The concept of what would happen to the Earth without humans came from aDiscovereditor, and the resulting article became the basis for your book. How did you wrap your head around the idea?

The editor said, “I want to know what would happen if we just disappeared right now.” She had read my Harper's piece about the aftermath of Chernobyl, where abandoned villages were being overtaken by nature. The more I thought about it, the more I realized it was a mechanism that could solve my problem of getting people to follow me on a journey to the world's major environmental issues.

Your polymers chapter is one of the most startling. When you show how much plastic is in our ocean today …

That was stunning to me. By keeping it cooler, seawater is protecting plastic from being broken up the way it would on land. But eventually it gets broken up into smaller particles, and then smaller and smaller organisms are ingesting it. Most of us already knew that otters, birds, and turtles are eating plastic, but who knew that it was going down to the level of plankton?

You outline in detail what will happen to a place like Manhattan within years of human disappearance. Were there aspects that surprised you?

I had never put all of that stuff together. The subways are below the water table. If there are no people around, there would be no electricity for the pumps. Subways would flood, and steel columns would start to erode. It takes maintenance to keep bridge expansion joints open. If they fill with debris and rust, the bridges are goners.

In fact, more people than ever are living in cities. How is urbanization affecting us?

Most of the people who live in urban areas are poor, and the architecture that is going up now is, frankly, deplorable. In Cyprus, townhouses have a 10-year guarantee of construction; 40 miles up the road, I'm seeing stuff built in biblical times. When we make stuff that is of the earth itself, it's stable, meant to last.

What would you counsel architects to do in the future?

There are many good architectural lessons that existed before we had such technological prowess that we thought we could overcome nature. Turns out we can't. Architects and ecologists have to be in a deep dialogue about engineering the future. Our cities can't keep eating up our ecosystem. It's energy inefficient, and it's coming back to bite us in a big way.