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In this paper, we develop a method to assess the environmental impacts of metal scenarios. The method is life cycle based, but enables forward looking and upscaling. The method aims at translating metal demand scenarios into technology-specific supply scenarios, necessary to make the translation into environmental impacts. To illustrate the different steps of the methodology, we apply it to the case of seven major metals. Demand scenarios for seven major metals are taken from literature. We translate those into technology-specific supply scenarios, and future time series of environmental impacts are specified including recycling rates, energy system transformation, efficiency improvement, and ore grade decline. We show that the method is applicable and may lead to relevant and, despite many uncertainties, fairly robust results. The projections show that the environmental impacts related to metal production are expected to increase steeply. Iron is responsible for the majority of impacts and emissions are relatively unaffected by changes in the production and energy system. For the other metals, the energy transition may have substantial benefits. By far, the most effective option for all metals appears to be to increase the share of secondary production. This would reduce emissions, but is expected to become effective only in the second half of the twenty-first century. The circular economy agenda for metals is therefore a long-term agenda, similar to climate change: Action must be taken soon while benefits will become apparent only at the long term.