The Aldo Leopold Foundation: "The Land Ethic"
Read the short summaries of the linked text. At the bottom of the page there is a link to a PDF Fact Sheet; click on the link and read the article. How do you think Leopold's views helped to shape environmental change in that era?
Click https://web.archive.org/web/20151201091850/http://www.aldoleopold.org/AldoLeopold/landethic.shtml link to open resource.