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Fotso-Nguemo, T. C., Chouto, S., Nghonda, J. P., Diedhiou, A., Kravitz, B., Yepdo, Z. D., ... & Abiodun, B. J. (2024). Projected impact of solar radiation modification geoengineering on water deficit risk over major Central African river basins. Environmental Research Letters.
Synopsis: This study assesses the potential impact of solar radiation modification geoengineering on water availability in the Niger, Lake Chad, Cameroon Atlantic, and Congo Basins. Using ensemble-mean simulations from GeoMIP6, findings indicate a robust decrease of up to 60% in water availability due to climate change, particularly in the Cameroon Atlantic Basin under high radiative forcing scenarios. By 2050, rapid population growth could exacerbate water deficits, affecting agriculture and hydropower. However, SRM methods like stratospheric sulfate aerosol injection and global solar dimming could increase water availability by up to 50%, especially in the Cameroon Atlantic Basin, offering potential adaptation strategies for local populations.
Heyen, D., & Tavoni, A. (2024). Strategic dimensions of solar geoengineering: economic theory and experiments. Journal of Behavioral and Experimental Economics, 102271.
Synopsis: This review examines the strategic implications of solar geoengineering technologies, which could facilitate rapid and cost-effective global temperature reduction. It highlights concerns regarding their usage, potential impacts on global relations, and how they might alter incentives related to other climate policy instruments, particularly mitigation efforts. By analyzing existing theoretical and experimental studies, the paper identifies key areas for future economic research to address these complex interactions and enhance understanding of solar geoengineering's broader implications on climate policy and cooperation.
Määttänen, A., Lameille, T., Kloeck, C., Boucher, O., & Ravetta, F. (2024). Uncertainties and confidence in stratospheric aerosol injection modelling: a systematic literature review. Oxford Open Climate Change, kgae007.
Synopsis: Model projections evaluating the efficacy of solar geoengineering, such as Stratospheric Aerosol Injection (SAI), involve uncertainties in scenarios, models, and natural variability. This study reviews 60 articles on SAI to analyze how they quantify and communicate uncertainties. Results show that attention to uncertainty has increased, employing various methods. However, model confidence is not always explicitly communicated, as strengths and weaknesses are implicitly known. Global quantitative assessments of SAI uncertainty remain challenging.
KH, U., Bala, G., & Xavier, A. (2024). Sensitivity of the global hydrological cycle to the altitude of stratospheric sulphate aerosol layer. Environmental Research Letters.
Synopsis: Stratospheric aerosol geoengineering (SAG) aims to counteract climate change. Modeling shows that cooling efficacy increases with aerosol layer altitude. Using a global climate model, researchers studied the impact of volcanic sulfate aerosols at different altitudes (22 km, 18 km, 16 km) on global and tropical precipitation. Results indicate that while cooling efficacy rises with altitude, precipitation changes are less sensitive to aerosol height. This is because the increased cooling efficacy is offset by fast precipitation adjustments. An atmospheric energy budget analysis explains this limited sensitivity of the hydrological cycle to aerosol altitude.
Eckert, C., Hernandez-Jaramillo, D. C., Medcraft, C., Harrison, D. P., & Kelaher, B. P. (2024). Drone-Based Measurement of the Size Distribution and Concentration of Marine Aerosols above the Great Barrier Reef. Drones, 8(7), 292.
Synopsis: Marine aerosol particles act as cloud condensation nuclei, influencing the atmospheric boundary layer by scattering solar radiation. The interaction of ocean waves and coral reefs may affect these particles. A study tested the hypothesis that marine aerosol distribution and size vary over three zones near One Tree Island, Great Barrier Reef. Using a modified drone, aerosol size distribution was measured. Results showed higher concentrations of aerosols below 85 nm in the lagoon compared to open water, with mean mode diameters constant across zones. Air temperature difference and salinity were significant variables, while wind stress magnitude was not. The study highlights the effectiveness of drone-based aerosol measurements.
Ryan, R. G., Toms-Hardman, L., Smirnov, A., Harrison, D., & Schofield, R. (2024). Measurement report: Aerosol vertical profiling over the Southern Great Barrier Reef using lidar and MAX-DOAS measurements. EGUsphere, 2024, 1-20.
Synopsis: Aerosol vertical profile measurements were taken using MAX-DOAS and mini-MPL at One Tree Island, Southern Great Barrier Reef, from February to April 2023. This study aids regional-scale aerosol modeling for solar radiation management. MPL retrieval showed extinction-to-backscatter and depolarization ratios consistent with clean marine aerosol. Aerosol layers extended beyond 2 km during midday but stayed below 1 km at other times. Comparing aerosol optical depth (AOD) from MAX-DOAS, MPL, and Microtops sun photometer revealed mean values of 0.083, 0.090, and 0.104, respectively. AOD variations suggest strong horizontal inhomogeneity, impacting future aerosol modeling.
Bolsen, T., Palm, R., & Kingsland, J. T. (2024). How scientific and partisan media shape support for research on stratospheric aerosol injection. Environmental Politics, 1-22.
Synopsis: A study on 441 US individuals in November 2023 explored the impact of three video presentations on support for stratospheric aerosol injection research. Two videos featured scientific experts either promoting or opposing SAI research, while a third, politicized video by Tucker Carlson opposed SAI. All videos significantly influenced support for or against SAI research. The politicized video notably reduced both support for research and trust in science and technology. The findings highlight the powerful effect of messaging on public opinion about SAI as a climate change strategy.
Goddard, P., Kravitz, B., Scribner, A., Milks, K., & Peterson, C. (2024). Incorporating Climate Engineering into Secondary Education: A New Direction for Indiana’s Science Classrooms. The Hoosier Science Teacher, 47(1), 38-48.
Synopsis: The Climate Engineering Teaching Module (CETM) has been implemented in fifteen Indiana high school classrooms over three years, educating students on geoengineering as a potential temporary solution to climate change. Findings show that CETM effectively raises awareness about the scientific, ethical, political, and economic aspects of geoengineering. It helps students understand the complexities and trade-offs, preparing them for future discussions and responsible decision-making on climate engineering. The module fosters critical thinking and equips students with knowledge to conceptualize beneficial and risk-minimized implementations of these technologies.
Luczak, J. (2024). Current State of Geoengineering. In The Palgrave Handbook of Environmental Policy and Law (pp. 1-20). Cham: Springer Nature Switzerland.
Synopsis: This chapter reviews responses to anthropogenic climate change, emphasizing the need for a combination of aggressive mitigation and adaptation strategies. It highlights growing interest in geoengineering as a supplementary approach. Findings indicate that while various geoengineering techniques are proposed, there is a significant lack of laws, regulations, and governance for their safe development and deployment. The chapter underscores the importance of establishing a regulatory framework to address policy and legal challenges related to geoengineering, providing a foundational understanding for policymakers and lawmakers.
Brown, H. Y., Wagman, B., Bull, D., Peterson, K., Hillman, B., Liu, X., ... & Lin, L. (2024). Validating a microphysical prognostic stratospheric aerosol implementation in E3SMv2 using observations after the Mount Pinatubo eruption. Geoscientific Model Development, 17(13), 5087-5121.
Synopsis: This paper introduces a stratospheric prognostic aerosol (SPA) capability in the DOE Energy Exascale Earth System Model (E3SMv2) to simulate sulfate aerosol formation and evolution. Findings indicate that E3SMv2-SPA accurately reproduces stratospheric aerosol lifetime, burden, and optical depth, aligning with remote sensing observations and the CESM2-WACCM model. However, the model underestimates aerosol effective radius by up to 30%, particularly in coarse-mode aerosols months after eruptions. Scattering efficiencies are 10%-80% higher in models, indicating greater surface diffuse radiation and cooling effects, while absorption efficiencies are 15%-40% lower, suggesting underestimation of stratospheric heating. Overall, E3SMv2-SPA's performance makes it a viable tool for simulating climate impacts from stratospheric sulfate aerosols.
Clark, C. J. (2024). Why Conceptions of Scale Matter to Artificity Arguments in SRM Ethics. Ethics, Policy & Environment, 1-13.
Synopsis: This essay explores ethical concerns surrounding solar radiation management (SRM), particularly regarding its potential to transform the planet into an artifact and the unpredictability of its consequences. Some ethicists reject SRM based on these worries. However, the essay suggests that environmental scientists' conceptual frameworks, particularly theories of scale such as discontinuity and panarchy, can help address these ethical concerns. Findings indicate that arguments against artificity may rely on disputable premises, offering a pathway to reconcile SRM strategies with ethical considerations.
Tan, M. L., Tew, Y. L., Liew, J., Bala, G., Tye, M. R., Chang, C. K., & Muhamad, N. (2024). Assessment of solar geoengineering impact on precipitation and temperature extremes in the Muda River Basin, Malaysia using CMIP6 SSP and GeoMIP6 G6 simulations. Science of The Total Environment, 174817.
Synopsis: This study evaluates the impact of solar geoengineering on precipitation and temperature extremes in the Muda River Basin, a key agricultural area in northern Peninsular Malaysia. Using a multi-model ensemble from the Geoengineering Model Intercomparison Project (GeoMIP6), the analysis focused on solar irradiance reduction (G6solar) and stratospheric sulfate aerosols (G6sulfur) strategies under moderate (SSP245) and high emission (SSP585) scenarios. Findings indicate that both G6solar and G6sulfur could effectively limit increases in annual and monthly mean precipitation and temperature extremes, projecting a 2 °C increase by the century's end compared to 3.5 °C under SSP585. While they may modulate flooding-related precipitation extremes, the G6sulfur strategy could worsen dry conditions, reducing precipitation during dry months and increasing consecutive dry days, posing significant risks to agriculture and freshwater supplies.
Hernandez-Jaramillo, D. C., Medcraft, C., Braga, R. C., Butcherine, P., Doss, A., Kelaher, B., ... & Harrison, D. P. (2024). New airborne research facility observes sensitivity of cumulus cloud microphysical properties to aerosol regime over the great barrier reef. Environmental science: atmospheres.
Synopsis: Researchers established a new airborne research platform using a Cessna 337 aircraft to study aerosol–cloud–radiation interactions, primarily for Marine Cloud Brightening but applicable across various research domains. After its first field deployment over the Great Barrier Reef (GBR), data was collected from two similar cumulus cloud cells under different aerosol regimes. Findings revealed that higher aerosol concentrations resulted in more numerous, smaller cloud drops, suppressing warm rain. This supports the hypothesis that cumulus clouds over the GBR are suitable for MCB. The study highlights the platform's utility and sets the stage for future investigations into aerosol–cloud interactions.
Tilmes, S., Rosenlof, K. H., Visioni, D., Bednarz, E. M., Felgenhauer, T., Smith, W., ... & Thompson, C. (2024). Research criteria towards an interdisciplinary stratospheric aerosol intervention assessment. Oxford Open Climate Change, 4(1).
Synopsis: Current research is fragmented, necessitating a comprehensive international assessment of SAI's impacts, risks, and future directions. This assessment aims to evaluate proposed scenarios and strategies through multidisciplinary criteria, categorized into technical requirements, response impacts, and societal considerations. By including these elements, the assessment fosters interdisciplinary collaboration, particularly with underrepresented regions like the Global South. Recurring global assessments are recommended to align research with decision-makers' needs regarding SAI's feasibility in addressing climate change and its societal and ecological trade-offs.
Sovacool, B. K., Baum, C. M., & Fritz, L. (2024). Minority groups, Indigenousness and Indigeneity, and place in social perceptions of future climate interventions. World Development, 183, 106719.
Synopsis: This article investigates public preferences for radical climate intervention technologies, focusing on their impacts on Indigenous peoples, minority groups, and rural populations. Using a large-scale survey of 30,284 participants across 30 countries, findings reveal that Indigenous and ethnic minority respondents are more familiar with and supportive of various geoengineering technologies, including stratospheric aerosol injection and marine cloud brightening. They favor small-scale trials and policy incentives while showing less support for restrictions on solar radiation management and engineered carbon removal. In contrast, non-members of these groups express greater support for national restrictions on such technologies. Overall, the results highlight the need for inclusive discussions on climate interventions, considering the perspectives of marginalized communities.
Hu, A., Liu, X., Ke, Z., Wagman, B., Brown, H., Lu, Z., ... & Peterson, K. (2024). Size-resolved process understanding of stratospheric sulfate aerosol following the Pinatubo eruption. EGUsphere, 2024, 1-28.
Synopsis: This study enhances the simulation of stratospheric sulfate aerosols in the E3SMv2 model by implementing a sophisticated gas-phase chemistry scheme (full chemistry, FC) and a 5-mode Modal Aerosol Module (MAM5). Compared to simplified chemistry (SC) and a 4-mode version (MAM4), the MAM5 experiments better capture the stratospheric sulfate burden post-Pinatubo eruption, with faster sulfate formation due to an added OH replenishment reaction. The MAM5 configuration generates more sulfate aerosol mass and achieves improved agreement with observations for aerosol optical depth (AOD), showing anomalies that align closely with AVHRR data. The largest changes in global mean net radiative flux at the top of the atmosphere were approximately -3 W/m² for MAM5, compared to about -1.5 W/m² for MAM4, indicating MAM5's superior performance in simulating the aerosol radiative effects.
Finus, M., & Furini, F. (2024). On the credibility of threats to avoid the deployment of solar geoengineering. Environmental Economics and Policy Studies, 1-21.
Synopsis: This analysis explores the governance dynamics of climate agreements in the context of solar radiation management, which poses risks of significant collateral damage. It demonstrates that climate agreements can remain stable through the threat of SRM deployment if collateral damages are perceived within specific thresholds. In scenarios where countries choose mitigation levels simultaneously (Nash–Cournot), SRM serves as the sole deterrent against free-riding. However, in a sequential decision-making context (Stackelberg), signatories gain the option to adjust their mitigation efforts, potentially imposing greater burdens on non-signatories to prevent SRM deployment. The findings are consistent across two commonly used game-theoretic frameworks, underscoring the complexities of international climate governance in the face of geoengineering strategies.
Wallgren, A. (2024). Balancing Sky-High Promises and Unknown Risks: Translations of Unwanted Futures in Risk Assessments of Solar Radiation Modification.
"The Degrees Initiative is a UK-based NGO that builds the capacity of developing countries to evaluate solar radiation modification (SRM), a controversial proposal for reducing some impacts of climate change by reflecting sunlight away from the Earth. Degrees is neutral on whether SRM should ever be used, but we believe that developing countries should be empowered to conduct their own research and to play a central role in SRM discussions. The initiative has been working in different forms for over a decade and our work receives worldwide coverage and widespread acclaim."
"At Deep Science Ventures, we see SRM as an additional tool to combat global warming - one that will buy us time to implement the emissions abatement and atmospheric removal technologies to align with our long-term climate target. As such, SRM can be seen as a treatment for the symptoms, while we scale solutions which solve the cause. However, solar radiation management or any form of geoengineering comes with large uncertainties and therefore high risks.
We aim to mitigate these risks by developing SRM approaches that are intrinsically controllable, yet still impactful, and adaptable to implement learnings to avoid unintended biophysical and social harm. These collaborator roles are opportunities to shape and define responsible SRM trials and lead by example on best practices to limit global warming."
Unlock exclusive insights on solar geoengineering! While all content on Solar Geoengineering Updatesis free for everyone, I invite those who can to become paid subscribers. Your support empowers this important work and helps us spread the message far and wide.
Extra-tropical cyclones - Reboita | Reviewer 2 does geoengineering
"How does SAI affect extra-tropical cyclones? Michelle Simões Reboita explains during a tight interview slot, but @geoengineering1 fails to understand (it takes him at least an hour to understand ANYTHING). Paper: Response of the Southern Hemisphere extratropical cyclone climatology to climate intervention with stratospheric aerosol injection. https://iopscience.iop.org/article/10.1088/2752-5295/ad519e/meta"
"Our guest is Gwynne Dyer, an author, columnist, broadcaster and lecturer on international affairs. In this episode, we discuss the key messages from his new book Intervention Earth: Life-Saving Ideas from the World’s Climate Engineers, based on extensive interviews with the world’s top climate scientists. We discuss his insights from these interviews on the state of our climate, and address controversies and concerns over carbon dioxide removal (CDR) and solar radiation management (SRM)."
Youth advocates on exploratory research into Solar Geoengineering | UnLivable Cultures
"In this episode, Cody talks with Anton Keskinen (Head of Strategy at Operaatio Arktis, and part time Rebel with Extinction Rebellion in Helsinki) and Clara Botto (Director of Youth Engagement Director of Youth Outreach for The Alliance for Just Deliberation on Solar Geoengineering, UNFCC Fellow, Advisory Board Member, Centre for Climate Repair and American Geophysical Union, among other things) about geoengineering, what Solar geoengineering is, geoengineering advocacy, its controversial nature, youth, climate justice, and Indigenous rights."
"Why do we need to better understand the role of aerosols on our ecosystems? And what can it help us learn? To provide the answer is Kelly Wanser, a climate innovation expert and founder and executive director of SilverLining. Kelly joins Climate Curious to explain the cooling effects of particles on clouds. Recorded live at TED 2024."
Navigating the Geopolitical Risks of Solar Geoengineering | Energy Policy Now
"Two experts discuss the geopolitical risks of solar geoengineering and the need for global governance frameworks to prevent conflict."
YOUTUBE VIDEOS
Episode 615 Thinning Icy Clouds | To Save The World
“David Mitchell is a climate change scientist who is exploring the possibility of reducing global warming by seeding cirrus clouds at the poles during the winter months, thereby allowing some of the infrared radiation under to atmospheric blanket to escape into outer space. Paul Beckwith is a climatologist who holds regular video lessons about developments in global warming.”
Geoengineering: Our Last Hope or a Risky Gamble? | Prime Time Topics
“As the planet heats up, scientists are increasingly exploring geoengineering, a controversial set of technologies that could manipulate the climate to combat global warming. But is it a viable solution or a risky gamble with potentially unknown consequences? Join PrimeTime Topics as we delve into the world of geoengineering, examining the potential benefits and drawbacks of different approaches, from reflecting sunlight back into space to removing carbon dioxide from the atmosphere. We'll discuss the ethical, political, and environmental challenges surrounding this emerging field, and explore the potential impact on our planet and future.”
Climate Intervention with Climate Scientist David Keith | Climate Chat
“In this Climate Chat episode, we interview climate scientist David Keith, Professor of Geophysical Science at the University of Chicago where he leads the Climate Systems Engineering program. David previously ran a similar program at Harvard. Dr. Keith founded Carbon Engineering, a company that captures CO2 from the atmosphere.”
Episode 618 Combined Ways of Cloud Cooling 1 | ToSaveTheWORLD
“Franz Oeste keeps coming up with new discoveries about cooling the planet. Now he says that white clouds produce OH radicals, which destroy methane. Clive Elsworth works with him. We dscuss it with a financial manager, Sander Epema, Robin Collins, and David Price.”
UNEP Foresight Report | Solar Radiation Management | Latest Update | Drishti IAS English | Drishti IAS : English
“The United Nations Environment Programme (UNEP) recently published its Foresight Report, warning that deploying Solar Radiation Management (SRM) technologies could lead to environmental disruptions within the next seven years. SRM aims to reduce global warming by reflecting some of the sun's energy back into space.”
Cooling Earth by Using Mirrors to Reflect Sunlight with Dr. Ye Tao, Founder and Executive Director of MEER | Synapse
“Welcome to this special episode of Hardware to Save a Planet. Joining us today is Dr. Ye Tao, Founder and Executive Director of MEER, a company that uses mirrors at scale to reflect sunlight and mitigate the impact of global warming. Join us as we discuss the innovative concept of MEER and its potential to combat climate change. Dr. Tao shares his insights on the urgent need for sustainable solutions and how MEER can help transition civilization toward a more sustainable future. We delve into the fascinating world of nanoparticle research and the possibilities of dimensional reduction. Discover the limitations of renewable energy and the importance of energy ROI. Dr. Tao also explores the exciting applications of mirrors in controlling sunlight and optimizing temperature reduction. Dr. Tao has a multidisciplinary background in physics, chemistry, engineering, and material science, which is uncommon among today's scientists. He received a doctorate from the Department of Chemistry at MIT in 2015 and completed the research requirements for a doctorate in Physics at ETH Zurich. Climate change and greenhouse gas accumulation are, in essence, a three-dimensional problem because we have emitted so much gas in a three-dimensional space, Earth's atmosphere, and it is very freely mixed. To clean this enormous volume of space, we have in front of us a 3D engineering problem, and if you factor in the time needed to suck all the air out and circulate it through a filter, then it becomes a four-dimensional problem. We are obsessed with removing greenhouse gases to try to open a window so the heat from Earth can escape. What if instead of letting the heat escape from Earth, we try to find a way to stop it from developing in the first place, just by reducing the amount of heat produced on the ground as the sun shines on the planet? And in fact, this is a much more efficient way of solving the problem, reducing it from its original three dimensions to just two dimensions.”
Cloud-brightening experiment halted on San Francisco Bay | KPIX | CBS NEWS BAY AREA
“Climate experiments, such as using sea salt particles to test potential cloud brightening, will continue to be funded. Anne Makovec and Molly McCrea report.”
Sci-Fi or Reality? Talking Tomorrow’s Climate Tech | The Aspen Institute
“It sounds like sci-fi: Scientists are beaming solar energy from space, subbing seaweed for plastic and brightening clouds to reflect sunlight to lower temperatures in a warming world. In this series of short talks, innovators working at the cutting edge of climate tech share recent breakthroughs in the field.”
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