Our escalating consumption of natural products and services directly impacts the planet. The challenge is to ensure that our needs are not exceeding the ecological capacity of the biosphere. But how to know if they do so? To answer this question and assess the human impact on nature, Wackernagel and Rees have developed Ecological Footprint that can measure how much natural capital we use to sustain our lifestyles and how much capital nature can provide us. On the other hand, to be able to present in a single measure for each economy and to focus strictly on the environmental...