A fairly and effectively analysis for the sharing of CO2 emissions reduction responsibility in China's provincial building sectors

China's goal to peak CO2 emissions by 2030-in accordance with the Paris agreement-is being jeopardized by the increasing carbon emissions from the building sector. Allocating CO2 emission reduction (CER) re-sponsibilities for the building sector to the provinces fairly and efficiently remains challenging. In this study, we first quantify the government leading targets regarding CER responsibilities, while clarifying the extent to which China considers the principles of equity and efficiency while allocating provincial CER responsibilities. Subse-quently, based on the carbon emission efficiency, CER potential, and abatement cost of China's building sector, we establish a more equitable and effective model for sharing the CER responsibilities in the building sector at the provincial level. Using data from the building sector in 30 provinces in China between 2005 and 2019, we define and compare the CER responsibilities that the building sector in each province should bear with the CER responsibility-sharing scheme under multiple perspectives. Results show that the Chinese government has not fully considered the principles of equity and efficiency in setting the CER targets for each province in the past 15 years. Our model for sharing the CER responsibility in the local building sector appears more reasonable and adequate: The marginal abatement cost (i.e., economic loss of abatement) is about 7% less than those of other schemes; additionally, it guarantees the fairness of development power. Overall, this study furthers the CER responsibility-sharing theory and constitutes a reference for implementing more effective energy saving and CER policies.