Synergistic sectoral actions can accelerate carbon reduction in consumption-intensive regions

Cities play a pivotal role in global carbon mitigation, but conventional accounting approaches often obscure the responsibilities of sectors that consume energy without directly emitting, particularly in service-oriented urban systems. This study develops a seven-step analytical framework centered on the scope-based emissions method to address the resulting mismatch between sectoral functions and carbon responsibilities in consumption-driven cities. Applied to Hong Kong, the framework reallocates indirect emissions based on inter-sectoral electricity flows and reduces the supply-to-demand emission distribution from 3.52 to 1.25, promoting a fairer distribution of emission responsibilities among sectors. Beyond tracing emission dynamics, it simulates mitigation scenarios under shared socioeconomic pathways to assess the value of cross-sectoral coordination. Results show that redistributing responsibilities and enhancing cross-sectoral collaboration can improve city-level mitigation performance, with synergistic policies projected to reduce emissions by 37.3% and 19.1% by 2050 compared to limited or no coordination. These findings underscore the value of integrating emission analysis with governance needs, offering an actionable tool to reassign responsibilities and coordinate mitigation in cities where sectoral misalignment hinders climate action.