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THIS WEEK’S TOP SRM HIGHLIGHTS
Research Paper: Radiative Forcing and Ozone Depletion of a Decade of Satellite Megaconstellation Missions (AGU)
Working Paper: Solar Radiation Modification: Scientific evidence does not support SRM as a viable climate solution (UNEP)
Essay: Bitch Less, Build More - Towards a more effective environmentalism (Contents May Shift)
News Feature: Can Some Very Tiny Particles Cool the Planet? One Tech Company Says Yes. (The New York Times)
Upcoming Event: Strategic Aspects of SRM Research: Geopolitical Dimensions (Co-Create)
YouTube Video: The unknowability of Solar Radiation Management, and why that matters (Centre for Climate Repair)
Read on to unpack more updates:
RESEARCH PAPERS
Stratospheric aerosol forcing for CMIP7 – Part 1: optical properties for pre-industrial, historical, and scenario simulations
Authors: Thomas J. Aubry, Matthew Toohey, Sujan Khanal, et al.
Synopsis: This paper presents the new CMIP7 stratospheric aerosol dataset used in climate models to simulate volcanic and background aerosol impacts from 1750–2023. Unlike CMIP6, the updated dataset relies more heavily on volcanic sulfur emission records and improved modeling of small-to-moderate eruptions, resulting in stronger estimated aerosol forcing and notable temperature differences in historical simulations. The authors highlight major uncertainties, especially before the satellite era, while outlining future improvements needed for continuous operational updates.
Strategic research priorities for marine climate interventions in Australia
Authors: Kerryn Brent, Lennart Bach, Andrew Lenton, Bronte Tilbrook, et al.
Synopsis: This paper explores marine climate interventions (mCIs), including ocean-based carbon dioxide removal and solar radiation management methods aimed at supporting climate mitigation and protecting marine ecosystems. Focusing on Australia, the authors outline key technical, social, and governance challenges that must be addressed over the next decade. They identify three priorities: expanding mCI research, strengthening monitoring and verification systems, and developing inclusive governance frameworks involving affected communities and First Nations groups before any future deployment decisions are made.
Vertical Legal Borrowing and Environmental Governance: Bridging Institutional Gaps for Climate Intervention and Natural Resource Management in Developing Countries
Authors: Princess Nice David
Synopsis: Researchers examine how developing countries can shape emerging governance frameworks for climate intervention technologies like CDR and SRM. Focusing on Nigeria, the study explores “vertical legal borrowing,” where domestic environmental laws and policies influence international governance. Comparing legal frameworks from countries including the Netherlands, Brazil, India, and the United States, the authors argue that developing nations can strengthen environmental governance through reciprocal learning and evolve from passive norm-takers into active contributors to global climate law.
Radiative Forcing and Ozone Depletion of a Decade of Satellite Megaconstellation Missions
Authors: Connor R. Barker, Eloise A. Marais, Eric Y. P. Tan, et al.
Synopsis: This study examines how rapidly growing satellite megaconstellations (SMCs) are affecting the atmosphere through rocket launches and satellite re-entries. Using global emissions data and climate modeling, researchers found that ozone loss from space activity remains small compared to regulated sources, with most depletion linked to chlorine from solid rocket fuels rather than SMCs. However, kerosene-fueled rockets used by SMCs emit large amounts of black carbon in the stratosphere, producing climate effects similar to solar geoengineering. The authors stress the need for atmospheric measurements and laboratory studies to better understand these impacts.
Stratospheric cooling and amplification of radiative forcing with rising carbon dioxide
Authors: Sean Cohen, Robert Pincus & Lorenzo M. Polvani
Synopsis: Scientists investigated why Earth’s stratosphere cools as atmospheric carbon dioxide rises, a key fingerprint of human-driven climate change. Using simplified spectroscopy and radiative transfer models, they found that cooling is mainly controlled by how CO₂ absorbs infrared radiation, with water vapour and ozone also influencing the effect. The study explains why cooling is stronger higher in the stratosphere, why each CO₂ doubling can cause up to ~8 K cooling, and how this cooling boosts CO₂ radiative forcing by ~50%.
From Particles to Policy: Technical Building Blocks for Multi-State SAI Coordination - Preprint
Authors: R. Yahav, A. Spector, D. Kushnir, M. C. Waxman
Synopsis: This paper examines a possible SAI pathway using engineered solid particles designed for improved safety, controllability, and traceability. It proposes two tools for future international coordination: measuring SAI-induced radiative forcing (SRF) directly from aerosol layers and embedding identifying signatures into particles. Drawing on examples like the Montreal Protocol and IAEA safeguards, the study outlines how shared technical metrics could support transparent SAI monitoring and cooperation.
Uptake of stratospheric species on minerals proposed for stratospheric aerosol injection - Preprint
Authors: Anais Lostier, Yair Segev, Tzemah Kislev, Gal Schwartz Roitman, Nadine Locoge, Manolis N. Romanias
Synopsis: This study compares how proposed solid particles for SAI interact with key stratospheric gases linked to ozone chemistry. Researchers found that NO₂ uptake is minimal across all tested materials, while HCl uptake varies greatly depending on surface chemistry and structure. Amorphous silica showed far lower reactivity than calcite or alumina, suggesting it may pose a smaller ozone depletion risk. The findings highlight the importance of designing low-reactivity particles to reduce SAI uncertainties and atmospheric risks.
STARDUST’S PREPRINTS
Paper#01: From Particles to Policy: Technical Building Blocks for Multi-State SAI Coordination
Authors: Roby Yahav, Amyad Spector, Doron Kushnir, and Matthew C. Waxman
Synopsis: Engineered solid particles could offer an alternative pathway for SAI, with properties tailored for improved safety, controllability, and traceability compared to sulfate aerosols. The study proposes technical tools such as direct measurement of SAI-induced radiative forcing and embedded particle signatures to support transparent international monitoring and cooperation. Drawing on precedents like the Montreal Protocol and IAEA safeguards, the authors outline how shared technical standards could aid future coordination while emphasizing that SAI deployment remains premature.
Paper#02: Engineered amorphous silica particles with minimized heterogeneous uptake behavior for stratospheric aerosol injection
Authors: Tzemah Kislev, Alina Berkman, Gal Schwartz Roitman, et al.
Synopsis: Researchers developed engineered amorphous silica particles for potential SAI applications, focusing on reducing chemical interactions with stratospheric gases linked to ozone depletion. Through controlled synthesis and surface engineering, the particles showed extremely low uptake of gases such as HCl, HNO₃, N₂O₅, and O₃ under lower-stratosphere conditions. Compared to crystalline quartz, the engineered particles demonstrated even weaker surface reactivity, suggesting they may significantly reduce risks of ozone-related atmospheric chemistry impacts.
Paper#03: Efficient dispersal of submicron solid particles for stratospheric aerosol injection
Authors: Yair Segev, Eitan Y. Levine, Yair Bar-Yoseph, et al.
Synopsis: This study demonstrates a method for dispersing solid particles for SAI using pneumatic systems and hydrophobic surface treatments. Researchers found that treated amorphous silica particles dispersed far more efficiently into climate-relevant submicron sizes than untreated particles, with smaller 300 nm particles performing best. Modeling and laboratory tests showed that surface engineering can reduce particle clumping, suggesting that practical aircraft-based deployment of solid-particle SAI may be technically feasible.
Paper#04: Composite sub-micron solid particles engineered to enable safe, controllable, efficient, and practical SAI
Authors: Stardust Labs
Synopsis: This paper defines key functionality requirements for particles proposed for SAI, including optical performance, atmospheric lifetime, manufacturability, and aircraft dispersal compatibility. The authors argue that effective SAI particles should be sub-micron, stable, and precisely engineered, with separate core and shell designs to optimize radiative properties and reduce chemical risks. Two promising designs are highlighted: engineered amorphous silica spheres and calcium-carbonate particles coated with silica shells, both aimed at reflecting around 1% or more of incoming solar radiation.
Paper#05: Solid-particle stratospheric aerosol injection: a 2-D modelling exploration of the design space
Authors: Yoav Lederer, Nahliel Wygoda, Dorri Halbertal and Brian E. J. Rose
Synopsis: This study introduces a two-dimensional climate modeling framework to evaluate solid particles proposed for SAI, including silica and calcite. The model examines how particle properties, agglomeration behavior, and injection strategies affect cooling efficiency and stratospheric heating. Results show that tropical injection provides the strongest cooling but also increases heating and particle growth, while seasonal or mid-latitude injection can reduce heating penalties. Calcite produced far lower stratospheric heating than silica due to its minimal infrared absorption.
Paper#06: Uptake of stratospheric species on minerals proposed for stratospheric aerosol injection
Authors: Anais Lostier, Yair Segev, Tzemah Kislev, Gal Schwartz Roitman, Nadine Locoge, Manolis N. Romanias
Synopsis: Researchers compared how proposed solid particles for SAI interact with key stratospheric gases linked to ozone chemistry. While NO₂ uptake was weak across all tested materials, HCl uptake varied dramatically depending on surface chemistry and structure. Amorphous silica showed the lowest reactivity and significantly lower potential for chlorine-driven ozone depletion than calcite or alumina. The findings highlight the importance of engineering low-reactivity particle surfaces to reduce atmospheric risks and uncertainties associated with SAI.
Paper#07: Feasibility Study for Industrial Scale Submicronic Engineered Amorphous Silica Particle (SEASP) Manufacturing for Stratospheric Aerosol Injection (SAI)
Authors: Tamir Kuzurbardov, Avi Yaverboim, Tzemah Kislev, Eli Abramov
Synopsis: This feasibility study examines how Submicronic Engineered Amorphous Silica Particles (SEASP) for SAI could be scaled from specialty chemical production to climate-relevant industrial manufacturing. Using a TEOS-based sol-gel process, the authors estimate that 250 kt/yr production modules could be operational within five years, with expansion to 1 Mt/yr regional hubs possible shortly after. The study identifies TEOS precursor supply as the main bottleneck but concludes that large-scale SEASP manufacturing for climate intervention appears technically and economically achievable.
WEB POSTS
Contents May Shift - Bitch Less, Build More - Towards a more effective environmentalism
The University of Chicago - UChicago Undergraduates Reach for the Stratosphere with PASCAL
C.f.g - From moratorium to mandate
University of Philippines - Solar Radiation Management and Climate Governance spotlighted at national dialogue
Science Literacy Project - Cooling the planet with balloons: Could a geoengineering gamble slow global warming?
TBS Graduates - SAU hosts seminar on solar radiation modification in climate-vulnerable Bangladesh
The Economic Times - Niti Aayog evaluates solar radiation modification to address extreme heat conditions in India
The New York Times - Can Some Very Tiny Particles Cool the Planet? One Tech Company Says Yes.
Yahoo - A closely guarded plan to cool Earth is revealed
The Hill Times - More awareness of geoengineering research needed for climate-change-fight: reader
IFL Science - Pollution From Megaconstellation Launches Is Changing The Atmosphere, Causing “A Climate Effect That’s A Little Bit Like Geoengineering”
ACIR Hub - How could SRM affect West Africa?
Heatmap - The World’s First Major Geoengineering Startup Unveils its Technology
The Degrees Initiative - Ghana hosts first technical workshop to build national expertise on solar radiation modification
Peter Dynes - Cooling the planet requires much more than planting trees
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REPORTS
UNEP - Solar Radiation Modification: Scientific evidence does not support SRM as a viable climate solution
UPCOMING EVENTS
18-19 May | University of Chicago - Frontiers in Climate Systems Engineering by CSEi
22 May | Online - Climate Intervention Virtual Symposia (NEW)
22 May | Online - Strategic Aspects of SRM Research: Geopolitical Dimensions by Co-Create (NEW)
25 May | Online - Exploring climate interventions and the science-policy interface by WCRP
26 May | Philadelphia, United States - Plan C for Civilization: Screening & Panel Discussion (WEST PHILLY) (NEW)
26 May | Online - How Could the First Decade of Solar Geoengineering Unfold? by SRM360
26-29 May | Tórshavn, Faroe Islands - Healthy Humans and Oceans in the Arctic
28 May | Arena 2 Plenum - Building and Sharing Knowledge of Climate Interventions by UArctic Congress
27-29 May | Belgium - International Forum on Solar Radiation Modification Research Governance by Co-Create
01 June | Online - CSAR lecture: Beyond Net Zero: Can We Repair The Climate? by University of Cambridge
02 June | Philadelphia, United States - Plan C for Civilization: Screening & Discussion (SOUTH PHILLY) (NEW)
02-04 June | Rwanda - The IAF Global Space Conference on Climate Change 2026 - Uniting Space and Earth for Climate Resilience
03 June | Online - Foundations of SRM Research & African Climate Implications by Emerging Climate Frontier (NEW)
05 June | Philadelphia, United States - Plan C for Civilization: Screening & Discussion (NORTH PHILLY) (NEW)
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
10-11 September | Washington, DC. - 2026 RFF and Harvard SRM Social Science Research Workshop
12-15 October | Malaysia - Global Tipping Points 2026 | Abstract Deadline: 15 May
Solar Geoengineering Events Calendar
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YOUTUBE VIDEOS
The unknowability of Solar Radiation Management, and why that matters | Centre for Climate Repair
“We are delighted to welcome Daniel Schrag, Sturgis Hooper Professor of Geology, Professor of Environmental Science and Engineering, and Professor of Public Policy at Harvard University. His lecture will explore the possibilities and uncertainties surrounding Solar Radiation Management, and why they matter for science, policy, and society.”
Big Bets to Prevent Climate Collapse | Climate Emergency Forum
“This episode explores how philanthropy can fund the risky, under‑the‑radar climate ideas that governments and markets often neglect. Host Herb Simmens speaks with Joshua Elliott, Chief Scientist at Renaissance Philanthropy, about why we now need ambitious, translational R&D instead of small, incremental tweaks.”
SHORT COURSE
18-19 June | Kwame Nkrumah University of Science and Technology - Short Course on Carbon Dioxide Removal (CDR) and Solar Radiation Modification (SRM) (NEW)
04 June | University of Health and Allied Sciences - Short Course on Carbon Dioxide Removal (CDR) and Solar Radiation Modification (SRM) (NEW)
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