Sustainable consumption, sustainable development, and green net national product

This paper examines how green net national product (NNP), which can be interpreted as “hypothetical” constant consumption, is related to sustainable development based on two levels of sustainable consumption. First, we focus on “maximum sustainable consumption” and assume that a utilitarian optimal path is sustainable if the level does not decrease. Then we show that from this standpoint nondecreasing green NNP is a necessary condition for the optimal path we take to satisfy the sustainability. Next we introduce the viewpoint of “long-run increasing consumption” based on “minimum sustainable consumption” and regard the optimal path as sustainable if the path has a long-run increasing consumption path. We demonstrate that nondecreasing green NNP is a sufficient condition for the consumption path to be long-run increasing. These investigations show that although green NNP is not sustainable consumption it is closely linked to sustainable development defined by sustainable consumption, so it represents an indicator of sustainable development.