In order to make the activity of the humanosphere fit to the global limits, a concept of material and energy requirements (mer) for a product/service was proposed and defined. The argument is based on a unified treatment of material cycles applicable to both biogeochemical cycles and sociogeochemical cycles, in which knowledge, physical inflow, srocks (coined word from stock and process), benefit, and outflow constitute basic elements of material circulation. There are five classes of mers: Direct material and energy requirement (D-mer), Extended material and energy requirement (E-mer), Total material and energy requirement (T-mer), Lifetime material and energy requirement (L-mer), and limited Lifetime material and energy requirement (limited L-mer). They may be derived from LCA inventory data and may be used for the formulation of the resource productivity and the eco-efficiency. It was found that the L-mer, which is all the material and energy needed for a product/service to complete its entire lifecycle, was the sum of all the E-mers used in its lifetime, if its lifecycle contains no recycling process. Problems associated with the application of the mers to global change, i. e., kinds of data to be collected, data reliability, their relation to global limits, their conversion, impact allocations to benefit, and multiple indicators, are discussed.

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The effect of recycling on material and energy requirements (mer) was examined. First, it was found that the lifetime mer (L-mer) for the loop of horizontal recycling was independent of mers associated with the extraction of resource and disposal of unneeded material. In the case examined, the merit of recycling rested upon the extended mer (E-mer) for recycling process being less than the sum of E-mers of mining, refining, and manufacturing. Secondly, the advantage of escalade recycling over cascade one was made clear in quantitative terms of different benefits. Thirdly, it was found that the mer that goes with the disposal increases with the number of recycles for a horizontal recycling. In case of a simple cascade/escalade recycling, on the contrary, no such an increase was found. For the cascade/escalade recycling, a multiple cascade/escalade scheme is necessary to become truly “recycling.” While a recycling and a prolonged life share many characteristics and are the same in terms of the mer in usage stage, a recycling further claims the mer in recycling stage. An application of the mer methodology to the evaluation of environmental effect of various products/services would have to take into account the insufficient availability of data and the very partial interest of our society in the global life support system. It is believed that the methodology has a potential to accommodate these realities.

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