Soylent Green is more important to us than the King James Bible. Instead of warning us of an imaginary hell, it alerts us of the real possibility of the horror of overpopulation.
The movie was way ahead of its time and a stern forewarning of what will happen if we continue reproducing like rodents.
Imagine the sense of loss as Edward G. Robinson watched the glory that once was Earth. We can't let it happen. There's still time. An age of solitude, an earth as desolate as the moon, after the incredible biodiversity and ineffable beauty that Gaia once knew, for me is unbearable to comtemplate.
Ironically, the actor died right after this scene. It was his last message.