Stock-flow relations in the socio-economic metabolism of the United Kingdom 1800-2017

Material stocks are the physical basis of production and consumption and shape the dynamics of resource use and socio-economic outcomes. We present an inflow-driven, long-term estimation of material stocks for the United Kingdom, covering 12 major materials from 1800 to 2017. We find the trajectory of the UK's stocks characterized by slow increases during the 19th century, followed by rapid growth and a slowdown in recent years. After a slump following the 2007/8 financial crisis, stock growth again accelerated to currently similar to 1% per year. Per capita stocks barely increased during the 19th century. Proliferation far beyond population growth only started after WWI and pushed stocks to currently similar to 272 tons/capita. Since WWI, material requirements for stock growth constituted a large share of domestic material consumption, indicating the importance of stock stabilization for reducing the size of societies' metabolism. We find that materials required for stock buildup were increasingly imported, while more and more end-of-life metals and paper were exported. Over the past 60 years, energy and CO2 efficiency of stock operation and production improved, but absolute savings were curtailed by ongoing stock expansion. Material stocks grew tightly coupled to GDP, since similar to 1995 showing first signs of relative decoupling. Alongside more than a doubling of per capita stocks from 1961 to 2005, life expectancy increased constantly but slowly. Interestingly, the indicator 'life satisfaction' remained fairly constant over that period. Directly targeting material stocks, for efficiency improvements but also limiting their ongoing expansion, is a crucial lever towards more sustainable resource use in the UK.