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Research Paper: Air quality impacts of stratospheric aerosol injections are likely small and mainly driven by changes in climate, not aerosol settling (EGU)
Preprint: Stratospheric ozone projections under sulfur-based stratospheric aerosol injection: Insights from the multi-model G6-1.5K-SAI experiment (EGUsphere)
Tool: Explore technical uncertainties in SAI research (Reflective)
Ban: Iowa considers criminalizing cloud seeding, geoengineering (E&E News by Politico)
Analysis: Should the Arctic be refrozen? (The Economist)
Upcoming Event: Normalizing Conversations about the Unthinkable (Yale Jackson School of Global Affairs)
Podcast: The State of the Climate 2026 | Zeke Hausfather (Cleaning Up Podcast)
Read on to unpack more updates:
Time Left to Critical Climate Feedback/Loops: Annual Solar Geoengineering-PLUS, Pathways to Planetary Self-Cooling
Authors: Alec Feinberg
Synopsis: This study projects that climate feedbacks will dominate global warming by late century, sharply increasing mitigation difficulty and tipping-point risks. It identifies a critical threshold where feedback loops exceed half of warming and proposes Annual Solar Geoengineering-PLUS (ASG+P) pathways—combining targeted Earth Brightening, Arctic SAI, limited space sunshades, and enhanced mitigation—to slow feedback amplification, extend mitigation timelines, and complement IPCC-aligned climate strategies while avoiding full-scale geoengineering risks.
Air quality impacts of stratospheric aerosol injections are likely small and mainly driven by changes in climate, not aerosol settling
Authors: Cindy Wang, Daniele Visioni, Glen Chua, and Ewa M. Bednarz
Synopsis: Using large CESM2-WACCM6 ensembles, this study evaluates public health impacts of Stratospheric Aerosol Injection (SAI) via changes in PM2.5 and surface ozone. Holding warming at 1.5 °C yields a small net global mortality reduction (~0.4%), with fewer ozone-related deaths but slightly higher PM2.5 mortality. Effects are modest, regionally uneven, sensitive to internal variability, and smaller than gains expected from near-term air quality policies.
Southern Ocean Sulfate Aerosol Sources Quantified From Sulfur Isotopes in Antarctic Ice Cores
Authors: U. A. Jongebloed, T. P. Fischer, P. R. Kyle, L. Kang, Y. A. Bhatti, B. Alexander
Synopsis: This study identifies passive volcanic degassing as a major, previously underrepresented source of sulfate over the Southern Ocean. Sulfur isotope evidence from Antarctic ice cores shows models underestimate volcanic contributions and overestimate DMS emissions. Correcting these biases improves agreement with observations and suggests current emission inventories may distort simulations of sulfate aerosols and aerosol–cloud interactions regionally and globally.
A unifying theory of foreign intervention in domestic climate policy
Authors: Anthony Harding, Juan Moreno-Cruz
Synopsis: This study develops a theory of climate-policy foreign intervention based on a policy externality space defined by exposure divergence and preference asymmetry between countries. It shows that behaviors like free-riding or free-driving arise from strategic position in this space, not from the climate policy itself. The framework explains when and why hegemonic actors intervene using extraction, rewards, or sanctions, and why governance varies across climate technologies and contexts.
Aerosol Forcing Is Negligible in AR6 Due to a Smaller Diagnosed ERF: Evidence from Two Independent Data Methods and SAI Implications - Preprint
Authors: Alec Feinberg
Synopsis: Using two AR6-consistent energy-budget diagnostics, this study finds a smaller effective radiative forcing by 2019 than central AR6 estimates, implying limited scope for a large compensating aerosol cooling offset. Strong feedback amplification reduces the forcing needed to explain observed warming, suggesting that declining anthropogenic aerosols are unlikely to trigger substantial extra warming, with implications for reassessing aerosol assumptions in climate mitigation and solar geoengineering debates.
Stratospheric ozone projections under sulfur-based stratospheric aerosol injection: Insights from the multi-model G6-1.5K-SAI experiment - Preprint
Authors: Ewa M. Bednarz, Amy H. Butler, James M. Haywood, Matthew Henry, et al.
Synopsis: Using the GeoMIP G6-1.5K-SAI multi-model experiment, this study assesses 21st-century impacts of Stratospheric Aerosol Injection on ozone. All models show a small global ozone decline (1–2%), driven by sulfate-induced halogen activation, strongest in Southern Hemisphere mid-to-high latitudes. Ozone depletion risks are larger earlier in the century as halogen levels fall, underscoring scenario-dependent uncertainties and the need for multi-model evaluation of SAI impacts.
Sulfur, soot, and salt tracks: How good are ship tracks as analogues for marine cloud brightening? - Preprint
Authors: Michael Diamond
Synopsis: Aerosol–cloud interactions create a large but uncertain cooling effect that obscures future warming estimates. Ship tracks are used as natural experiments, but changing fuel regulations have altered aerosol composition, raising doubts about their relevance for marine cloud brightening (MCB). Using satellite data and simulations, this study tests whether historical sulfur- and soot-based ship tracks reliably represent salt-based tracks, finding key differences that could mean MCB efficacy is currently underestimated.
Cloud-resolving Simulations of Low Marine Clouds and Their Response to Aerosol Perturbations - Preprint
Authors: Ehsan Erfani
Synopsis: Marine low clouds strongly influence Earth’s radiative balance, yet their response to aerosols remains highly uncertain for climate projections and Marine Cloud Brightening (MCB). Using large-eddy simulations initialized from 54 representative Northeast Pacific stratocumulus states, this study links aerosol concentration to liquid water path, cloud fraction, mesoscale structure, and cloud transitions, providing a process-based framework to assess aerosol perturbations and MCB efficacy under realistic conditions.
The Politics of Geoengineering: Perspectives from the Social Sciences
Synopsis: This book provides the first comprehensive social science analysis of geoengineering, examining the political, legal, economic, and societal dimensions of CDR and SRM. Through SWOT and regional perspectives, it explores governance, ethical, and geopolitical risks, offering policymakers and scholars practical frameworks to navigate the “risk versus risk” dilemma of climate intervention.
CHAPTERS
Chapter 01: Geoengineering has shifted from theory to contested policy, with technology outpacing governance. The analysis highlights political, legal, economic, and justice dimensions and calls for urgent global oversight.
Chapter 2 examines Carbon Dioxide Removal (CDR) as geoengineering, analyzing CO2 extraction, storage, and conversion, with SWOT insights on techniques and implications for sustainable climate action.
Chapter 3 explores Solar Radiation Modification (SRM) to reflect sunlight and curb warming, analyzing stratospheric, space-based, and ground methods with a SWOT assessment of their potential.
Chapter 4 covers CDR and SRM as climate interventions, highlighting their costs, risks, and governance challenges, and stresses that international cooperation is key to their safe and effective deployment.
Chapter 5 reviews solar geoengineering research and governance in the Asia-Pacific, highlighting North-South disparities, public perceptions, and the need for inclusive, globally coordinated discussions.
Chapter 6 examines CDR in Africa, assessing its climate potential, human rights risks, and how the African Union’s legal framework could guide safe, rights-based geoengineering.
Chapter 7 explores geoengineering’s role in protecting biodiversity, highlighting risks of CDR and SRM, potential ecological impacts, and the need for strong governance to safeguard ecosystems and climate goals.
Chapter 8 covers international law’s role in geoengineering governance, highlighting the need for harmonized, multilateral standards, inclusive frameworks, and science-based legal solutions for effective oversight.
Chapter 9 explores links between solar geoengineering and ecocide law, arguing that ecocide frameworks, combined with polycentric governance, could guide legal oversight and protect the global commons.
Chapter 10 examines space-based geoengineering as a potential climate solution, highlighting the need for careful legal regulation under the Outer Space Treaty and possible updates to international space law.
Chapter 11 highlights the uncertain future of geoengineering, emphasizing the urgent need for anticipatory, agile governance grounded in shared human values to guide research, deployment, and global cooperation.
Chapter 12 explores public engagement with geoengineering, highlighting challenges, trends, and empirical insights from Portugal, and calls for institutionalized participation, a People’s Charter, and serious policymaker attention.
Chapter 13 uses science fiction to explore terraforming, examining how novels like Robinson’s Mars trilogy and Weir’s Artemis highlight decision-making, governance, corporate influence, and identity in interplanetary colonization.
Share Solar Geoengineering Updates
Global Newswire – Reflective launches Uncertainty Database for Stratospheric Aerosol Injection Research
Trail Guide to a Gigaton – Things happen: Geoengineering for boy scouts
LootPress – West Virginia Senate Bill Seeks to Ban Unauthorized Weather and Atmospheric Manipulation
DSG – Holding Two Truths: Global Climate Questions and Local Climate Action
The Economist – Should the Arctic be refrozen?
Upon Further Reflection – Ensuring Continuity for Atmospheric Research
New Scientist – Termination shock could make the cost of climate damage even higher
E&E News by Politico – Iowa considers criminalizing cloud seeding, geoengineering
The ARC: Thoughts on a safe climate future – Beasts of Burden Meet Climate Interventions: Rebuilding an ice-age ecosystem with millions-of-year-old technology
Inevitable & Obvious – How Do You Shift an Overton Window?
SRM360 – Towards a Roadmap for Sunlight Reflection Research
Reflective – Explore technical uncertainties in SAI research
The Atlantic – The ‘Doomsday Glacier’ Could Flood the Earth. Can a 50-Mile Wall Stop It?
LinkedIn – Cooling the Planet: What Business Leaders Need to Know About Geoengineering
Solar Geo-what? – Dig into cooling the planet (Ben Kalina)
03 February | Online - Funding SRM Research Responsibly: From Principles to Practice and Back by Co-Create
04 February | United States - Normalizing Conversations about the Unthinkable by Yale Jackson School of Global Affairs (NEW)
11 February | United States - C4E PJAC: PLAN C for CIVILIZATION Screening (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
18 March | University of Cambridge - Climate Repair: Hope or Hype? by Centre for Climate Repair (NEW)
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
Solar Geoengineering Events Calendar
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The State of the Climate 2026 | Ep242: Zeke Hausfather | Cleaning Up Podcast
“How do we model the climate system? How warm will 2026 be? And can geoengineering be anything more than a bandaid?
This week on Cleaning Up, Bryony Worthington sits down with leading climate scientist Dr. Zeke Hausfather on the day the 2025 global temperature data is released. Despite a La Niña year, the planet has just experienced one of its hottest years on record — pushing us ever closer to the 1.5°C threshold.
Zeke explains why recent warming has accelerated, how declining air pollution may be unmasking hidden heating, and what disappearing cloud cover could mean for climate sensitivity.
The conversation ranges from the surprising accuracy of early climate models, the risks of rising nationalism, and what the U.S. withdrawal from international science means for the world.
They also tackle controversial questions: Are worst-case climate scenarios still plausible? Is geoengineering a dangerous distraction — or an emergency brake? And can carbon removals ever work economically at scale.”
Net Zero Speaks to Gernot Wagner | Planet Classroom Network
“Climate economist Gernot Wagner (Columbia Business School) briefs the world on 2025’s climate reality: what works now, what’s blocking projects, why geoengineering needs guardrails, and how to make net-zero credible and fair. A practical roadmap for policymakers, businesses, and educators seeking progress today.”
Clare Farrell – How to move from binary to systemic climate thinking? | Operaatio Arktis
“XR Co-Founder Clare Farrell sat down in an all-encompassing interview with OA’s Anni Pokela to discuss aerosols, James Hansen, approaches to climate intervention research and the knowledge base of international institutions as well as civil societies in the face of accelerating global warming.”
Can SRM Prevent Tipping Points? | Climate Chat
“In this Climate Chat episode, host Dan Miller discusses SRM and its possible impact on various tipping points.”
Time Left to Critical Climate Feedback: Annual Solar Geoengineering-PLUS, Pathways for Self-Cooling | dfrsoft
Live Discussion: Could Solar Geoengineering Help Protect Coral Reefs? | SRM360
“Corals face a bleak outlook as climate change and ocean acidification worsen.
An expert panel featuring Daniel Harrison, Ken Caldeira, and Cheryl Harrison discuss:
– How climate change impacts corals
– If warm-water corals could go extinct
– The potential impacts and limitations of regional and global solar geoengineering”
What can engineering do for the climate? Centre for Climate Repair, Cambridge | Centre for Climate Repair
“Glacier protection, carbon capture, and working in the real world. With Prof Jerome Neufeld, Rishul Karia, and Dr Zeynep Clulow.”
Bad Idea #37 “1.5 degrees” with Kwesi Quagraine and Erle Ellis | WePlanet
“Is the 1.5°C temperature target helping or hindering climate action? In this episode of Saving the World from Bad Ideas, Mark Lynas sits down with his co-authors Kwesi Quagraine (climate scientist at NCAR) and Erle Ellis (professor at University of Maryland Baltimore County) to discuss their groundbreaking new paper published in Nature that proposes a complete rethinking of how we measure climate progress.
The team argues that global average temperature targets — the organizing principle of climate policy since Paris 2015 — are intangible, unactionable, and increasingly counterproductive now that we’ve essentially crossed the 1.5°C threshold. Instead, they propose the Clean Energy Shift (CES) — a simple, measurable metric that tracks how fast clean energy is displacing fossil fuels in real time.”
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