Spatial heterogeneity of demographic structure effects on urban carbon emissions

As the main body to promote economic development, the role of demographic structure on carbon emissions cannot be ignored. Based on data from the three national censuses in 2005, 2010 and 2015, this paper constructs urban-level demographic structure indicators and uses the Geographically Weighted Regression Model to study the spatial heterogeneity of demographic structure changes on carbon emissions and the corresponding mechanism at the microlevel. The results show that: (i) there was a negative correlation between household size and carbon emissions; (ii) the effects of labour ratio and dependency ratio on carbon emissions between coastal and northeastern cities are significant differences, for example, there is a significant negative relationship between labour ratio and carbon emissions in most cities in the Northeast. Overall, in most cities, the labour force ratio is positively correlated with carbon emissions, while the juvenile dependency ratio is negatively correlated with carbon emissions; (iii) demographic structure affects carbon emissions through cost mechanisms and consumption upgrade mechanism; and (iv) the medical and housing needs of the elderly are positively correlated with carbon emissions. Therefore, cities should seize the positive aspects of demographic changes. For example, policies dedicated to increasing fertility willingness in the short term are effective measures to deal with the aging population, declining birthrate and environmental challenges. It is necessary to respect the inherent laws of population development, meanwhile, based on the city's functional orientation, to cultivate differentiated leading industries, and build a green and low-carbon city through the coordinated development of population structure and employment structure. •The spatial heterogeneity of demographic structure affects carbon emissions is investigated.•Demographic structure affects carbon emissions via cost mechanisms and consumption upgrades mechanisms.•There was a negative correlation between household size and carbon emissions.•Fertility affects carbon emissions is more pronounced in the Northeast.•The Chinese government should encourage the concentration of labor force in big cities.