By David K. Johnson, Ph.D., King’s College
When it comes to how big a problem population growth will be, we should probably just say “I don’t know”. Humanity may or may not outstrip the Earth’s ability to sustain it. But since we don’t know, we still need to discuss it and what could be done, so we’re not caught off guard. So what might we do?

Dystopian Future and Overpopulation
Soylent Green is a 1973 film set in 2022 that heralds a dystopian future plagued by overpopulation. Regular foods, such as meats and grain, are rare and the bulk of everyone’s diet consists of rations made by the Soylent Corporation—dry wafers called Soylent Green.
The story follows Frank Thorn, played by Charlton Heston, on his investigation into the murder of William Simonson, a wealthy Soylent Corporation board member—who, Thorn discovers, was killed because he discovered the Soylent Corporation’s big secret: that Soylent Green is made out of people. It’s people!
This is a transcript from the video series Sci-Phi: Science Fiction as Philosophy. Watch it now, on Wondrium.
Population Growth and Production of Food
When we take up the issue of the Earth’s inability to feed the entire world’s population, it seems inevitable. Yet, the key to answering this question, of course, is accurate projections of population growth. However, as it turns out, these are very difficult. Unlike climate change, there is no scientific consensus.
In 2017, there were 7.5 billion people worldwide, but since the ’70s, the rate of growth has been decreasing. According to one UN estimate, it’ll eventually turn negative and, by 2100, there will be as few as 6.2 billion. Another projects a continuing increase and 15.8 billion by 2100.
In reality no one knows for sure both-the trajectory of human population and production of food.
We can imagine technological solutions to the food problem. Lab-grown meat. Turn insects into protein bars, like in Snowpiercer. Star Trek universe “food replicators” that rearrange matter and energy into whatever food you like.
Learn more about universal fate in Star Wars.
‘The Mark of Gideon’ and Euthanasia
But if we don’t also do something about population growth, we could end up like the people of the planet Gideon in the episode of the original Star Trek series, ‘The Mark of Gideon’.
In the episode, Gideon was once a paradise. No illness, people’s bodies regenerated from injury—death became virtually unknown. But over time, this turned the paradise turned into a dystopia, with so many people that Gideon became “encased in a living mass”. According to Odona, a native to Gideon, it was so crowded that, to be alone, Gideonites would be willing die—if only they could.
But their solution brings us to the second point for considerstion: Euthanasia. Because to deal with their overpopulation problem, the Gideonites tried to harvest a virus from Capt. Kirk—one to which he was immune, but was so deadly it can kill even a Gideonite.
Their hope was that Gideonites would volunteer to infect themselves with it, to thin the population. Given our worries about overpopulation, it makes one wonder whether euthanasia could be morally and effectively used as a solution to overpopulation.
Logan’s Run
A similar, but in some ways opposite, approach is embraced in the 1976 movie Logan’s Run. It’s set in a seemingly ideal society where everyone is young, beautiful, and healthy. At age 30, everyone is renewed into youth—essentially reincarnated as a baby—in a ritual called Carousel, where they are taken into the air and disappear.
The story follows Logan, who’s a ‘Sandman,’ a sort of policeman who pursues ‘Runners’—people who refuse to submit to Carousel. When Logan realizes that he will be called to Carousel four years too early, he himself becomes a Runner, and tries to flee to Sanctuary—the place Runners try to reach to live out their lives.
By the end of the movie, Logan learns that Sanctuary is a myth—but so too is renewal. People aren’t born into a new life in Carousel; they’re just vaporized to keep the size of the population in check.

Learn more about complicated view of morality.
Voluntary Euthanasia
The solution to overpopulation in Logan’s society is similar to the Gideonites in that it’s euthanasia. But it’s also the opposite.
But the two examples make us wonder about a middle-ground solution. What about offering up voluntary euthanasia to the elderly? After all, when some get old, they would rather die. This is the point of “do not resuscitate” orders. If their health is failing, they’d rather not live in anguish.
Could allowing people to be euthanized if they so choose—helping them peacefully kill themselves—be a morally acceptable way to deal with overpopulation?
Concept of Euthanasia in Soylent Green
This seems to be a method of controlling overpopulation embraced by the society in Soylent Green. When Thorn’s friend, Sol Roth learns the Soylent Corporation’s horrible secret, he immediately goes to a euthanasia center.
He selects his favorite classical music, drinks poison, and then peacefully dies while he is treated to pictures of rare natural wonders, such as flowers, and deer, and lakes. Apparently, this is a common practice in that society.
Interestingly, this was the last scene Edward G. Robinson, who played Sol, ever performed. He was dying of bladder cancer. Many suspect that’s why the performance was so good. He was saying goodbye. He died 12 days after filming was complete. Should Robinson have had the option of dying peacefully, before the cancer killed him?
The issue of whether voluntary euthanasia would be morally acceptable as a solution to overpopulation really comes down to whether it would be acceptable for one person to assist in the suicide of the other if they so choose.
Common Questions about Overpopulation and Euthanasia
Accurate projections of population growth are very difficult to obtain, as, unlike climate change, there is no scientific consensus.
To deal with the problem of overpopulation , the Gideonites tried to harvest a virus from Capt. Kirk which was deadly enough to kill a Gideonite. Their hope was that Gideonites would volunteer to infect themselves with it, to thin the population.
The solution to overpopulation in Logan’s society was similar to the Gideonites in that it’s euthanasia. But it’s also the opposite. Instead of the youth of the society volunteering to be euthanized, the elders of the society have euthanasia forced upon them.