The Sorcerer's Apprentice
"In the sweat of thy face shalt thou eat bread"—it has always been that way.
Most men have been slaves of necessity, while the few who were not lived by exploiting others who were. Although mechanization has eased that burden in the advanced countries, it is still the case for the majority of the human race. Limited resources (mainly fossil fuels), as well as negative consequences of industrialization such as global warming, have made some people question whether American living standards can ever be extended to most of the human race. They're pessimists, and they're wrong.
Hardly anyone seems to realize it, but we're on the threshold of an era of unbelievable abundance. Within a generation—sooner if we want it enough—we will be able to make a self-replicating machine, first seriously suggested by John von Neumann.
Such a machine would absorb energy through solar cells, eat rock and use the energy and minerals to make copies of itself. Numbers would grow geometrically, and if we manage to design one with a reasonably short replication time—say six months—we could have trillions working for humanity in another generation. You might compare this process to a single cell of blue-green algae, which replicates over the summer until it covers the entire pond. But unlike algae, a self-replicating machine would be programmed and controlled by us. If it could make it its own mechanical and electronic parts, it would also be able to make toasters, refrigerators, and Lamborghinis, as well as the electricity to power them. We could make the deserts bloom, put two cars in every pot, and end world poverty, while simultaneously fighting global warming. It's closer than you think, since the key technologies are already being developed for use in rapid prototyping and desktop manufacturing. Aristotle thought that slavery would only end when looms weave by themselves: we're almost there.
Right now the human race uses about 13 trillion watts: the solar cells required to produce that much power would take up less than a fifth of one percent of the Earth's land surface—remember that the Earth intercepts more solar energy in an hour than the human race uses in a year. That's a lot of solar cell acreage, but it's affordable as long as they make themselves. We could put them in deserts—in fact, they'd all fit inside the Rub' al Khali, the Empty Quarter of Saudi Arabia. As I understand it, we like depending on the Saudis for energy.
But there are better ways. Solar energy works better in space—sure, the weather is better, but also consider that the vast majority of the Sun's energy misses the Earth. In fact only about one part in two billion warms this planet. Space-based self-replicating systems could harvest some of that lost sunlight—enough to make possible a lot of energy-expensive projects that are currently impractical. An interstellar probe is a bit beyond our means right now, and the same is true of terraforming Venus or Mars. That will change within our children's lifetimes.
I'm reminded of Mickey Mouse as the sorcerer's apprentice in Fantasia... He enchanted a broomstick to fetch water, but didn't know how to stop it. When he split the broom with an axe, over and over, each of the pieces took up a pail—and before you know he was in over his head. But where he saw a crisis, we see opportunity.