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Higher efficacy of SO2 and accumulation mode-H2SO4 stratospheric aerosol injection: insights from CESM2 and GEOS-Chem with Advanced Particle Microphysics (APM)
Authors: Fangqun Yu, Gan Luo and Arshad Arjunan Nair
Synopsis: This study examines the uncertain radiative efficacy of stratospheric aerosol injection using size-resolved aerosol microphysics in CESM2 and GEOS-Chem. Comparing SO₂ and accumulation-mode sulfuric acid (AM-H₂SO₄) injections across multiple models, results show a large inter-model spread. APM-based simulations place SO₂ efficacy at the high end, while AM-H₂SO₄ consistently delivers ~55–75% higher efficacy due to more favorable particle sizes, with strong implications for SAI design, costs, and risks.
Impacts of stratospheric aerosol injection on the upwelling systems along the eastern boundaries of the southern tropical Atlantic Ocean
Authors: Folly Serge Tomety, Babatunde J Abiodun, Serena Illig, et al.
Synopsis: This study assesses how SAI could moderate climate change impacts on the Angola–Benguela upwelling system under SSP2-4.5. Models project up to 1.4 °C warming with largely stable main-season upwelling but altered secondary-season dynamics. SAI offsets ~90% of upper-ocean warming, shoals the thermocline, and reverses most secondary-season upwelling intensification, though it fails to restore large-scale offshore circulation, revealing uneven regional effectiveness.
Climate Crisis and Solar Radiation Management as a Desperate Measure in Kim Stanley Robinson’s The Ministry for the Future
Authors: Nithya Prabha, Sasi Rekha, P. Suganya
Synopsis: Kim Stanley Robinson’s climate fiction offers a lens on the real-world rise of SRM amid escalating climate crises. In 2026, SRM stands as a controversial, disruptive intervention promising rapid cooling while provoking ethical and governance debates. Parallels with The Ministry for the Future highlight how SRM, though provisional, reinforces existing power structures even as research expands through stratospheric aerosol and marine cloud-brightening proposals.
Beware the Toll Dodgers: defending the Tollgate Principles for governing solar geoengineering
Authors: Stephen M. Gardiner & Arthur R. Obst
Synopsis: This paper defends the Tollgate Principles (TGPs), which frame the ethical “price” required to justify pursuing solar geoengineering. Responding to key critiques, it clarifies misunderstandings and resolves perceived tensions, arguing that TGPs remain a vital, though incomplete, contribution to geoengineering governance. The authors caution against “Toll Dodgers” who dismiss ethics-centered approaches, highlighting broader lessons for governing controversial technologies responsibly.
Impact on cloud properties of reduced-sulphur shipping fuel in the Eastern North Atlantic
Authors: Gerald G. Mace, Sally Benson, Peter Gombert, and Tiffany Smallwood
Synopsis: The 2020 global reduction in shipping fuel sulphur (~80%) created a natural experiment to study aerosol–cloud interactions. Comparing pre- and post-2020 observations at the ARM Eastern North Atlantic site shows a ~15% drop in cloud condensation nuclei, leading to fewer cloud droplets and larger droplet sizes. Increased liquid water path offset these changes, yielding minimal shifts in cloud optical depth and albedo, underscoring complex cloud–climate feedbacks.
A system dynamics framework for untangling solar radiation modification perceptions in the global south
Authors: Mauricio Uriona Maldonado, Caroline Rodrigues Vaz, Sara Grobbelaar and Rhythm Singh
Synopsis: As interest in Solar Radiation Modification grows amid inadequate mitigation, this study centers Global South perspectives often missing from governance debates. Using a System Dynamics framework and stakeholder engagement in Brazil, it maps feedbacks shaping SRM perceptions. The analysis highlights key reinforcing loops around mitigation deterrence and tensions between rapid cooling benefits and equity concerns, showing SD as a powerful tool for inclusive sense-making and more equitable SRM governance.
Ship fuel sulfur content regulations may exacerbate mass coral bleaching events on the Great Barrier Reef
Authors: Robert G. Ryan, Daniel P. Harrison, Lasse Johansson & Robyn Schofield
Synopsis: Using WRF-Chem, this study assesses how 2020 shipping fuel sulphur regulations altered aerosols, clouds, and radiation over the Great Barrier Reef. During February 2022, an additional ~11 W m⁻² of daytime shortwave radiation reached the reef post-regulation, mainly under clear-sky conditions. Sustained increases of 5–11 W m⁻² likely raised sea-surface temperatures by 0.05–0.15 °C, adding an estimated 5–10% thermal stress during coral bleaching events.
Regulating the Unthinkable: Climate Interventions as a Test Case for Risk Governance
Authors: Alberto Alemanno and Masa Sugiyama
Synopsis: As climate overshoot risks rise, this article examines governance challenges surrounding climate interventions such as SRM and CDR. It explores legitimacy, justice, legal fragmentation, risk analysis, precaution, markets, intellectual property, and regional perspectives. Synthesizing contributions from a Special Issue of the European Journal of Risk Regulation, it highlights tensions over how risks are compared and governed, concluding that climate intervention governance is a critical test of modern risk regulation and collective self-governance under deep uncertainty.
Aluminum Oxide and Calcium Carbonate: Potential Alternative Particles for Applications in Solar Geoengineering - Preprint
Authors: Eliana Linder and Sophia Zouak
Synopsis: This experiment explores alternatives to sulfate aerosols for solar geoengineering, testing calcium carbonate (CaCO₃) and aluminum oxide (Al₂O₃) under simulated lower-stratospheric conditions. Using an air chamber and solar cell measurements, Al₂O₃ reduced light transmission most during high-mass injection, while CaCO₃ performed better under lower-mass suspension. Under humid conditions, both showed similar reductions in light, suggesting non-sulfate particles could offer promising, though context-dependent, solar radiation reflection potential.
Summary maps of mean surface SO4 aerosol changes over the Coral Sea and GBR in different simulation scenarios
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Belfer Center for Science and International Affairs – Arctic Climate Interventions: A Climate Justice Challenge
The Conversation – Climate engineering: what are we talking about? What are the benefits and what new risks does it present?
CDA Institute – The Janus dichotomy of solar geoengineering for the Canada–U.S. security relationship
The Guardian – A bid to clean up shipping industry intensified a coral bleaching event on Great Barrier Reef, study says
DSG – Colonialism, SRM, and Contending with DSG’s Privilege
Inevitable & Obvious – The Stabilization Framework
New Scientist – Termination shock could make the cost of climate damage even higher
Dungeon of Science – Strategic Approaches to Climate Risk in South Asia: Interview with Dr. Soumitra Das
Michigan Today – The value in planning ahead
Nature – As we breach 1.5 °C, we must replace temperature limits with clean-energy targets
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Call for Applications – Solar Radiation Management (SRM) Fellow at Emerging Climate Frontiers | Deadline to apply: 15 February 2026
Call for Abstract – Session: AS07: Climate Intervention: Understanding its physical mechanisms and impacts | Deadline: 30 January 2026
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29 January | University of Cambridge & Online - What can Engineering do for the climate? by Centre for Climate Repair (NEW)
30 January | Online - Climate Intervention Virtual Symposium #23 (NEW)
30 January | Online - Could solar geoengineering help protect coral reefs? by SRM360
03 February | Online - Funding SRM Research Responsibly: From Principles to Practice and Back by Co-Create (NEW)
9-13 March 2026 | Kyoto, Japan - CMIP Community Workshop (CMIP26)
03-08 May | Vienna, Austria & Online - EGU26
13-15 May | University of Nottingham - IAA Planetary Sunshade Workshop by Planetary Sunshade Foundation
17-19 March | Tokyo, Japan - Sixteenth GeoMIP 2026 Meeting by Alan Robock and Daniele Visioni
28 – 29 May | Belgium - International Forum on Solar Radiation Modification Research Governance by Co-Create
02-04 June | Rwanda - The IAF Global Space Conference on Climate Change 2026 - Uniting Space and Earth for Climate Resilience
20-21 June | United States - Bridging the Knowledge Gaps in Climate Engineering with Experiments, Models, and Observations by Gordon Research Seminar
21-26 June 2026 | United States - Gordon Research Conference - Bridging Observations, Models, and Impacts in Solar Radiation Modification Research
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Inside ARIA | BBC Podcast
“ARIA is the UK government’s bold new bet on science and technology. Its mission? To chase breakthroughs so radical they could spawn trillion-pound industries and reshape everyday life.
The Advanced Research and Invention Agency was created to be fast-moving - exempt from the usual public sector bureaucracy. No slow funding rounds. No rigid procurement rules. Just speed, agility, and a mandate to take risks. It’s backed by MPs across the political spectrum - but is it a smart use of public money?
The idea came from Dominic Cummings, inspired by America’s ‘DARPA’ - the agency behind the internet, GPS, and personal computing. ARIA launched in 2022 and has already sunk millions into 12 audacious programmes: from designing crops with massively synthetic genomes to building robots on entirely new principles, and developing cutting edge neurotechnologies for psychiatric illness.
Evan Davis goes inside ARIA to meet the people steering this high-stakes experiment and explore the frontier science they’ve chosen to back. Can ARIA deliver world-changing innovation - or will it prove an expensive gamble?”
Comparing SRM and Opioids - Clark | Reviewer 2 does geoengineering
“In this episode, @geoengineering1 is joined by Britta Clark, a postdoctoral researcher at Harvard University, to unpack why solar geoengineering is increasingly compared to opioids. They discuss how this framing casts SRM as temporary “relief” from climate warming and why it raises concerns about potentially slowing emissions cuts. The conversation focuses on how climate models, policy debates, and public discourse can quietly shift expectations about how fast emissions reductions should happen once solar geoengineering is considered, even when people say it should not delay the energy transition. Together, they explore why this tension matters and what it could mean for future climate decisions.
Paper: Clark, B. (2025). Solar geoengineering, delay, and addiction. Climatic Change, 178(11), 209. https://doi.org/10.1007/s10584-025-04059-3
Science vs. Economics on Climate Change | Climate Chat
“In this Climate Chat episode, host Dan Miller discusses how economic assessments of the risks of climate change differ greatly from scientific assessments.”
Shipping Fuel Regulations and Increased Coral Bleaching Risk on the Great Barrier Reef | Remove and Reflect Podcast
“This episode covers a research paper that investigates how international shipping regulations intended to reduce air pollution have unintentionally contributed to extreme heat stress on Australia’s Great Barrier Reef. By lowering the sulfur content in maritime fuel in 2020, the industry decreased the presence of reflective sulfate aerosols that previously shaded the ocean surface from intense solar radiation. Scientists utilized atmospheric modeling to demonstrate that this aerosol reduction allowed more sunlight to reach the water, particularly during the hot, calm periods that precede mass coral bleaching. The study estimates that these cleaner shipping standards increased thermal stress on corals by approximately 5% to 10% during the 2022 bleaching event. Consequently, the findings highlight a complex conflict between improving air quality and protecting vulnerable marine ecosystems from accelerated global warming.”
How to Combat Climate Change in the System | Peter Mccarthy | TEDx Talks
“This talk by Peter McCarthy examines the complex and growing relationship between international climate law, particularly the Paris Agreement, and geoengineering. Drawing on his background as a U.S.-trained lawyer and climate law researcher, McCarthy explains how global temperature became the central metric of the Paris Agreement and why that choice matters. Using vivid, personal examples about how temperature can feel radically different depending on context, he shows that temperature is a deceptively simple but deeply complex target for governing the climate system.”
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