碳中和目标下负排放策略的综合效应——基于N‑DSGE模型的数值模拟分析

Comprehensive effect evaluation of negative emission technologies under the carbon neutrality goal:a numerical simulation analysis based on the N‑DSGE model

全球气候变化已达“气候紧急状态”,包括中国在内的诸多国家和地区先后宣布碳中和目标和净零排放承诺。在气候变化减缓和传统的适应措施之外,自然科学领域和气候经济学领域探讨负排放技术经济可行性的研究越来越多,但从可持续发展经济学视角对负排放技术综合效应的评估还比较少。该研究基于可持续发展经济学的生态价值理论,将气候变化综合评估模型与宏观经济学动态随机一般均衡(DSGE)模型相结合,构建包含自然生态系统部门的N‑DSGE模型,对负排放技术的气候效应、生态效应、经济效应以及福利效应进行综合评估。评估结果表明:①当可用技术条件下传统减排措施达到最大减排潜力后,可以依靠负排放技术实现净零排放乃至净负排放。②低强度、小规模实施负排放技术具有正向的气候、生态和经济效应,然而随着负排放技术实施强度增大,气候效应增强,经济效应削弱,社会综合福利明显降低。③敏感性分析证明了评估结果的稳健性,并进一步表明负排放技术的实施效果会受到传统减排水平和自然碳汇能力的影响。基于评估结果,应谨慎扩大负排放技术实施规模和实施强度,加强科学技术研发,降低技术成本;对不同负排放技术采取差异化发展策略;加强负排放技术实施的治理,尽可能避免和最小化其负面影响,促进气候、生态和经济等可持续发展目标的协同;部署负排放技术不应放松传统减排的努力,应降低碳达峰峰值,同时提升自然生态系统的碳汇能力。

Global climate change has reached a‘climate emergency.’Many countries and regions,including China,have successively announced the carbon neutrality goal and the net zero emission commitment.In addition to the traditional mitigation and adaptation measures to climate change,studies on negative emission technologies and economic feasibility are in full swing in the fields of natural science and climate economics,but there are few studies on the evaluation of the comprehensive effect of negative emission technologies from the perspective of sustainable development economics.Based on the ecological value theory of sustainable development economics,this paper combined the comprehensive assessment model of climate change with the dynamic general stochastic equilibrium(DSGE)model of macroeconomics and constructed an N-DSGE model including natural ecosystem sectors to comprehensively assess the climate,ecological,economic,and welfare effects of negative emission technologies.The assessment results showed that:①When the traditional emission reduction measures reached their maximum emission reduction potential under the available technical conditions,negative emission technologies could be used to achieve net zero emissions or even net negative emissions.②The low-intensity and small-scale implementation of negative emission technologies had positive climate,ecological,and economic effects.However,with the increase in the implementation intensity of negative emission technologies,the climatic effect was enhanced,the economic effect was weakened,and the comprehensive social welfare was significantly reduced.③The sensitivity analysis proved the robustness of the assessment results and further indicated that the implementation effect of negative emission technologies would be affected by the traditional emission reduction level and natural carbon sink capacity.Based on the evaluation results,China should carefully expand the implementation scale of negative emission technologies,strengthen scientific and technological research and development,and reduce technology costs.China should also adopt differentiated development strategies for different negative emission technologies,strengthen the governance of negative emission technology implementation,avoid and minimize the negative impact of these technologies as much as possible,and promote the synergy of sustainable development goals in terms of climate,ecology,and economy.Even if negative emission technologies are deployed,traditional efforts to reduce emissions cannot be relaxed.Efforts should be made to reduce peak carbon emissions while enhancing the carbon sink capacity of natural ecosystems.