It's pretty fascinating stuff. I was especially struck when I saw an interview he did specifically on Chicago. He observes,
"The foliage in [Lincoln Park] will definitely be the seed source from which the forests will start succeeding down the streets and eventually inside of the buildings. Winds will blow all kinds of seeds out of the park.
Helping the process along will be squirrels throughout the city, taking up residence in bungalows, two-flats and high-rises. They'll bring in seeds of all sorts, and, pretty soon, trees will be growing out of living room windows.
Within a few decades you'll find a tremendous wild snarl of stuff growing over buildings, coming up from the streets. Just imagine, no one maintaining the streets anymore. And the plastic bags would be clogging the sewers, and you'll get all this leaf litter because nobody would be raking leaves.
Gone will be the cockroaches, which only survive in the northern climate in the comfort of our heated buildings.
Gone, too, will be the rats -- no garbage for them to eat, and a lot more raptors to prey on them.
On the other hand, you'll get wildlife coming back in here. Certainly there will be plenty of coyotes. They will outcompete the dogs. Eventually wolves will probably range all over America. They'll be eating deer. There's going to be plenty of deer. Whether moose will make it down here or not, it's a function of climate change.
The predators are going to get the cattle. As the cattle go, buffaloes should regenerate and spread."
Can you picture a herd of buffalo roaming through the Loop?