In the 1970s, we crossed a global threshold when the rate of human demand for ecological resources began to outpace the rate at which nature could provide them. Today, we consume the equivalent of 1.5 earths in terms of the resources we use and the natural systems we rely on to absorb our waste. And if everyone on earth lived the lifestyle of the average American, we would need five planets.
How do we know this? By measuring our “ecological footprint,” a measure of natural resource consumption as a function of goods and services purchased. Using natural-resource accounting techniques, the balance of consumption for all countries is precisely measured against the world’s capacity to regenerate those resources. When combined with a mathematical input-output model, calibrated by socioeconomic and demographic data, the analysis can be performed at a wide range of scales: personal, household, factory, company, country, planet.
A few years ago, we invited Oakland-based — founded by , the creator of the environmental footprint concept — to present at a ϴforum. After the forum, we got to talking about how a San Francisco footprint analysis could broaden the conversation around sustainable urbanism. Global Footprint Network’s staff was inter