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NEWS: Stardust Solutions, a Geoengineering Startup, Raises $60 Million to Build a Solar-Reflecting System by 2030 (Heatmap)
RESEARCH PAPER: Engineering and logistical concerns add practical limitations to stratospheric aerosol injection strategies (Scientific Reports)
RESEARCH PAPER: Geoengineering prioritization: a study of a proposed expression of mitigation deterrence (Springer Nature Link)
SURVEY: Exclusive: Climate scientists expect attempts to dim the sun by 2100 (New Scientist)
DOCUMENTARY: Plan C For Civilization World Premiere (DOC NYC)
Read on to unpack more updates:
Global and regional thermosteric and dynamic sea level change under stratospheric aerosol injection
Authors: Frédéric Bonou, Aubains Hounsou-Gbo A. Nathanael Dossa, Maiella Toupe, Marcel Kouakou, Arnaud Kouekam, Toussaint Mitchodigni, Zacharie Sohou, Alan Robock, and Ben Kravitz
Synopsis: This study examines how SAI affects global and regional sea level rise using ARISE-SAI-1.5 simulations with CESM2. While SAI maintains surface temperatures near 1.5°C, sea levels still rise—though at a slower rate. Compared to SSP2-4.5, SAI reduces thermal expansion by 49% (3.7→1.9 mm/yr) and ocean heat content by 42%. Notably, SAI lessens sea level rise in the Atlantic Gulf Stream region, highlighting its potential to moderate oceanic change.
Emergency geoengineering & the virtues of Earth stewardship
Authors: Allen Thompson
Synopsis: This paper explores the moral implications of SRM as a form of planetary management. While geoengineering may seem a justified response to climate change, the author argues that true virtue-based planetary stewardship cannot include SRM. Responsible planetary management, though morally obligatory, must avoid hubristic control of Earth’s systems. Thus, even as a “lesser evil,” deploying SRM, such as stratospheric aerosol injection, cannot align with virtuous moral practice.
Effect of stratospheric aerosol injection on marine heatwave events off the coast of South Africa
Authors: Djoirka M. Dimoune, Babatunde J. Abiodun, Marek Ostrowski, Founi M. Awo, Folly S. Tomety, Annette Samuelsen, Issufo Halo & Isabelle Ansorge
Synopsis: This study examines how SAI affects marine heatwaves (MHWs) in the Agulhas Bank off South Africa. Using ARISE-SAI-1.5 and SSP2-4.5 simulations, results show global warming increases MHW frequency, duration, and intensity by up to 150%, 200%, and 15%, respectively, while SAI mitigates these impacts. Machine learning analysis identifies nine SST anomaly patterns, with SAI cooling influences reducing MHW severity and potentially benefiting regional ocean productivity.
Geoengineering prioritization: a study of a proposed expression of mitigation deterrence
Authors: Amanda Sie, Steven R. Brechin & Christopher P. Borick
Synopsis: This study investigates “geoengineering prioritization,” the tendency to favor GE technologies, like solar radiation management or carbon removal, over traditional climate mitigation. Using 2020 U.S. national survey data, results show that support for ocean fertilization, air capture, and space mirrors, along with conservative beliefs, confidence in scientists, and non-White identity, predict GE prioritization. Such views may enable future mitigation deterrence, underscoring the need for deeper research on public attitudes toward GE.
Assessing the performance of solar radiation management geoengineering simulations
Authors: Michael F. Wehner
Synopsis: This study evaluates the effectiveness of SAI in offsetting global warming by comparing climate model simulations targeting specific temperature reductions. Using data from single-model and multi-model experiments, results show that while most SAI schemes successfully maintain global mean temperatures, regional outcomes, such as precipitation and tropical cyclone patterns, vary widely and often exceed natural internal variability, highlighting uncertainties in regional climate control.
Assessing the Response of Surface Cloud Radiative Effects to Stratospheric Aerosol Injections Over West and Central Africa
Authors: Atanas Dommo, Francis Nkrumah, Kwesi A. Quagraine, Nana Ama Browne Klutse, Gandome Mayeul Léger Davy Quenum, Hubert A. Koffi
Synopsis: This study analyzes how SAI under the ARISE-SAI-1.5 scenario affects surface cloud radiative effects (CREs) across Southern West Africa, Central Africa, and the Sahara, compared to SSP2-4.5. Using CESM2-WACCM6 simulations, results show SAI reduces shortwave cloud cooling and enhances longwave warming, with regional variations. These changes, partly due to natural variability, reflect high sensitivity to cloud properties and suggest complex precipitation responses under SAI deployment.
Unequal socioeconomic exposure to drought extremes induced by stratospheric aerosol injection
Authors: Weijie Fu, Xu Yue, Chenguang Tian, Rongbin Xu, and Yuming Guo
Synopsis: This study evaluates how SAI influences global drought extremes using GeoMIP6 and GLENS simulations. While high-emission scenarios project a 7.33% rise in extreme droughts by 2100, SAI reduces this by about 2%. Cooling from SAI lessens drought frequency but is partly offset by reduced precipitation, creating regional inequities. Developing countries face smaller benefits, or even higher drought exposure, highlighting the risk of SAI worsening global hydroclimatic disparities.
Africa’s regional and local climate response to stratospheric aerosol injection characteristics
Authors: Naomi Kumi, Caleb Mensah, Kwesi A. Quagraine, Trisha D. Patel, Frederick Otu-Larbi, Nana Agyemang Prempeh, Mariam Nguvava, Tiro Nkemelang, Babatunde J. Abiodun, Christopher Lennard, Mark G. New, Romaric C. Odoulami
Synopsis: This study assesses how different SAI strategies affect Africa’s climate under the high-emission RCP8.5 scenario using GLENS simulations. All SAI experiments, GLENS, GLENS_low, and GLENS_eq, produce strong cooling, with GLENS_eq most effective in reducing temperature extremes. However, regional disparities persist, such as residual warming in the Sahel and North Africa. While SAI mitigates extreme rainfall, it also intensifies drying, highlighting trade-offs for agriculture and water-dependent regions.
Engineering and logistical concerns add practical limitations to stratospheric aerosol injection strategies
Authors: Miranda Hack, V. Faye McNeill, Dan Steingart & Gernot Wagner
Synopsis: This study examines the technical and governance challenges of SAI, particularly using solid mineral aerosols as a safer alternative to sulfates. While solids could reduce ozone and radiation risks, large-scale deployment faces major uncertainties, such as aerosol aggregation, dispersion limits, supply chain constraints, and governance complexities. These factors significantly narrow the feasible “low-risk” design space for SAI, suggesting that practical risks may be higher than current models imply.
Aerosol Effective Radiative Forcing Accelerates Earth’s Energy Imbalance In Recent Decades - Preprint
Authors: Tianle Yuan, hua song, Ryan Kramer, Lazaros Oreopoulos, Shiv Priyam Raghuraman, Robert Wood, Mian Chin
Synopsis: This study quantifies the role of aerosol-cloud interactions (ERFACI) in Earth’s rising energy imbalance (EEI). Using satellite data, researchers find ERFACI contributed a warming trend of 0.33 ± 0.03 W/m² per decade (2000–2020) across oceans between 60°S–60°N. This warming results from reduced cloud droplet concentrations linked to declining aerosol emissions. The findings help reconcile observed and simulated EEI trends, suggesting weaker overall cloud feedback and significant implications for climate mitigation strategies.
Dominant patterns of sea surface temperature anomalies associated with marine heatwaves (MHWs) events off the South African coast in the present-day climate (PRS) and future climate under the SSP2-4.5 scenario without and with SAI
(Source)
State of the Planet - How Hard Is It to Dim the Sun?
Science Daily - Scientists say dimming the sun could spark global chaos
New Scientist - Exclusive: Climate scientists expect attempts to dim the sun by 2100
Politifact - RFK Jr.’s ‘chemtrails’ probe shows the power conspiracy theories have to shape health policy
RFF - Addressing Social Science Questions About Solar Radiation Modification
IUCN World Conservation Congress - Developing a policy on geoengineering
Heatmap - Stardust Solutions, a Geoengineering Startup, Raises $60 Million to Build a Solar-Reflecting System by 2030
RFF - Recordings of presentations and the associated slides and papers: 2025 RFF and Harvard SRM Social Science Research Workshop: Governance in a Fractured World
DSG - The Compass for SRM: Collective Need Over Private Profit
ScienceDirect - Are we ready to dim the sun?
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Call for Abstracts - AOGS 2026: Session AS07 - Climate Intervention: Understanding its Physical Mechanisms and Impacts | Abstract submission: November 3, 2025 - January 23, 2026
This session aims to bring together researchers, students, practitioners, and thought leaders to share insights, findings, and best practices in the field of climate intervention or geoengineering.
Lead Writer / Editor at SRM360 | Remote
“SRM360 is a non-profit knowledge broker dedicated to opening up the conversation around SRM – creating clear informational tools and a platform for debate.”
What On Earth with Laura Lynch | CBC Listen
“Work is underway to pump seawater onto ice in Nunavut as a way to thicken it in the face of climate change. The experiment is showing some promising results but there are also concerns about its impact on ecosystems. Journalist Alec Luhn travelled onto the ice to see what was happening and to listen to local Indigenous elders about what the ice means to them. He also considers the moral hazard of trying to geoengineer a solution and whether it distracts from the real work needed to cut emissions.”
WCRP Lighthouse Activity: Virtual Workshop Series on Stratospheric Aerosol Injection (SAI)-Session 1 | World Climate Research Programme
WCRP Lighthouse Activity: Virtual Workshop Series on Stratospheric Aerosol Injection (SAI)-Session 2 | World Climate Research Programme
WCRP Lighthouse Activity: Virtual Workshop Series on Stratospheric Aerosol Injection (SAI)-Session 3 | World Climate Research Programme
WCRP Lighthouse Activity: Virtual Workshop Series on Stratospheric Aerosol Injection (SAI)-Session 4 | World Climate Research Programme
Biblical Justification for Solar Geoengineering | Robbie Tulip
“Biblical rejection of arrogance and prediction of catastrophic global change indicates support for sunlight reflection technology to slow and reverse global warming.”
Engineering and logistical concerns add practical limitations to SAI strategies | Remove and Reflect Podcast
“This episode covers an academic paper that explores the practical limitations and risks associated with implementing Stratospheric Aerosol Injection (SAI), a proposed solar geoengineering strategy to counter climate change. The authors analyze how engineering and logistical concerns, such as the difficulty of dispersing solid mineral aerosols in the optimal size range and the resulting formation of inefficient aggregates, significantly constrain the design space for “low-risk” SAI compared to idealized models. Furthermore, the source discusses macroscopic constraints like supply chain issues for various aerosol candidates and the critical role of governance and coordinated deployment strategies in mitigating environmental risks and determining the overall effectiveness of SAI. Ultimately, the paper concludes that these overlooked practical factors mean that a low-risk SAI strategy, especially one using solid aerosols, is more limited than current literature suggests, favoring sulfate-based methods due to their more defined risk space.”
28 October | Online - Live Discussion: Could Solar Geoengineering Help or Harm the Amazon? by SRM360
30 October | Online & In-person (UK) - Discover Climate Repair: is this for real by Centre for Climate Repair (NEW)
31 October | Online - Introducing: Sunshade Temperature mitigation using Asteroids and Rings system by Planetary Sunshade Foundation
31 October | Online - Climate Intervention Virtual Symposia #21
Saturdays 01 November - 22 November 22 | Online & In-person - An Intro to Climate Systems Engineering by Members of the Climate Systems Engineering Initiative (including David Keith, Tiffany Shaw, and B.B. Cael)
3-7 November | Pune, India - 11th WMO Scientific Conference on Weather Modification
13 November | New York - Documentary Plan C For Civilization World Premiere (NEW)
14 November | Online - Planetary Sunshade Foundation - annual update by Planetary Sunshade Foundation
14 - 30 November | Online - Documentary Plan C For Civilization World Premiere (NEW)
15 November | New York - Documentary Plan C For Civilization World Premiere (NEW)
01 December | Online & In-person (UK) - Good COP, Bad COP: First reflections on COP30 by Centre for Climate Repair (NEW)
15-19 December | New Orleans, Louisiana - 2025 American Geophysical Union Meeting
9-13 March 2026 | Kyoto, Japan - CMIP Community Workshop (CMIP26)
21-26 June 2026 | United States - Gordon Research Conference - Bridging Observations, Models, and Impacts in Solar Radiation Modification Research
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