Soylent Green has simple sets, but the movie comes through loud and clear. It doesn't need to be literally true,
it uses just enough facts to inflate simple ideas into a grand picture. Edward G Robinson was a master of many different kinds of roles. His send off was quite memorable. The way things have turned out, it seems like it is humanity that is more susceptible to the whims of nature than the other way around. A little known fact about the blue green bacteria making all that oxygen is that if the environment isn't that great for it, it doesn't die, it just reverts to a form that recycles carbon dioxide and water back and forth, getting enough energy for it to survive, but no extra energy expended towards making free oxygen.