Would Aliens Survive an Environmental Apocalypse?

An environmental apocalypse driven by climate change and plundered resources is a terrifying prospect: dry forests burning in the blistering heat, seas swelling with Arctic ice and humans starving as crops fail across the planet.

But is this Armageddon inevitable? Is our technology-hungry species built to fail? An international team of scientists writing in the journal Astrobiology have turned to hypothetical alien civilizations to find out if a truly sustainable society is even possible.

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The effects of climate change over time are pictured in this illustration. Getty Images

University of Rochester astrophysicist Adam Frank and team created mathematical models to evaluate how a technologically-advanced alien society—or "exo-society"—would develop alongside an evolving planet.

The scientists used historical examples to produce their models, including the case of Easter Island. Famous for its huge human statues, the island's population faced near-extinction by the 18th century.

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"What we know about Easter Island was that people arrived there maybe in 400 AD [and] built a vibrant civilization," Frank said. "We think they overshot the carrying capacity of their island. They used up all their resources and their numbers came down pretty quickly...basically, the civilization collapsed."

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An alien version of the stone figures famously found on Easter Island. Scientists used a case study of the island's history in their research. Michael Osadciw/University of Rochester

The team built four different civilization scenarios: die-off, sustainability, collapse without resource change and collapse with resource change. In a die-off, the population rises quickly, peaks, and rapidly dies off as temperatures rise. The population wouldn't disappear, but it would become a fraction of its former self.

"Imagine if 7 out of 10 people you knew died quickly," Frank said in a statement. "It's not clear a complex technological civilization could survive that kind of change."

In a sustainability scenario, the rising population and temperatures reach a steady balance. Societies compensate for growing environmental pressures by switching to low-impact resources like wind and solar power. But, if a civilization did not slow their use of resources, they might face a collapse-without-resource-change situation, where the population will grow quickly, peak and then plummet. In this scenario, civilization might completely disappear.

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Four graphs describe the survival scenarios modeled by the study authors. Michael Osadciw/University of Rochester

But the most frightening scenario, Frank said, is collapse in spite of resource change. In this case, humans switch to low-impact resources too late. This delays a population's ultimate demise, but it eventually still crumbles. "Even if you did the right thing, if you waited too long, you could still have your population collapse," he said.

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The study—which, the authors wrote, offers "a highly simplified representation" of an incredibly complex topic—is really an intellectual exercise rather than a reliable characterization of a civilization's future.

But, Frank says, it still provides a stark warning for our own civilization.

"If you change the earth's climate enough, you might not be able to change it back," he saidt. "These models show we can't just think about a population evolving on its own. We have to think about our planets and civilizations co-evolving."