Cyclic manufacturing: necessary and sufficient conditions and minimum rate policy for environmental enhancement under growth uncertainty

Economic development and rising consumption increase pressure on the environment. Sustainable production and consumption face the challenge of mitigating impacts under uncertainty in economic growth, trade, raw material availability and prices, variable consumer behavior and technological innovation. Necessary and sufficient conditions and a minimum rate policy for environmental enhancement under uncertainty are presented. They take into account variability in sales/consumption, in net product and material trade and in manufacturing technology and associated impacts. Three main criteria are considered. K1: reduced final wastes. K2: reduced extraction of virgin raw materials. K3: reduced impacts from manufacturing. The conditions are expressed in terms of the cycle rate, which is the generalization of the recycle rate and of readily monitored product flows, e.g. overall sales. Key advantages of the method are discussed. (A): simplicity and flexibility to simulate different growth conditions. (B): a readily determined, standardized rate policy, leading to reduced impacts in K1, K2 and K3. It is quantitatively established that for lower wastes, uncertainty in growth compels increase of the cycle rate larger than a threshold related to sales. For lower virgin material extraction, the threshold includes net product/material trade as well. Reduction of manufacturing impacts requires intensification of cleaner processes with adequately lower marginal impacts. In periods of economic austerity, the policy may be relaxed: enhancement is achieved via lower rate targets. It is concluded that cleaner production becomes all the more important as reuse/recycle flows increase and that such innovation may avert environmental degradation from manufacturing, even under significant growth.