How Does Urban Scale Influence Carbon Emissions?

Abstract

Low-carbon cities aim to minimize greenhouse gas emissions in the context of climate change in the process of urbanization. Maintaining these cities at an appropriate physical scale has been proven to contribute to carbon reduction. Therefore, this study extended the definition of the city scale to an integrated framework with three dimensions: the construction land area, population, and economy. The urban construction land of 258 cities in China during 2012 to 2019 was divided into commercial, industrial, residential, and traffic sectors, and carbon emissions were calculated for each. The regression relationship between carbon emissions and the urban scale revealed by panel data analysis showed the following conclusions: (1) carbon emissions were concentrated in north China, provincial capital cities, and municipalities directly under the central government during the research period, and the industrial sector was the main emission resource, accounting for more than 85% of the total emissions. (2) Carbon emissions per unit of land decreased with the increasing land scale, regardless of the land-use type. The growth rate of carbon emissions was slower than that of the population, and cities also became more efficient as their economic scale expanded. (3) Compared with small cities, the large ones benefited more from increasing commercial and traffic land areas, whereas industrial emissions for production needs exhibited significant agglomeration characteristics. Overall, low-carbon planning should focus on the driving role of provincial capital cities as large cities tend to be more efficient, and develop the emission reduction potential of major industrial cities as well.