ABSTRACT
A central theme of sustainable development is the integration of economic, social and environmental concerns. This principle is at the heart of the Bruntland Commission report, the Earth Summit agreements and various national policies and strategies. Chapter 8 of Agenda 21 (UN 1992), agreed to at the Earth Summit on Integrating Environment and Development in Decisionmaking, states:
A first step towards the integration of sustainability into economic management is the establishment of better measurement of the crucial role of the environment as a source of natural capital and as a sink for by-products generated during the production of man-made capital and other human activities.
