Tipping points toward urban pollution advantage? Scaling of carbon dioxide emissions in the American urban areas

Abstract

The high level of urbanisation in the USA may have led to the generation of very high emissions of carbon dioxide (CO2) in cities. This study examines the scaling relationship of CO2 emission as a function of population size across a large number of US cities, conducting scaling analyses on multiple subgroups of cities with varying population sizes. The findings indicate that while superlinear or linear scaling can be applied to the total sample of cities, these changes to sublinear scaling for the subgroups of more populous cities. In addition, this study finds that the tipping point toward said sublinear scaling lies at the subgroup of the 75 most populous cities. The implications of the findings will be discussed.