Solar Radiation Management Research Articles

Youth Climate Questions

AbstractAnthropogenic climate change and environmental crises are pressing challenges of our time, with changes to the climate system observed in every global region. Disastrous impacts on nature, including people, have already been observed in the form of drought, floods and extreme heat events across the planet. This study examines the role of an interdisciplinary approach to exploring different responses to climate-related disasters and potential disasters. The work we report takes place in the context of recent research on dialogue on climate interventions with youth. Climate interventions are large-scale interventions into the Earth’s climate system and include proposals such as solar radiation management, ocean liming, and carbon capture and storage technologies. Research and development of climate interventions as a response to one set of disasters (in the present and in-the-making), created as a result of anthropogenic climate change, are associated with much uncertainty and controversy. We explored these uncertainties and controversies with young people, scientists and policymakers, resulting in a set of illustrated climate conversation cards. In this paper, we analyse the questions produced by young people to find requests for data and knowledge from across disciplines, and for an exploration of ethics, feelings, positions and priorities. We also found problematisations of technofixes and desire for socio-political action. The implications for science and disaster education are discussed.

Demographics shape public preferences for carbon dioxide removal and solar geoengineering interventions across 30 countries

Climate intervention technologies such as carbon dioxide removal and solar geoengineering are becoming more actively considered as solutions to global warming. The demographic aspects of the public serve as a core determinant of social vulnerability and the ability for people to cope with, or fail to cope with, exposure to heat waves, air pollution, or disruptions in access to modern energy services. This study examines public preferences for 10 different climate interventions utilizing an original, large-scale, cross-country set of nationally representative surveys in 30 countries. It focuses intently on the demographic dimensions of gender, youth and age, poverty, and income as well as intersections and interactions between these categories. We find that support for the more engineered forms of carbon removal decreases with age. Gender has little effect overall. Those in poverty and the Global South are nearly universally more supportive of climate interventions of various types.

Impact of Solar Radiation Management on Andean glacier-wide surface mass balance

Solar Radiation Management (SRM) is a climate intervention strategy aimed at mitigating global warming by reducing incoming solar radiation. We investigate the potential influence of SRM on Andean glacier-wide surface mass balance, as glaciers are crucial for downstream ecological functions along the west coast of South America. We numerically simulate the surface mass balance response of thousands of glaciers to SRM and other climate change scenarios throughout the 21st century. Results indicate Pan-Andean negative mass balance, irrespective of the scenario or glacier-climate regimes. However, SRM tends to modify interannual variability and temperature sensitivity in several regions. Our findings also suggest that if SRM had been implemented in the late 1980’s, it would have been effective in avoiding the negative trajectory seen today. The Andes feature nearly all mountain hydroclimatic regimes, representing a globally relevant example of SRM impacts. These findings emphasize the urgency of drastic emissions reduction.

Solar Geoengineering: History, Methods, Governance, Prospects

Solar geoengineering, also called sunlight reflection or solar radiation modification (SRM), is a potential climate response that would cool the Earth's surface and reduce many other climate changes by scattering on order 1% of incoming sunlight back to space. SRM can only imperfectly correct for elevated greenhouse gases, but it might complement other climate responses to reduce risks, while also bringing new risks and new challenges to global governance. As climate alarm and calls for effective near-term action mount, SRM is attracting sharply increased attention and controversy, with many calls for expanded research and governance consultations along with ongoing concerns about risks, misuse, or overreliance. We review SRM's history, methods, potential uses and impacts, and governance needs, prioritizing the approach that is most prominent and promising, stratospheric aerosol injection. We identify several policy-relevant characteristics of SRM interventions and identify four narratives that capture current arguments over how SRM might be developed or used in sociopolitical context to either beneficial or destructive effect, with implications for near-term research, assessment, and governance activity.

Heat transfer enhancement using ternary hybrid nanofluid for cross-viscosity model with intelligent Levenberg-Marquardt neural networks approach incorporating entropy generation

Thermal heat transfer analysis of trihybrid nanofluids using an intelligent Levenberg-Marquardt neural network (ANN-LMA) approach, with a focus on entropy generation, has been conducted. The flow equations were modeled in Cartesian coordinates and simplified using dimensionless variables. Partial differential equations were converted into ordinary differential equations through appropriate similarity transformations. These ordinary differential equations were then solved using the finite element method applied to a data set evaluated from (ANN-LMA) approach. This dataset can be input into MATLAB to generate predicted solutions for flow patterns. The ANN-LMA technique was employed to evaluate the efficiency of heat transfer characteristics for nanofluids in various scenarios. Incorporating carbon nanotubes (both single-wall (SWCNT) and multi-wall (MWCNT)) along with iron oxide in water, the study demonstrates their effectiveness in enhancing heat transfer. These nanofluids have broad industrial applications, such as in coolant enhancement, cancer therapy, and solar radiation management, and show promising results. This study specifically examines the flow properties of water-based CNT cross-trihybrid nanofluids over a convectively heated surface, leveraging their unique characteristics. Improvements in heat transfer are achieved through the introduction of dissipative heat, thermal radiation, and external heat sources or sinks. The performance of the computational solver was assessed using error histograms, regression analyses, and Mean Squared Error (MSE) results. The physical significance of the designed factors is graphically depicted and discussed in detail. It was found that radiative heat increases surface heat energy through substantial accumulation, thereby enhancing heat transfer properties, while dissipative heat, due to Joule dissipation and other external sources, significantly raises the fluid temperature.

Global perspectives on solar geoengineering: A novel framework for analyzing research in pursuit of effective, inclusive, and just governance

We present a novel analytical framework to evaluate the ethical, political, and justice implications of research on perceptions of emerging technologies. Using the literature on perspectives on solar geoengineering (SG) as an object of study, we develop a framework that interrogates the research process itself. Our framework interrogates whose perceptions are being studied, by whom, using what methods, following which lines of inquiry, and crucially, for what purposes. We do this through the case of SG, a controversial emerging climate intervention technology with potential global social and environmental impacts. We find that SG perspectives research raises important political and justice concerns related to whose perspectives are being studied and for what purposes. We show that SG perspectives research centers the perspectives from the Global North, underrepresents youth perspectives, and that some research aims to increase public support for SG. Ours is the first study to aggregate and quantify this rich empirical data to enable us to visualize these inequities. We also find that investigations of support for SG dominate the literature at the neglect of other important lines of inquiry, such as how cross-cultural perspectives on public engagement and capacity building can inform efforts to institutionalize the inclusion of youth and the Global South in SG discussions. We further find widespread motivation to inform decision-making but without clear direction about how best to do so. We chart a pathway for future perspectives research on SG and broader climate interventions, centered around four recommendations that seek to ameliorate some of these limitations and enhance the potential for perspectives research to enable more effective, inclusive, and just solar geoengineering governance.

Early engagement will be necessary for atmospheric methane removal field trials

Abstract Atmospheric methane removal (AMR) refers to a suite of emerging technologies and practices that destroy atmospheric methane. There is growing interest in AMR field trials to better understand the risks and benefits of various approaches. Building on rights-based rationales from international law and core principles of environmental justice, we argue that AMR field trials should not proceed before meaningful public engagement occurs. We also draw preliminary lessons from ocean fertilization and solar radiation management (SRM) cases to highlight the significance of involving members of the public in conversation about climate intervention technologies in early stages of the research and development process. While we emphasize that engagement is not a checkbox for gaining social license, these cases illustrate how neglecting public engagement can be unnecessarily detrimental to proposed research. We further point to an enhanced weathering experiment to highlight how early engagement can foster ethical processes and outcomes, which enhance alignment of research with societal values. While empirical evidence does not yet support the argument that engagement always results in the outcomes researchers desire, it does always result in justice enhancing outcomes and should therefore be pursued regardless. We advocate for diverse engagement approaches based on the nature of the technology, with a focus on collaboration with impacted communities, the public, and international interdisciplinary researchers. To ensure responsible research practices, the article calls for the development of comprehensive governance frameworks and ethical guidelines for field trials.

The Quality of the Air we Breathe is Getting Worse, the Dust can be Dangerous: In what way?

Based on the observation that air quality measuring devices have shown increased levels of dust pollution in recent years, we carried out an investigation over two years. This confirmed the assumption of increasing air pollution: a significant increase in the parts per million of dust particles. By analysing the filter contents of an air ionizer, we were able to find various pollutants: Arsenic, aluminum, titanium, fluorides, barium as well as mold spores. The causes can be assumed to be Geoengineering, Solar Radiation Management and Stratospheric Aerosol Injection. Air purification devices are therefore becoming increasingly important.

Assessing the Spurious Impacts of Ice-Constraining Methods on the Climate Response to Sea-Ice Loss using an Idealised Aquaplanet GCM

Abstract Coupled climate model simulations designed to isolate the effects of Arctic sea-ice loss often apply artificial heating, either directly to the ice or through modification of the surface albedo, to constrain sea ice in the absence of other forcings. Recent work has shown that this approach may lead to an overestimation of the climate response to sea-ice loss. In this study, we assess the spurious impacts of ice-constraining methods on the climate of an idealised aquaplanet general circulation model (GCM) with thermodynamic sea ice. The true effect of sea-ice loss in this model is isolated by inducing ice loss through reduction of the freezing point of water, which does not require additional energy input. We compare results from freezing point modification experiments with experiments where sea-ice loss is induced using traditional ice-constraining methods, and confirm the result of previous work that traditional methods induce spurious additional warming. Furthermore, additional warming leads to an overestimation of the circulation response to sea-ice loss, which involves a weakening of the zonal wind and storm track activity in midlatitudes. Our results suggest that coupled model simulations with constrained sea ice should be treated with caution, especially in boreal summer, where the true effect of sea-ice loss is weakest but we find the largest spurious response. Given that our results may be sensitive to the simplicity of the model we use, we suggest that devising methods to quantify the spurious effects of ice-constraining methods in more sophisticated models should be an urgent priority for future work.

A mathematical modelling for solar irradiance reduction of sunshades and some near-future albedo modification approaches for mitigation of global warming

To address the global warming problem, one of the space-based geoengineering solutions suggests the construction of an occluding disc that can work as a solar curtain to mitigate solar irradiation penetration to the earth atmosphere. A widely discussed concept needs the construction of a large-scale sunshade system near the Sun–Earth L1 equilibrium point in order to control the average global temperature. However, to improve the accuracy of theoretical estimations, more consistent modeling of the Sun-Curtain-Earth system and solar irradiance reduction rate are required. This study revisits the mathematical modeling of the solar irradiance reduction system and considers the fundamentals of shading physics. Simplified mathematical modeling of solar irradiance reduction rate is derived based on the solar flux density. For the climate control, controllability of the reduction rate by using some physical parameters (e.g., flux reflection rate and angle of the curtain) is discussed. Based on the results of this model, the technical challenges and feasibility of constructing a sunshade system at L1 Lagrange point are evaluated. Some technologically feasible, near-future options for the warming problem are discussed briefly.

On Thin Ice: Solar Geoengineering to Manage Tipping Element Risks in the Cryosphere by 2040

AbstractTipping elements are features of the climate system that can display self‐reinforcing and non‐linear responses if pushed beyond a certain threshold (the “tipping point”). Models suggest that we may surpass several of these tipping points in the next few decades, irrespective of which emissions pathway humanity follows. Some tipping elements reside in the Arctic and Antarctic and could potentially be avoided or arrested via a stratospheric aerosol injection (SAI) program applied only at the poles. This paper considers the utility of proactively developing the capacity to respond to emergent tipping element threats at the poles as a matter of risk management. It then examines both the air and ground infrastructure that would be required to operationalize such capability by 2040 and finds that this would require a funded launch decision by a financially credible actor by roughly 2030.

Minority groups, Indigenousness and Indigeneity, and place in social perceptions of future climate interventions

Radical climate intervention technologies such as carbon dioxide removal and solar radiation management pose difficult questions as potential remedies for destructive climate change. The effect these technologies could have on Indigenous peoples and minority groups, and those living in rural areas, could be profound and potentially calamitous. Drawing on a large-scale, cross-country set of nationally representative surveys (n = 30,284 participants, with at least 1,000 in each country) in 30 countries and 19 languages, this article examines public preferences for climate intervention technologies through the three dimensions of minority groups, Indigenousness, and place. The survey explores 10 climate intervention or geoengineering technologies: stratospheric aerosol injection, marine cloud brightening, space-based geoengineering, afforestation and reforestation, soil carbon sequestration, blue carbon and marine biomass, direct air capture with carbon storage, bioenergy with carbon capture and storage, enhanced rock weathering, and biochar. Comparing the full sample of respondents with a subsample self-identifying as ethnic minorities or Indigenous peoples, it finds this latter category of respondents has greater familiarity with these technologies than non-members, are more positive about small-scale trials and have more positive attitudes towards engineered options (versus nature-based options). Those in cities also expressed stronger support for small-scale field trials. Moreover, members of Indigenous groups or ethnic minorities expressed significantly higher levels of support for small-scale trials for nearly all technologies, were more supportive of policy incentives, and, inter alia, less supportive of policy restrictions. Conversely, non-members of Indigenous or ethnic minority groups expressed small but significantly greater support for independent national restrictions being placed on solar radiation management and engineered forms of carbon removal.

Why Conceptions of Scale Matter to Artificity Arguments in SRM Ethics

ABSTRACT Ethicists have raised a variety of concerns about solar radiation management (SRM). This essay investigates the specific worries associated with artificity: Does SRM transform the planet into an artifact? Should experimental SRM strategies be implemented if the consequences are unpredictable? These worries have led some to strongly reject SRM. But the conceptual framework used by environmental scientists to understand the scope of management interventions might offer a way to adequately defuse the perceived ethical concerns about artificity. Concepts from theories of scale, like discontinuity and panarchy, are discussed to demonstrate how the artificity arguments appear to depend on disputable premises.

Strategic dimensions of solar geoengineering: Economic theory and experiments

Solar geoengineering denotes a set of technologies that would enable a fast and relatively cheap global temperature reduction. Besides potential physical side-effects, a major concern is the strategic dimension: Who is going to use solar geoengineering and how would it affect others? How does the presence of solar geoengineering change the strategic incentives surrounding other climate policy instruments such as mitigation? We review the existing theoretical and experimental contributions to those questions and outline promising lines of future economic research.

On the credibility of threats to avoid the deployment of solar geoengineering

AbstractWe analyze how geoengineering in the form of solar radiation management (SRM), associated with the potential of high collateral damages, affects the governance architecture of climate agreements. We investigate under which conditions signatories to a climate agreement can avoid the deployment of SRM and implement a climate agreement on mitigation. We show that a climate agreement with all countries can be stable with the threat to deploy SRM in case a country free-rides. The threat is deterrent if collateral damages are perceived to be sufficiently high (lower threshold), but only credible if those damages are not too high (upper threshold). SRM deployment is the only threat available to signatories if they choose mitigation levels simultaneously with non-signatories (Nash–Cournot scenario). However, if signatories choose mitigation levels before non-signatories (Stackelberg scenario), an additional punishment option arises. Then if collateral damages are sufficiently large, signatories can reduce their mitigation levels and impose a heavier burden on non-signatories that would find it profitable to avoid the deployment of SRM. We show that our results are robust in two analytical frameworks frequently employed in the game-theoretic analysis of international environmental agreements.

Assessment of solar geoengineering impact on precipitation and temperature extremes in the Muda River Basin, Malaysia using CMIP6 SSP and GeoMIP6 G6 simulations

The concept of solar geoengineering remains a topic of debate, yet it may be an effective way for cooling the Earth's temperature. Nevertheless, the impact of solar geoengineering on regional or local climate patterns is an active area of research. This study aims to evaluate the impact of solar geoengineering on precipitation and temperature extremes of the Muda River Basin (MRB), a very important agricultural basin situated in the northern Peninsular Malaysia. The analysis utilized the multi-model ensemble mean generated by four models that contributed to the Geoengineering Model Intercomparison Project (GeoMIP6). These models were configured to simulate the solar irradiance reduction (G6solar) and stratospheric sulfate aerosols (G6sulfur) strategies as well as the moderate (SSP245) and high emission (SSP585) experiments. Prior to the computation of extreme indices, a linear scaling approach was employed to bias correct the daily precipitation, maximum and minimum temperatures. The findings show that the G6solar and G6sulfur experiments, particularly the latter, could be effective in holding the increases in both annual and monthly mean precipitation totals and temperature extremes close to the increases projected under SSP245. For example, both G6solar and G6sulfur experiments project increases of temperature over the basin of 2 °C at the end of the 21st century as compared to 3.5 °C under SSP585. The G6solar and G6sulfur experiments also demonstrate some reliability in modulating the increases in precipitation extreme indices associated with flooding to match those under SSP245. However, the G6sulfur experiment may exacerbate dry conditions in the basin, as monthly precipitation is projected to decrease during the dry months from January to May and consecutives dry days are expected to increase, particularly during the 2045–2064 and 2065–2084 periods. Increases dry spells could indirectly affect agricultural and freshwater supplies, and pose considerable challenges to farmers.

Analysis of OPEN LETTER: We Call for an International Non-Use Agreement on Solar Geoengineering

The climate and environmental problems are becoming increasingly severe, and changing the world. Under such a circumstance, solar geoengineering has been proposed. The article pay attention to an important question which related to the building of solar geoengineering- Practicality. While affirming that the proposal to sign the International Agreement on the Non-Use of Solar Geoengineering is correct, we also questioned some specific suggestions mentioned in the agreement. This article will analyze the original document from four points: introduction, attitude, recommendations, and critical opinion.

Neural Networks to Find the Optimal Forcing for Offsetting the Anthropogenic Climate Change Effects

Abstract Of great relevance to climate engineering is the systematic relationship between the radiative forcing to the climate system and the response of the system, a relationship often represented by the linear response function (LRF) of the system. However, estimating the LRF often becomes an ill-posed inverse problem due to high-dimensionality and nonunique relationships between the forcing and response. Recent advances in machine learning make it possible to address the ill-posed inverse problem through regularization and sparse system fitting. Here, we develop a convolutional neural network (CNN) for regularized inversion. The CNN is trained using the surface temperature responses from a set of Green’s function perturbation experiments as imagery input data together with data sample densification. The resulting CNN model can infer the forcing pattern responsible for the temperature response from out-of-sample forcing scenarios. This promising proof of concept suggests a possible strategy for estimating the optimal forcing to negate certain undesirable effects of climate change. The limited success of this effort underscores the challenges of solving an inverse problem for a climate system with inherent nonlinearity. Significance Statement Predicting the climate response for a given climate forcing is a direct problem, while inferring the forcing for a given desired climate response is often an inverse, ill-posed, problem, posing a new challenge to the climate community. This study makes the first attempt to infer the radiative forcing for a given target pattern of global surface temperature response using a deep learning approach. The resulting deeply trained convolutional neural network inversion model shows promise in capturing the forcing pattern corresponding to a given surface temperature response, with a significant implication on the design of an optimal solar radiation management strategy for curbing global warming. This study also highlights the technical challenges that future research should prioritize in seeking feasible solutions to the inverse climate problem.

Public perceptions on solar geoengineering from focus groups in 22 countries

Solar geoengineering maintains a vocal presence as a stop-gap measure in assessments of climate and sustainability action. In this paper, we map prospective benefits and risks, and corresponding governance approaches, regarding three major proposals for solar geoengineering (stratospheric aerosol injection, marine cloud brightening, and a space-based sunshield). We do so by engaging with 44 focus groups conducted in 22 countries split between the global North and South. We compare results against previous research on the public perceptions of solar geoengineering as well as wider activities in assessment, innovation, and decision-making. We find that global South groups exhibit greater hope but an arguably richer range of concerns for solar geoengineering, in the context of observable inequities in climate action and potential geopolitical conflict. Meanwhile, a strong, global preference for multilateral coordination and public engagement from the conduct of research onwards is offset by skepticism of effective multilateralism and public discourse.

A Coordinating Small Organic Molecule with Tunable Lower Critical Solution Temperature for Efficient Management of Solar Radiation.

Structurally well-defined small molecules with lower critical solution temperature (LCST) behavior offer enormous prospects for fine-tuning their phase transition properties to be "on-demand" applied in the specific scene but are still underexplored. Herein, a novel amphiphilic small LCST molecule is rationally designed and synthesized. The molecule, namely TG, features a conjugation of multiple short ethylene glycol (EG) chains with the functional coordinating terpyridine (Tpy) moiety. The molecule TG demonstrates excellent LCST behavior down to 0.05× 10-3 m in a water solution. And a cloud point Tcp = 30.9°C with a very short thermal hysteresis ΔT = 0.2°C and good reversibility can be achieved when c = 0.1× 10-3 m. The excellent LCST properties of TG have enabled its successful performance as the smart window for solar radiation management with the ∆Tlum, ∆TIR, and ∆Tsol being 83.6%, 49.1%, and 67.2%, respectively. Moreover, the presence of Tpy moiety in TG enables its coordination with Ru3+ and the resulting complex also exhibits modulated LCST behavior with different concentration-dependent Tcp. These studies would provide novel small-molecule-based scaffolds for constructing better solar radiation management systems as well as other thermal-responsive smart materials.