Target decomposition of regional CO2 emissions peaking under multiple allocation models: a case study in Jiangsu province, China

Target decomposition of carbon emissions peaking is critical for fulfilling carbon peaking and carbon neutrality eventually. Decomposing the national target at the provincial and city levels provides a direction for multi-level governments to mitigate regional CO2 emissions effectively. Using 13 cities in China's Jiangsu Province as an example, this study built a top-down regional target decomposition scheme of CO2 emissions peaking, combined with selected emission allowance allocation models and linear planning model, to predict and coordinate carbon emissions and peaking times of the cities. The study showed that large variations exist in the CO2 emissions allowances for different cities under different emissions allowance allocation principles. The target decomposition scheme based on an efficiency-directed model with consideration of the current emissions situation, ability to pay, energy efficiency, and development potential was most feasible. This suggested a combination of economic efficiency, fair development, and functional zoning principles. According to the sequence of peaking times, the 13 cities were classified into three clusters: leading cities, province-synchronized cities, and delayed cities. The CO2 emission peak times of cities have linear relationships with regional per capita GDP, which also indicates differentiated CO2 mitigation responsibilities. Regional target decomposition scheme of carbon peaking provides effective guidance for regional low-carbon policies and national carbon neutrality.