Measuring Sustainability

The definition of ?sustain' is to keep something in existence. It is this objective and definition that provide some insight into the metrics that are required to measure sustainability and adequately respond while something is still viable. Indicators do not always adequately measure sustainability because they provide answers to whether sustainability was achieved. If the answer is ?no', they have done little to ?keep something in existence' and can not undo prior losses. Keeping something in existence requires metrics that guide human decisions and activities that could threaten losses so that such losses are avoided. Because intact natural, social, and economic systems are essential to sustain human life, keeping these systems intact requires that human actions/behaviors and development move toward harmony with these systems. Therefore, sustainability metrics must directly address human objectives and environmental, social, and economic constraints that influence meeting these objectives.