Broadway Boulevard – a paved multi-lane road, cutting a straight path across fifteen miles of desert, bringing the city uncomfortably close to the Rincon and Tucson mountains. This is progress, of a sort. Sixty years ago, the city would have been scarcely visible, with none of these highways or towers yet constructed. There would have been water flowing year-round in the Santa Cruz fiver. I am no Christian, but post-war Tucson calls to mind Isaiah 40:4:

…every mountain and hill shall be made low: and the crooked shall be made straight, and the rough places plain.

The cost of this progress is evident through the rapidly diminishing resources of the surrounding desert. Do cities grow as most organisms do, toward a determined final form? Or are cities more like cancers, growing rapidly until a collapse brought on by resource depletion? Is there anything fundamentally different between a large city and a small city? Our laboratory thinks about these issues of scale, and some of my work is beginning to address some universal ‘ecological’ constraints on economic development. It’s too early to share these results, but you may want to read about Geoffrey West’s work on cities – he is a physicist who has collaborated with our lab.

Edge.org: Why Cities Keep Growing, Corporations and People Always Die, and Life Gets Faster

Interesting as all these ideas may be, I’m not yet sure they will help us with many practical issues. It is hard to look at a photograph like this one and feel optimistic.