China's changing city-level greenhouse gas emissions from municipal solid waste treatment and driving factors

With cities’ intertwined challenges of garbage siege and climate change, it is imperative to explore the greenhouse gas (GHG) emissions from municipal solid waste (MSW) treatment and the determinants of the emissions change. However, related quantitative analysis with high spatial resolution in China has been lacking, which hinder tailored policymaking. To fill the gap, this study develops a long time-series inventory of GHG emissions (including CH4, CO2 and N2O) from MSW for 294 Chinese prefecture-level cities. The temporal and spatial logarithmic mean divisia index (LMDI) model is further used to reveal the drivers behind the emissions change and difference. Results showed that domestic GHG emissions from MSW treatment increased from 39.24 Mt CO2e in 2006 to 128.81 Mt CO2e in 2019, 63.41%-88.95% of which were CH4 emissions accounting for 8.13%-10.22% of China's total CH4 emissions. First-tier cities and new first-tier cities (6.44%) contributed 35.44% to the national emissions in 2019. Furthermore, the national increased emissions were primarily driven by economic output (66.09%), while the MSW treatment intensity per GDP caused emissions reduction by 5.23%. The spatial decomposition verified that the population size was the dominant driving factor for differences between the national average and city-level emissions. Improvements in MSW treatment structure may be the effective abatement strategy for cities in Northwestern China (e.g., Yinchuan, Xining and Lanzhou). These findings could provide insights into the GHG emission mitigation of cities’ MSW sector for a future carbon-neutral society.