In recent months, several conservative governors have rejected federal funds to begin constructing high-speed rail lines in their states. But a high-speed rail advocate argues that such ideologically driven actions are folly, as other U.S. states and countries around the world are moving swiftly to embrace a technology that is essential for competitive 21st-century economies.

How significant would it be if America’s 29 million small businesses increased their energy efficiency and reduced their emissions? Judging from the example of one California entrepreneur, the impact could be far greater than you might expect.

The practice of “commissioning,” in which an engineer monitors the efficiency of a building from its design through its initial operation, just may be the most effective strategy for reducing long-term energy usage, costs, and greenhouse gas emissions from buildings. So why is it so seldom used?

After years of reluctance, scientists and governments are now looking to adaptation measures as critical for confronting the consequences of climate change. And increasingly, plans are being developed to deal with rising seas, water shortages, spreading diseases, and other realities of a warming world.

Mostly conceived by international architects, China’s eco-cities were intended to be models of green urban design. But the planning was done with little awareness of how local people lived, and the much-touted projects have largely been scrapped.

In the last few decades, urban sprawl, once regarded as largely a U.S. phenomenon, has spread across Europe. Now an emerging group of planners is promoting a new kind of development — mixed-use, low-carbon communities that are pedestrian-friendly and mass-transit-oriented.

U.S. cities have been using green planning to spark economic development, helping create a real urban renaissance in America. With a new administration soon to arrive in Washington, these same approaches may finally start being used on a national scale.