Since I was raised as a country boy, with an inherited scorn for city-dwellers and "flatlanders", I've never had much of a taste for high population density. But as I get older and wiser (if only by comparison), the potential of cities is starting to look attractive. Not necessarily the current actuality of cities, but what they could be. What they might be starting to be. What we're finally figuring out how to make them.

Much of human economic activity, most agriculture excepted, is best performed in cities. Transport of stuff, and of people, and of culture is best done over short distances. Large numbers of folks making short trips (for whatever purpose) makes mass transit not only economical, but absolutely necessary. In my experience, Hong Kong (for all its challenges) is proof positive of this. Many cities in Europe and several of the (older) downtown areas in the Eastern USA provide corroboration. LA, Long Island, the DC suburbs, Houston and most of Florida provide instructive counter-examples.

More than 60% of Greenback's GHG emissions result from operating our buildings, and that percentage would only go up if good public/mass transit were available. So, in an urban setting, efficiently operating buildings are the key to success.

If you talk about efficient building design and operation to any campus sustainability administrator, the first sentence out of his/her mouth will include the word "LEED". The USGBC's Leadership in Energy and Environmental Design program has helped US architects and commercial builders get familiar with, and behind, a better building standard. (In spite of my current grumbling, which remains entirely valid and appropriate.) But even if all new buildings for the next 40 years are built to the highest (platinum) LEED standard, that's not going to get us to the buildings, neighborhoods and metropoleis we need. We need to go farther than LEED.

Two standards that go the next step currently exist. The first one has been around for a while, and so has a track record which is easily investigated. It's the passivhaus standard which, as the name implies, eliminates the need for active heating or cooling of any kind -- even in northern Europe (which has weather similar to that up here in Backboro). Passive houses use about 10% of the energy a similar-sized typical house consumes, or about a quarter of what more new "low energy" houses still require. An addendum to the standard suggests/requires that what energy is used come from renewable sources. And passivhaus technology scales well; it's been used in apartment blocks (including public housing) and would be a good choice for residence halls.

Beyond even the passivhaus standard is one that's emerging from the International Living Building Institute. More comprehensive (it requires effectively zero site impact, only current/renewable energy, only sustainable and local materials, maximal diversion of construction waste, water independence, high indoor air quality and other comfort factors, and an active educational component), it sets a standard that no building has currently met. Still, all the technological problems have been solved, additional up-front costs range from 4% to 50% (depending on location and building type), and lifespan building costs are almost certain to be lower than with conventional construction techniques.

One of the challenges any concept of sustainable urban reconstruction must face is the fact that so many buildings already exist. Another is that the structure of the commercial real estate industry (various builders, owners, tenants, and financiers each with their own set of concerns and risks to manage) makes the trade-off between capital and operating costs quite complex. But both of these have been solved (admittedly, to a standard more consistent with LEED than with passivhaus or Living Building) in such projects as the renovation of the Empire State Building. And, for university campuses where academic buildings and residence halls are less likely to go on the market anytime soon (let's hope!), the financial management issues are significantly simpler.

Put this all together, and what's created is the possibility of urban areas which are actually "climate positive". Rather than contributing (however much or little) to climate disruption, they (and the people who live and work in them) actually remove more greenhouse gases from the atmosphere than they emit. More than a dozen of these projects are already underway or gearing up around the world. Given today's technological infrastructure, they're dependent on the electrical grid getting smarter and generation getting more sustainable, but that needs to happen anyways. Sustainable cities will need sustainable food and energy suppliers, but at least it looks like the demand side is becoming manageable and attractive.

And that "attractive" part is important, if we're ever going to turn the "exurbs" back into the countryside that sustainable agriculture is going to need.