We can dream of a world in which a greatly reduced human population lives in a partially restored paradise; in which farming has been abandoned, and green deserts given back to the earth; where the remaining humans are settled in cities, emulating the noble idleness of hunter-gatherers, their needs met by new technologies that leave little mark on the Earth; where life is given over to curiosity, pleasure and play.
There is nothing technically impossible about such a world. New technologies cannot undo the laws of thermo-dynamics; but they can be friendlier to the Earth than the old technologies. Microchips allow technology to be partially dematerialised, making it less energy-intensive. Solar power allows energy consumption to be partly decarbonised, reducing its environmental impact. James Lovelock has suggested using nuclear power to counter global warming. E. O. Wilson has proposed that genetically modified foods have a role in a far-reaching programme of conservation and population control.
A high-tech Green utopia, in which a few humans live happily in balance with the rest of life, is scientifically feasible; but it is humanly unimaginable. If anything like it ever comes about, it will not be through the will of homo rapiens.
So long as population grows, progress will consist in labouring to keep up with it. There is only one way that humanity can limit its labours, and that is by limiting its numbers. But limiting human numbers clashes with powerful human needs. The Kurds and the Palestinians see large numbers of children as a survival strategy. Where communities are locked in intractable conflict, a high birth rate is a weapon. In any future we can realistically foresee, there will be many such conflicts. Zero population growth could be enforced only by a global authority with draconian powers and unwavering determination. There never has been such a power, and there never will be.
And yet … What if a shift in our place in the world were to come about without anyone planning it? What if our designs for the future were moves in a game in which we are only passing players?