What would happen to our planet — to our cities, to our industries, to nature — if humans disappeared?
There are several developing theories for what could drive humanity to extinction, and it is unlikely that we’d all simply disappear in an instant. Nevertheless, imagining our sudden and complete eradication from the planet — perhaps by an as-yet undiscovered, human-specific virus, [author Alan] Weisman said — is the most powerful way to explore what could occur if humans left the planet.
In Weisman’s own research, this question took him firstly into cities, where some of the most dramatic and immediate changes would unfold, thanks to a sudden lack of human maintenance. Without people to run pumps that divert rainfall and rising groundwater, the subways of huge sprawling cities like London and New York would flood within hours of our disappearance.
Looking beyond the city limits to the great swathes of farmland that currently cover half of Earth’s habitable land, there would be a swift recovery of insects, as the application of pesticides and other chemicals ceases with humanity’s demise. “That’s going to start a real cascade of events,” Weisman said. “Once the insects are doing better, then the plants are going to do much better, then the birds.” Surrounding habitats — plant communities, soils, waterways and oceans — will recover, free from the far-reaching influence that chemicals have on ecosystems today.