Exploring the Contribution Roles from Municipal Cities in the Rise in Household CO₂ Emissions in China: From a Local Scale Analysis in the Global Context

A major source of carbon dioxide emissions (CO₂) arises from the household sector. Recent studies have reported increasing household CO₂ emissions (HCO₂) in many countries. Cities represent a key administrative level in China and can be managed to mitigate HCO₂ if spatial and temporal variations in HCO₂ are understood at fine scales. Here, we applied panel data analysis to map HCO₂ at a pixel scale of 1 km in China using remotely sensed time series nighttime light data, grid population density data, and provincial energy consumption statistics from 2000 to 2020. Spatial and temporal variations in HCO₂ were observed with four growth modes, including high growth (HG), low growth (LG), negative growth (NG), and high negative growth (HNG), for different periods, i.e., 2000–2010, 2010–2020, and 2000–2020. We proposed a local scale analysis of HCO₂ growth patterns within a global context to assess the contribution roles of 372 municipal cities to the changes in the national total HCO₂ (T-HCO₂). The results indicated that T-HCO₂ has tripled in the last two decades, but the roles of the contribution to the increase varied among cities. The local scale analysis revealed that more cities contributed to the rise in T-HCO₂ through HG and LG than those that suppressed it through NG and HNG. The majority of the cities displayed contributions to the rise in T-HCO₂ through two or more of the growth modes, confirming a significant variation in HCO₂ across locations, even within a city. This study provides a new approach to understanding the roles cities play in the long-term dynamics of T-HCO₂. We recommend increased efforts to encourage HCO₂ mitigation in cities that have contributed to the rise in T-HCO₂ to help neutralize carbon emissions at the national level.