| Subscribe to our newsletter to receive monthly updates on Solar Geoengineering:
RESEARCH PAPERSLee, W. R., Chen, C. C., Richter, J. H., MacMartin, D. G., & Kravitz, B. (2024). First simulations of feedback algorithm-regulated marine cloud brightening. Authorea Preprints. Abstract Feedback control algorithms, an important tool in climate intervention strategy design, are widely used in stratospheric aerosol injection (SAI) simulations but have never been implemented for marine cloud brightening (MCB). Using the Community Earth System Model (CESM2), we present the first simulations of feedback control-regulated MCB. Our controller, which regulates global mean temperature (T0) by varying the area of MCB coverage over time, successfully maintains the desired T0 of 1.5°C above the preindustrial in the SSP2-4.5 global warming scenario comparably to a contemporary SAI controller. After 35 years of intervention, the surface temperature response when MCB has been gradually ramped up over time in this way is similar to a constant intervention with similar global mean temperature (including strong regional heterogeneity), but system memory may cause differences in Arctic sea ice and the Atlantic Meridional Overturning Circulation (AMOC).
Ellis, S. L., Butcherine, P., Tagliafico, A., Hendrickson, C. A., Kelaher, B. P., Schulz, K. G., & Harrison, D. P. Shading responses are species-specific in thermally stressed corals. Frontiers in Marine Science, 11, 1333806. Authors Light is critical to coral growth through endosymbiont photosynthesis but can also act with elevated temperatures to cause coral bleaching. When more light is absorbed than can be used for photosynthesis, elevated irradiance can damage symbiont photosynthetic machinery.Hence, solar-radiation management through shading has been suggested to alleviate coral bleaching during marine heatwaves. Acropora divaricata and Acropora kenti were tested at two temperatures with 30% shading and an unshaded control to determine the relative impacts of light and temperature on coral bleaching severity. The coral bleaching response was assessed by photochemical (pulse amplitude modulated fluorometry), physiological (symbiont density, chlorophyll a concentration, catalase activity, and lipid peroxidation), and physical (mean intensity of grey or 'percentage whiteness') markers. Shading significantly reduced the bleaching response in A. divaricata, whilst for some parameters A. kenti responded negatively to shade. In A. divaricata, shading prevented photochemical collapse up to the experiment's maximum 4.4 degree-heating weeks (DHW). Biomarkers of coral bleaching stress responded to shade and water temperature at 4.4 DHW; catalase activity was greatest in the shaded and ambient temperature treatment. Shading did not reduce the effects of bleaching in A. kenti; the mean intensity of grey and light saturation coefficient was greatest in the shaded treatment. Shading did, however, reduce lipid peroxidation at 3 DHW.Our results suggest shading during thermal stress may only protect some coral species, highlighting the need to consider species-specific responses when evaluating the potential efficacy of coral bleaching interventions.
Wang, J., Zhao, L., & Moore, J. C. (2024). Projected thermally driven elderly mortality for Beijing under greenhouse gas and stratospheric aerosol geoengineering scenarios. Earth's Future, 12(7), e2024EF004422. Abstract Beijing is undergoing multiple challenges including urbanization, warming and aging. The Beijing megalopolis of 20 million people now suffers more cold-related than heat-related deaths. Stratospheric aerosol injection (SAI) geoengineering is designed to lower surface temperatures, so if SAI were ever done, it may reduce future heat-related mortality, while also increasing cold-related mortality. Here we use four Earth System Models (ESM) downscaled to 10 km resolution with the Weather Research and Forecasting (WRF) system to capture urban temperature, humidity and wind speeds. Temperature-related mortality risk were calculated using a distributed lag nonlinear model (DLNM) of the elderly (over 65s) under the dynamically downscaled moderate (RCP4.5) and extreme (RCP8.5) greenhouse gas, and the G4 SAI scenarios. We used population demographics for all five shared socioeconomic pathways (SSP) and various adaptation measures. Heat-related excess deaths under G4 are 630∼3,160 per year fewer than RCP4.5, while cold-related deaths are 370∼1,990 more than RCP4.5 during 2060–2069, with a marginally significant net reduction. G4 significantly reduces the excess deaths relative to RCP8.5. Both heat-related and cold-related mortality will increase by 240∼490% when the aging population is accounted for, and decrease by 11%, 23% and 44% under low, medium and high adaptation relative to a no adaptation scenario. Dynamical downscaling produces better quality climate simulations than commonly used statistical approaches, and in the case of Beijing, significantly fewer heat-related deaths. The marginal health benefits of modest future SAI in Beijing may be representative of the population impacts in the extra-tropics where deaths due to cold are more than those caused by heat.
Heyen, D., & Tavoni, A. (2024). Strategic dimensions of solar geoengineering: economic theory and experiments. Journal of Behavioral and Experimental Economics, 102271. Abstract Solar geoengineering denotes a set of technologies that would enable a fast and relatively cheap global temperature reduction. Besides potential physical side-effects, a major concern is the strategic dimension: Who is going to use solar geoengineering and how would it affect others? How does the presence of solar geoengineering change the strategic incentives surrounding other climate policy instruments such as mitigation? We review the existing theoretical and experimental contributions to those questions and outline promising lines of future economic research.
WEB POSTSThe Solar Geoengineering Updates Newsletter (July'2024) — Monthly Updates Solar Geoengineering UpdatesUnlock exclusive insights on solar geoengineering! 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… 3 days ago · 3 likes · Andrew Lockley List of Research Topics Selected by Teams:
Climate tech’s biggest trouble-maker: an interview with Andrew Song of Make Sunsets (Plan B Post) Plan B PostThis week, an exclusive Plan B Post interview with a man Time magazine calls climate tech’s biggest troublemaker: Andrew Song, Co-founder of Make Sunsets… 5 days ago · 1 like · 2 comments · Dave Platter
UPCOMING EVENTSSolar Geoengineering Events Calendar
BOOK
PODCASTNavigating the Geopolitical Risks of Solar Geoengineering | Energy Policy Now | Navigating the Geopolitical Risks of Solar Geoengineering Energy Policy Now 43:03 |
"Two experts discuss the geopolitical risks of solar geoengineering and the need for global governance frameworks to prevent conflict."
| |
