Reel Science

The most underrated sci-fi thriller on Netflix reveals a controversial scientific theory

It's a controversial idea — and maybe not totally backed by demographic trends.

Are humans doomed to wipe out Earth’s natural resources — and ourselves — through a rapidly growing population?

It’s a hot-button question demographers have grappled with for the past half-century, ever since the publication of the controversial 1968 book The Population Bomb by Paul Ehrlich. It’s also a question that has recently emerged in entertainment, and no movie tackles it more head-on than the 2017 original Netflix sci-fi thriller What Happened to Monday.

The narrator in the movie’s opening scene doesn’t pull any punches. “Every four days, there’s a million more people on this planet,” they say. “How is the world going to cope with this explosion in population?”

This premise of overpopulation leads to the story’s central dilemma, centering on identical septuplets — each one named for a day of the week — who must secretly survive in a dictatorial regime that effectively outlaws siblings due to overpopulation in the year 2043.

But is What Happened to Monday actually an accurate harbinger of population and birth trends in real life or alarmist sci-fi nonsense? Tomas Sobotka, who leads the Vienna Institute of Demography’s research group on Comparative European Demography, tells Inverse that while overpopulation is a real concern in some parts of the world, we probably aren’t headed towards the dystopian future portrayed by Netflix.

“Overpopulation" is a very tricky concept and difficult to define,” Sobotka says.

Reel Science is an Inverse series that reveals the real (and fake) science behind your favorite movies and TV.

Is overpopulation a threat to our future?

Will population growth overwhelm the world, as this scene from What Happened to Monday implies.


What Happened to Monday starts out somewhat accurately, bombarding viewers with dystopian, yet realistic images of crowded cities and climate change.

“In the last fifty years we’ve doubled our population, tripled the amount of food and water we use, and we have quadrupled the use of fossil fuels,” the narrator states.

The movie then predicts overpopulation will continue for the next century, citing an oft-cited statistic from old UN reports: the population will reach 10 billion by 2100. As the rest of the film shows, this kind of overpopulation has grim consequences for both these seven siblings and the planet as a whole.

But the movie’s premise significantly oversimplifies Earth’s real population trends.

It’s true that “some regions are expected to see huge population rise in the coming decades” Sobotka says, due to high fertility as well as improvements in health and mortality. The largest population growth will occur in sub-Saharan Africa, which will double in population over the next thirty years according to the 2019 UN World Population Prospects. Nine countries alone will account for more than half of population growth through 2050: India, Nigeria, Pakistan, the Democratic Republic of Congo, Ethiopia, Tanzania, Indonesia, Egypt, and the US.

However, other parts of the world are projected to experience significant population declines — and that decline is already happening in some regions. Some parts of Eastern and Southern Europe have lost more than 20 percent of their population since the 1990s due to lower immigration and fertility rates.

“As fertility rates continue sliding in most countries, population decline will become increasingly common, also in some large countries,” Sobotka says.

Even China, the world’s most populous nation, will likely experience population decline soon due to shrinking birth rates — maybe even this year according to a new report.

So our future reality will probably mirror the opposite of What Happened to Monday suggests. Instead of out-of-control population growth, depopulation could very well be the norm as we approach 2100.

“India's population may peak around 2050, and, soon thereafter, population decline may become a more common experience globally than population growth,” Sobotka says.

Are fertility rates going to spike?

The baby boom is a looming threat in the movie, but that’s not necessarily the case in reality.


One of the factors triggering overpopulations in the movie is the rise of genetically modified organisms (GMOs) in agriculture. To offset declining crop production caused by climate change, researchers and farmers have accelerated the use of genetically modified foods worldwide.

But the movie suggests GMOs have sent women’s fertility rates spiking by leading to a dramatic surge in “multiples” — twins, triplets, and, yes, septuplets — of children being born.

While there is some scientific debate about links between the pesticide glyphosate (sometimes used to grow GMOs) and birth defects, there’s little if any evidence suggesting they increase fertility rates.

“It's funny,” Sobotka says. “I'd expect stuff like genetic defects and genetically modified food to lead to infertility rather than to spiking fertility.”

Recent research also suggests the idea that declining sperm quality and count — from exposure to chemicals — will lead to infertility in men. While these concerns may be “overblown” they should still be taken seriously, Sobotka says.

In any case, the movie’s portrayal of increasing fertility rates is likely not going to pan out in reality.

“Globally, fertility is likely to continue falling,” Sobotka says. A myriad of factors ranging from more reliable contraceptive use to delayed parenthood to concerns about climate change are all reducing fertility rates.

Some countries like South Korea and Japan are experiencing significant enough population decline that national policies encourage couples to have more children — the polar opposite of the fascist population suppression methods in What Happened to Monday.

“Today, many countries which used to have high fertility several decades ago already reached low period fertility levels below two children per woman,” Sobotka says. These countries include places like Malaysia and Brazil.

Countries in certain regions, such as Nigeria in sub-Saharan Africa, report higher fertility rates and larger families on average, Sobotka says. But fertility rates in the region are currently declining and will likely continue to decline over the coming decades.

What’s the connection between population and authoritarianism?

What Happened to Monday hints at the real life links between population change and eco-authoritarianism.


In Netflix’s sci-fi thriller, concerns about the impact of overpopulation on human survival and the climate lead the state to enact draconian population control laws loosely mirroring China’s longstanding one-child policy, which officially ended in 2015.

The movie’s links between population, climate change, and authoritarianism mirror a real-life phenomenon known as eco-authoritarianism, which occurs when governments enact more oppressive laws to protect the environment — a looming concern as climate change occurs.

“Countries with limited state capacity will struggle to deal with the consequences of population expansion, economic development, and the environmental degradation with which they are associated,” writes political scientist Mark Beeson in a 2010 review.

But while these concerns about population control may play out in What Happened to Monday, they are not a foregone conclusion in the real world, experts suggest.

“So far, the link between climate change and population policies does not clearly show up” in data, says Sobotka.

It’s true that some of the countries most vulnerable to climate change “are expected to experience substantial population growth in the next decades,” he adds. But governments in some regions, like sub-Saharan Africa, “often do not have full control over their territories and are not capable of implementing larger-scale population control policies.”

Governments in India and Bangladesh — two countries with higher fertility rates and population growth — have embraced policies encouraging smaller family size “in part due to long-standing concerns about food production and environmental degradation,” Sobotka explains.

For his part, Sobotka suggests governments lean more on education when it comes to curbing population growth and not necessarily the authoritarian methods suggested by the movie.

“In any case, the best ‘population control policy’ in high fertility countries is to rapidly expand literacy and education, especially for women — this would be the single most important factor contributing to future empowerment of women and fertility decline.”

What Happened to Monday is now streaming on Netflix.

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