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Green? Dense? Walkable?
Alex Steffen, 19 Mar 08

Here's a debate where none is needed: the argument about whether green building, compact communities, or transit-supportive design is a better approach to improving the world.

The latest piece to kick up some dust is a report from the Commission for Environmental Cooperation, which, as reported by Reuters, says

"Green" construction could cut North America's climate-warming emissions faster and more cheaply than any other measure...

Elsewhere, people reaffirm that North Americans' best bet for carbon reduction is walking and taking transit, while others (often including myself) think density is the best lever, if we have to pick one with which to start.

Now, it's rarely much of an argument. There are green builders who are against growth management, and urban planners who hate transit and love cars, and transpogeeks who think architects are a useless form of decorator, but by and large, most advocates for each of these positions support the others, but just want to see their approach be taken on first.

But, of course, the whole argument is silly, and can be answered "all three, at once." All three strategies are mutually reinforcing (and equally difficult to implement without one another).

What we ought to be shooting for are compact communities, at sufficient densities to support lots of good transit options, composed entirely of high-quality, reasonably-sized green buildings, arranged around streets and public spaces that encourage walking and enjoying one's community, served by green infrastructure.

What I'd love to see is someone crunch the numbers not of a single approach -- increasing density for 7 units per acre to 9, or reducing energy use by 25%, or doubling trips taking by transit, or any of the other single-answer ideas that keep getting quantified -- but of a synergistic combined approach.

Because I'll bet money that when all these approaches are combined, the resulting economic and environmental benefits add up to far more than the sums of the parts seen through the studies done so far. It might well be that building bright green communities pays for itself while improving the quality of life of the people who live there... and saving the planet.

And if that's true, we're burning money as well as planet when we delay, go slow, and engage in false arguments about priorities.

(Creative Commons photo credit

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Not much to debate here, I agree. It makes me wonder, though, the extent to which the largest "planned cities" of our time - notably in India and China - are adopting these principles. I don't recall the particulars, but I've seen some mind-boggling descriptions of large numbers of cities being planned to house 10s of millions of people in each of these countries over the coming 20 years or so. This would seem to be the lowest hanging fruit for full-fledged adoption of these principles.

Posted by: Kent Ragen on 19 Mar 08

One common false dichotomy is the green car vs. better urban planning debate.

The all-electric vehicle has an extremely limited range compared to gasoline-powered vehicles, and most have a top speed of around 40mph.

Hydrogen produced by electrolysis of water using any renewable energy is going to be more expensive than gasoline is now to move the same distance.

All of this necessitates a reduction in travel distances to the point where it makes sense to just design the city around walking and transit anyway, and use green cars as a supplement to these modes. Green cars could be especially effective if the city was dense and connected enough to support a carshare system.

I think it is the focus on trying to maintain our current way of life at all costs that is harmful. We need to accept that there are going to be big changes, and start making those changes immediately. It takes oil to make this transition and the longer we wait, the more difficult it will be.

Posted by: Patrick on 21 Mar 08

In my view it is not a number crunching problem. Just about everyone knows that the combined approach will result in a much higher value than the individual pieces. The problem is the lack of political will to bring the institutional pieces together. The cities, property owners, transit agencies, developers and other players all have separate ways of looking at value. Until we find a way to bring them together we will be moving too slowly.

Posted by: Paul Reinhart on 23 Mar 08

Because of the complex interactions between land use, transportation, and behavior, there is only one model powerful enough to crunch those numbers: UrbanSim, coincidentally developed at the University of Washington. And it doesn't quite do energy calculations yet, but it will.

What you have to model though is not the principles but how you achieve them. Pricing, regulation, incentives, public investment? Do all jurisdictions cooperate or can people flee to the exurbs? Individuals make their own decisions and it's not always what you hope.

Increasing the low end of residential density is certainly effective. For one thing, it lets the low end (the greatest emitters) reach transit-supporting density, meaning that transit needs less subsidy. That makes the transit target easier to achieve. It also makes it more likely that walkable businesses get enough customers to survive. The high end of residential density by and large has no effect on total carbon emissions.

Green building methods are effective by themselves, as long as we are raising minimum standards, not just giving free PR to luxury condos and corporate headquarters.

If you want a single lever it would be a carbon tax. Put a price on it and watch the invisible hand of the market work its magic without political lobbying at every turn.

Posted by: Martin Laplante on 25 Mar 08



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