The Civilization series of games takes players through the course of history, allowing them to guide a society/nation from way back in prehistory up through the near future (say, 2100). You develop technologies, choose political systems, and raise armies. There are various ways to "win" the game: military conquest, achieving a just and happy society, or building a spaceship that will travel to Alpha Centauri. It's a great pastime for any of us who harbor the suspicion that the world would be a better place if we were installed as a benevolent dictator.
Although the game is supposed to take you to the near future, apparently (I've never played) you can keep going if you choose to. Which is exactly what one commenter at Reddit did: he has been nursing a single game of Civilization II for ten years now, bringing his virtual global society up to the year 3991 AD. (Via It's Okay to Be Smart, a wonderful blog.) At which point we may ask: what have we learned? The news is not good. If you've ever read 1984, the outcome will be eerily familiar. I can do no better than quote:
The world is a hellish nightmare of suffering and devastation.
There are 3 remaining super nations in the year 3991 A.D, each competing for the scant resources left on the planet after dozens of nuclear wars have rendered vast swaths of the world uninhabitable wastelands.
The ice caps have melted over 20 times (somehow) due primarily to the many nuclear wars. As a result, every inch of land in the world that isn't a mountain is inundated swamp land, useless to farming. Most of which is irradiated anyway.
It gets better from there. What we actually learn about is the structure of the game. We have one player against the computer (who manages multiple civilizations), each with certain goals -- a paradigmatic game theory problem. Such games can have "equilibrium strategies," where no player can make a unilateral change that would improve their situation. Assuming that this player isn't simply missing something, it's likely that the game has reached one such equilibrium. That could be the only equilibrium, or there could be a happier one that might have been reached by making different decisions along the way. What we would like to learn, but can't, is whether this has any relevance to the real globe. It might! But maybe not. The Earth isn't a closed system, so the "escape to another planet" option is on the table. But the Solar System is quite finite, and largely forbidding, and other stars are really far away. So limiting our attention to the Earth alone isn't necessarily a bad approximation. Right now the human population of the Earth is very far from equilibrium, either politically, or technologically, or socially, or simply in terms of sheer numbers. A real equilibrium wouldn't be burning through finite resources like fossil fuels at such a prodigious rate, continually inventing new technologies, and constantly re-arranging its political map. But it's possible (probably unlikely) that we could reach a quasi-equilibrium state in another couple of centuries. With a system as complicated as human civilization on Earth, naive extrapolation of past trends toward the future isn't likely to tell us much. But "sustainable" isn't a synonym for "desirable." If there could be such a near-term equilibrium, would it be a happy one, or the game-prognosticated future of endless war and suffering? Not clear. I have some measure of optimism, based on the idea that real people wouldn't simply persist in the same cycles of conflict and misery for indefinite periods of time. It only seems that way sometimes.