Billions of galaxies and trillions of planets populate our universe. Yet, to the best of our knowledge, ours is the only one to host living organisms. As we hurtle down a path of climate change and possible self-destruction, some scientists are asking the question: Is it actually possible to build a sustainable energy-intensive civilization or are all doomed to fail?
Adam Frank, a professor of physics and astronomy at the University of Rochester, New York, and colleagues published a study in the journal Astrobiology looking at the various possible pathways open to alien civilizations (or "exo-civilizations") as they develop, exploit their planet's resources, and deal with the ensuing climate change.
“Given that more than 10 billion trillion planets likely exist in the cosmos, unless nature is perversely biased against civilizations like ours, we’re not the first one to appear,” he wrote in an article for The Atlantic.
"And just as most species that have ever lived on Earth are now extinct, so too most civilizations that emerged (if they emerged) may have since ended.”
The study involves mathematical models built from laws in physics, chemistry, and simple population biology. In the end, they found there were three distinct trajectories a civilization may take. But be warned, it makes for rather grim reading.
This "cosmic Easter Island"-type scenario was, Frank points out, disconcertingly the most common. Here, the civilization uses the energy available to it and grows exponentially as a result. However, by doing so, they change the environment. The planet can no longer sustain the population and so a "die-off" occurs, killing as much as 70 percent of the civilization until it achieves a viable – and sustainable – state.
The Soft Landing
The best possible trajectory for a civilization that has "out-grown" its host is the soft landing. As in the previous scenario, the population grows and the environment changes but together the civilization and planet reach a new equilibrium, thereby preventing a mass die-off.
The Full-Blown Collapse
As you might tell from the name, this would be the absolute worst outcome. It could happen if the planet is unable to cope with the changes to the environment and the conditions change rapidly, causing the civilization to "nose-dive" into extinction.
It's worth noting that the model is fairly simplistic. Frank says they made the equations as straightforward as possible and calls it a "first stab" at the science of exo-civilizations. However, the more accurate and detailed we can get the climate physics and the models, the more accurate and detailed we can get the results.
"[I]t’s too early to answer the question, 'Does anyone make it?'" he explains. Then adds, "Even though our initial models were simple, they still revealed a radical truth about the challenge we face as we push the Earth into its human-dominated era."
[H/T: The Atlantic]