What is the preservation of land, water, air and sun?

I believe the definition you're referring to is that of conservation, a movement that started in the late 1800s, largely with the help of a naturalist named John Muir.  He advised President Teddy Roosevelt to set aside some land for national parks and is the father of our modern park system.

Later, in the 1960s, a modern movement began to look at ceaning up pollution in air and waterways.  The "Green" movement we know today is just the latest version of the conservationism they started a long time ago, and is no standard scientific practice, and is taught widely in the public schools.