Context
William Rees, an ecologist at UBC, has developed what he has termed the "eco-footprint" concept, which continues to get growing attention in many different areas. It is somewhat similar to the notion of "embodied energy" of the 1970-80s. It begins with the idea the all consumption of energy, food and materials ultimately relies on solar energy that is transformed on Earth through photosynthesis. Human consumption can ultimately be related to the land area on Earth that is needed to provide the photosynthesis or other ecological services needed to support that consumption. An important, indirect, non-economic measure of consumption is thus the amount of land area required to support a given population at a given level of consumption. It basically uses Vitousek 's perspective of appropriated photosynthesis, and focuses on land area as the proxy for photosynthesis. We are using this concept to attempt to model the human consumption levels for a population in an area of the world in terms of the appropriated carrying capacity, or eco-footprint, that it consumes, now and under various scenarios. Eventually we hope to develop functions that relate the extent of carrying capacity extracted from an area to potential ecological degradation (e.g., species extinction, etc.). Hence this is a way to link population and wealth to consumption patterns, and then attempt to link those to ecological constraints locally and globally.

Work plan
The ecological footprint model is being developed independently in Analytica ®, with an ultimate goal of direct links to ICAM. The variable groups that are being defined include: land productivity, including marine land and uninhabited land; consumption as defined by income, population and the nature of products consumed; technology scenarios; and eventually, global ecological constraints .

The intent is to develop a framework for calculating the ecological footprint of North America. We plan to divide North America into four sub-regions, rural and urban, north and south. The index will in essence be a non-economic measure of human consumption, that can then later be related to ecological constraints. We see this effort as a means to bring consumption levels and ecological measures more squarely into ICAM.