Abstract

Sustainability is about preserving human existence. Indicators and metrics are absolutely necessary to provide at least a semi-quantitative assessment of progress towards or away from sustainability. Otherwise, it becomes impossible to objectively assess whether progress is being made. The subject, however, is by its nature complex and multidisciplinary. Indicators and metrics must, therefore, encompass a wide of issues relevant to human existence, and they must be useful in “steering” the system towards a sustainable trajectory. They must, however, be well grounded in science and allow for comparisons across different systems. As a minimum, metrics must represent economic strength, human environmental burden, energy use, and system order and stability. A comprehensive suite of metrics is essential to the kind of adaptive management that is necessary for practical implementation of sustainability.