巴黎协定背景下全球减排博弈模拟研究

构建了具有7个国家集团的全球多国家集团气候博弈集成评估模拟系统,针对《巴黎协定》背景下各国至2050年以及2100年的减排目标,分别对减排博弈的纳什均衡、博弈不确定性以及外部政策对减排博弈的影响展开了模拟分析。研究发现：在基准情景下,全球各国将在2030年后均选择不减排策略,全球至2100年升温达到2.62℃;而模型参数的不确定性也未能突破全球零减排的纳什均衡;而仅当在全球范围内对不减排采取惩罚措施时,全球零减排的纳什均衡点被打破。但在当前《巴黎协定》减排承诺下,为达到2℃的温控目标,加大2030—2050年的减排幅度至关重要,否则全球将在2040年左右突破2℃阈值。

Game simulation on emission reduction under the background of the Paris Agreement

A seven-region based integrated assessment model is established in this paper targeting to model the emission reduction game worldwide. Under the Paris Agreement, given the emission mitigation scheme by 2025/2030, 2050, and 2100 for each country (region) as gaming strategy, the Nash equilibrium, the uncertainties of the game and the influences from external mitigation mechanisms are evaluated in each strategy combinations. In the reference scenario, no country (region) would take emission reduction after 2030 for the sake of their own optimal social welfare improvement, leading the global temperature rising to 2.62℃ by 2100. The Nash equilibrium remains stable even when the climatic and economic parameters are disturbed. As an alternative, an external sanction on non-mitigation is applied; in this scenario, climate change mitigation propagates across countries (regions) according to various sanction levels, in which developed countries tend to adopt mitigation strategy earlier than developing countries as a response to the non-mitigation sanction. Meanwhile, under the Paris Agreement, simulation also reveals the emission reduction from 2030 to 2050 has become crucial for making the 2℃ threshold viable if no extra mitigations are implemented before 2030. An emission reduction target higher than the “developed and developing countries cutting emission 80% and 50% on 1990 level by 2050” is required in this circumstance, otherwise the global temperature will overshoot 2℃ around 2040.