Loads of chemicals and hazardous wastes have been introduced into the atmosphere that didn't even exist in 1948. The environmental condition of the planet is far worse than it was 42 years ago.
Franklin Roosevelt was very concerned about environmental issues.
In the state of Wisconsin it's mandated that teachers in the social sciences and hard sciences have to start giving environmental education by the first grade, through high school.
The most important environmental issue is one that is rarely mentioned, and that is the lack of a conservation ethic in our culture.