'Earth Alone': I made my species disappear

In what may be one of the most ambitious “thought experiments” ever, science writer Alan Weisman has undertaken to describe what would happen to the planet if all humans were to suddenly vanish. His notions, detailed in his coming book The World Without Us, are previewed in this month’s Scientific American, complete with eerie renderings of post-human cityscapes. Read the interview with Weisman and see if you agree with him.

What Weisman came up after talking to experts in various fields is sobering, startling – and humbling. New York’s subway system would be flooded within two days; nuclear reactors would burn or melt down within a week; in a matter of months, our great skyscrapers, highways and other structures would be crumbling. “I discovered that our huge, imposing, overwhelming infrastructures that seem so monumental and indestructible are actually these fairly fragile concepts,” he told SciAm. Most traces of humanity would be swallowed up in primeval forests within centuries. Even plastics and the pollutants we generate could eventually break down as microbes adapt to consume them.

The species Weisman says would be the big winners after we all flew the coop are birds (who wouldn’t hit buildings and power lines anymore), trees, mosquitoes and feral house cats. The losers, other than cattle – and obviously, other domesticated animals – might be a surprise: Rats would soon starve and disappear without humans’ garbage to eat. Head lice would become extinct because they’ve adapted so specifically to us (a nice thought). And cockroaches, contrary to the popular notion that they'd survive any calamity, could not live outside the tropics without heated buildings. Who would replace us? Probably baboons – and they’d get a boost in their brain development from all the ready-made tools and gadgets we’d leave lying around. “Planet of the Apes” wasn’t so far off.

Would the earth be better off without us? “I don’t think it’s necessary for us to all disappear for the earth to come back to a healthier state,” Weisman says. Well, thank goodness for that.