and all debts are eventually paid.