Emphasizing egalitarianism in the allocation of China's provincial carbon emission allowances

China plans to allocate the provincial carbon emission allowances (CEA), but the CEA scheme has not been determined. Uncertain decisionmaker preferences lead to the uncertainty of the CEA scheme, hindering provinces from setting climate targets. Thus, we investigate different CEA schemes under various preferences from the fairness—efficiency perspective. We developed a CEA scheme set (consisting of 176851 CEA schemes) based on four criteria: egalitarianism, capacity, responsibility, and efficiency. By constructing a desirability evaluation index, we find the most desirable CEA schemes corresponding to various preferences from the CEA scheme set. The results show that egalitarianism can co-improve fairness and efficiency on top of the existing CEA scheme. Relying mainly on egalitarianism supplemented by efficiency is a desirable allocation mode for any decisionmaker. Regardless of the preferences, these situations generally exist: 1) Guangdong and Shandong will get the highest CEA; 2) Municipalities directly under the central government and less developed provinces will get the lowest CEA; 3) North, Northwest, and Northeast China will bear high emission reduction pressures before 2030. These findings will provide essential guidance for decisionmakers in formulating CEA schemes and provinces in formulating emission reduction policies.