Solar Radiation Management Research Articles

Solar geoengineering is scary - that's why we should research it.

Research on blocking sunlight needs a dose of realpolitik. Research on blocking sunlight needs a dose of realpolitik.

Right to Food and Geoengineering

Climate change poses grave risks to food security, and mitigation and adaptation actions have so far been insufficient to lessen the risk of climate-induced violations of the right to food. Could safeguarding the right to food, then, justify some forms of geoengineering? This article examines geoengineering through the analytical lens of the right to food. We look at the components of food security and consider how the acceptability of geoengineering relates to the right to food via its impacts on these components. Our examination shows that results vary greatly between different forms of geoengineering: while some forms of geoengineering fail to respect the right to food, certain other forms may even become obligatory to protect the right to food. It appears that there is no support for aerosol-based solar radiation management, whereas some carbon dioxide removal methods can help protect or promote the right to food. The ethical challenges related to carbon dioxide removal methods are, we note, similar to those that will also be faced in the course of climate change mitigation.

Dust as a solar shield

We revisit dust placed near the Earth–Sun L1 Lagrange point as a possible climate-change mitigation measure. Our calculations include variations in grain properties and orbit solutions with lunar and planetary perturbations. To achieve sunlight attenuation of 1.8%, equivalent to about 6 days per year of an obscured Sun, the mass of dust in the scenarios we consider must exceed 1010 kg. The more promising approaches include using high-porosity, fluffy grains to increase the extinction efficiency per unit mass, and launching this material in directed jets from a platform orbiting at L1. A simpler approach is to ballistically eject dust grains from the Moon’s surface on a free trajectory toward L1, providing sun shade for several days or more. Advantages compared to an Earth launch include a ready reservoir of dust on the lunar surface and less kinetic energy required to achieve a sun-shielding orbit.

Hydrological Consequences of Solar Geoengineering

As atmospheric carbon dioxide concentrations rise and climate change becomes more destructive, geoengineering has become a subject of serious consideration. By reflecting a fraction of incoming sunlight, solar geoengineering could cool the planet quickly, but with uncertain effects on regional climatology, particularly hydrological patterns. Here, we review recent work on projected hydrologic outcomes of solar geoengineering, in the context of a robust literature on hydrological responses to climate change. While most approaches to solar geoengineering are expected to weaken the global hydrologic cycle, regional effects will vary based on implementation method and strategy. The literature on the hydrologic outcomes and impacts of geoengineering demonstrates that its implications for human welfare will depend on assumptions about underlying social conditions and objectives of intervention as well as the social lens through which projected effects are interpreted. We conclude with suggestions to reduce decision-relevant uncertainties in this novel field of Earth science inquiry. ▪ The expected hydrological effects of reducing insolation are among the most uncertain and consequential impacts of solar geoengineering (SG). ▪ Theoretical frameworks from broader climate science can help explain SG's effects on global precipitation, relative humidity, and other aspects of hydroclimate. ▪ The state of the knowledge on hydrological impacts of SG is unevenly concentrated among regions. ▪ Projected hydrological impacts from SG are scenario dependent and difficult to characterize as either harmful or beneficial.

High-transmittance pNIPAm gel smart windows with lower response temperature and stronger solar regulation

Improving the solar regulation and reducing the response temperature of thermochromic smart windows are pivotal importance for energy-saving buildings. However, such two strategies are challenging to be integrated into one window. Herein, a solution for simultaneously regulating the surface tension of the scattering center and the capturing-releasing capacity of pNIPAm for water is implemented, successfully carrying out the enhancement of solar regulation and the reduction of response temperature. The maximum solar shielding and regulation of the modified sandwich structured pNIPAm gel device can reach up to 88.45% and 71.81%, an increase of 52.29% and 73.71% respectively, compared to a pure pNIPAm gel device with the same thickness. Besides, the response temperature is reduced to around 28 ℃, making modified devices have the ability to respond promptly at the comfortable room temperature range boundary (22–28 ℃). Different from flowing, strengthless modified doped microgels, the high-transmittance modified pNIPAm gels maintain the stable patterning performance, and have great potential for further applications. Similar conclusions are obtained using different solvents to reduce the attraction between pNIPAm-water, and the surface tension of water. Therefore, this universal modification framework deserves attention for the future design of energy-saving windows.

Northern-high-latitude permafrost and terrestrial carbon response to two solar geoengineering scenarios

Abstract. The northern-high-latitude permafrost contains almost twice the carbon content of the atmosphere, and it is widely considered to be a non-linear and tipping element in the earth's climate system under global warming. Solar geoengineering is a means of mitigating temperature rise and reduces some of the associated climate impacts by increasing the planetary albedo; the permafrost thaw is expected to be moderated under slower temperature rise. We analyze the permafrost response as simulated by five fully coupled earth system models (ESMs) and one offline land surface model under four future scenarios; two solar geoengineering scenarios (G6solar and G6sulfur) based on the high-emission scenario (ssp585) restore the global temperature from the ssp585 levels to the moderate-mitigation scenario (ssp245) levels via solar dimming and stratospheric aerosol injection. G6solar and G6sulfur can slow the northern-high-latitude permafrost degradation but cannot restore the permafrost states from ssp585 to those under ssp245. G6solar and G6sulfur tend to produce a deeper active layer than ssp245 and expose more thawed soil organic carbon (SOC) due to robust residual high-latitude warming, especially over northern Eurasia. G6solar and G6sulfur preserve more SOC of 4.6 ± 4.6 and 3.4 ± 4.8 Pg C (coupled ESM simulations) or 16.4 ± 4.7 and 12.3 ± 7.9 Pg C (offline land surface model simulations), respectively, than ssp585 in the northern near-surface permafrost region. The turnover times of SOC decline slower under G6solar and G6sulfur than ssp585 but faster than ssp245. The permafrost carbon–climate feedback is expected to be weaker under solar geoengineering.

How to Argue about Solar Geoengineering

ABSTRACTShould high‐income countries engage in solar geoengineering research and possible deployment? On the assumption that the speed of the energy transition will be insufficient to abate catastrophic climate impacts, research into solar geoengineering begins to look like a technically and socially feasible route to mitigate such impacts. But on the assumption that a rapid and relatively just energy transition is still within the realm of political possibility, research into solar geoengineering looks more like an ideological tool designed to divert time and resources from less risky climate solutions. At the heart of debates over solar geoengineering, then, is disagreement over what political actors can be expected to do in the future. In this article, I argue that both objectors to and proponents of solar geoengineering research often make background assumptions regarding expected future actions that are either (a) inaccurate or (b) inconsistent. I propose an account of expected future actions that avoids these problems and sketch what the debate over solar geoengineering looks like with these assumptions in place.

Toward Dangerous US Unilateralism on Solar Geoengineering

ABSTRACT As social scientists, we are concerned about the impact of the National Academies Report on solar geoengineering. It has already set into motion a major, federally coordinated national research program in the United States to develop this dangerous technology. We emphasize that scientists and researchers are not the ones who will be making decisions on deployment, so research and development should not proceed without integrating broader international perspectives. If the US government does not pause to establish effective international governance and public participation before investing more in solar geoengineering, then the NAS report will have – regardless of the intentions of the committee – opened the door for the US to unilaterally shape and advance the global development of solar geoengineering.

Risk from responses to a changing climate

Effectively responding to intensifying climate change hazards requires identifying risks arising from each response, as well as risks arising from the dynamic interactions between responses. Using examples of managed retreat and solar geoengineering, we illustrate the importance of understanding response as a determinant of climate change risk. We highlight a continuum of severity of response risks, both at the site of deployment and across temporally and geographically distant contexts. While responses might moderate a specific hazard, due to the complexity of climate change risk they may be ineffective at reducing net climate-related risk for any given actor or system. We also show how some responses to climate change affect vulnerability, exposure, and other responses to climate change independent of the targeted hazard and can lead to maladaptation. We conclude by emphasizing the importance of integrating climate change responses together with other determinants of risk to better inform climate risk management and guide research on the feasibility of individual response options.

Sudden Reduction of Antarctic Sea Ice Despite Cooling After Nuclear War

AbstractA large‐scale nuclear war could inject massive amounts of soot into the stratosphere, triggering rapid global climate change. In climate model simulations of nuclear war, global cooling contributes to an expansion of sea ice in the Northern Hemisphere. However, in the Southern Hemisphere (SH), an initial expansion of sea ice shifts suddenly to a 30% loss of sea ice volume over the course of a single melting season in the largest nuclear war simulation. In smaller nuclear war simulations an expansion in sea ice is instead observed which lasts for approximately 15 years. In contrast, in the largest nuclear war simulation, Antarctic sea ice remains below the long term control mean for 15 years, indicating a threshold that must be crossed to cause the response. Declining sea ice in the SH following a global cooling event has been previously attributed to shifts in the zonal winds around Antarctica, which can reduce the strength of the Weddell Gyre. In climate model simulations of nuclear war, the primary mechanisms responsible for Antarctic sea ice loss are: (a) enhanced atmospheric poleward heat transport through teleconnections with a strong nuclear war‐driven El Niño, (b) increased upwelling of warm subsurface waters in the Weddell Sea due to changes in wind stress curl, and (c) decreased equatorward Ekman transport due to weakened Southern Ocean westerlies. The prospect of sudden Antarctic sea ice loss after an episode of global cooling may have implications for solar geoengineering and further motivates this study of the underlying mechanisms of change.

On the Role of Solar Geoengineering in Combatting Climate Change: Harvard University vs. Indigenous Voices

On the Role of Solar Geoengineering in Combatting Climate Change: Harvard University vs. Indigenous Voices

The Future Is the Termination Shock: On the Antinomies and Psychopathologies of Geoengineering. Part One

Abstract As capitalist society remains incapable of addressing climate breakdown, one measure is waiting in the wings: solar geoengineering. No other technology can cut global temperatures immediately. It would alleviate the symptoms of the crisis, not its causes. But might it be combined with radical emissions cuts? This essay, the first instalment of two, scrutinises the rationalist-optimist case for geoengineering: the idea that soot planes in the sky can shield the Earth from the worst heat while society rids itself of fossil fuels. A more likely outcome is that they encourage business-as-usual to continue, while negative side-effects from geoengineering itself pile up. The logic of the enterprise points in the direction of a catastrophic termination shock. A subsequent, second instalment will subject geoengineering to a materialist psychoanalysis and argue that it represents a fantasy of repression, setting itself up for a dreadful return of the repressed.

Stratospheric aerosol injection may impact global systems and human health outcomes

Solar radiation management (SRM) is a climate engineering strategy to reduce temperature increases due to global climate change. The most well-researched SRM methodology is stratospheric aerosol injection (SAI), which involves increasing the concentration of aerosol particles in the stratosphere to reduce the amount of solar radiation reaching Earth’s surface. The most considered and heavily researched aerosol for SAI is sulfate. SAI has been extensively modeled using various climate scenarios and investigated using data from previous volcanic eruptions, which provide an analog of the climate effects of SAI. Prior research has determined that SAI will not only decrease global temperatures but is likely to have direct impacts on ecosystem and public health. This review seeks to investigate the various ways by which SAI may impact global public health outcomes related to hydrologic cycling, atmospheric chemical cycling, frequency of natural disasters, food system disruptions, and ecological health through the pathways of water, air, soil, and biota. SAI has the potential to decrease negative health outcomes associated with rising temperatures but may have a myriad of impacts on global environmental systems. Anthropogenically altering the global climate, through both the release of greenhouse gases or through climatic engineering, has unknown consequences, many of which will likely impact global health and quality of life. A more holistic approach is necessary to understand the relative benefits and harms in using SAI as compared to the implication of global climate change.

The next climate war? Statecraft, security, and weaponization in the geopolitics of a low-carbon future

The impacts of global climate change on international security and geopolitics could be of historic proportion, challenging those of previous global threats such as nuclear weapons proliferation, the Great Depression, and terrorism. But while the evidence surrounding the security impacts of climate change is fairly well-understood and improving, less is known about the security risks to climate-technology deployment. In this study, we focus on the geopolitical, security, and military risks facing negative emissions and solar geoengineering options. Although controversial, these options could become the future backbone of a low-carbon or net-zero society, given that they avoid the need for coordinated or global action (and can be deployed by a smaller group of actors, even non-state actors), and that they can “buy time” for mitigation and other options to be scaled up. We utilize a large and diverse expert-interview exercise (N = 125) to critically examine the security risks associated with ten negative emission options (or greenhouse gas removal technologies) and ten solar geoengineering options (or solar radiation management technologies). We ask: What geopolitical considerations does deployment give rise to? What particular military applications exist? What risks do these options entail in terms of weaponization, misuse, and miscalculation? We examine such existing and prospective security risks across a novel conceptual framework envisioning their use as (i) diplomatic or military negotiating tools, (ii) objectives for building capacity, control, or deterrence, (iii) targets in ongoing conflicts, and (iv) causes of new conflicts. This enables us to capture a far broader spectrum of security concerns than those which exist in the extant literature and to go well beyond insights derived from climate modelling or game theory by drawing on a novel, rich, and original dataset of expert perceptions.

A Controlled Experiment of Surface Albedo Modification to Reduce Ice Melt

AbstractLoss of reflectivity in the Arctic and the wider cryosphere is known to increase global temperature rise through an ice‐albedo feedback loop, which has the potential to lead to loss of summertime ice cover in the Arctic Ocean, and to accelerate global warming. Despite the urgency of this situation, there are few options being developed to preserve and restore ice reflectivity. Localized surface albedo modification using reflective materials offers a potential pathway to restore Arctic ice. We conducted a controlled experiment to determine effects of surface albedo modification on ice melt and thermodynamic processes of a pond. We applied a coating of hollow glass microspheres (HGMs) to a test section, while leaving a control section unmodified. Laboratory measurements show that the loading of HGM materials used corresponds to a reflectivity of 30%. We measured ice and snow thickness, albedo, incoming and outgoing shortwave and longwave radiation, and ice, water, and ambient temperatures. A 1‐D thermodynamic model was developed to quantify the effect of albedo modification on the processes of heat transfer, energy absorption and ice melt. The albedo increased from 0.17 on a control section to 0.36 on a test section. During the 2‐week melt period, there was a 29% reduction in net radiative energy into the test section and a 33% reduction of ice melting rate measured by volume. This experiment using quantitative methods elucidates the mechanisms of ice preservation through surface albedo modification and demonstrates its effectiveness.

Energy-saving and thermal comfort potential of vernacular urban block porosity shading

Built environment configurations of vernacular architecture are the result of an evolutionary adaptation to climatic conditions, while the historic districts of many cities worldwide are shaped by their extensive architectural heritage. These factors, coupled with the present day awareness and renewed interest in the passive retrofitting of buildings, have prompted a review of traditional strategies, most notably direct solar radiation management through courtyard perforations. Although the vernacular courtyard microclimate has been discussed in the literature in recent years, few studies have successfully translated its climatic benefits to the city scale in order to assess its real potential. There is a notable absence of overall urban estimations of the impact on energy-saving and thermal comfort of some of the most effective strategies, such as the use of shading devices. Combining state-of-the-art GIS-based tools and statistical data analysis from field monitoring campaigns this research performs a large-scale evaluation in urban courtyards in the historic centre of a Mediterranean city. Based on the results obtained it can be stated that a widespread use of shading devices can increase the number of hours of comfort, according to PET, by 27% and can reduce global cooling demand by 31%.

Comparative planetology as a foundation for associating space law with solar geoengineering governance: stratospheric aerosol injection and variations of sulfur dioxide in Venus’s atmosphere

Mankind often seeks solutions to climate change and environmental crises, but rarely considers the feasibility of outer space to overcome such critical issues. Among many solar geoengineering approaches is stratospheric aerosol injection (SAI) whose concept suggests artificial control of the global temperature by spreading tones of sulfur dioxide into Earth’s stratosphere. Given that the classic ‘technology control dilemma’ represents the central problem of solar geoengineering governance, however, this paper adopts a VenusEarth comparative planetology method by addressing volcanology and atmospheric circulation aspects. An international regulatory framework engaging space law in solar geoengineering governance is consequently presented, which classifies two separate legislations: (1) research-based legislation (comparative planetology and Earth science) and (2) non-research-based legislation (national and international governance, ethical issues, economic factors, military utilization). Further highlighting climate change issues, SAI manifests the Anthropocene and regards Earth’s stratosphere as an “inner environment”, while comparative planetology manifests the Anthropocosmos and regards space as an “outer environment”. This polymorphous consideration of atmospheric and space elements identifies a new approach of climate change techniques. Human relations that concern both environments should examine how social scientists would regard these separate boundaries or perceive them as a mergence between the two major epochs.

Changing the climate risk trajectory for coral reefs

Coral reefs are extremely vulnerable to climate change and their recent degradation will continue unless we can instigate strong global climate action with effective regional interventions. Many types of intervention have been proposed and some aspects of their deployment are now being tested. However, their long-term efficacy under climate change can only be evaluated using complex biophysical models applied over a range of plausible socio-economic pathways. The associated uncertainties in climate trajectories, ecological responses, and the mitigating effects of interventions, necessitate the use of a risk-based approach to evaluating model results. I show that ensemble modeling can be used to develop rigorous risk assessments suitable for comparing intervention strategies. A major strength of this approach is that all the key elements required for risk assessment (exposure, sensitivity, adaptive capacity, and impacts) can be generated by the model in a dynamically consistent form. This is a major advance on semi-quantitative climate change vulnerability risk assessments that estimate these quantities independently and then combine them under additional assumptions. Applying ensemble modeling risk assessment to the Great Barrier Reef (GBR) suggests that regional intervention strategies, such as solar radiation management (SRM) and control of coral predators, can slow the increase in risk and potentially avoid extreme risks predicted for the second half of the century. Model results further suggest that deployments focused within the northern and central GBR will be most effective due to underlying patterns of reef connectivity.

Beyond climate stabilization: Exploring the perceived sociotechnical co-impacts of carbon removal and solar geoengineering

The scientific literature on the co-impacts of low-carbon energy systems—positive and negative side effects—has focused intently on climate mitigation, or climate adaptation. It has not systematically examined the prospective co-impacts of carbon removal (or negative emissions) and solar geoengineering. Based on a large sample of diverse expert interviews (N = 125), and using a sociotechnical approach, in this study we identify 107 perceived co-impacts related to the deployment of carbon removal and solar geoengineering technologies. Slightly less than half (52) were identified as positive co-impacts (38 for carbon removal, 14 for solar geoengineering), whereas slightly more than half (55) were identified as negative co-impacts (31 for carbon removal, 24 for solar geoengineering). We then discuss 20 of these co-impacts in more depth, including positive co-impacts for nature-based protection, the expansion of industry, and reduction of poverty or heat stress as well as negative co-impacts for water insecurity, moral hazard, limited social acceptance and path dependence. After presenting this body of evidence, the paper then discusses and theorizes these co-impacts more deeply in terms of four areas: relationality and risk-risk trade-offs, co-deployment and coupling, intentional or unintentional implications, and expert consensus and dissensus. It concludes with more general insights for energy and climate research, and policy.

Conducting more inclusive solar geoengineering research: A feminist science framework

Solar geoengineering, or deliberate climate modification, has been receiving increased attention in recent years. Given the far-reaching consequences of any potential solar geoengineering deployments, it is prudent to identify inherent biases, blind spots, and other potential issues at all stages of the research process. Here we articulate a feminist science-based framework to concretely describe how solar geoengineering researchers can be more inclusive of different perspectives and potentially contradictory conclusions, in the process illuminating potential implicit bias and enhancing the conclusions that can be gained from their studies. Importantly, this framework is an adoptable method of practice that can be refined, with the aim of conducting better research in solar geoengineering. As an illustration, we retrospectively apply this framework to a well-read solar geoengineering study (also led by the first author of this study), improving transparency by revealing its implicit values, conclusions made from its evidence base, and the methodologies that study pursues. We conclude with a set of recommendations for the geoengineering research community whereby more inclusive research can become a regular part of practice. Throughout this process, we illustrate how feminist science scholars can use this approach to study climate modeling.