An urban metabolism approach to sustainability in the city of Östersund, Sweden

Urban Metabolism is a metaphor that allows us to look at the city as a living organism. Just like an organism, the city requires food and water for its existence and turns them into wastes. Having information on how much of certain material is flowing in and out of the city, can create a picture of its efficiency. In 1965, Abel Wolman put up an urban metabolism model for an assumed North American city with a population of 1 million inhabitants, evaluating material in- and outflows per unit of capital use. Making cities sustainable is about using materials at a rate that allows the surroundings to replenish them. They should also be able to handle the city’s waste so that it does not accumulate and pollutes. In that way, adjusting or re-using flows can improve a city’s sustainability and research on urban metabolism can point out where these changes are needed. As a start for urban metabolism research in the city of Östersund, located in the mountains of mid Sweden, a small literature review accompanied with a small first assessment of the metabolism of the city were performed. The urban metabolism concept has developed a lot since the first attempts by Wolman and others. 1) Internal throughflows have been developed; 2) a focus on consumption patterns, e.g. with the ecological footprint approach; 3) environmental impact, assessed with e.g. LCA; 4) ecosystem approaches, based on an energy backbone as e.g. emergy accounting, but also dynamic ecosystem approaches; 5) spatial aspects addressed with GIS assessment; 6) urban planning and design approaches; 7) social-industrial ecology; 8) urban ecology approaches; 9) urban political ecology approaches; 10) ecological economics. Notable is also that there is not yet a standardized framework. The first rough assessment of metabolism of the city of Östersund reveals that 1) the total use of technical energy is divided equally between transports, heating, and electricity use; 2) electricity is locally produced, but only to the extent of 0.25%. The locally produced electricity is to 94% of renewable type; 3) imported food and agricultural products is estimated at 40 000 tonnes; 4) annual freshwater use is ca 8 million cubic meters, most of it used by households. Ca 6.7 million cubic meter finds its way to the wastewater treatment plant; 5) solid waste is estimated at 200 000 tonnes, with construction waste as the largest fraction; 6) natural energies flowing through the town are estimated at 33 TWh of solar insolation. As seen from the literature review, the further research of the urban metabolism of Östersund can take many routes. So far, the first steps of the so-called MEFA approach have been taken, but methods focused on the spatial, ecological, social, and political aspects of urban metabolism can still be added to enhance the analysis