Spoiler warning: This article discusses plot details from the 2018 movie Avengers: Infinity War.





In the recently-released Avengers: Infinity War, Thanos the Mad Titan kills half of all life in the universe. In Infinity Gauntlet, the 1990s comic book series which inspired Infinity War, Thanos’ motivation for this act of cosmic genocide was his quest “to woo the female personification of Death into accepting him as a lover.” In Infinity War, however, Thanos’ motivation is markedly different: “He firmly believes that the population of the universe has grown too much to survive on the finite resources of the cosmos. So, he wants to kill half of them, in the hopes that a drastically reduced population will force civilizations to better limit themselves and survive for future generations, instead of devolving into an early end fighting and dying over a lack of resources.”





As James Whitbrook points out, this environmentalist reasoning appears in an earlier comic book series in which Thanos asks the Silver Surfer to help him correct “a great imbalance in the universe,” including planet Earth: “More humans than ever are living longer, consuming more resources (and turning them into waste), and dangerously damaging the environment than ever before. Thanos sees correcting the imbalance as a mercy to what he sees as a sentient species being cruelly forced to live in intense conditions.” In Infinity War, Thanos deploys this same reasoning to explain to his adopted daughter Gamora why he believed it to be a rightful cause to end half of all life in the universe, including her home planet on which his invading army killed half the population — and her family.





Despite being a fictional character, Thanos’ reasoning has deep precedents in environmentalism, and his fear of overpopulation persists in actual environmentalist thought today. The 18th century English cleric Thomas Malthus, for example, famously warned that overpopulation “would lead to famine, disease, and poverty.” His warning, however, “came right on the cusp of industrialization, modern sanitation, and the era of vaccines,” and the Malthusian catastrophe was avoided. Today, Paul Ehrlich, the author of The Population Bomb (1968), continues to argue that “the world’s optimum population is less than two billion people — 5.6 billion fewer than on the planet today.” While the 1970s’ “green revolution in intensive agriculture” helped the world to avoid his book’s dire prediction of the mass starvation of “hundreds of millions of people,” Ehrlich warns that agricultural pesticides and the industrial production of other synthetic chemicals has brought about “an increasing toxification of the entire planet … that may be more dangerous to people and wildlife than climate change.”





Indeed, from an environmentalist perspective, humanity stands in the same position as Thanos, with human activity having severely impacted wildlife and the natural world with man-made pollution, “the destruction of wild areas for farming and logging,” and “poaching and exploitation for food.” These have caused significant losses in wildlife. Researchers have calculated that “animal populations plummeted by 58% between 1970 and 2012, with losses on track to reach 67% by 2020.” If the worst-case scenario of two-thirds losses is actualized, humanity would turn out to be worse than Thanos.





As Thanos observed, overpopulation also has dire effects on human life. In the slums of the world’s overpopulated cities, the impoverished residents have to struggle with difficult living conditions including “unbreathable air, uncontrolled emissions,” and the lack of access to good food and clean drinking water. Current demographic trends will make this a reality for an increasing number of people. As the world’s population grows towards 11 billion people over the coming decades, experts estimate that 80-90% will live in cities. The bulk of this massive urban population will be found in Asia and Africa, where hundreds of cities which are currently small are projected to “grow exponentially,” and “within 35 years more than 100 cities will have populations larger than 5.5 million people.” In the worst-case scenario, these cities will become “ungovernable — too unwieldy to adapt to rising temperatures and sea levels, and prone to pollution, water shortages and ill health.”





Science-fiction author Kim Stanley Robinson sees urbanization as “a great opportunity” to save the planet.





Should the worse-case scenario be actualized, mass death events could eventually occur in these overcrowded cities, with the ravages of pandemics and natural disasters decimating large numbers of people. However, from an ecological perspective, such mass death events could serve as major “natural selection events” which remove “many of the weak and frail from the population.” Scientists studying the Black Death — the 14th century plague which killed almost half of the population of Europe — have discovered that “the Europeans who made it through the Black Death inherited a much better world. Food prices dropped, labor wages increased, and there was a boost in the standard of living.” These benefits were direct consequences of the depopulation caused by the plague: the smaller population meant reductions in both the demand for food and the supply of labor. With this improved standard of living following the Black Death, “a much greater fraction of the population survived to middle age and beyond.”





While the experience of the Black Death may support Thanos’ solution to overpopulation, less extreme solutions have been proposed. Despite its challenges, science-fiction author Kim Stanley Robinson sees urbanization as “a great opportunity” to save the planet. As he observes, by concentrating people, cities effectively remove them from the natural world: “If we managed urbanization properly, we could nearly remove ourselves from a considerable percentage of the planet’s surface. That would be good for many of the threatened species we share this planet with, which in turn would be good for us, because we are completely enmeshed in Earth’s web of life.”





Robinson sees urbanization as the means to achieve the influential biologist E. O. Wilson’s radical Half-Earth (2017) proposal: “The idea is right there in the name: leave about half the Earth’s surface mostly free of humans, so wild plants and animals can live there unimpeded as they did for so long before humans arrived. Same with the oceans, by the way; about a third of our food comes from the sea, so the seas have to be healthy too.”





Most appealingly, for Robinson, is that global urbanization is already happening, which means the re-wilding of half of the Earth is a very real possibility: “With people already leaving countrysides all over the world to move to the cities, big regions are emptier of humans than they were a century ago, and getting emptier still. Many villages now have populations of under a thousand, and continue to shrink as most of the young people leave … So emptying half the Earth of its humans wouldn’t have to be imposed: it’s happening anyway. It would be more a matter of managing how we made the move, and what kind of arrangement we left behind.”





However, this “matter of managing how we made the move, and what kind of arrangement we left behind” is no simple challenge. Apart from the questions of how the remaining rural populations are to be persuaded to migrate to the overcrowded cities, not to mention how these cities are to care for their burgeoning populations — including how to feed everybody after all agricultural land has been given over to the wilderness — governments will also have to tackle the question of how their populations are going to support themselves. If the urban economy is not able to generate meaningful employment for large sections of the population, this could give rise to a crisis in law and order, with the unemployed masses turning to the informal economy or even crime to find their means of subsistence. This is not an academic question. In India, for example, the country’s recent economic growth has been “largely jobless”:





“There’s an accumulated shortage of around 80 million jobs, but the number of jobs created in the financial year 2018 is an estimated 600,000 … This month, the country will see a spike in demand for jobs as a fresh batch of college graduates enters the workforce. Recently, more than 25 million people applied for less than 90,000 positions on India’s state-run railways, and 200,000 applied for 1,167 jobs of police constables in Mumbai. In a country expected to add over 280 million people to the job market by 2050, that ought to set off alarm bells.”





As the economist Paul Krugman warned during his recent visit to India: “India’s lack in the manufacturing sector could work against it, as it doesn't have the jobs essential to sustain the projected growth in demography. You have to find jobs for people.” In the absence of job creation, the discontent of the poor — including the unemployed urban youth — has “boiled over into more overt expressions,” including “growing protests around the country.” The challenges faced by India today serve as a warning of what the world could face in the foreseeable future.





References





Berezow, A. B. (2014, May 7). Black Death: The Upside to Killing Half of Europe. RealClear Science.





Carrington, D. (2016, October 27). World on track to lose two-thirds of wild animals by 2020, major report warns. The Guardian.





Carrington, D. (2018, March 22). Interview: Paul Ehrlich: ‘Collapse of civilisation is a near certainty within decades.’ The Guardian.





D’Cunha, S. D. (2018, May 3). Economist Paul Krugman warned India's growth model could cause problems. Was he right? Forbes.





DeWitte S. N. (2014). Mortality risk and survival in the aftermath of the medieval Black Death. PLoS ONE 9(5): e96513. doi:10.1371/journal.pone.0096513





Ehrlich, P. R. (1968). The Population Bomb. New York: Ballantine Books.





Nobel-winner Paul Krugman warns India story could end with mass unemployment. (2018, March 17). Economic Times.





Potenza, A. (2018, May 4). Thanos’ plan in Avengers: Infinity War has historical precedent, but he applies it wrong. The Verge.





Robinson, K. S. (2018, March 20). Empty half the Earth of its humans. It’s the only way to save the planet. The Guardian.





Vidal, J. (2018, March 19). The 100 million city: is 21st century urbanisation out of control? The Guardian.





Whitbrook, J. (2018, April 30). Thanos’ motivations in Avengers: Infinity War have much stronger comic connections than you think. io9.





Wilson, E. O. (2017). Half-Earth: Our Planet’s Fight for Life. New York: Liveright.



