The Tuvalu Syndrome

Geoengineering research has historically been inhibited by fears that the perceived availability of a technological fix for climate change, such as the deployment of space-based deflectors, may undermine greenhouse gas abatement efforts. I develop a game theoretic model to show that the credible threat of unilateral geoengineering may instead strengthen global abatement and lead to a self-enforcing climate treaty with full participation. A ‘rogue nation’ may wish to unilaterally geoengineer if it faces extreme climate damages (as with Tuvalu), or if there are minimal local side effects from geoengineering, such as hydrological cycle disruption or stratospheric ozone depletion. However, the costly global side effects of geoengineering may make it individually rational for other countries to reduce emissions to the level where this rogue nation no longer wishes to unilaterally geoengineer. My results suggest a need to model the impacts of a “selfish geoengineer” intent only on maximizing net domestic benefits, as well as a “benevolent geoengineer” out to restore global mean temperature and minimize global side effects.     

CMIP6地球工程模式比较计划（GeoMIP）概况与评述

太阳辐射管理地球工程是应对气候变化的备用措施。地球工程模式比较计划（GeoMIP）是第六次国际耦合模式比较计划（CMIP6）的重要组成部分。GeoMIP设计了一系列理想化地球工程试验,包括直接减少太阳辐射强度、向平流层注入硫酸盐气溶胶、向海表上空云层注入气溶胶凝结核、增加海水反照率等。在GeoMIP的统一模拟框架下开展地球工程模拟试验,进一步揭示了不同地球工程措施对全球气候的影响和作用机理,从而帮助我们更好地认知气候系统对地球工程的响应过程。更多的中国气候模式参加GeoMIP将提升我国在地球工程研究和国际气候谈判中的国际影响力和话语权。     

Messing with nature? Exploring public perceptions of geoengineering in the UK

Anthropogenic influence on the climate – and possible societal responses to it – offers a unique window through which to examine the way people think about and relate to the natural world. This paper reports data from four, one-day deliberative workshops conducted with members of the UK public during early 2012. The workshops focused on geoengineering – the deliberate, large-scale manipulation of the planetary environment – as one of three possible responses to climate change (alongside mitigation and adaptation). Here, we explore one of the most pervasive and wide-ranging themes to emerge from the workshops: whether geoengineering represented an unprecedented human intervention into ‘nature’, and what the moral consequences of this might be. Using the concept of ‘messing with nature’ as an analytical lens, we explore public perceptions of geoengineering. We also reflect on why ‘messing with nature’ was such a focal point for debate and disagreement, and whether the prospect of geoengineering may reveal new dimensions to the way that people think about the natural world, and their relationship to it.     

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.     

Operationalizing climate targets under learning: An application of cost-risk analysis

Reviewing the existing studies of public perception and drawing analogies from other risk technologies, this paper explores the public positions on research and implementation of geoengineering as a means to combat climate change. Existing studies on geoengineering perceptions show low levels of awareness and a lack of knowledge. Hence, existing attitudes on geoengineering can be judged instable and stimulus-dependent. When judged in isolation, at least one third favors the use of geoengineering technologies preferring CDR over SRM technologies; when judged in comparison to other climate mitigation options, approval rates lose considerably support. Moreover, people seem to cautiously support research but oppose deployment while attitude formation depends on personal values and belief systems. The results of the empirical studies were fed into a Delphi workshop with experts for reflecting on the future development of public opinion and for designing a communication and public involvement process that corresponds to the empirical insights gained from the perception studies.     

Geoengineering: Could— or should— we do it?

Schemes to modify large-scale environment systems or to control climate have been seriously proposed for over 50 years, some to (1) increase temperatures in high latitudes, (2) increase precipitation, (3) decrease sea ice, (4) create irrigation opportunities or to offset potential global warming by spreading dust in the stratosphere to reflect away an equivalent amount of solar energy. These and other proposed geoengineering schemes are briefly reviewed from a historical perspective. More recently, many such schemes to advertently modify climate have been proposed as cheaper methods to counteract inadvertent climatic modifications than conventional mitigation techniques such as carbon taxes or pollutant emissions regulations. Whereas proponents argue cost effectiveness, critics of geoengineering argue that there is too much uncertainty to either (1) be confident that any geoengineering scheme would work as planned, or (2) that the many decades of international political stability and cooperation needed for the continuous maintenance of such schemes to offset century long inadvertent efforts is problematic. Moreover, there is potential for transboundary conflicts should negative climatic events occur during geoengineering activities since, given all the large uncertainties, it could not be assured to victims of such events that the schemes were entirely unrelated to their damages. Nevertheless, although I believe it would be irresponsible to implement any large-scale geoengineering scheme until scientific, legal and management uncertainties are substantially narrowed, I do agree that, given the potential for large inadvertent climatic changes now being built into the earth system, more systematic study of the potential for geoengineering is probably needed.     

针对冰盖的定向地球工程研究

针对冰盖的定向地球工程研究旨在增强冰盖稳定性和减缓冰盖物质流失,从源头上减少冰盖对海平面上升的贡献,有望为应对气候变化和保护海岸线争取几百年的时间。冰盖地球工程主要作用在冰底和冰架-海洋界面上,主要途径如下：(1)排干或冻结冰盖底部水来干燥冰床,增强冰盖底部摩擦力;(2)在海洋中建造人造岛来支撑漂浮的冰架;(3)在冰架前端建造水下隔离墙,阻止温暖的海水到达冰川底部以减缓其融化。冰盖地球工程包括数值模拟、方案设计、工程试验和政治法律等诸多方面的研究。国际上的研究团队正在开展数值模拟和方案设计方面的研究,工程试验和政治法律等方面的研究尚未起步。预计工程试验的难度阶梯很可能是从实验室试验开始,到小尺度的野外试验,接着到格陵兰冰盖的入海冰川,最后到南极冰盖的入海冰川。针对冰盖的定向地球工程研究很有可能成为21世纪全球变化领域新兴的研究方向。     

Governing geoengineering research: why, when and how?

Research on geoengineering – deliberate management of the Earth’s climate system – is being increasingly discussed within the science and policy communities. While justified as necessary in order to expand the range of options available to policy makers in the future, geoengineering research has already engendered public controversy. Proposed projects have been protested or cancelled, and calls for a governance framework abound. In this paper, we consider the reasons why geoengineering research might be subject to additional governance and suggest mechanisms that might be usefully applied in developing such a framework. We consider criteria for governance as raised by a review of the growing literature on geoengineering and other controversial scientific topics. We suggest three families of concern that any governance research framework must respond to: the direct physical risks of the research; the transparency and responsibility in decision making for the research; and the larger societal meanings of the research. We review what mechanisms might be available to respond to these three families of concern, and consider how these might apply to geoengineering research.     

Technical characteristics of a solar geoengineering deployment and implications for governance

ABSTRACT

Consideration of solar geoengineering as a potential response to climate change will demand complex decisions. These include not only the choice of whether to deploy solar engineering, but decisions regarding how to deploy, and ongoing decision-making throughout deployment. Research on the governance of solar geoengineering to date has primarily engaged only with the question of whether to deploy. We examine the science of solar geoengineering in order to clarify the technical dimensions of decisions about deployment – both strategic and operational – and how these might influence governance considerations, while consciously refraining from making specific recommendations. The focus here is on a hypothetical deployment rather than governance of the research itself. We first consider the complexity surrounding the design of a deployment scheme, in particular the complicated and difficult decision of what its objective(s) would be, given that different choices for how to deploy will lead to different climate outcomes. Next, we discuss the on-going decisions across multiple timescales, from the sub-annual to the multi-decadal. For example, feedback approaches might effectively manage some uncertainties, but would require frequent adjustments to the solar geoengineering deployment in response to observations. Other decisions would be tied to the inherently slow process of detection and attribution of climate effects in the presence of natural variability. Both of these present challenges to decision-making. These considerations point toward particular governance requirements, including an important role for technical experts – with all the challenges that entails.

Key policy insights

• Decisions about solar geoengineering deployment will be informed not only by political choices, but also by climate science and engineering.

• Design decisions will pertain to the spatial and temporal goals of a climate intervention and strategies for achieving those goals.

• Some uncertainty can be managed through feedback, but this would require frequent operational decisions.

• Some strategic decisions will depend on the detection and attribution of climatic effects from solar geoengineering, which may take decades.

• Governance for solar geoengineering deployment will likely need to incorporate technical expertise for making short-term adjustments to the deployment and conducting attribution analysis, while also slowing down decisions made in response to attribution analysis to avoid hasty choices.

     

Multilateral parametric climate risk insurance: a tool to facilitate agreement about deployment of solar geoengineering?

States will disagree about deployment of solar geoengineering, technologies that would reflect a small portion of incoming sunlight to reduce risks of climate change, and most disagreements will be grounded in conflicting interests. States that object to deployment will have many options to oppose it, so states favouring deployment will have a powerful incentive to meet their objections. Objections rooted in opposition to the anticipated unequal consequences of deployment may be met through compensation, yet climate policy is inhospitable to compensation via liability. We propose that multilateral parametric climate risk insurance might be a useful tool to facilitate agreement on solar geoengineering deployment. With parametric insurance, predetermined payouts are triggered when climate indices deviate from set ranges. We suggest that states favouring deployment could underwrite reduced-rate parametric climate insurance. This mechanism would be particularly suited to resolving disagreements based on divergent judgments about the outcomes of proposed implementation. This would be especially relevant in cases where disagreements are rooted in varying levels of trust in climate model predictions of solar geoengineering effectiveness and risks. Negotiations over the pricing and terms of a parametric risk pool would make divergent judgments explicit and quantitative. Reduced-rate insurance would provide a way for states that favour implementation to demonstrate their confidence in solar geoengineering by underwriting risk transfer and ensuring compensation without the need for attribution. This would offer a powerful incentive for states opposing implementation to moderate their opposition.

Key policy insights

• States favouring deployment of solar geoengineering will need to address other states’ objections—unilateralism is implausible in practice

• This might be partially achieved using parametric climate risk insurance based on objective indicators

• A sovereign risk pool offering reduced-rate parametric insurance underwritten by states backing deployment could facilitate cooperation on solar geoengineering deployment

• States favouring deployment would demonstrate their confidence in solar geoengineering by supporting the risk pool

• Opposing states would be insured against solar geoengineering risks and proposing states would be incentivized to guard against overconfidence

     

Ethics and intentional climate change

In recent years the idea of geoengineering climate has begun to attract increasing attention. Although there was some discussion of manipulating regional climates throughout the 1970s and 1980s, the discussion was largely dormant. What has reawakened the conversation is the possibility that Earth may be undergoing a greenhouse-induced global warming, and the paucity of serious measures that have been taken to prevent it.In this paper I assess the ethical acceptability of ICC, based on my impressions of the conversation that is now taking place. Rather than offering a dispassionate analysis, I argue for a point of view. I propose a set of conditions that must be satisfied for an ICC project to be morally permissible and conclude that these conditions are not now satisfied. However, research on ICC should go forward so long as certain other conditions are met. I do not intend this to be the last word on the subject, but rather the first word. My hope is that others will be stimulated to think through the ethics of ICC.     

地球工程情景下中国七大区域未来强降水和极端强降水的变化特征对比分析(2010—2099年)

地球工程作为人类影响全球气候的重要工程手段,具有重要的现实意义和科学价值。目前学界在地球工程对极端降水的影响研究方面还处于初始阶段。在这种背景下,基于BNU-ESM模式中地球工程(G4实验)和非地球工程(RCP4.5)情景下的日值降水数据,以95%和99%分位数作为强降水和极端强降水的阈值,分别对比分析两种情景下中国及七大地理分区的强降水和极端强降水在2010—2099年(整个研究时段)、2020—2069年(地球工程实施期间)和2070—2099年(地球工程实施结束)的差异特征。结果表明:(1) 2010—2099年地球工程有利于中国多数地区强降水量和极端强降水量的增加;(2)在实施地球工程的2020—2069年,整体上抑制了中国多数地区强降水量和极端强降水量;(3)在地球工程实施结束后的2070—2099年,地球工程后续影响整体上有利于中国多数地区强降水量和极端强降水量的增加;(4)不同研究时段中国七大地理分区的强降水量和极端强降水量变化趋势均有一定区域差异,且这种差异特征在不同研究时期表现在不同地区。      

Fast versus slow response in climate change: implications for the global hydrological cycle

Recent studies have shown that changes in global mean precipitation are larger for solar forcing than for CO₂ forcing of similar magnitude. In this paper, we use an atmospheric general circulation model to show that the differences originate from differing fast responses of the climate system. We estimate the adjusted radiative forcing and fast response using Hansen’s “fixed-SST forcing” method. Total climate system response is calculated using mixed layer simulations using the same model. Our analysis shows that the fast response is almost 40% of the total response for few key variables like precipitation and evaporation. We further demonstrate that the hydrologic sensitivity, defined as the change in global mean precipitation per unit warming, is the same for the two forcings when the fast responses are excluded from the definition of hydrologic sensitivity, suggesting that the slow response (feedback) of the hydrological cycle is independent of the forcing mechanism. Based on our results, we recommend that the fast and slow response be compared separately in multi-model intercomparisons to discover and understand robust responses in hydrologic cycle. The significance of this study to geoengineering is discussed.     

Adapting and coping with climate change in temperate forests

A growing body of research documents how individuals respond to local impacts of global climate change and a range of policy efforts aim to help individuals reduce their exposure and improve their livelihoods despite these stressors. Yet there is still limited understanding of how to determine whether and how adaptation is occurring. Through qualitative analysis of focus group interviews, I evaluated individual behavioral responses to local forest stressors that can arguably be linked to global climate change among landowners in the Upper Midwest, USA. I found that landowner responses were planned as well as autonomous, more proactive than reactive, incremental rather than transformational, and aimed at being resilient to change and transitioning to new conditions, rather than resisting change alone. Many of the landowners’ responses can be considered forms of adaptation, rather than coping, because they were aimed at moderating and avoiding harm on long time horizons in anticipation of change. These findings stand in contrast to the short-term, reactive, and incremental responses that current socio-psychological theories of adaptation suggest are more typical at the individual level. This study contributes to scientific understanding of how to evaluate behavioral adaptation to climate change and differentiate it from coping, which is necessary for developing conceptually rigorous analytical frameworks to guide research and policy.     

Public perceptions of geoengineering research governance: An experimental deliberative approach

Recent attempts to conduct experiments in climate ‘geoengineering’ have demonstrated the deeply controversial nature of this field of scientific research. Social scientists have begun to explore public perceptions of geoengineering, and have documented a significant degree of concern over the effective governance of research and experimentation in this area. Yet, public perception on what constitutes a legitimate geoengineering experiment and how it should be governed remains under-researched. In this article we report on a series of experimental deliberative workshops with members of the public designed to elicit and explicate diverse understandings of geoengineering experiments and their governance. In contrast to previous methods of invited public deliberation, which privilege egalitarian-consensual models of discourse and decision-making, we test a novel approach that places majoritarian, individualistic, and consensual forms of public deliberation on an equal footing. Our study suggests that the perceived controllability of experimental interventions is central to public views on their acceptability, but that controllability is itself a complex, multifaceted quality, drawing together a set of heterogeneous concerns about the purpose and repercussions of scientific work. The citizens who participated in our workshops employed four criteria to adjudicate the acceptability of geoengineering experiments: (1) the degree of containment; (2) the uncertainty surrounding experimental outcomes; (3) the reversibility of impacts; and (4) the scientific purity of the enterprise. We theorize that the public legitimacy of geoengineering experiments depends on variable, context-specific combinations of these criteria, and that technical determinations of the proper ‘scale’ or ‘location’ for geoengineering research will be poor predictors of the sorts of public concerns that will be triggered by further experimentation in this area.     

Governing geoengineering research for the Great Barrier Reef

Coral reefs are highly vulnerable to the impacts of rising marine temperatures and marine heatwaves. Mitigating dangerous climate change is essential and urgent, but many reef systems are already suffering on current levels of warming. Geoengineering options are worth exploring to protect the Great Barrier Reef (GBR) from extreme warming conditions, but we contend that they require strong governance and public consultation from the outset. Australian governments are currently funding feasibility testing of three geoengineering proposals for the GBR. Each proposal involves manipulating ocean or atmospheric conditions to lower water temperatures and thereby reduce the threat of mass coral bleaching events. Innovative strategies to protect the GBR and field testing of these is essential, but current laws do not guarantee robust governance for field testing of these technologies. Nor do they provide the foundation for a more coherent national policy on climate intervention technologies more generally. Responsible governance frameworks, including detailed risk assessment and early public consultation, are necessary for geoengineering research to build legitimacy and promote scientific progress.

Key policy insights

• Marine heatwaves pose a serious threat to coral reefs, including Australia’s iconic Great Barrier Reef.

• Australian governments have recognized the threats of warming waters, and are funding research of geoengineering options for the Great Barrier Reef.

• The limited earlier field testing of geoengineering demonstrates the need for specific governance to manage risks, build legitimacy and maintain public support.

• Australia requires a framework to govern geoengineering research and development before deployment of such technologies.

     

What makes climate change adaptation effective? A systematic review of the literature

Increased understanding of global warming and documentation of its observable impacts have led to the development of adaptation responses to climate change around the world. A necessary, but often missing, component of adaptation involves the assessment of outcomes and impact. Through a systematic review of research literature, I categorize 110 adaptation initiatives that have been implemented and shown some degree of effectiveness. I analyze the ways in which these activities have been documented as effective using five indicators: reducing risk and vulnerability, developing resilient social systems, improving the environment, increasing economic resources, and enhancing governance and institutions. The act of cataloging adaptation activities produces insights for current and future climate action in two main areas: understanding common attributes of adaptation initiatives reported to be effective in current literature; and identifying gaps in adaptation research and practice that address equality, justice, and power dynamics.     

The Oxford Principles

Scientific momentum is increasing behind efforts to develop geoengineering options, but it is widely acknowledged that the challenges of geoengineering are as much political and social as they are technical. Legislators are looking for guidance on the governance of geoengineering research and possible deployment. The Oxford Principles are five high-level principles for geoengineering governance. This article explains their intended function and the core societal values which they attempt to capture. Finally, it proposes a framework for their implementation in a flexible governance architecture through the formulation of technology-specific research protocols.     

Perceptions and responses to climate policy risks among California farmers

This paper considers how farmers perceive and respond to climate change policy risks, and suggests that understanding these risk responses is as important as understanding responses to biophysical climate change impacts. Based on a survey of 162 farmers in California, we test three hypotheses regarding climate policy risk: (1) that perceived climate change risks will have a direct impact on farmer's responses to climate policy risks, (2) that previous climate change experiences will influence farmer's climate change perceptions and climate policy risk responses, and (3) that past experiences with environmental policies will more strongly affect a farmer's climate change beliefs, risks, and climate policy risk responses. Using a structural equation model we find support for all three hypotheses and furthermore show that farmers’ negative past policy experiences do not make them less likely to respond to climate policy risks through participation in a government incentive program. We discuss how future research and climate policies can be structured to garner greater agricultural participation. This work highlights that understanding climate policy risk responses and other social, economic and policy perspectives is a vital component of understanding climate change beliefs, risks and behaviors and should be more thoroughly considered in future work.