Integrated benefit-cost analysis of China's optimal adaptation and targeted mitigation

In this work, we develop a regional integrated assessment framework by incorporating both adaptation and mitigation mechanisms to conduct benefit-cost analysis of China's optimal adaptation and portray the relative adaptation cost curve. In particular, we explore the influence of induced optimal mitigation, given the 2-degree warming-increase target, on the effectiveness of adaptation. Although adaptation alone may not be able to tackle all the risks of climate change, it remains a benefit-cost effective option. Our results show that China's optimal adaptation strategy can avoid, on average, 28% of climate damage over the entire simulation horizon. With respect to the reduction of adverse climate effects, the effect of a policy mix of both adaptation and mitigation does not appear to be “1 + 1 ≥ 2” despite the combination strategy is still the better option compared to adaptation or mitigation alone. Robustness analysis reveals that the choice of time scales is important for policy effectiveness assessment, and the discount rate tells most of the story. Specifically, the lower the discount level, the higher the policy effectiveness; and the effectiveness of targeted policy would be significantly reinforced if a longer time scale is considered, given the same discount rate.