“Consumption-based footprinting” is a mouthful, but while it may not flow smoothly off the tongue, it’s an elegant concept — and an important way of looking at our problems.

A footprint, of course, is the measurement of the total impacts of a thing, be it a building, business, or ballgame. Consumption, of course, describes the things we use. So consumption-based footprinting is an attempt to measure the total impacts of everything we use. Boiled down: If we use it, its emissions are ours, no matter where the thing originated.

Now, footprinting is a bit of an arcane art. Because cities themselves are brain-boggling in their complexity, modeling the kinds and amounts of greenhouse gases their economies create represents a considerable task. It is not an impossible task, however, especially if what we’re seeking is a model good enough to guide decision-making, not a perfect reflection of reality.