The consumption model is based on the observation that world population is highly correlated with cumulative consumption (the total amount of resources consumed since a given point in time) for ecological resources and energy.
BELOW: World population and resources, as fractions of their calculated values at the end of 2007. This graph combines projections from consumption of ecological resources (measured by the Global Ecological Footprint), energy (production), and economic resources (measured by the Gross World Product).
Consumption of three types of resources are simulated: ecological ("footprint"), energy, and economic ("GWP"). Several representative scenarios are described on this site: no change ("business as usual"), no growth (of population and per capita consumption), and high growth (increasing resources to maintain current trends in the growth of population and per capital consumption).
See the following: