Catalogs of Geoengineering 

Catalogs of Geoengineering 

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Article
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The Paris Agreement introduced a 1.5 °C target to control the rise in global temperature, but clear arrangements for feasible implementation pathways were not made. Achieving the 1.5 °C target imposes high requirements on global emission reduction. Nationally Determined Contributions of all Parties are far from the 1.5 °C target, and conventional e...

Citations

... 77 Based on modelled scenarios, it is highly unlikely that these temperature targets can be achieved without substantial implementation of CDR measures, 78 with perhaps SRM being required as well. 79 Against this backdrop, the Paris Agreement outcomes have lent additional momentum and weight to the policy argument that further research and development of climate engineering measures is urgently needed. ...
Technical Report
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Abstract Some climate engineering technologies are being developed to remove CO2 from the atmosphere (carbon dioxide removal, CDR), which is expected to contribute to reducing and preventing climate change. Some other technologies (solar radiation modification, SRM) would artificially cool the planet and could reduce some symptoms and risks of climate change. Meaningful steps may need to be taken soon to lay a foundation for a decision process regarding research, policy, regulation and possible use. Driven by questions and needs from the international policymaking community to better understand the potential benefits as well as opportunities, risks, uncertainties and other challenges of CDR and SRM, at both technical and governance levels, this report reviews and compares technologies and their potential contributions, costs, risks, uncertainties, before surveying the current legal and institutional landscape of governance regarding climate engineering. It then addresses trade-offs between risks and discusses possible options for international governance, including criteria for evaluating options. The need for more inclusive approaches and the pros- and cons of institutional fragmentation are emphasized. Options for sites of international governance are discussed, for various technologies, as well as general principles and specific recommendations to: distinguish between CDR and SRM as well as among CDR techniques; accelerate authoritative, comprehensive, and international scientific assessment; encourage the research, development, and responsible use of some CDR techniques; internationally build capacity for evaluating CDR and SRM; facilitate non-state governance; and explore potential further governance of SRM while remaining agnostic concerning its use.
... The effort explicitly does not include technology development, or outdoor experiments..." . (Chen and Xin, 2017) have proposed several policy suggestions for China to strengthen research on and response to geoengineering. ...
Technical Report
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The report provides an initial high-level review of twenty-seven proposed marine geoengineering techniques - with its potential subsets - for climate mitigation that focuses on their efficacy, practicality, side-effects, knowledge gaps, verification and potential environmental and socio-economic impacts.
... It is increasingly clear that, even if fully implemented, the first round of national pledges to address climate change will not in themselves be enough to meet the temperature targets under the 2015 Paris Agreement (Chen & Xin, 2017;Rogelj et al., 2016). This reality has led to increased scholarly attention, and more recently attention from policy makers and civil society more broadly, on the possibility of developing climate engineering technologies. ...
Article
Two recently proposed solar radiation management (SRM) experiments in the United States have highlighted the need for governance mechanisms to guide SRM research. This paper draws on the literatures on legitimacy in global governance, responsible innovation, and experimental governance to argue that public engagement is a necessary (but not sufficient) condition for any legitimate SRM governance regime. We then build on the orchestration literature to argue that, in the absence of federal leadership, U.S. states, such as California, New York, and other existing leaders in climate governance more broadly have an important role to play in the near-term development of SRM research governance. Specifically, we propose that one or more U.S. states should establish a new interdisciplinary advisory commission to oversee and review the governance of SRM research in their states. Centrally, we propose that state-level advisory commissions on SRM research could help build legitimacy in SRM research decisions through the inclusion of, at minimum: meaningful public engagement early in the research design process; an iterative and reflexive mechanism for learning and improving both participatory governance mechanisms and broader SRM governance goals over time; as well as mechanisms for adaptation and diffusion of governance mechanisms across jurisdictions and scales.
... According to the Hadley Centre-Climatic Research Unit Version 4 (HadCRUT4) data set (Morice et al., 2012(Morice et al., ), 2015(Morice et al., , 2016(Morice et al., , and 2017 were the warmest years since records began in 1850 (Osborn, 2018;UK Met Office, 2018). In the face of dangerous climate change and insufficient current ambition to mitigate greenhouse gas emissions for achieving the international climate goal set in the Paris Agreement (Höhne et al., 2017;Rogelj et al., 2016), potential geoengineering methods that aim at deliberately cooling the climate have received increased attention (e.g., Chen & Xin, 2017;Parson, 2017). ...
Article
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Stratospheric sulfate aerosol injection (SAI) has been proposed as a way to geoengineer climate. While swift global mean surface cooling is generally expected from tropical SAI, the regional impacts of such perturbation on near-surface air temperature (SAT) are projected to be spatially inhomogeneous. By using existing simulations from the Geoengineering Model Intercomparison Project G4 scenario, where 5 Tg/year of sulfur dioxide (SO2) is injected into the tropical stratosphere to offset some of the warming in a midrange representative greenhouse gas concentration pathway (RCP4.5) between 2020 and 2070, we examine the regional detectability of the SAI surface cooling effect and attempt to find the best spatial scale for potential SAI monitoring. We use optimal fingerprint detection and attribution techniques to estimate the time horizon over which the SAI surface cooling effect would be detected after implementation in 2020 on subglobal scales, ranging from the near-global in situ observational coverage down to subcontinental regions. We show that using the spatiotemporal SAT pattern across the Northern and Southern extratropics and the Tropics, and across the Northern and Southern Hemispheres, as well as averaging SATs over the whole globe robustly result in successful SAI detection within 10 years of geoengineering implementation in a majority of the included plausible geoengineering realizations. However, detecting the SAI effect on SAT within the first decade of implementation would be more challenging on subcontinental scales.
... There is high confidence that planetary warming will continue throughout the 21st century even if we immediately stopped emitting greenhouse gases into the atmosphere (e.g., References [5][6][7][8][9]). Some resent studies (e.g., References [10][11][12][13]) suggest that geoengineering technologies can serve as a supplementary measure to stabilize climate as "in the absence of external cooling influence" [14], it is hard to achieve the Paris Agreement climate goals. Solar radiation management (SRM) by injection of sulfur aerosols into the stratosphere [15,16] is one of the most feasible and promising solutions for inducing negative radiative forcing (RF) from aerosols in order to at least partially compensate the positive RF from atmospheric greenhouse gases. ...
... We find the control function α A (t) generating the corresponding temperature anomalies T(t) and T D (t) that minimizes the objective function: (12) subject to the dynamics (4) and (5) and given initial T(t 0 ) = 0 and T D (t 0 ) = 0, as well as final (terminal) T t f = T f conditions. ...
Article
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In this paper, we apply the optimal control theory to obtain the analytic solutions of the two-component globally averaged energy balance model in order to estimate the influence of solar radiation management (SRM) operations on the global mean surface temperature in the 21st century. It is assumed that SRM is executed via injection of sulfur aerosols into the stratosphere to limit the global temperature increase in the year 2100 by 1.5 °C and keeping global temperature over the specified period (2020–2100) within 2 °C as required by the Paris climate agreement. The radiative forcing produced by the rise in the atmospheric concentrations of greenhouse gases is defined by the Representative Concentration Pathways and the 1pctCO2 (1% per year CO2 increase) scenario. The goal of SRM is formulated in terms of extremal problem, which entails finding a control function (the albedo of aerosol layer) that minimizes the amount of aerosols injected into the upper atmosphere to satisfy the Paris climate target. For each climate change scenario, the optimal albedo of the aerosol layer and the corresponding global mean surface temperature changes were obtained. In addition, the aerosol emission rates required to create an aerosol cloud with optimal optical properties were calculated.
... It has been suggested that geoengineering, otherwise known as solar radiation management (SRM), may be a stopgap measure to halt these impacts, stabilizing Earth's temperature at 1.5 K, before CO 2 mitigation can take effect (Chen and Xin, 2017). Here we evaluate the impact of SRM on Arctic sea ice decline and compare with mitigation methods alone, through the implementation of SRM, in our climate model HadGEM2-ES. ...
Article
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An assessment of the risks of a seasonally ice-free Arctic at 1.5 and 2.0 ∘C global warming above pre-industrial levels is undertaken using model simulations with solar radiation management to achieve the desired temperatures. An ensemble of the CMIP5 model HadGEM2-ES uses solar radiation management (SRM) to achieve the desired global mean temperatures. It is found that the risk for a seasonally ice-free Arctic is reduced for a target temperature for global warming of 1.5 ∘C (0.1 %) compared to 2.0 ∘C (42 %), in general agreement with other methodologies. The SRM produced more ice loss, for a specified global temperature, than for CO2 mitigation scenarios, as SRM produces a higher polar amplification.
... And in terms of actual pol- icy, the £8.6 m UK Greenhouse Gas Removal Research Programme aims to test several approaches, although at that scale these would be at best pilot and proto- type experiments rather than demonstrations in the sense we use it here. Ying and Yuan (2017) provide a Chinese perspective on designing policy for NETs. Other papers are less specific on the removal technique used but raise upscaling issues, such as game theo- retic incentives (Sandler 2017). ...
Article
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We assess the literature on innovation and upscaling for negative emissions technologies (NETs) using a systematic and reproducible literature coding procedure. To structure our review, we employ the framework of sequential stages in the innovation process, with which we code each NETs article in innovation space. We find that while there is a growing body of innovation literature on NETs, 59% of the articles are focused on the earliest stages of the innovation process, 'research and development' (R&D). The subsequent stages of innovation are also represented in the literature, but at much lower levels of activity than R&D. Distinguishing between innovation stages that are related to the supply of the technology (R&D, demonstrations, scale up) and demand for the technology (demand pull, niche markets, public acceptance), we find an overwhelming emphasis (83%) on the supply side. BECCS articles have an above average share of demand-side articles while direct air carbon capture and storage has a very low share. Innovation in NETs has much to learn from successfully diffused technologies; appealing to heterogeneous users, managing policy risk, as well as understanding and addressing public concerns are all crucial yet not well represented in the extant literature. Results from integrated assessment models show that while NETs play a key role in the second half of the 21st century for 1.5 °C and 2 °C scenarios, the major period of new NETs deployment is between 2030 and 2050. Given that the broader innovation literature consistently finds long time periods involved in scaling up and deploying novel technologies, there is an urgency to developing NETs that is largely unappreciated. This challenge is exacerbated by the thousands to millions of actors that potentially need to adopt these technologies for them to achieve planetary scale. This urgency is reflected neither in the Paris Agreement nor in most of the literature we review here. If NETs are to be deployed at the levels required to meet 1.5 °C and 2 °C targets, then important post-R&D issues will need to be addressed in the literature, including incentives for early deployment, niche markets, scale-up, demand, and—particularly if deployment is to be hastened—public acceptance.
... In summary, the 1.5 K target appears difficult to achieve by conventional mitigation or using current CDR technology alone without incurring an overshoot, that is, a scenario in which global warming exceeds 1.5 K and is "brought back" to a desired temperature by CDR and mitigation (Scenario 3 in Figure 1). Alternatively solar geoengineering, else known as solar radiation management (SRM), has been proposed as a method for cooling the planet and could be used to stabilize Earth's temperature at 1.5 K instead of incurring a temperature overshoot (Scenario 4 in Figure 1) (Chen & Xin, 2017). SRM refers to a range of climate interventions that aim to increase the reflectivity of the atmosphere or surface to sunlight, hence reducing the absorption of solar energy within the climate system (Shepherd, 2009). ...
Article
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The 2015 Paris Agreement aims to limit global warming to well below 2K above preindustrial levels, and to pursue efforts to limit global warming to 1.5 K, in order to avert dangerous climate change. However, current greenhouse gas emissions targets are more compatible with scenarios exhibiting end-of-century global warming of 2.6-3.1 K, in clear contradiction to the 1.5 K target. In this study, we use a global climate model to investigate the climatic impacts of using solar geoengineering by stratospheric aerosol injection to stabilize global-mean temperature at 1.5 K for the duration of the 21st century against three scenarios spanning the range of plausible greenhouse gas mitigation pathways (RCP2.6, RCP4.5, and RCP8.5). In addition to stabilizing global mean temperature and offsetting both Arctic sea-ice loss and thermosteric sea-level rise, we find that solar geoengineering could effectively counteract enhancements to the frequency of extreme storms in the North Atlantic and heatwaves in Europe, but would be less effective at counteracting hydrological changes in the Amazon basin and North Atlantic storm track displacement. In summary, solar geoengineering may reduce global mean impacts but is an imperfect solution at the regional level, where the effects of climate change are experienced. Our results should galvanize research into the regionality of climate responses to solar geoengineering.
... 77 Based on modelled scenarios, it is highly unlikely that these temperature targets can be achieved without substantial implementation of CDR measures, 78 with perhaps SRM being required as well. 79 Against this backdrop, the Paris Agreement outcomes have lent additional momentum and weight to the policy argument that further research and development of climate engineering measures is urgently needed. ...
Thesis
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Deliberate large-scale interventions in the Earth’s climate system – known collectively as ‘geoengineering’ – have been proposed in order to moderate anthropogenic climate change. This thesis explores one of the possible technologies, stratospheric aerosol injection solar radiation management (SAI). My original contribution to knowledge is to make a number of interlinked contributions to understanding how interested and affected parties frame and think about SAI risk, and, how its future governance may evolve. The qualitative study addresses two research questions: how might deployment risks be incorporated into SAI governance; and, might SAI governance be plural? Governance framings are explored through the lens of the technical and social risks of SAI. A theorising of risk by Renn (2008) that incorporates the challenges of uncertainty, ignorance and incertitude, using a typology of risk and a linked risk management model is adopted to explore how SAI risks maybe be incorporated into SAI governance. A conceptual framework of SAI governance, drawing on Bulkeley’s (2012) climate change governance theories of consent, consensus and concord, is used to suggest how decisionmaking might be enacted, and authority negotiated, taken, and given during SAI governance. Semi-structured stakeholder interviews were undertaken to discern perspectives on SAI risk and risk governance, identifying the underlying rationales, and, providing empirical evidence to assess the theoretical arguments. Findings describe how SAI governance may take shape and its characteristics. They suggest complex understandings of risk will contribute to the construction of a plural, inclusive and deliberative process of governance that, critically, will evolve in an un-rushed manner over time. The research suggests that risk management theories may help inform how other socially constructed Earth systems might be governed. In addition, the modalities of authorisation and the transnational governing processes proposed by the governance framework appear to provide a useful tool that could help interested and affected parties’ understandings of, and participation in, future SAI governance. The thesis suggests SAI is a useful case study to inform the broader environmental governance debate and the geoengineering-climate change interface. Some suggestions for further research in this direction are suggested.
Article
To meet the nationally determined contributions proposed by the countries that signed the Paris Agreement, investments must be made in renewable generation technologies such as solar and wind. However, due to their high variability, these technologies pose challenges in terms of meeting demand or generating excess electricity. For this reason, energy system models are designed to capture this variability by considering flexibility technologies. Nevertheless, it is important to note that some energy system models lack integration with other sectors. Therefore, integrated assessment models have been employed to evaluate mitigation strategies, as they endogenously consider the linkages between energy and non-energy sectors. In addition, due to their complexity, these models do not account for the variability of renewable resources. Hence, this research aims to address this issue. This work represents the first attempt to evaluate how the introduction of hourly resolution affects the outcomes of integrated assessment models, specifically focusing on the Global Change Analysis Model (GCAM). We employ a soft-linking approach between the GCAM and the Highway to Renewable Energy Systems model (H2RES, an hourly level energy system model) to accomplish this. The proposed approach is tested using Chile’s Nationally Determined Contributions under different hydrological profiles in the power sector. The results show that it is possible to use the capacity obtained from the Global Change Analysis Model and implement it on an hourly scale. However, the feasibility of implementation depends on high levels of flexibility technologies, such as battery energy storage. When given the choice of investments in renewable sources and flexible technologies, the optimal dispatch of the H2RES model show small differences than those obtained by GCAM-Chile. H2RES differs from GCAM-Chile in approximately 5% for wind and 3% for solar electricity generation in the year 2050. However, feasible integration of significant renewable sources is obtained with relatively high Critical Excess Electricity Production levels, reaching 20% in 2050. This excess electricity is attributed to the necessity for flexible technologies to manage the intermittency of renewables sources when hourly profiles of such sources are considered.