Soylent Green (1973)

In the movie, Soylent Green, Detective Thorn is a run-down cop living with his friend Sol. The year is 2022 and the city of New York has an overwhelming population of 40,000,000 people and the city is very limited on resources and food like fruit, vegetables, and meat are very rare luxuries.

When the director of the ration food company, Soylent, is assassinated, Thorn is investigating the case and is looking for clues to why he was murdered. Thorn goes to other's houses of people who knew the murdered director. He finds two books about the Soylent company and asks Sol to look through for any helpful information. Sol learns that the latest Soylent ration, "Soylent Green," is made of people, he kills himself. Thorn goes to the company to learn for himself this awful truth and is then chased down by the murdered director's bodyguard but in the end, Thorn kills the bodyguard with a knife but is wounded during the fight. He is then carried off by a medical staff shouting, "SOYLENT GREEN IS PEOPLE!!"

This movie depicts what could happen if the world became limited on resources and each city becoming overpopulated. The main idea that is directed to people is that we need to take care of the earth or else this could happen.