I think it is interesting that a majority of the changes happened between the 50s and the 70s. I guess it might be attributed to post-war optimism and the golden age of capitalism that lasted just about the same era.
There's what people sometimes call the dark green / bright green distinction: can we solve the problems caused by technology with other, different, technology?
Environmentalism and precautionary principle thinking in general steer away from techno-optimism by asking "what could go wrong with this?"
The "down" arc: thalidomide, Chernobyl, Challenger, oil crisis, "Silent Spring", global warming, and the rise of environmentalism.
(someone have that graph about all the good things stagnating in 1971?)