可计算一般均衡框架下的气候变化经济影响综合评估

气候变化是21世纪人类面临的重大挑战之一,并对自然系统和社会经济系统造成了各种负面影响。对气候变化的影响进行经济评估是气候变化研究中的重要问题。而可计算一般均衡框架下的综合评估模型（CGE_IAMs）是评估气候变化经济影响的有效手段之一,文中对气候变化影响经济评估的主要CGE_IAMs进行了文献调研,并对这些模型进行了比较分析。研究表明不同模型在温室气体排放、气候参数的处理方式以及气候影响的引入机制等方面有着较大区别,因而各模型对气候变化影响的经济评估结果也有一定的差异。此外,当前CGE_IAMs在评估气候变化经济影响时存在支撑数据未及时更新、方法不细致以及评估不全面等问题。未来该领域的相关研究应该更加关注于模型与支撑数据的精细化和开源化,此外还应加强CGE_IAMs中经济模块与复杂气候模式的耦合。     

构建一个经济-气候新模型评价气候变化对粮食产量的影响

将气候变化研究和农业经济研究相结合,构建了一个经济-气候新模型,用来评价全球气候变化对粮食产量影响的问题。提出在经济模型C-D生产函数中添加气候变化因子,建立一个新的评价模型,作为连接气候变化因素和经济变化因素的桥梁,并对该模型的性能及合理性进行了初步的模拟和验证。     

IPCC第五次评估报告中所用的气候模式有进步吗?

<正>IPCC第五次评估报告(AR5)第一工作组报告已经问世,由于气候模式是研究气候变化的机理与成因及预测与预估的重要手段和方法,在这次报告中至少有一半的章都需要用到气候模式,因此政策制定者和公众极其关注的问题是:与以往的评估报告相比,IPCC AR5中所用的气候模式有进步吗?为了回答这个问题,在汇集1250余篇相关参考文献的基础上,AR5对目前参加全球耦合模式比较计划第五阶段(CMIP5)的46个地球系统模式、15个中等复杂程度的地球系统模式(EMIC)以及大批区域动力降尺度气候模式和统计降尺度气候模型     

气候变化影响中国粮食安全研究的新思路北大核心CSCD

鉴于气候变化影响粮食安全问题的特殊性和复杂性,本文试图从自然科学和社会科学的交叉研究入手,提出一种新的研究的思路和方法,即:运用计量经济学模型对气候变化数据进行统计分析,使用计量经济学方法来评估气候这一外部驱动因素引发的社会经济系统变化与观测到的气候变化引发的社会经济系统变化之间的关系;在厘清“气候变化影响量”对粮食产量的影响的基础上,预估我国未来30年特别是经济社会发展两个关键节点2035年和2050年的粮食生产的气候变化风险,文章给出了一种新的研究视角,构建了研究内容和研究方法,力争实现定性研究与定量研究相结合,以科学预测为政策指导提供有力支撑。     

黄河源区未来地面气温变化的统计降尺度分析

大气环流模式(GCMs)模拟预测的气候变化情景,必须经过降尺度处理后才能得出次网格尺度上未来气候变化的时空分布细节,才能满足评估气候变化对资源、环境和社会经济等影响的需要.本文在简单介绍了目前降尺度模型的研究现状后,重点分析了统计降尺度方法的优缺点及适用性,并应用黄河源区7个站点1961-1990年的实测地区最高气温和最低气温资料,对统计降尺度模型(SDSM)的应用进行了分析和验证.首先利用SDSM建立大尺度气候要素和地面气温变量间的统计转换关系,确定模型应用的预报因子变量,然后用独立的观测资料验证模型的可靠性,最后把建立好的统计关系应用于英国Hadley中心海气耦合模式(HadCM3 SERS B2)的输出,分别生成了黄河源区7个站点未来3个时段2020s,2050s和2080s的气温变化情景.在此基础上,应用Arc/GIS的Kriging插值方法获得整个区域的气温变化情景进行分析.结果表明,日最高气温模拟值随时间推移增幅很快,3个时段(2020s,2050s和2080s)的平均气温变化情景分别为1.34,2.60和3.90℃,而日最低气温变化相对不明显,3个时段的平均气温变化情景分别为0.87,1.49和2.27℃.表现在每个季节和每个月的变化情景又各不相同,日最高气温以春季和秋季变化最显著,而日最低气温则以夏季和秋季的变化最为明显.     

土地利用变化对气候影响的研究进展

为满足人类对食物、纤维、水和居住地的需求,全球土地利用格局发生了巨大的变化,IPCC 第四次评估报告（IPCC,2007）指出土地利用变化是人类影响气候的重要强迫之一。土地利用变化对气候的影响分为生物地球物理作用和生物地球化学作用。分别对有关生物地球物理作用和生物地球化学作用的研究进展以及研究热点进行了综述;并从定量评估两者对气候影响的相对贡献以及两者共同效应的角度,回顾了辐射强迫计算和耦合模式数值模拟两种方法的研究进展,及其在森林恢复、人工造林以及碳封存等气候变化应对措施可行性评估中的应用。最后分析和展望了当前土地利用变化对气候影响相关研究中的不确定性以及未来发展方向。     

共享社会经济路径(SSPs)的应用与展望

共享社会经济路径(Shared Socioeconomic Pathways, SSPs)是新一代气候变化情景的重要组成部分。SSPs从提出至今已有10年的发展,对于推动气候变化预估与影响研究、支撑气候政策决策的作用逐渐凸显。文中基于179篇主题检索文献分析了SSPs发展和应用的进展,以及在当前气候变化研究中的应用特点。研究发现,次国家和部门层面的SSPs故事线拓展开始兴起,水资源、土地和健康是影响评估领域的关注焦点,方法学上强调模型间耦合与多模型比较。当前SSPs在中国的发展与应用集中于基本要素的预估及气候影响评估,路径对各省间及城乡间社会经济发展差异的刻画有待加强。基于情景发展和应用的现状,最后从加强与气候建模团队的合作、支持影响与脆弱性研究、拓展全球情景、加强模型间比较、提高决策支持力5个方面讨论了SSPs的未来研究展望。     

CDF-T方法在站点尺度日降水预估中的应用

基于1961-2015年上海降水观测数据和8个全球气候模式GCMs模拟的日降水量数据,采用累计概率分布函数构建转换模型CDF-T建立了站点尺度日降水量的统计降尺度模型。结果表明,降尺度模型显著改善了GCMs对降水日数偏多、降水强度偏低和降水量偏少的模拟结果。与利用全年日降水序列建模结果相比,利用汛期日降水序列建模更好地刻画了汛期降水的累计概率分布曲线,同时提高了汛期总降水量、降水强度和年平均暴雨日数、暴雨量、暴雨强度的均值和变化趋势的降尺度效果。模型对较长年份的暴雨重现期订正效果更佳。与当代(2006-2015年)气候相比,2016-2095年上海降水呈现以下特征:全年和汛期总降水量和降水强度增加,降水日数减少,未来可能出现更多的旱涝年;汛期降水极端性增强,暴雨降水均值和极端值均增加;50年以上重现期的年最大日降水量未来呈前40年减少后40年增加的变化。CDF-T模型为站点尺度气候变化影响评估和未来预估提供降尺度技术和基础气候数据。     

利用随机天气模式及多种插值方法生成逐日气候变化情景的研究

针对目前大气环流模式在用于气候变化影响评估研究中时间分辨率较低的局恨性, 以及气候情景的要求和气候变化影响研究的需要, 结合GCM的模拟试验结果, 利用随机天气模式WGEN生成了中国东北地区未来气候变化的逐日情景, 其中包含了可能的气候变率信息, 可与作物动力模式等气候影响模式嵌套, 研究作物生长发育及其产量的可能变化, 及气候变率变化的可能影响等.     

冰冻圈变化及其影响研究——现状、趋势及关键问题

通过对冰冻圈研究在中国的重要作用和对冰冻圈科学在国内外研究现状的系统总结和分析,凝炼出了目前面临的关键科学问题及未来研究重点。总体来看,国际上更多关注冰冻圈变化对气候、海平面和环境的影响;而作为中、低纬度地区冰冻圈最发育的中国而言,冰冻圈变化对生态、水、环境及气候均具有重要影响。目前需要解决的关键科学问题为不同类型冰川对气候变化的响应机理及水资源影响评估的尺度转化机制、冻土与植被间水热传输过程的准确模拟、冰冻圈物理过程参数化及其与气候模式的耦合。为解决上述关键科学问题,需要开展以下研究：冰冻圈过程及其对气候变化的响应机理研究、冰冻圈变化的影响研究和冰冻圈变化的适应对策研究。     

Integrated assessment of abrupt climatic changes

One of the most controversial conclusions to emerge from many of the first generation of integrated assessment models (IAMs) of climate policy was the perceived economic optimality of negligible near-term abatement of greenhouse gases. Typically, such studies were conducted using smoothly varying climate change scenarios or impact responses. Abrupt changes observed in the climatic record and documented in current models could substantially alter the stringency of economically optimal IAM policies. Such abrupt climatic changes — or consequent impacts — would be less foreseeable and provide less time to adapt, and thus would have far greater economic or environmental impacts than gradual warming. We extend conventional, smooth IAM analysis by coupling a climate model capable of one type of abrupt change to a well-established energy–economy model (DICE). We compare the DICE optimal policy using the standard climate sub-model to our version that allows for abrupt change — and consequent enhanced climate damage — through changes in the strength (and possible collapse) of the North Atlantic thermohaline circulation (THC). We confirm the potential significance of abrupt climate change to economically optimal IAM policies, thus calling into question all previous work neglecting such possibilities — at the least for the wide ranges of relevant social and climate system parameters we consider. In addition, we obtain an emergent property of our coupled social–natural system model: “optimal policies” that do consider abrupt changes may, under relatively low discount rates, calculate emission control levels sufficient to avoid significant abrupt change, whereas “optimal policies” disregarding abrupt change would not prevent this non-linear event. However, there is a threshold in discount rate above which the present value of future damages is so low that even very large enhanced damages in the 22nd century, when a significant abrupt change such as a THC collapse would be most likely to occur, do not increase optimal control levels sufficiently to prevent such a collapse. Thus, any models not accounting for potential abrupt non-linear behavior and its interaction with the discounting formulation are likely to miss an important set of possibilities relevant to the climate policy debate.     

气候变化对区域经济影响的投入-产出模型研究

利用经济学“投入-产出”分析方法的基本原理，结合气候变化对工业影响的统计模型、对 农业产量影响的计算机模拟系统，建立了气候变化对区域经济影响的投入-产出模型。研究 了当气候变化对工业、农业部门的生产和产品发生影响时，导致的对国民经济其他部门的拉 动需求量和各个部门间的投入-产出流量的变化，从而预测各个部门的国内生产总值和总产 出量，对２０１０，２０２０年的经济发展。综合分析 气候变化对各部门的影响，找出适应区域经济平衡发展的适应对策，为决策者 提供一些参考建议。     

Confronting the challenge of integrated assessment of climate adaptation: a conceptual framework

Key limitations of integrated assessment models (IAMs) are their highly stylized and aggregated representation of climate damages and associated economic responses, as well as the omission of specific investments related to climate change adaptation. This paper proposes a framework for modeling climate impacts and adaptation that clarifies the relevant research issues and provides a template for making improvements. We identify five desirable characteristics of an ideal integrated assessment modeling platform, which we elaborate into a conceptual model that distinguishes three different classes of adaptation-related activities. Based on these elements we specify an impacts- and adaptation-centric IAM, whose optimality conditions are used to highlight the types of functional relationships necessary for realistic representations of adaptation-related decisions, the specific mechanisms by which these responses can be incorporated into IAMs, and the ways in which the inclusion of adaptation is likely to affect the simulations’ results.     

The coupling of optimal economic growth and climate dynamics

In this paper, we study optimal economic growth programs coupled with climate change dynamics. The study is based on models derived from MERGE, a well established integrated assessment model (IAM). We discuss first the introduction in MERGE of a set of “tolerable window” constraints which limit both the temperature change and the rate of temperature change. These constraints, obtained from ensemble simulations performed with the Bern 2.5-D climate model, allow us to identity a domain intended to preserve the Atlantic thermohaline circulation. Next, we report on experiments where a two-way coupling is realized between the economic module of MERGE and an intermediate complexity “3-D-” climate model (C-GOLDSTEIN) which computes the changes in climate and mean temperature. The coupling is achieved through the implementation of an advanced “oracle based optimization technique” which permits the integration of information coming from the climate model during the search for the optimal economic growth path. Both cost-effectiveness and cost-benefit analysis modes are explored with this combined “meta-model” which we refer to as GOLDMERGE. Some perspectives on future implementations of these approaches in the context of “collaborative” or “community” integrated assessment modules are derived from the comparison of the different approaches.     

对地球系统模式与综合评估模型双向耦合问题的探讨

概述了地球系统模式和综合评估模型在研究人类活动与气候变化问题上的优势和劣势,明确了将二者进行双向耦合的必要性,客观分析了综合评估模型耦合过程中存在的主要问题,同时系统总结了国际和国内解决耦合难点的主要方法和最新进展,最后分析和讨论了双向耦合模式的不确定性来源和解决方法,为我国进行地球系统模式与综合评估模型双向耦合提供新思路和方法。     

Some thoughts on the value added from a new round of climate change damage estimates

This paper offers some thoughts on the value added of new economic estimates of climate change damages. We begin with a warning to beware of analyses that are so narrow that they miss a good deal of the important economic ramifications of the full suite of manifestations of climate change. Our second set of comments focuses attention on one of the most visible products of integrated assessment modeling—estimates of the social cost of carbon which we take as one example of aggregate economic indicators that have been designed to summarize climate risk in policy deliberations. Our point is that these estimates are so sensitive to a wide range of parameters that improved understanding of economic damages across many (if not all) climate sensitive sectors may offer only limited value added. Having cast some doubt on the ability of improved estimates of economic damages to increase the value of economic damage estimates in integrated assessment modeling designed to inform climate policy deliberations, we offer an alternative approach—describing implicitly a research agenda that could (a) effectively inform mitigation decisions while, at the same time, (b) providing economic estimates for aggregate indicators like the social cost of carbon.     

The economics (or lack thereof) of aerosol geoengineering

Anthropogenic greenhouse gas emissions are changing the Earth’s climate and impose substantial risks for current and future generations. What are scientifically sound, economically viable, and ethically defendable strategies to manage these climate risks? Ratified international agreements call for a reduction of greenhouse gas emissions to avoid dangerous anthropogenic interference with the climate system. Recent proposals, however, call for a different approach: to geoengineer climate by injecting aerosol precursors into the stratosphere. Published economic studies typically neglect the risks of aerosol geoengineering due to (i) the potential for a failure to sustain the aerosol forcing and (ii) the negative impacts associated with the aerosol forcing. Here we use a simple integrated assessment model of climate change to analyze potential economic impacts of aerosol geoengineering strategies over a wide range of uncertain parameters such as climate sensitivity, the economic damages due to climate change, and the economic damages due to aerosol geoengineering forcing. The simplicity of the model provides the advantages of parsimony and transparency, but it also imposes severe caveats on the interpretation of the results. For example, the analysis is based on a globally aggregated model and is hence silent on intragenerational distribution of costs and benefits. In addition, the analysis neglects the effects of learning and has a very simplistic representation of climate change impacts. Our analysis suggests three main conclusions. First, substituting aerosol geoengineering for CO₂ abatement can be an economically ineffective strategy. One key to this finding is that a failure to sustain the aerosol forcing can lead to sizeable and abrupt climatic changes. The monetary damages due to such a discontinuous aerosol geoengineering can dominate the cost-benefit analysis because the monetary damages of climate change are expected to increase with the rate of change. Second, the relative contribution of aerosol geoengineering to an economically optimal portfolio hinges critically on, thus far, deeply uncertain estimates of the damages due to aerosol forcing. Even if we assume that aerosol forcing could be deployed continuously, the aerosol geoengineering does not considerably displace CO₂ abatement in the simple economic optimal growth model until the damages due to the aerosol forcing are rather low. Third, substituting aerosol geoengineering for greenhouse gas emission abatement can fail an ethical test regarding intergenerational justice. Substituting aerosol geoengineering for greenhouse gas emissions abatements constitutes a conscious risk transfer to future generations, in violation of principles of intergenerational justice which demands that present generations should not create benefits for themselves in exchange for burdens on future generations.     

Vulnerable or Resilient? A Multi-Scale Assessment of Climate Impacts and Vulnerability in Norway

This paper explores the issue of climate vulnerability in Norway, an affluent country that is generally considered to be resilient to the impacts of climate change. In presenting a multi-scale assessment of climate change impacts and vulnerability in Norway, we show that the concept of vulnerability depends on the scale of analysis. Both exposure and the distribution of climate sensitive sectors vary greatly across scale. So do the underlying social and economic conditions that influence adaptive capacity. These findings question the common notion that climate change may be beneficial for Norway, and that the country can readily adapt to climate change. As scale differences are brought into consideration, vulnerability emerges within some regions, localities, and social groups. To cope with actual and potential changes in climate and climate variability, it will be necessary to acknowledge climate vulnerabilities at the regional and local levels, and to address them accordingly. This multi-scale assessment of impacts and vulnerability in Norway reinforces the importance of scale in global change research.     

Incorporating Catastrophes into Integrated Assessment: Science, Impacts, and Adaptation

Incorporating potential catastrophic consequences into integrated assessment models of climate change has been a top priority of policymakers and modelers alike. We review the current state of scientific understanding regarding three frequently mentioned geophysical catastrophes, with a view toward their implications for integrated assessment modeling. This review finds inadequacies in widespread model assumptions regarding the nature of catastrophes themselves and climate change impacts more generally. The possibility of greatly postponed consequences from near- and medium-term actions suggests that standard discounting practices are inappropriate for the analysis of climate catastrophe. Careful consideration of paleoclimate and geophysical modeling evidence regarding the possibility of changes in ocean circulation suggests a reframing of the source of climate change damages in economic models, placing changes in climate predictability, rather than gradual changes in mean values, at the focus of economic damage assessments. The implications of decreases in predictability for the modeling of adaptation are further discussed.     

Integrated assessment of smallholder farming’s vulnerability to drought in the Brazilian Semi-arid: a case study in Ceará

Smallholder farming is among the most vulnerable sectors due to its great social and economic sensitivity. Despite future climate change, current climate variability is already an issue of concern that justifies adaptation efforts. In Brazil, the Semi-Arid Region is a climate hotspot, well known for both historic socioeconomic setbacks, and agriculture failures caused by dry spells and severe droughts. In 2010, the Brazilian government enacted the National Policy on Climate Change, which states as one of its key goals the identification of vulnerabilities and the adoption of adequate measures of adaptation to climate change. The improvement of vulnerability assessment tools is a response to the growing demand of decision makers for regular information and indicators with high spatial and temporal resolution. This article aims at undertaking a comparative assessment of smallholder farming’s vulnerability to droughts. An integrated assessment system has been developed and applied to seven municipalities located in the Brazilian Semi-Arid Region (within the State of Ceará). Results show regional vulnerability contrasts driven by institutional and socioeconomic factors, beyond climatic stressors.