One popular answer to this since it was proposed was nuclear war. If a species had sufficient technology to send radio signals and travel through space, it also had sufficient technology to wipe itself out. A nuclear exchange between hostile tribes would eliminate most higher terrestrial life on our planet. Alien civilizations may have also developed weapons we can't conceive of and used them on themselves in mutually assured destruction.
This article looks at the fact that a sufficiently advanced civilization would destroy its own climatological life-support system by harnessing the amount of energy needed to create that civilization. That energy would make the planet unlivable eventually and undermine its own existence. That reminds me of Tom Murphy's calculation that if energy use continues to grow exponentially for another four centuries, the waste heat alone would boil the planet. And what if Guy McPherson is right, and runaway climate loops turn the planet into a Venusian furnace the way the oxygenating bacteria described below created the initial conditions for life? Is it possible that the habitat destruction caused by energy harnessing is what kills civilizations before they fly off into space?
The defining feature of a technological civilization is the capacity to intensively “harvest” energy. But the basic physics of energy, heat and work known as thermodynamics tell us that waste, or what we physicists call entropy, must be generated and dumped back into the environment in the process. Human civilization currently harvests around 100 billion megawatt hours of energy each year and dumps 36 billion tons of carbon dioxide into the planetary system, which is why the atmosphere is holding more heat and the oceans are acidifying. As hard as it is for some to believe, we humans are now steering the planet, however poorly.Is A Climate Disaster Inevitable? (New York Times)
Can we generalize this kind of planetary hijacking to other worlds? The long history of Earth provides a clue. The oxygen you are breathing right now was not part of our original atmosphere. It was the so-called Great Oxidation Event, two billion years after the formation of the planet, that drove Earth’s atmospheric content of oxygen up by a factor of 10,000. What cosmic force could so drastically change an entire planet’s atmosphere? Nothing more than the respiratory excretions of anaerobic bacteria then dominating our world. The one gas we most need to survive originated as deadly pollution to our planet’s then-leading species: a simple bacterium. The Great Oxidation Event alone shows that when life (intelligent or otherwise) becomes highly successful, it can dramatically change its host planet. And what is true here is likely to be true on other planets as well.
But can we predict how an alien industrial civilization might alter its world?...We know that Mars was once a habitable world with water rushing across its surface. And Venus, a planet that might have been much like Earth, was instead transformed by a runaway greenhouse effect into a hellish world of 800-degree days.
By studying these nearby planets, we’ve discovered general rules for both climate and climate change. These rules, based in physics and chemistry, must apply to any species, anywhere, taking up energy-harvesting and civilization-building in a big way. For example, any species climbing up the technological ladder by harvesting energy through combustion must alter the chemical makeup of its atmosphere to some degree. Combustion always produces chemical byproducts, and those byproducts can’t just disappear. As astronomers at Penn State recently discovered, if planetary conditions are right (like the size of a planet’s orbit), even relatively small changes in atmospheric chemistry can have significant climate effects. That means that for some civilization-building species, the sustainability crises can hit earlier rather than later.
Even if an intelligent species didn’t rely on combustion early in its development, sustainability issues could still arise. All forms of intensive energy-harvesting will have feedbacks, even if some are more powerful than others. A study...found that extracting energy from wind power on a huge scale can cause its own global climate consequences. When it comes to building world-girdling civilizations, there are no planetary free lunches.
This realization motivated me, along with Woodruff Sullivan of the University of Washington, to look at sustainability in its astrobiological context. As we describe in a recent paper, using what’s already known about planets and life, it is now possible to create a broad program for modeling co-evolving “trajectories” for technological species and their planets. Depending on initial conditions and choices made by the species (such as the mode of energy harvesting), some trajectories will lead to an unrecoverable sustainability crisis and eventual population collapse...One answer to the Fermi paradox is that nobody makes it through — that climate change is fate, that nothing we do today matters because civilization inevitably leads to catastrophic planetary changes.
This actually seems like a reasonable resolution to the Fermi Paradox. It makes sense. However, if you read the article, you'll see at the end he holds out hope that some civilizations can escape this fate: "Depending on initial conditions and choices made by the species (such as the mode of energy harvesting), some trajectories will lead to an unrecoverable sustainability crisis and eventual population collapse. Others, however, may lead to long-lived, sustainable civilizations." However, I don't place much faith in that for this reason.
Given what we know of biology, species compete against one another for territory, status, etc. It's possible that primate species like ours are the only ones who can harness extrasomatic energy in a form we can recognize. If that's true, than any potential species will have the same social instincts as we do such as the desire to make war, to compete for status, etc. This will preclude the necessary cooperation and open the door for nuclear war and climate change. Both of these would require not only unilateral disarmament, but actual intentional shrinkage of the species and the foresight of a species to limit its reproduction, energy capture, and environmental destruction. And I don't think biological creatures are capable of this by their nature.
Since his was a physics simulation, my assumption is that it did not take into account these socio-biological realities and thus is incomplete. The competition that capitalists fetishize is indeed the driver of growth, but it also has the seeds of not only its own destruction, but most likely of our entire species as well. Here is some more evidence:
Rate of environmental degradation puts life on Earth at risk, say scientists (Guardian) Humans are ‘eating away at our own life support systems’ at a rate unseen in the past 10,000 years, two new research papers say.
Scientists: Human activity has pushed Earth beyond four of nine ‘planetary boundaries’ (Washington Post)
At the rate things are going, the Earth in the coming decades could cease to be a “safe operating space” for human beings. That is the conclusion of a new paper published Thursday in the journal Science by 18 researchers trying to gauge the breaking points in the natural world.
The paper contends that we have already crossed four “planetary boundaries.” They are the extinction rate; deforestation; the level of carbon dioxide in the atmosphere; and the flow of nitrogen and phosphorous (used on land as fertilizer) into the ocean.
“What the science has shown is that human activities — economic growth, technology, consumption — are destabilizing the global environment,” said Will Steffen, who holds appointments at the Australian National University and the Stockholm Resilience Center and is the lead author of the paper.
Three minutes and counting (Bulletin of the Atomic Scientists)
These are not future problems, but rather urgent matters, according to Steffen, who said that the economic boom since 1950 and the globalized economy have accelerated the transgression of the boundaries. No one knows exactly when push will come to shove, but he said the possible destabilization of the “Earth System” as a whole could occur in a time frame of “decades out to a century.”
The IPCC reported that global warming is unequivocal and unprecedented and already responsible for widespread damage. It warned that warming—if unchecked by urgent and concerted global efforts to greatly reduce greenhouse gas emissions—would reach 3 to 8 degrees Celsius (about 5.5 to 14.5 degrees Fahrenheit) by the end of the century. This may seem like a modest rise in the average global temperature. After all, people at a given location often experience much greater temperature swings in the course of a single day. But that is a local variation, not a change in the average temperature of the surface of the entire planet. A similarly “modest” global average warming of 3 to 8 degrees Celsius brought Earth out of the frigid depths of the last ice age, utterly transforming the surface of the planet and in the process making it hospitable to the development of human civilization. To risk a further warming of this same magnitude is to risk the possibility of an equally profound transformation of Earth’s surface—only this time the planet’s hospitality to humanity can by no means be taken for granted.Does that sound like a civilization that's going to change it's tune anytime soon? Maybe we should ask the folks in Davos, or Bill Gates who thinks cell phones will solve everything.