Population and welfare are growing. Providing the world with metals is becoming a major challenge. Only by closing the loop will metals be available in sufficient quantities, not just now but also in the future: urban mining, the substantial re-use and recycling of metals. In this MOOC we will explore the challenges related to metals supply, both scarcity and environmental impacts, and the conditions and consequences of a circular economy for metals, based on the reports of UNEP's International Resource Panel.