Set in the year 2022, Soylent Green depicts a dystopia, a Malthusian catastrophe that occurs because humanity has failed to pursue sustainable development and has not halted uncontrolled population growth; New York City's population is 40,000,000, with more than half of it unemployed. Global warming, air and water pollution have produced a year-round heatwave and a thin, yellow, daytime smog. Food and fuel are scarce resources, because of animal and plant decimation, housing is dilapidated and overcrowded, and widespread government-sponsored euthanasia is encouraged to control and reduce overpopulation.
Meat, bread, cheese, fruit, vegetables, and even alcoholic beverages are scarce and extremely expensive; for example, a six-ounce jar of strawberry jam is 150 "Ds" (US Dollars). Like the soylent food factories, the farms producing foodstuffs are heavily guarded and off-limits to civilians. For most of the populace, natural foods are a rarely, if ever, enjoyed luxury. The government dispenses rations of synthetic food — soylent yellow, soylent red — made by the Soylent Corporation; their newest and most popular version, soylent green, is made from plankton, according to the food firm.
Soylent's food products are mostly distributed as brightly colored crackers which may be eaten with margarine, although they are also seen being sold as bread-like buns and in crumb form. The word "soylent" is a portmanteau combining soybean and lentil (cheap, very high-yield crops).
Specific Soylent products are distributed to the populace on different days of the week, however, yet even the those supplies are limited and there is much competition among people to get their rations early. The competition is such that if the supply is exhausted, rioting for food is common. To deal with this problem, the distribution centers are heavily guarded by police who deal with rioters very heavy-handedly, using "scoops" — scoop-equipped dump truck scooping and dumping rioters into the containers in back; such callous, violent treatment invariably is fatal to some rioters.
In contrast, the rich elite live in spacious apartments, with regular access to real food, tobacco, and alcohol, though even then they often are of poor quality. Some of the rich can even afford "furniture", the film's term for concubines economically attached to the apartments.
Robert Thorn, (Charlton Heston), is a New York City police detective investigating the murder of William R. Simonson (Joseph Cotten), a director of the Soylent Corporation. Thorn lives with his aged "police book" partner Sol Roth (Edward G. Robinson) in a one-room tenement apartment. Long before, Sol was a college professor, but now is employed as a police researcher. Unlike most people in A.D. 2022, including Thorn, Sol received a formal education and is literate; education of any sort is available only to the wealthy elite. Sol and people such as he are known as "books", because real books are out of print, as there is no wood for paper, along with electricity, water, food, and printing press shortages.
During his investigation of Simonson's murder, Thorn slowly uncovers a conspiracy, which would be revealed to him if only he can learn what occurs in the HOME euthanasia centers. When the dispirited Sol opts for euthanasia, Thorn forces his way into the euthanasia center, making two shocking discoveries. First, he sees motion pictures of the beautiful Earth of former times that are shown only to those about being euthanised. It startles him he cries when he sees how beautiful the Earth was before it eroded to its current state in the 21st century. When Sol goes "home," Thorn is too late to stop him; he cries bitterly at Sol's death. Second, when Thorn follows the disposal of Sol's cadaver, he discovers that soylent green includes the recycled cadavers of the people who have used the government-sponsored HOME euthanasia centers, leading to his famous outcry: "Soylent Green is people!" -scififlicks.o- some great quotes. --\ IMDB \__
- The actual Soylent Green in the movie is made out of food-colored tofu.
- Charlton Heston's tears at Sol's death were real, as Heston was the only cast member who knew that Edward G. Robinson was dying of terminal cancer. This was the 100th and last movie in which Robinson appeared. He died nine days after the shooting was done, on January 26, 1973.
- A character is briefly seen operating a Computer Space arcade game (Spacewar, developed by students at MIT), marking the movie as one of the first to show the emerging pop cultural phenomenon of video games.
- This was the last feature film to have exteriors shot using the old MGM back lot.
- Chuck Connors had a hard time fighting Heston in the movie because he didn't like hitting "Moses", Heston's role in the film The Ten Commandments.
- In the cartoon Futurama, Bender the robot and Elzar the Neptunian chef compete for the title of Iron Cook. Soylent Green is used as the theme ingredient, and Ethan "Bubble Gum" Tate, one of the judges, makes the statement, "Soylent Green is my kind of people!" A reference to a Soylent Cola is also made in one episode, which is made from people. As Leela describes the drink, "It varies from person to person".