What philosopher has had the biggest philosophical legacy in the environment moment?

Question

What philosopher has had the biggest philosophical legacy in the environment moment?

Answer 1

Rousseau's state of nature theory is the beginning of the environmental moment. Locke saw tress to be cut, fields to harvested, and land to be converted into property by labor. Rousseau saw the serenity of nature. Nature was the pure and the simple that we need to get back to.  

Answer 2

sally mcfague has been pretty big, she has been part of many documentaries about global climate instability and is quite well respected.   baird callicot and aldo leopold have also made an impact.  frankly, if there is a philosopher worth their weight in dirt and they support environmentalism, they're well-known.  i'm really attracted to paul katz's ideas.

you should consider getting a copy of the book in the first link below, it has a lot of good work.  alternatively, one of my college professors has a lot of neat suggestions for good reading; her name is hilda koster, you can find info about her in the second link below

maybe i misunderstood your starting point, are you concerned with many of the 19th century writers, such as thoreau?  sadly, i'm not well-versed in the american pragmatists.