Figure . Three scenarios for energy transition, predicted by IEA. STEPS only considers the existing policies, which can control the temperature increase by 2.7 ℃ in 2100; (2) APC assumes that all the pledged targets will become policies, which can control the temperature increase by 2.1 ℃ in 2100; (3) net-zero case, corresponds to the temperature increase by 1.5 ℃ in 2050. (Note: this net-zero case scenario is proposed by IEA, but not the only scenario path to achieve net-zero emissions.) Some key points are as follows.