Alan Weisman. The World Without Us (2007)

     Alan Weisman. The World Without Us (2007) Suppose every human being would disappear from the face of the Earth? Maybe in a moment, maybe over a few hours or days, but complete disappearance. What would happen to the Earth and the traces of human occupation?
     That’s the thought experiment Weisman runs in this book. He begins by considering how the natural world would take over from us, by rotting and crumbling our homes, our subways, our roads,  and so on. He deals with the effects of our industrial legacy, and considers how the artificial chemicals we’ve dumped into the biosphere might influence future evolution. Finally, he talks about what may remain of our works of the mind the imagination.
     The answers are sobering. Natural processes begin to destroy our artefacts as soon as we stop maintaining them. Subways will flood. Houses will rot away. Bridges will sag and fall. The foundation of skyscrapers will rust, the buildings will lean and then fall. Trees, vines, grasses will grow in and on our works and will crack and split and crumble them. Our corpses will decay, although some of their containers will survive a few hundred years or so. Highly stable molecules will be recycled through the biosphere until some microbes evolve to eat them. Plastics will degrade into flakes, then into nanometre particles, by which time something may have learned how to extract the energy locked up in those molecules. Ceramic tile and pottery will survive thousands of years until geologic processes bury and metamorphose them.
     And Pioneer I and II, and Voyager 1 and 2, and assorted other probes will drift through space and may at some time fetch up in a star system. But the odds that any sentient, intelligent life form will find and decode their significance is vanishingly small.
     Well then, what, if any, traces of our existence will survive us, and for how long? The answer is, lots, but not what you expected. Plastics, ceramics, earthworks and radioactive trash will survive the longest on Earth. The space probes and radio waves will survive longest of all, drifting through space until space dust abrades the probes and radio waves attenuate so much that they can no longer distinguished from background radiation.
     The subtext of this book is anther question: Can we survive our own successes? Technology is gift that we’ve used to procreate excessively and mine the riches of the planet. Doing that, we’ve changed it, and it will never revert to its pre-human state. In this, we are like all other successful top-level predators. But like any other creature, we will eventually become extinct, either by making our habitat lethal to ourselves, or by evolving into something else. Kurt Vonnegut imagined the latter scenario in Galapagos. Weisman’s book implies that if we don’t do something to at least partly reverse our reconstruction of Earth, a few of us may survive when the inevitable collapse occurs, and those few will become one among many species competing to survive on a planet that begins to reclaim its own. Our continued success is not guaranteed.
     Even if we manage to stumble and muddle our way through the catastrophe that’s already moving through the biosphere, eventually the Sun will destroy us. Weisman doesn’t mention the hope that others have expressed, that homo sapiens terrestris may become homo sapiens stellaris, but even if that remote possibility becomes reality, the Earth and humans as we know them will have ceased to exist.
     An oddly exhilarating book, despite the depressing and gloomy forecasts and implications. Read it. ****