In 2018, half of all sentient life disappeared with Thanos’ snap of the fingers in Avengers: Infinity War. Five years passed.
Then, it all was (mega spoiler alert, but come on, the movie’s been out for a month now) salvaged in Endgame. Professor Hulk, equipped with a fully-powered Infinity Stone-loaded gauntlet, brought all that life—including the 3.5 billion humans who had been turned into dust—back into existence with a snap. Then Tony Stark managed to retrieve the stolen Infinity Stones from the time-travelling, Mad Titan’s grip, snap his fingers and turn the forces of doom into dust themselves.
If you thought that resolution was complex, it was plain-sailing compared to the bizarre and cascading effects the life-halving original snap would have had on Earth’s ecosystems. But the choices the 3.5 billion humans left on Earth made would have equally serious consequences, especially when the 3.5 billion people lost to the snapocalypse came unexpectedly screaming back into existence. Millions of relationship statuses would abruptly be changed to “it’s complicated,” but an even more pressing issue for the fate of the planet is how sustainable (or not) those who remained chose to live.
It’s hard to say for sure how humanity would respond in that five-year period given that half the population disappearing in an instant is uncharted territory. But the five years when Earth’s population was halved hold both promise and peril.
Alistair Currie, the head of communications for family planning and environmental sustainability nonprofit Population Matters, said that we’re currently using 1.7 Earths-worth of resources. He made it clear to Earther from the outset that the group unequivocally opposes Thanos’ insane plan, but speculated that halving the population would put humanity (temporarily) in the black as far as resource use goes.
That would bring about some immediate benefits. The world could feed people more easily, and with less initial demand, it would allow the remaining population to promote food growth and production in a far more sustainable way. Jaise Kuriakose, an expert in carbon budgets and emissions pathways at the University of Manchester, told Earther that people could also majorly change their diets and consumption patterns. This could lead to a reduction in food waste and shrink the embarrassingly high carbon footprint of American and (to a slightly lesser extent) European lifestyle.
The post-snapture world would be a little like Pripyat after the Chernobyl nuclear disaster, albeit without the radioactive fallout. Currie said that nature could reclaim some of the land it had lost to people, especially if humanity encouraged the rewilding of suddenly empty landscapes.
Carbon emissions could fall as well. Katharine Hayhoe, director of the Climate Science Center at Texas Tech University, explained that halving the population evenly across all socioeconomic classes wouldn’t cut emissions by 50 percent. After all, the vast majority of carbon emissions come from a very small part of the population (that would be the wealthy), and certain services would still have large footprints even if people aren’t using them as much, such as transportation. Nevertheless, she told Earther emissions could drop by perhaps 35 or 40 percent, presuming everybody didn’t start consuming like Americans.
There’s no guarantee all these things will happen, though, or that they’ll be permanent, because they would all require humanity to make good choices post-snapocalypse.
Abdulhakim Abdi, a sustainability scientist at Lund University, speculated that the drop in carbon emissions and ecological damage would probably become excuses for humanity to not push for any important action to ensure things stay that way. Even if there was a groundswell of support to enact positive change, Abdi told Earther the odds of success are limited given that “we still haven’t been able to get to a consensus regarding the current climate crises despite the fact that things are getting progressively worse.
“We are a myopic species, despite our large brains,” he added.
A nearly 155-year-old paradox would also likely doom humanity to continue down its pathway of consuming too many resources. In 1860s England, coal-fired steam engines were becoming more efficient. Several experts thought that coal consumption would drop thanks to these technological improvements, but English economist William Stanley Jevons noticed that, along with a drop in the price of coal, England’s consumption of coal rose. The increased demand for electricity led to an accelerated depletion in coal caches.
The so-called Jevons’ Paradox still applies today. Research shows that no matter how efficiently a product is made, demand for that product rises along with the demand for resources it requires. With that in mind, it’s easy to doubt the notion that the 3.5 billion survivors will learn to become more sustainable.
Even if, against all these odds, humanity manages to go down the best case road of a greatly decarbonized and eco-friendly economy in those interim years, when the population is restored in 2023, it doesn’t mean these behaviors will continue into the future. With all those people needing space to live, will they demand to move back into and rebuild on lands now occupied by rewilded nature? Will more sustainable methods of food production collapse under the strain of twice as many mouths to feed, especially those with high resource lifestyles? Will nations go back to burning coal and natural gas simply because that’s what they did only five years earlier with a similarly sized population?
Not knowing 3.5 billion missing people would suddenly return five years on from their vanishing is a major confounding factor. With the expectation that the population would for some time remain low, the production of things like vaccines and insulin would likely drop. Restoring the population overnight would leave the world with a huge deficit of medical supplies and other crucial resources.
Food supply chains and the global economy would also get quite the shock, post-snapture reversal. From 2018 to 2023, food prices would likely have dropped due to lower demand, but after the re-appearance, demand would skyrocket, causing a major price hike and disaster for poorer nations without the capital to purchase enough food. The overnight jump in global and local demand for food, said Abdi, would cause food production to spike, a sudden shift that may cause significant ecological damage.
The potential knock-on effects and endless. Countries with less automation would find manufacturing rates decline precipitously during the interim; suddenly double the population, and you might have far weaker infrastructure. Democratic nations would have to adjust how governments get elected in the interim, especially if large swaths of the governments themselves were dusted. Doubling the eligible voting population overnight would trigger major disruptions in how elections are run and perhaps which parties are elected to power.
Being such an unprecedented and unpredictable situation, some of the chaos of the world of 2023 would be understandable. The future is nevertheless hugely shaped by the choices we make, during both those five years and from 2023 onwards.
No matter what else happens, Kuriakose said, humanity’s fate is in the hands of the very wealthy few, whether in the fictional realm of Endgame or in reality. If they don’t lower their consumption rates, the world as a whole is in profound trouble.