节能减排与森林保护的综合减排效果——基于DICE模型的模拟分析

Comprehensive Abatement Effects of Energy Conservation,Emission Reduction and Forest Conservation:Based on DICE Model

【目的】研究节能减排与森林保护2种减排途径配套对经济和气候变化的综合影响,尤其对《巴黎协定》提出的“在全球温度上升控制在2℃的基础上向1.5℃努力”目标的实现路径、成本和收益进行分析,明确森林保护在减缓和应对气候变化中的重要作用,为将森林保护纳入气候协定谈判提供理论依据,促进低成本减排,推动经济适度增长,改善生态环境,提高气候政策效率。【方法】选取4种情景(基准情景、最优情景、2℃情景和1.5℃情景),依据应对气候变化的不同途径,除基准情景外的其他各情景细分为“综合减排”(节能减排与森林保护有机结合)和“直接减排”(仅采取节能减排措施,不考虑森林保护的减排增汇潜力)2类。将森林保护控制变量及其成本函数引入DICE-2013R模型,采用GAMS软件编写程序语言,运用PATHNLP求解器求解,模拟节能减排与森林保护2种途径配套的综合减排效果,并与单一直接减排效果进行比较。【结果】1)2种减排途径合理配搭,可降低应对气候变化总成本(气候变化损害和总减排成本),一定程度上缓解实质性减排压力,为节能减排技术研发争取时间;2)总碳排放峰值有所下降,工业碳排放峰值有所上升,后者略高于前者;3)应合理规划节能减排与森林保护减排增汇二者比例,以实现总减排成本最小化,适度温和的节能减排水平与森林保护水平组合可使得最优情景减排成本较低且社会福利最大;4)考虑森林保护对气候变化的潜在贡献,《巴黎协定》2℃和1.5℃温控目标的碳社会成本显著下降,碳社会成本与碳价之间的差异趋于缩小;5)2种减排途径有机结合可同时实现降碳、增汇、经济发展的良性循环,提高《巴黎协定》气候目标的效率,使1.5℃目标由原来的成本无效率转变为成本有效,尽管净收益非常少。【结论】在经济新常态下,工业生产面临沉重下行压力,企业对节能减排的承压能力普遍下降。在此结构调整期,政府应出台更多政策引导公共资金和民间资金投资于造林再造林等林业碳汇活动,打好加强节能减排和增加森林碳汇的“组合拳”,实现降碳、增汇、经济发展的良性互动。

【Objective】Studying the comprehensive effects of energy conservation,emission reduction and forest conservation on the economic and climate change,especially analyzing the realization path,costs and benefits of the climate targets of“to ensure that the global average temperature is higher than the pre-industrial level within 2℃and make efforts to control the temperature within 1.5℃”proposed by Paris Agreement,as well as clarifying the important role of forest conservation in mitigating and coping with climate change,will provide a theoretical basis for the integration of forest conservation into climate negotiations,promote low-cost emission reduction,maintain moderate economic growth,as well as improve the ecological environment and the efficiency of climate policies.【Method】This paper sets up four scenarios.Depending on the approaches taken to tackle climate change,each scenario(excepting baseline scenario)is subdivided into two categories,i.e.,comprehensive abatement and direct abatement.Comprehensive abatement represents an organic combination of energy conservation,emission reduction and forest conservation.On the contrary,direct abatement means that only energy conservation and emission reduction measures are taken,without considering the potential contribution of forest conservation to climate change.Introducing the forest conservation control variables and cost functions into the DICE-2013R model,using the GAMS(general algebraic modeling system)software to program and the PATHNLP solver to solve the model,this paper simulates the comprehensive abatement effects of energy conservation,emission reduction and forest conservation,and compares it with the single direct abatement situation.【Result】Firstly,the organic combination of these two approaches,i.e.,energy conservation,emission reduction and forest conservation,is conducive to cut down the total cost of tackling climate change(climate change damage and total carbon abatement costs),as well as to alleviate the pressure of substantial carbon abatement to a certain extent by buying time for R&D of carbon abatement technology.Secondly,the combination of these two approaches makes the peak of total carbon emissions decrease and the peak of industrial carbon emissions increase.The latter is slightly higher than the former.Thirdly,the government should rationally design the proportion of direct abatement(i.e.,energy conservation and emission reduction)and indirect abatement(forest conservation,which will reduce carbon emissions and increase carbon sinks),so as to minimize the total carbon abatement costs.The moderate combination of energy conservation,emission reduction and forest conservation makes the lowest costs of carbon abatement and the highest social welfare under the optimal case.Fourthly,considering the potential contribution of forest conservation to climate change,the social carbon costs of 2℃ and 1.5℃targets proposed by Paris Agreement are significantly declined.The difference between social carbon cost and carbon price tends to shrink.Last but not the least,the combination of these two approaches can achieve the virtuous circle of reducing carbon emission,increasing forest carbon sinks and promoting economic development.In comprehensive abatement situation,the efficiency of Paris Agreement is improved and 1.5℃ target transfers from cost inefficiency into cost efficiency,although the net income is limited.【Conclusion】In the new economic normal,industrial production is facing heavy downward pressure.The abilities to save energy consumption and reduce emissions are weakened generally.In this period of structural adjustment in China,the government should introduce more policies to guide public funds and private funds to invest in afforestation and reforestation as well as other forest carbon sinks activities,take full advantages of the“combination boxing”(i.e.,strengthen energy conservation and emission reduction,increase forest carbon sinks),so as to achieve the virtuous circle of reducing carbon emission,increasing forest carbon sinks and promoting economic development.