We’re now serving 7 billion on planet Earth, according to a UN projection released last week. Some estimates put world population at 10 billion by 2100. Where are all those people going to live?

via NPR

It’s hard to wrap your mind around a number like 7,000,000,000. That’s an awful lot of zeros. As a start, check out National Geographic’s new project: a year-long series on world population, including a gorgeous image gallery and this simple, three-minute video summarizing the pace and ramifications of population growth:

The video makes the point that if population growth is a problem, it’s not strictly a problem of space: 7 billion people could stand shoulder to shoulder in roughly the area of Los Angeles, the video claims. The problem is economics: the rise of megacities as more and more rural dwellers look for work in urban areas, the concomitant growth of slums, and the lopsided allocation of resources on our fair planet.

The truth is: the UN’s big “7 Billion” announcement earlier this week is pretty fuzzy math…really, it’s just a milestone-peg to encourage media outlets to talk, at least for a couple of days, about the problems surrounding population growth: housing, resources, hunger, deforestation, etc.

OK! Let’s talk. That’s the idea behind Housing Revolution—the creation of my friend Peter Aronson, a journalist based in Dharamsala, India. I’ve been collaborating with Peter as producer of HR’s new podcast series—conversations with innovators around the world about how to build better cities, how to use resources more wisely, and most of all, how to house—safely, sustainably, and affordably— the swelling populations of poor urban dwellers in our world, the billions flocking to already teeming cities to find work.

Our first podcast featured Vijay Govindarajan (an utterly fascinating fellow) and his $300 House initiative—a design challenge project that aims to create prototypes for affordable, sustainable homes for the world’s poor; in our upcoming podcast we’ll be speaking with Elizabeth Hausler, who’s working to build earthquake-safe communities in places like Haiti, Indonesia, and Pakistan, where most earthquake deaths result from cheap, haphazard construction that collapses with people inside.

A lot of what we’ll be talking about at HR will, like our first two podcasts, address sustainability, affordability, and safety for homes in the developing world. Meanwhile, there’s plenty to say about building and breakneck consumption of resources in America and other big economies. As this recent NPR story (As Population, Consumption Rise, Builder Goes Small) points out, people in growing economies like China and India may try to emulate America as they prosper economically…which means soaring resource use in those countries as well.

A company called Zeta Communities is proposing one way for some Americans to decrease their energy footprint: The company is producing small modular homes on a factory floor near Sacramento, CA—some of them as small as 300 square feet, and stackable. Will American city dwellers buy in?

ZETA Communities factory floor (via NPR)

“The problem is there just isn’t enough cheap energy or water or land for 9 billion or 10 billion people to live the same way,” posits NPR reporter Christopher Joyce. “So what if Americans set a different example? Consume less by living smaller? The Japanese do it. Can small be beautiful in the U.S.? Some people think so.”

This is by no means an endorsement of ZETA Communities’ product—just an acknowledgement of an interesting idea that, like the super-efficient Clayton Homes i-house, aims to address the problems of sprawl and energy-guzzling construction in America (e.g. our 100-year-old house in Nashville with crazed electric bills)…via the market. It’ll be interesting to see who buys.

Related post: The Housing Revolution Manifesto