In my column for CNN, I look at potential sources of economic growth in America's future:
Crisis begets innovation.
In the Great Depression, Americans and Britons developed important new technologies: television, movie sound, refrigeration, automatic transmissions for cars. The supermarket was born, as were the passenger aviation industry and the first franchised food company: Dairy Queen.
Big industrial companies such as General Motors and U.S. Steel consolidated their dominance at the expense of weaker rivals. States and the federal government planned and opened the first freeways. Millions of Americans moved off the farms of the South and West to populate California and Florida.
In a decade of economic deprivation, in other words, we can begin to see the shape of postwar America: the suburbanized, mass-production economy into which the baby boomers would be born.
Can we see any similar promise of progress today? I think we can. I discern three glimmers of light on the horizon:
1. A transition has begun from coal to natural gas as America's most important source of electric power. Natural gas emits about half as much carbon dioxide per unit of energy as coal. That's not as clean as solar or wind, but those technologies cannot (yet) compete on price.
Fracking offers hope that natural gas will soon cost least of all. If that hope comes true, the transition from coal to gas will generate a huge burst of economic activity and accelerate the transition to a more sustainable future for humanity.
2. Americans are on the move again, this time from exurb and suburb to downtown, not only where you might expect it -- San Francisco -- but also where you wouldn't: Cleveland's most central census tracts added 20% to their population from 2000 to 2010.
Newark, New Jersey, added population for the first time since 1950. Ten thousand people moved to downtown Philadelphia; 15,000 to Los Angeles' once ghostly downtown; 2,000 to downtown Detroit. Downtown Baltimore is up 11% since 2006. The Loop in Chicago is up 76% in the past decade. Central Louisville is being rebuilt.