[martincmartin]

In the '70s, movies like Soylent Green depicted how people thought Earth may turn out: more and more people supported by limited resources, food riots, etc. e.g. China introduced the one child policy to head this off.

In the '80s, movies like War Games and The Day After depicted how people thought Earth may turn out: nuclear war triggered through Mutually Assured Destruction. (Source: I lived through the '80s.)

you get the idea.