Which metric is NOT considered a consumption metric in sustainability assessments?

In sustainability assessments, consumption metrics are typically used to measure the use of natural resources and the environmental impact associated with that consumption. Water, fossil fuels, and biotic resources all represent direct consumption metrics because they quantify the amount of these resources used, which directly links to sustainability efforts aimed at reducing resource depletion or environmental degradation.

Greenhouse gas emissions, while they are related to consumption, do not measure the direct consumption of a resource. Instead, they represent an output or consequence of energy use and resource consumption rather than the consumption itself. Therefore, greenhouse gases serve as an impact metric, indicating the results of consuming other resources rather than measuring the consumption of those resources directly.

Consequently, the metric not considered a consumption metric in sustainability assessments is indeed greenhouse gas emissions, as it reflects an environmental outcome rather than a direct consumption measurement.