Relating SDG11 indicators and urban scaling - An exploratory study

Targets towards "Sustainable Cities and Communities" are formulated under the 11th Sustainable Development Goal (SDG). In parallel, recent city science suggests that economies of scale could improve city efficiency and thereby support urban sustainability. In this paper we inspect the association between country-wide SDG11 indicators and urban scaling exponents, i.e. the scaling between an indicator value vs. city population, separated by countries. We investigate "convenient access to public transport", "ratio of urban area growth rate and population growth rate", "particulate matter levels", and "green space area". Overall, we obtain mixed results, where in some cases the urban scaling exponent correlates with the country-wide indicator value and in other cases they are uncorrelated. Urban green space mostly scales sub-linearly and the exponents by country are independent of the SDG indicator. Good public transport, in turn, is achieved by also providing good service to small cities. We conclude that urban scaling can provide additional information but not for all considered indicators.