Investigating the socio-metabolic trajectories of 9 world-regions - Economy-wide flows and in-use material stocks of buildings and infrastructure from 1900 -2010

During the 20th century, annual global material use increased nearly 10-fold (Krausmann et al. 2009), but with strongly differing world-regional trajectories (Schaffartzik et al., 2014). Much of these materials accumulated in... [ view full abstract ]

During the 20^th century, annual global material use increased nearly 10-fold (Krausmann et al. 2009), but with strongly differing world-regional trajectories (Schaffartzik et al., 2014). Much of these materials accumulated in stocks of buildings, infrastructure, machinery and durable goods, where they are in-use for many decades and enable economic productivity and human wellbeing. Systematic knowledge about material stock dynamics is crucial for understanding long-term resource use trends and recycling and waste potentials, thereby informing the development of strategies towards more sustainable resource use, or a circular economy.

This presentation presents novel estimates for 9 world-regions of economy-wide material stocks in infrastructures, buildings and durable goods from 1900 – 2010, based on a dynamic material stocks and flows model (the MISO model). We apply top-down modelling, tracking annual cohorts of additions to stocks, utilizing a global material flow database covering the time period 1850 – 2010 (Krausmann et al., 2009; Schaffartzik et al. 2014), and distinguish input flows of 12 major stock building materials: concrete, asphalt, bricks/stones/tiles, aggregates (recycled and virgin), copper, steel, aluminum, all other metals, solid-wood products, paper and plastics. By applying lifetime distributions we can estimate end-of-life waste from stocks and recycling potentials. We furthermore perform Monte-Carlo simulations, applying uncertainty ranges for all model parameters and the material use data. This allows us to: identify further research & data requirements for improved stock estimations, discuss possible ranges of global and world-regional material stocks in-use and give an outlook on future resource implications of ongoing trends.

In conclusion, we reflect on quantitative long term developments of material stocks in 9 different regions and discuss the relation of economic development and stocks. We finalize with reflections on the importance of understanding material stock dynamics, because these will drive future demand for materials and energy, determine future waste production and recycling potential with strong implications for circular economy strategies.