Your tax dollars at work: study posits how space aliens might solve climate change
From the Atlantic, buy one of the authors of the study, Adam Frank:
The universe does many things. It makes galaxies, comets, black holes, neutron stars, and a whole mess more. We’ve lately discovered that it makes a great deal of planets, but it’s not clear whether it regularly makes energy-hungry civilizations, nor is it clear whether such civilizations inevitably drive their planets into climate change. There’s lots of hope riding on our talk about building a sustainable civilization on Earth. But how do we know that’s even possible? Does anyone across the cosmos ever make it?
Remarkably, science has now advanced to point where we can take a first step at answering this question. I know this because my colleagues and I have just published a first study mapping out possible histories of alien planets, the civilizations they grow, and the climate change that follows. Our team was made up of astronomers, an earth scientist, and an urban ecologist.
It was only half-jokingly that we thought of our study as a “theoretical archaeology of exo-civilizations.” “Exo-civilizations” are what people really mean when they talk about aliens. Astronomers refer to the new worlds they’ve discovered as “exoplanets.” They’re now gearing up to use the James Webb Space Telescope and other instruments to search for life by looking for signs of “exo-biospheres” on those exoplanets. So if we have exoplanets and exo-biospheres, it’s time to switch out the snicker-inducing word “aliens” for the real focus of our concerns: exo-civilizations.
We’re interested in how exo-civilizations develop on their planets. 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. That means each exo-civilization that evolved from its planet’s biosphere had a history: a story of emergence, rising capacities, and then maybe a slow fade or rapid collapse. 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 long since ended. So we’re exploring what may have happened to others to gain insights into what might happen to us.
Of course, we have no direct evidence relating to any exo-civilizations or their histories. What we do have, however, are the laws of planets. Our robot emissaries have already visited most of the worlds in the solar system. We’ve set up weather stations on Mars, watched the runaway greenhouse effect on Venus, and seen rain cascade across methane lakes on Titan. From these worlds we learned the generic physics and chemistry that make up what’s called climate. We can use these laws to predict the global response of any planet to something like an asteroid impact or perhaps the emergence of an energy-hungry industrial civilization.
Full essay here
The Anthropocene Generalized: Evolution of Exo-Civilizations and Their Planetary Feedback
We present a framework for studying generic behaviors possible in the interaction between a resource-harvesting technological civilization (an exo-civilization) and the planetary environment in which it evolves. Using methods from dynamical systems theory, we introduce and analyze a suite of simple equations modeling a population which consumes resources for the purpose of running a technological civilization and the feedback those resources drive on the state of the host planet. The feedbacks can drive the planet away from the initial state the civilization originated in and into domains that are detrimental to its sustainability. Our models conceptualize the problem primarily in terms of feedbacks from the resource use onto the coupled planetary systems. In addition, we also model the population growth advantages gained via the harvesting of these resources. We present three models of increasing complexity: (1) Civilization-planetary interaction with a single resource; (2) Civilization-planetary interaction with two resources each of which has a different level of planetary system feedback; (3) Civilization-planetary interaction with two resources and nonlinear planetary feedback (i.e., runaways). All three models show distinct classes of exo-civilization trajectories. We find smooth entries into long-term, “sustainable” steady states. We also find population booms followed by various levels of “die-off.” Finally, we also observe rapid “collapse” trajectories for which the population approaches n = 0. Our results are part of a program for developing an “Astrobiology of the Anthropocene” in which questions of sustainability, centered on the coupled Earth-system, can be seen in their proper astronomical/planetary context. We conclude by discussing the implications of our results for both the coupled Earth system and for the consideration of exo-civilizations across cosmic history. Key Words: Anthropocene—Astrobiology—Civilization—Dynamical system theory—Exoplanets—Population dynamics. Astrobiology 18, 503–518.
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