人为气溶胶排放对气候影响的模拟以及历史责任归因研究

Allocation of responsibilities and obligations for climate change between countries is the difficulty and hotspot in international climate change negotiations. Presently, the attribution of historical responsibility for climate change has been well understood based on the anthropogenic carbon dioxide emissions or greenhouse gas emissions. However, the considerable cooling of aerosol emissions, which represent a strong spatial heterogeneity and vary widely among countries in a manner similar to greenhouse gas emissions, attracts less attention. A few research on aerosols are also inadequate and lack of comprehensive analysis. This poses a challenge to tackle climate change in line with the principle of "common but differentiated responsibilities". Therefore, this project addresses this shortcoming and perform a quantitative analysis on the impacts of anthropogenic aerosol emissions on the previous attribution of historical responsibility for climate change. First, we compose a comprehensive analysis of the space-time evolutions of anthropogenic aerosol and its precursor emissions. Second, using an earth system model CESM, we aim to investigate the climate system responses (such as aerosol burden, optical depth, radiative flux and climatic factors) to anthropogenic aerosols and sulphate aerosols emitted from globe, developed countries and developing countries. Finally, we quantify the influence of sulphate aerosols and total aerosols originating from developed countries and developing countries in the attribution of historical responsibility for climate change. This project will be a supplementary of the previous research which are only based on greenhouse gases, and beneficial for (i) improvements in the knowledge of the attribution of historical responsibility for climate change, (ii) providing a reference for the international climate change negotiations and formulation of emissions reduction policy and pollution control plan.

气候变化的责任和义务区分是国际气候谈判的难点和热点。目前关于气候变化历史责任归因已有了深入认识，但大多局限于人为二氧化碳排放或者温室气体排放，少量针对气溶胶的研究也存在不足，缺乏综合性分析。这对遵循“共同但有区别的责任”原则应对气候变化提出了挑战。因此，本项目将以人为气溶胶的历史责任归因为研究目标。在系统分析人为气溶胶及其前体物排放的时空演变特征的基础上，利用地球系统模式CESM，分别探究全球、发达国家和发展中国家人为总的气溶胶和硫酸盐气溶胶对气候系统（如大气气溶胶浓度、光学厚度、辐射通量以及各圈层气候因子等）的影响及其机制，进而定量评估人为气溶胶和硫酸盐气溶胶排放对发达国家和发展中国家的气候变化历史责任归因的影响。本项目的开展对仅依据温室气体排放的评估结果有很好的补充作用，有助于完善气候变化的历史责任归因，为国家参与国际谈判、制定减排政策提供科学依据。

气候变化的责任和义务区分是国际气候谈判的难点和热点。目前关于气候变化历史责任归因已有了深入认识，但大多局限于人为二氧化碳排放或者温室气体排放，少量针对气溶胶的研究缺乏综合性分析。这对遵循“共同但有区别的责任”原则应对气候变化提出了挑战。因此，本项目将以人为气溶胶的历史责任归因为研究目标。在系统分析人为气溶胶及其前体物排放的时空演变特征的基础上，利用地球系统模式，分别探究全球、发达国家和发展中国家人为气溶胶对气候系统的影响及其机制，进而定量评估人为气溶胶和硫酸盐气溶胶排放对发达国家和发展中国家的气候变化历史责任归因的影响。研究结果再次证实历史人为气溶胶排放对全球辐射和气候的影响不可忽略，它能够显著补偿温室气体的增温效应。人为气溶胶排放对辐射和气候的影响具有显著的区域性特征。就全球和半球平均而言，历史人为气溶胶排放以及不同国家集团人为气溶胶排放对辐射和气候具有相似的影响，如减少地气系统获得的净的太阳辐射能、降低全球或者半球的平均温度、减少降水、减少上层海洋热容量以及抑制北半球海冰覆盖过快消融等；对于人为气溶胶排放的强迫，温度响应最敏感的区域为北半球高纬地区，而降水响应最敏感的区域为赤道附近的热带区域。对历史气候平均态而言，发达国家与发展中国家对人为气溶胶排放、气溶胶浓度变化、地气系统净短波辐射变化以及气候效应的相对贡献分别约为70%-30%、55%-45%、70%-30%以及80%-20%。发达国家地区气溶胶浓度、温度和降水的变化主要受本地人为排放的影响；而发展中国家地区受到较大的外源排放的影响，甚至可能超过本地排放的影响。发展中国家对全球和北半球陆地季风区夏季降水的影响大于发达国家。赤道太平洋纬向大气环流（即沃克环流）在发达国家和发展中人为排放情景下可能表现出不同的环流异常。本项目对仅依据温室气体排放的评估结果有很好的补充作用，有助于完善气候变化的历史责任归因，为国家参与国际谈判、制定减排政策提供科学依据。