ABSTRACT
The measure of value called emergy is used to evaluate the flows of energy and resources that sustain the biosphere including the economy of humans. A biosphere perspective, one that seeks to balance humanity and environment, needs a valuation system free of human bias. The stocks of natural capital and flows of environmental resources are evaluated in emergy and related to Global World Product. Emergy measures value of both energy and material resources within a common framework. Different forms of energy have different abilities to do work, and it is necessary to account for these different abilities if energies are to be evaluated correctly. The global economy is driven by the interplay of both renewable and nonrenewable energy flows. During times of transition and decline criteria forjudging sustainability need to include several factors: the net yield of the process, its environmental load, its use of nonrenewables.
