Buried nuclear plants? Underground stadiums? The next great frontier will be underground, especially if the human population can’t find a way, above ground, to house the estimated 9.3 billion people by 2050:

The federal government has taken an interest, convening a panel of specialists under the banner of the National Academy of Engineering to produce a report, due out later this year, on the potential uses for America’s underground space, and in particular its importance in building sustainable cities. The long-term vision is one in which the surface of the earth is reserved for the things we want to see and be around—houses, schools, yards, parks—while all the other facilities that are needed to make a city run, from water treatment plants to data banks to freight systems, hum away underground.

Though the basic idea has existed for decades, new engineering techniques and an increasing interest in sustainable urban growth have created fresh momentum for what once seemed like a notion out of Jules Verne. And the world has witnessed some striking new achievements. The city of Almere, in the Netherlands, built an underground trash network that uses suction tubes to transport waste out of the city at 70 kilometers per hour, making garbage trucks unnecessary. In Malaysia, a sophisticated new underground highway tunnel doubles as a discharge tunnel for floodwater. In Germany, a former iron mine is being converted into a nuclear waste repository, while scientists around the world explore the possibility of building actual nuclear power plants underground.

Very interesting, but consider the criticism:

But even the most avid proponents of underground development agree that it’s unlikely that underground housing or even office space will become common any time soon—too many people feel unsafe, claustrophobic, or disoriented spending extended periods of time underground. Indeed, being in a confined space can be risky when something goes wrong. One study found that although traffic accidents are less frequent in tunnels than on open roads, the chances of being killed in such an accident are higher. Fire can also be particularly perilous when it breaks out underground—a 2003 arson incident in a Seoul metro station left almost 200 dead—which means it’s crucial to have in place powerful ventilation systems, well-defined emergency procedures, and a high degree of compartmentalization, to prevent the spread of smoke and flames.

As for the more psychological effects of underground life, engineers and designers are chipping away at the problem of how to make underground facilities feel less alienating. Working on the design of an underground research laboratory in South Dakota, where scientists would be spending long hours 8,000 feet under the earth’s surface, Craig Covil—a principal at the engineering firm Arup, who is also working on the LowLine—said he and his team considered imaginative design techniques involving air flow, acoustics, and light that would essentially “trick” people’s senses and reduce the discomfort they might otherwise feel.

Good read.