Weekly Solar Geoengineering Updates (23 June - 29 June 2025)
Weekly SRM roundup of research papers, web posts, events, jobs, projects, podcasts, videos and much more.
1. This Week’s Top SRM Highlights
2. Research Papers
3. Thesis
4. Web Posts
5. SRM Projects
6. Call for Abstract
7. Upcoming Events
8. Podcasts
9. YouTube Videos
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RESEARCH PAPER: When Are Small-Scale Field Experiments in Solar Geoengineering Worth Pursuing? - Preprint (Phil Sci)
THESIS: Cellulose nanocrystals as a candidate for solar geoengineering (University of Cambridge)
WEB POST: Mirrors in space and underwater curtains: can technology buy us enough time to save the Arctic ice caps? (The Guardian)
UPCOMING EVENT: Virtual workshop series on Stratospheric Aerosol Injection to be held 6 – 9 October 2025 via Zoom (WCRP)
PODCAST: SRM moratoria - Bodansky (Reviewer 2 does geoengineering)
VIDEO: Should We Dim the Sun? (The Aspen Institute)
Read on to unpack more updates:
Key Gaps in Models' Physical Representation of Climate Intervention and Its Impacts
Authors: Sebastian D. Eastham, Amy H. Butler, Sarah J. Doherty, Blaž Gasparini, Simone Tilmes, et al.
Synopsis: SRM could ease climate impacts, but big uncertainties limit informed debate. Gaps stem from limited understanding and model limitations. In this study, experts identified three key modeling gaps for stratospheric aerosols, cirrus, and marine clouds, stressing needs for better aerosol physics, atmospheric chemistry, and cloud interactions. Improved models and new observations can reduce unknowns, clarify SRM’s risks and benefits, and support better climate decisions.
Political ideology and views toward solar geoengineering in the United States
Authors: Beatrice Magistro, Ramit Debnath, Danny Ebanks, Paul O. Wennberg, R. Michael Alvarez
Synopsis: Political polarization hinders climate action in the US, with conservatives often skeptical of government-led policies. Solar geoengineering, a technological climate fix, may transcend this divide due to its novelty and tech-based appeal. Analyzing a national sample of 2,109 voters, the study finds that familiarity with SG reduces polarization over its effectiveness, risks, and strategies. Raising SG awareness could promote bipartisan support for climate policy and bridge ideological gaps.
When Are Small-Scale Field Experiments in Solar Geoengineering Worth Pursuing? - Preprint
Authors: O'Loughlin, Ryan and Visioni, Daniele
Synopsis: A new paper proposes four heuristics—scientific rigor, safety, usefulness, and transparency—to assess when small-scale solar geoengineering field experiments are worth pursuing. These should guide dynamic, iterative evaluation within the research community, helping align experiments with evolving modeling needs, ethical debates, and responsible inquiry standards. The goal is to improve climate models while maintaining careful oversight and accountability.
Cellulose nanocrystals as a candidate for solar geoengineering
Author: Daniel Warnes
Synopsis: This thesis explores cellulose nanocrystals (CNCs) as a safer, bio-sourced SAI candidate. Findings show CNCs can scatter sunlight effectively, with low longwave absorption, and that their aerosol morphology can be tuned by controlling suspension stability. While CNCs are less suited for MCB, they hold promise for SAI and merit further climate modelling.
News Ghana - Climate Groups Condemn Geoengineering as Colonial Distraction at UN Talks
The Narwhal - On solid ice: the plan to refreeze the Arctic
The Guardian - Mirrors in space and underwater curtains: can technology buy us enough time to save the Arctic ice caps?
NKAA Research - Marine Cloud Brightening May Cool the Earth — But Could Impact the Ozone Layer
SRM360 - The Arctic Is Running Out of Time
UK Parliament - Geo-engineering and the Environment
New Scientist - The bold plan to save a vital ocean current with giant parachutes
Click Orlando - Florida weather-control ban takes effect this week. Here’s what that means
Earth Observation Center - Cooling the Atmosphere? – Solar Radiation Management
Four Centric - Blocking the Sun: The UK’s Bold Climate Experiment and What It Really Means
Project Syndicate - Africa Is Not a Solar Geoengineering Test Site
Exploring Emergence - The False Dilemma of Decarbonization and Solar Radiation Management
Harrison & Team - Marine Cloud Brightening in a complex world– moving beyond the Twomey effect
University of Chicago - CSEi is funding interdisciplinary research projects to advance our understanding of climate systems engineering
Call for Abstract for CMIP Workshop - Session: Progress in modelling SRM through GeoMIP | Submission deadline: 13 August 2025
Call for Abstract - Virtual workshop series on Stratospheric Aerosol Injection by WCRP | Deadline: 15 August 2025
04 July | UK - Exeter Climate Conference (2 - 4 July 2025)—Plenary 5: Geoengineering and the concept of responsible climate intervention
04-05 September | Washington DC - 2025 RFF and Harvard SRM Social Science Research Workshop: Governance in a Fractured World
6 – 9 October | Online - Virtual workshop series on Stratospheric Aerosol Injection (NEW)
23 October | Helsinki - ATLAS25: Risk Management of Earth System Tipping Points by Operaatio Arktis
3-7 November | Pune, India - 11th WMO Scientific Conference on Weather Modification
15-19 December | New Orleans, Louisiana - 2025 American Geophysical Union Meeting
9-13 March 2026 | Kyoto, Japan - CMIP Community Workshop (CMIP26) (NEW)
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"In Part 2 of “Smoke and Mirrors: Geoengineering and International Law”, Kate Cook and Mary Church of CIEL look more closely at the legal implications of these technologies including current international restrictions on their deployment, adopted under a number of different treaty regimes, as well as the implications of human rights law and the climate regime."
SRM moratoria - Bodansky | Reviewer 2 does geoengineering
"Daniel Bodansky discusses his recent article on the drawbacks of a global moratorium on solar radiation management deployment.
The conversation critiques whether a moratorium is feasible or effective, arguing it could hinder critical research, be difficult to enforce, and unintentionally become a proxy for a permanent ban. Instead, the discussion highlights the need for more research and stronger governance frameworks to better understand and responsibly manage geoengineering.
Article: Biniaz, S., & Bodansky, D. (2025, May 13). Why a global “moratorium” on solar radiation management deployment should get a chilly reception. Just Security. https://www.justsecurity.org/113295/moratorium-srm-deployment-chilly-reception/"
Weakening the Greenhouse Effect Through Stratospheric Aerosol Injection | Remove and Reflect Podcast
"This episode discusses an article that proposes an alternative stratospheric aerosol injection (SAI) method to combat global warming, focusing on weakening the carbon dioxide greenhouse effect rather than solely reflecting sunlight. While traditional SAI methods involve scattering aerosols like sulfate to increase Earth's albedo, this research explores using absorptive aerosols such as black carbon in the upper stratosphere. The key mechanism involves these aerosols warming the carbon dioxide emission level, which enhances outgoing infrared radiation without altering CO2 concentrations. Through idealized climate model simulations, the authors found this approach to be significantly more efficient per unit aerosol mass compared to conventional scattering methods, emphasizing the need for further research into its potential impacts and side effects."
Should We Dim the Sun? | The Aspen Institute
"As the planet warms, blocking some sun could be our emergency escape hatch—or a devastating Pandora’s box. Solar geoengineering—deliberately reflecting sunlight to cool the planet—is emerging as one of the most controversial tools on the table. Some think it all but inevitable, but there’s critical research ahead before it could ever be deployed at scale."
"Explosive volcanic eruptions offer crucial empirical insights into the effects of natural and anthropogenic stratospheric injections on Earth’s climate. The composition and early dispersion of injected materials, whether volcanic or man-made, play a key role in determining the long-term evolution of aerosol and gaseous plumes in the stratosphere.
Our findings underscore the pivotal role of the early evolution of volcanic clouds in shaping the climate impacts of eruptions. They highlight the necessity of accurately simulating or prescribing these processes within climate models. By comparing Pinatubo and Hunga, we identified new mechanisms and critical uncertainties that must be accounted for when optimizing strategies such as solar radiation management."
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While all content on Solar Geoengineering Updates is 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.