Estimation of global urban domestic material consumption

From the projections available in the World Urban Prospects (2014) there will likely be over 6.3 billion urban dwellers in 2050, an increase of 2.7 billion people from 2010. In terms of gross numbers, more than 80 per cent of... [ view full abstract ]

From the projections available in the World Urban Prospects (2014) there will likely be over 6.3 billion urban dwellers in 2050, an increase of 2.7 billion people from 2010. In terms of gross numbers, more than 80 per cent of urban dwellers in 2050 will be in the developing world. If all the World's future citizens are to experience the current levels of infrastructure and service provision seen in existing cities, this will entail a great deal of material flows. It would be helpful to policy makers interested in material trade and costs and waste flows to have some perspective on the material flow consequences of this looming global issue but there are no globally comprehensive data on urban material consumption.

Although there has been an exponential increase in the incidence of urban metabolism in the literature, studies and data with global scope are extremely rare. In an attempt to estimate the current and future global urban domestic material consumption (DMC), we developed several techniques using available urban, national and regional data. Approaches include regression relationships with urban income per capita, and fitted mathematical modelling of change in urban DMC/capita with a logistic function. We present the methods and a sensitivity analysis in the context of the overall project, specifically, a sequel to the United Nations’ International Resource Panel report on City Level Decoupling (2013). As part of this work we have developed a future ‘Baseline’ scenario for major global regions in which current aggregate observations about major material consumption indicators are assumed to continue into the future to at least 2050. Global urban DMC is estimated in this scenario to grow faster than the global urban population reaching nearly 90 billion tons per year in 2050. This represents more than a 110 per cent increase in global urban DMC while there is nearly an 80 per cent increase in global urban population for the period 2010 to 2050.

The East Asia region currently has the largest aggregate urban DMC (9 billion tons/year) and that position among major global regions will remain as urban DMC increases to over 19 billion tons/year. Africa is likely to see the greatest change with its urban population projected to increase by more than 800 million by 2050. Although Africa currently has the lowest per capita and lowest total urban DMC of all major global regions, it will become the second largest in terms of projected total urban DMC by 2050 (18 billion tons).  

We also discuss the merits of the DMC indicator in the context of the city as the final destination for manufactured and processed goods.