Tregoning points to the millennial generation, whose employment and wage growth has been weakest in the economic recovery. They may not have a lot of income now to be able to live where they want, but they're willing to live in a smaller space and have all the amenities of a mixed-use, mixed-income neighborhood.
"Small units are going to be in demand, and most of our communities haven't built those small units before," she said. "Yes, it's a niche, but we have no product."
As for transportation, she envisions lots of streetcars and other public transit. Some of the lanes that we're now using to park vehicles are going to be given over to pedestrians, bicyclists or transit users because people are going to be driving a lot but owning fewer cars.
"Every car that we have is going to be driven by more people, and more times a day, but we will store those vehicles less. The streets are going to look a lot different."
Not just the streets. The buildings and landscapes will, too, as cities try to adapt themselves to the growing crisis of climate change.
"Clearly cities are already starting to and will increasingly have to grapple with the adaptation that's required by climate change. That adaptation will have to account for sea level rise, more intense storms, more flooding in coastal areas and in inland areas from rivers," said Douglas Foy, CEO of Serrafix, a strategic consulting firm focused on environmental, energy, transportation and climate change issues.
(Read more: Megacities' explosive growth poses epic challenges)
Foy, former secretary of commonwealth development in the administration of then-Massachusetts Gov. Mitt Romney, points to potential new building codes requiring that electrical and IT systems be put on higher floors. He also said urban planners will need to incorporate more green space into flood-prone cities because that will turn out to be one of the best barriers or adjustments to flooding and storm issues. He points to Boston's "Emerald Necklace," an 1,100-acre chain of parks, as being an enormously valuable flood control device, because you can flood the esplanade with the Charles River.
"It's natural features built into cityscape. They are a comparatively inexpensive way to be resilient," said Foy.
Foy and Tregoning also envision cities in which cars drive themselves, parking spaces tell you when they're vacant and restaurants grow their own food on their roofs. These cities will also have to address the so-called, "heat island effect," which is when their internal energy ends up heating themselves from within. This is why large cities are often 10 to 15 degrees hotter than their nearby suburbs.
"You're going to see lots of green roofs, greener streets, ...more street trees that provide shade," said Tregoning.