| SOLAR GEOENGINEERING WEEKLY SUMMARY (20 JANUARY 2024 - 26 JANUARY 2025) Subscribe to receive the monthly updates:
TABLE OF CONTENTS1. Deadlines2. Research Papers3. Web Posts4. Upcoming Events5. Podcasts6. YouTube Videos
DEADLINES
RESEARCH PAPERSPatrick, H. O. (2025). Reflections on COVID-19 Adaptive Responses as a Template for Climate Intervention-Geoengineering Engagement.AbstractThe discourse on geoengineering applications as a climate intervention strategy has been met with opposing views across many quarters. The central argument underlined the need for more research as solar geoengineering applications' implications are widely unknown. While the discourse raises justice, equity, and governance issues, an underlining debate is how geoengineering engagement should be tailored going forward. Using a systematic desktop review methodology, the paper provides a descriptive overview of Covid-19 responses and possible points to consider for climate interventions. The rationale is to examine the extent to which vertical and horizontal reactions and public opinions influence policy response and actions for Covid-19 adaptation and coping mechanisms as a lesson for Solar geoengineering engagement. It concludes that as a lesson for effective climate intervention, there is a need to develop strategic partnerships among various stakeholders, create an alignment between research objectives and the community's needs and peculiarities, consider the ethics of practice and develop a monitoring and governance framework to avoid possible stakeholders' excesses.
Haywood, J., Boucher, O., Lennard, C., Storelvmo, T., Tilmes, S., & Visioni, D. (2024). World Climate Research Program Lighthouse Activity: An Assessment of Major Research Gaps in Solar Radiation Modification Research. Frontiers in Climate, 7, 1507479.AbstractIt is increasingly evident that maintaining global warming at levels below those agreed in the legally binding international treaty on climate change. i.e. the Paris Agreement, is going to be extremely challenging using conventional mitigation techniques. While future scenarios of climate change frequently include extensive use of terrestrial and marine carbon dioxide removal in the second part of the 21st century, it is unproven that these techniques can be scaled-up to reach the scale required to significantly reduce concentrations of atmospheric carbon dioxide and significant uncertainties and detrimental side-effects exist. These issues have led to increasing interest in so-called “Solar Radiation Modification” whereby the global mean temperature of the Earth is reduced by either blocking a small fraction of sunlight from reaching it or by increasing the Earth’s albedo to reflect a small proportion of incident sunlight back out to space. Here we systematically identify key research gaps associated with the two most prominent Solar Radiation Modification techniques i.e. Stratospheric Aerosol Injection (SAI) and Marine Cloud Brightening (MCB). We provide an assessment of the research gaps associated with other less prominent SRM techniques. We assert that transparency and inclusivity in SRM research is essential in providing objective and impartial research findings to each and every stakeholder in an equitable way.
Nkrumah, F., Quenum, G. M. L. D., Quagraine, K. A., Tilmes, S., Klutse, N. A. B., Dommo, A., ... & Bediako, R. (2025). Climate response to stratospheric aerosol injection during the Harmattan season in West Africa. Environmental Research: Climate.AbstractStratospheric Aerosol Injection (SAI), a proposed climate intervention, aims to reduce the amount of solar radiation reaching the Earth's surface by increasing the reflectivity of the atmosphere, thereby offsetting the warming effect of greenhouse gases. During the Harmattan season (December-February) in West Africa, a natural meteorological phenomenon injects dust and sand particles into the atmosphere, leading to a cooling effect. In this study, we investigate the influence of SAI on West African surface temperature, dust, and other meteorological variables using the Whole Atmosphere Community Climate Model (WACCM) under the Shared Socioeconomic Pathway 2-4.5 (SSP2-4.5) scenario and the Assessing Responses and Impacts of Solar Climate Intervention on the Earth system with Stratospheric Aerosol Injection (ARISE-SAI) dataset. Our findings indicate that SAI intervention significantly impacts the projected surface temperatures, specific humidity, and wind speed changes during the Harmattan season. Compared to a future without SAI, the intervention shows a significant net cooling effect over most parts of West Africa during the mid-future period (2050-2069). Also, SAI intervention significantly decreases moisture content over southern and northern West Africa in the near-future (2035-2054), mainly due to the net cooling effects over West Africa, when compared to a future without SAI. This feature is enhanced in the mid-future period. The cooling effects of SAI are likely to reduce the air's capacity to hold moisture, leading to lower specific humidity levels relative to a future without SAI. It could also have negative implications, such as increased aridity compared to a future without SAI in the northern and central regions of West Africa. These findings also highlight the potential for SAI to improve air quality in certain areas but also underscore the need for careful consideration of implementation strategies and possible trade-offs. The changes from SAI observed are specific to the ARISE simulation and may differ from other SAI simulations.
Braga, R. C., Rosenfeld, D., Hernandez, D., Medcraft, C., Efraim, A., Moser, M., ... & Harrison, D. (2025). Cloud processing dominates the vertical profiles of aerosols in marine air masses over the Great Barrier Reef. Atmospheric Research, 107928.AbstractThe cloud condensation nuclei (CCN) concentrations greatly determine the vertical microphysical evolution and rain initiation of warm convective clouds. We investigated the vertical profile of aerosol particles large enough (diameter > 60 nm) to act as CCN in marine air masses over the Great Barrier Reef. Such data were collected during an aircraft research campaign in February 2024. The results show a strong relationship between the microphysical processes measured in the cloud and the aerosol properties measured at the same altitude. The number concentration of aerosol particles decreases significantly above cloud bases due to CCN activation into cloud droplets. For heights above the in-cloud rain initiation level, the aerosol concentrations decrease further due to the scavenging of particles by drizzle and raindrops. The Hoppel minimum in particle size distributions is observed up to the altitude at which the coagulation process intensifies. Furthermore, a tail of larger aerosol particles was measured above the altitudes of rain initiation. These results suggest that the vertical profile of aerosols measured in marine air masses is dominated by cloud processing.
Ji, D., Cui, M., Chen, Y., & Dai, Y. (2025). Permafrost response in northern high‐latitude regions to 1.5 C warming and overshoot scenarios achieved via solar radiation modification. Journal of Geophysical Research: Atmospheres, 130(2), e2024JD041772.AbstractThe thawing of carbon-rich northern high-latitude permafrost might unleash irreversible changes in the Earth's climate system. Previous studies have suggested that solar radiation modification (SRM) can significantly slow the degradation of permafrost, potentially restoring its extent and soil carbon stocks to levels comparable to those under equivalent global warming caused by greenhouse gas increases alone. However, this study identifies that the efficacy of SRM in mitigating permafrost degradation is contingent upon the warming trajectory and the timing of SRM intervention. Employing SRM to keep global warming at a maximum of 1.5°C can substantially reduce permafrost degradation; however, simulations suggest that by 2300, approximately half of the permafrost area reduction and one-third of the carbon losses expected under the high-emissions SSP5-8.5 scenario would still take place. By employing SRM to achieve a return to 1.5°C warming stabilization levels after a temperature overshoot, it is possible to effectively restore the permafrost area. However, the lost permafrost carbon cannot be regained. Additionally, the soil carbon within permafrost regions displays contrasting trends between the phases of overshoot and subsequent stabilization. Our simulations show that achieving the 1.5°C warming target after a 4°C temperature overshoot could necessitate up to 7% increase in SRM application due to permafrost carbon release. Moreover, perturbed parameter ensemble simulations indicate that the key parameter influencing the uncertainty of soil carbon losses in permafrost regions under 1.5°C warming and overshoot scenarios is distinct from that under the SSP5-8.5 scenario.
Gernowo, R., Faqih, A., Koesuma, S., Listyarini, J., Hakim, D. K., & Kusuma, D. A. The Impact of Solar Radiation Management in Mitigation Hazard at Indonesia. Case Study: The Extreme Rainfall of Surigae Tropical Cyclone in Papua Province, Indonesia. Case Study: The Extreme Rainfall of Surigae Tropical Cyclone in Papua Province, Indonesia.AbstractThe province of Papua is situated in the eastern part of Indonesia. Recently, there has been a notable increase in the frequency of tropical cyclones and severe weather phenomena in this area. Understanding the ramifications of tropical cyclones, particularly their influence on weather patterns, including extreme rainfall, is crucial. This study seeks to explore the consequences of extreme rainfall and identify possible solutions. The tropical cyclone Surigae, which made landfall on April 18, 2021, considerably affected the region, particularly on Timor Island and Sumba Island. We employed the ERA5 model to analyze the atmospheric dynamics related to rainfall during these tropical cyclone events. Additionally, we applied Bias correction from GeoMIP to evaluate the rainfall data and compare the outcomes. The findings indicate a strong correlation between both datasets, with a general decrease trend observed.
WEB POSTS
UPCOMING EVENTSSolar Geoengineering Events Calendar
PODCASTSNews Roundup: Hottest Year, SRM Under Trump, International SRM Discussions, And More | Climate Reflections: The SRM360 Podcast | News Roundup: Hottest Year, SRM Under Trump, International SRM Discussions, And More Climate Reflections: The SRM360 Podcast 30:59 |
"2024 was the hottest year on record. Could that change how policymakers think about SRM? How might the new administration in the US approach SRM? Do experts think countries will effectively develop international SRM regulations? We discuss a recent paper examining the topic, and find that the outlook is not optimistic. We also discuss another recent study which found that although SAI would cause some deaths, implementing SAI could still save hundreds of thousands of lives for every 1 degree C of cooling, thanks to its reduction in climate change-caused heat-related deaths. Finally, we explore a new book chapter on Cirrus cloud thinning, and answer a question from our listeners.To discuss the latest SRM news, Climate Reflections Host Pete Irvine is joined by Blaž Gasparini, a Senior Scientist at the University of Vienna in Austria, and an expert in Cirrus clouds, Claudia Wieners, an Assistant Professor in Climate Physics at Utrecht University in the Netherlands studying the impacts of Stratospheric Aerosol Injection (SAI) on Atlantic circulation, and Shuchi Talati, a climate technology governance expert and founder and Executive Director of the Alliance for Just Deliberation on Solar Geoengineering."
YOUTUBE VIDEOSClimate Engineering Is Coming, But Not Like You Think | Sabine Hossenfelder "Climate engineering is a last ditch effort to protect humans from climate change – and we’re getting closer every day. Unfortunately, attempts of scientists to study the consequences of climate engineering have been stalled by environmental activists repeatedly. It’s a problem because climate engineering will come, and we would be better off if we understood the consequences."
Geoengineering part 1: the case to try modifying the climate | The Conversation "Geoengineering, the modification of the climate using technological interventions to reverse climate change, is a hugely divisive issue and we’ve decided to explore it in two episodes.In this first episode, we talk to scientists working on potential geoengineering technologies who argue the case for conducting research into these interventions. We speak to Shaun Fitzgerald, director of the Centre for Climate Repair at the University of Cambridge in the UK and Hugh Hunt, deputy director at the Centre, as well as Ben Kravitz, assistant professor of Earth and atmospheric sciences at Indiana University in the US. We're also joined by Stacy Morford, environment and climate editor at The Conversation in the US."
Geoengineering part 2: the case against reflecting sunlight to cool the Earth | The Conversation "In the second of two episodes on geoengineering, we hear the case against trying to reflect sunlight to cool the Earth.Solar radiation modification has attracted attention and investment in recent years as a way to potential reverse the effects of climate change, but it remains a controversial idea.We hear from researchers pushing a non-use agreement for solar geoengineering who explain why they believe these types of technologies are a dangerous distraction from what needs to be done to reduce fossil fuel emissions.Featuring Chukwumerije Okereke, professor in global governance and public policy at the University of Bristol, and Co-Director at the Center for Climate Change and Development at Alex Ekwueme Federal University in Nigeria and Aarti Gupta, professor of global environmental governance at Wageningen University in the Netherlands. And responses from Shaun Fitzgerald at the Centre for Climate Change at the University of Cambridge in the UK."
Solar radiation modification: What should Europe’s strategy be? | Scientific Advice Mechanism "Solar Radiation Modification (SRM) covers a range of technologies that have the potential to cool the Earth’s climate. SRM is therefore the subject of intense and controversial debate around whether it might provide a means to tackle global warming and the devastating impacts of climate change.What are SRM technologies, what do we know about them, and what are they designed to do? How might they be deployed, what are the risks, and possible consequences? What are the attitudes and interests of stakeholders, such as the public, business and politicians? What strategy and policy should Europe adopt on the research and possible deployment of SRM?"
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