Mapping the anthropogenic stock in Germany: Metabolic evidence for a circular economy

The world's industrialised nations have accumulated a wealth of assets in the form of buildings, infrastructure and other durable goods. These assets constitute a valuable reservoir of secondary raw materials. This “anthropogenic material stock” should be understood as a future capital stock that must be systematically managed and exploited. Yet this capital stock has hitherto been largely ignored in discussions on resource efficiency, which instead have focused on inputs of primary raw materials. This is partly due to insufficient knowledge of the size and constitution of this material stock as well as its dynamics. Therefore, a project was set up by Germany's Federal Environment Agency to provide the missing information. Project results offer a comprehensive view of material stocks, inflows and outflows connected to durable goods. Thus we note an annual per capita growth in Germany's anthropogenic material stock of 10 t. In the last 50 years an estimated 42 billion tons of material has been added to the anthropogenic stock. Not all of this can be classified to primary groups of goods. Around 28 million tons of material has been consumed by buildings, infrastructure, building services as well as durable consumer goods. Of this figure, over 99% can be located in the built environment. This mass is approximately 79 times larger than the material mass currently consumed every year by these sectors. Annual outflow from the stock is around 0.8%. The annual rate of growth of the observed stock of goods is 0.5%. The various figures can be further broken down according to individual groups of goods and material groups. This knowledge provides the necessary foundation for the long-term monitoring of the anthropogenic stock and, moreover, is an important step in the evidence-based development of a model to incorporate and to improve closed-loop material flows as well as to support politics of securing supply of raw materials.