If a hiker leaves a footprint on a trail, what footprint does a building leave? a city? an industrial society? It’s not just a physical imprint on the piece of ground the building covers; it’s also the physical impact of the amount of land needed provide the resources to build and sustain the building.
If we translated that Scouting ethic to architectural and industrial design, we would encounter the challenge of Zero Ecological Footprint. Can we design buildings–or industrial facilities, or entire cities–that are biologically invisible? that use no more energy or water than native flows? that emit nothing that can’t be biologically rendered on site?
Medicine’s ancient Hippocratic Oath pledges physicians to “do no harm.” What if the designers of our urban and industrial infrastructures made a similar pledge? We habitually assume that doing some harm is an inevitable, in fact a natural, part of doing good, or doing anything. “You can’t make an omelet without breaking eggs.”
“Do no harm” might not be an attainable reality (since, as the second law of thermodynamics tells us, any physical transaction will have “disordering” consequences), but what if it were a serious design goal? What would a building look like, if it used only ambient energies — the sunlight falling on the site, and the wind blowing through it? if it used only ambient water… and returned only clean water to waterways and aquifers?
But what of materials? A building is a capital investment of materials as well as energy–and the days of building a log cabin from the trees in your own woodlot are gone for most of us, and not an option for office buildings and factories. The land that provides the building materials, as well as the sustenance for its inhabitants, are also part of a building’s ecological footprint.
Well then, what about the ecological footprint of an entire city or even a region, which includes of course, the sustenance needs of its residents? What, in the words of Peter Vitousek, is a city’s “Appropriated Carrying Capacity”?
William Rees and Mathias Wackernagel looked in some detail at the “ecological footprint” required to sustain one citizen of Vancouver, British Columbia. Their conclusion: “The total land required to support present consumption levels by the average Canadian is 4.27 hectares (2.3 hectares for carbon dioxide assimilation alone).” That’s a per capita ecological footprint of about 4.3 hectares, “almost three times their ‘fair Earthshare’ of 1.5 hectares.”
Extrapolating that analysis, they determined that the ecological footprint of the city of Vancouver is nearly 200 times its area; comparable research on 30 European cities has found comparable numbers. Of course cities are dense, and have always depended on trade with a larger region, so Rees and Wackernagel looked at the Fraser Basin in which Vancouver sits; they determined that the people of the Fraser Basin have “overshot the terrestrial carrying capacity of their geographic home territory by a factor of 13.8.”
What difference does this make? Zoom the model out to national economies. Japan and the Netherlands are exceptionally prosperous countries, ones that serve as models to many others. But can they be models, Rees and Wackernagel wonder, if their national ecological footprints are “about eight and 15 times larger than their total domestic territories respectively”?
Somewhere this shell game has to end. If human beings now “directly or indirectly appropriate almost 40% of net terrestrial photosynthesis to their own use,” according to Vitousek, and if 20% of the worlds population now consumes some 80% of the world’s commercial resources, it quickly becomes clear that the “developed” world is no model for the “developing” world to emulate. “If everyone on Earth lived like the average Canadian,” writes David Suzuki, “we’d need at least three Earth’s to provide all the material and energy essentials we currently use.”
Rees and Wackernagel put it bluntly: “Global sustainability cannot be (ecological) deficit-financed; simple physics dictates that not all countries or regions can be net importers of biophysical capacity.” And as Paul Hawken pointedly notes, physics trumps economics every time.
So, since countries and regions are composed of cities and communities, which are composed of buildings and infrastructures, we return to our opening challenge: Can we design buildings–or industrial facilities, or entire cities–that are biologically invisible? that offer a Zero Ecological Footprint. Perhaps not. But how close could we get?
[For further discussion of these concepts, see Our Ecological Footprint: Reducing Human Impact on the Earth, by Mathias Wackernackel and William Reese (New Society Publishers, 1996)]