WEEKLY SUMMARY (25 MARCH - 31 MARCH 2024) *Subscribe to our newsletter to receive monthly updates on Solar Geoengineering:* Solar Geoengineering Updates <https://solargeoengineeringupdates.substack.com?utm_source=substack&utm_campaign=publication_embed&utm_medium=email> Monthly news summaries about solar geoengineering. Links to scientific papers, news articles, jobs, podcasts, and videos. <https://solargeoengineeringupdates.substack.com?utm_source=substack&utm_campaign=publication_embed&utm_medium=email> By Andrew Lockley <https://solargeoengineeringupdates.substack.com?utm_source=substack&utm_campaign=publication_embed&utm_medium=email> ------------------------------ RESEARCH PAPERSStratospheric circulation response to stratospheric aerosol injections remains uncertain <https://europepmc.org/article/ppr/ppr823532>
Diallo, M., Dunker, N., Eichinger, R., Ploeger, F., Garny, H., Ern, M., ... & Hegglin, M. (2024). Stratospheric circulation response to stratospheric aerosol injections remains uncertain. *Abstract* Mitigating global warming through stratospheric aerosol injection (SAI), which aims to reproduce the cooling effects of tropical volcanoes on surface climate, is emerging as a potential strategy for limiting near–surface global warming to around 1.5–2◦C above pre–industrial levels. However, knowledge of how the stratospheric circulation will respond to SAI, and the resulting feedback on surface climate and weather, remain highly uncertain. Here, we quantify the stratospheric circulation response to the 1991 Mount Pinatubo eruption and compare its response to a future global warming scenario with and without tropical SAI. We show that the shallow branch of the stratospheric circulation slows down in climate models and observations following tropical aerosol perturbations due to reduced lower stratospheric planetary and gravity wave breaking. However, the depth and strength of the deep branch response is highly uncertain. Climate models show a strengthening of the deep branch due to enhanced middle/upper stratospheric planetary and gravity wave breaking, contrasting with the observed weakening of the deep branch induced by reduced planetary and gravity wave forcing. As interest in SAI continues to grow, our results demonstrate the urgent need to study the impact of gravity/planetary wave uncertainty on ozone recovery, surface climate and weather. Solar Geoengineering: Assessing Whether Lack of Scientific Evidence Justifies Halting Solar Geoengineering Research <https://thesciencebrigade.com/jst/article/view/52> Lonkar, A. (2024). Solar Geoengineering: Assessing Whether Lack of Scientific Evidence Justifies Halting Solar Geoengineering Research. *Journal of Science & Technology*, *5*(2), 57-68. *Abstract* This article examines the relevance of the research on solar geo-engineering, which has become the new buzz-word in climate change mitigation. With current climate mitigation policies becoming evidently inadequate, one needs to look at science for the panacea. Solar geoengineering is a double-edged sword, capable of giving desirable results in the near future but equally capable of multiplying the complexities of the problem in long term future. There continue to exist certain deep-rooted concerns about the necessity and end-use consequences of this technology. The article attempts to examine both these facets. It also throws light on the concerns of indigenous communities and the principle of intergenerational justice with respect to the conduct of solar geoengineering research. The article ends with a conclusion which aims at giving a balanced solution to the research question. Trends in integrated assessments of solar radiation modification considering its side-effects <https://www.researchgate.net/profile/Takanobu-Kosugi/publication/374002715_Trends_in_integrated_assessments_of_solar_radiation_modification_considering_its_side-effects/links/65e137d4c3b52a117001d584/Trends-in-integrated-assessments-of-solar-radiation-modification-considering-its-side-effects.pdf> Kosugi, T. Trends in integrated assessments of solar radiation modification considering its side-effects. *Abstract* The implementation of SRM is expected to reduce the global average temperature rise at a relatively low cost. However, there are concerns that it will have considerable side effects. Therefore, to address SRM in integrated assessment models, the models have been expanded to introduce climate variables other than temperature, such as precipitation, as well as variables related to the environment other than climate. Environmental effects associated with measures against climate change extend beyond those caused by SRM. Similar concerns apply to mitigation measures such as biomass energy use, despite the differing nature of these measures. Refinement of integrated assessment models to allow for a variety of effects could be useful in assessing not only SRM but also mitigation measures [29]. SRM research from a natural science perspective based on Earth system models is also progressing. This research is expected to comprehensively clarify the environmental impacts of SRM and devise SRM implementation techniques that can reduce environmental damage [30-32]. However, the social effects of SRM, as represented by international conflicts, are difficult to resolve only through scientific and technological innovations. The role of governance is crucial [33]. Future challenges will include determining ways to utilize integrated assessment models to contribute to the discussion of SRM research and development and implementation policies (including bans). A Proposal of Geoengineering Method as Global Warming Countermeasure： Stratospheric O3 Increase to Reduce Earth's Surface Temperature <https://www.preprints.org/manuscript/202403.0854/v1> Ohmori, T. (2024). A Proposal of Geoengineering Method as Global Warming Countermeasure: Stratospheric O3 Increase to Reduce Earth's Surface Temperature. *Abstract* A method of geoengineering/solar radiation management is proposed as global warming countermeasure. The idea is to decrease surface temperature by increasing stratospheric ozone. One-dimensional (vertical) radiative-convective equilibrium temperature calculations show that surface temperature can be lowered by increasing the amount of ozone in the stratosphere. It was the increase in altitude above about 25 km that reduced surface temperatures. The method of increasing the amount of ozone (O3 injection), the rate of decrease of surface temperature after the ozone increase, and the rate of decrease of ozone concentration by photochemical reaction and diffusion/transport after the ozone increase are discussed. A survey of interventions to actively conserve the frozen North <https://link.springer.com/article/10.1007/s10584-024-03705-6> van Wijngaarden, A., Moore, J. C., Alfthan, B., Kurvits, T., & Kullerud, L. (2024). A survey of interventions to actively conserve the frozen North. *Climatic Change*, *177*(4), 58. *Abstract* The frozen elements of the high North are thawing as the region warms much faster than the global mean. The dangers of sea level rise due to melting glacier ice, increased concentrations of greenhouse gases from thawing permafrost, and alterations in the key high latitude physical systems spurred many authors, and more recently international agencies and supra-state actors, to investigate “emergency measures” that might help conserve the frozen North. However, the efficacy and feasibility of many of these ideas remains highly uncertain, and some might come with significant risks, or could be even outright dangerous to the ecosystems and people of the North. To date, no review has evaluated all suggested schemes. *The objectives of this first phase literature survey (which can be found in a separate compendium* (https://doi.org/10.5281/zenodo.10602506), are to consider all proposed interventions in a common evaluation space, and identify knowledge gaps in active conservation proposals. We found 61 interventions with a high latitude focus, across atmosphere, land, oceans, ice and industry domains. We grade them on a simple three-point evaluation system across 12 different categories. From this initial review we can identify which ideas scored low marks on most categories and are therefore likely not worthwhile pursuing; some groups of interventions, like traditional land-based mitigation efforts, score relatively highly while ocean-based and sea ice measures, score lower and have higher uncertainties overall. This review will provide the basis for a further in-depth expert assessment that will form phase two of the project over the next few years sponsored by University of the Arctic. ------------------------------ *CONFERENCE PAPERS*Multi-model simulation of solar geoengineering indicates avoidable destabilization of the West Antarctic ice sheet <https://meetingorganizer.copernicus.org/EGU24/EGU24-7071.html> Moore, J., Chen, Y., Yue, C., Jevrejeva, S., Visioni, D., Uotilla, P., & Zhao, L. (2024). *Multi-model simulation of solar geoengineering indicates avoidable destabilization of the West Antarctic ice sheet* (No. EGU24-7071). Copernicus Meetings. *Abstract* Heat transported in Circumpolar Deep Water is driving the break-up of ice shelves in the Amundsen Sea sector of Antarctica, that has been simulated to be unavoidable under all plausible greenhouse gas scenarios. However, climate intervention scenarios have not been considered. Solar geoengineering changes global thermal radiative balance, and atmospheric and oceanic transportation pathways. We simulate stratospheric aerosol injection (SAI) designed to reduce global mean temperatures from those under the unmitigated SSP5-8.5 scenario to those under the SSP2-4.5 scenario with six CMIP6-class Earth System Models. These consistently show intensified Antarctic polar vortex and sub-polar westerlies, which mitigates changes to easterly winds along the Amundsen Sea continental shelf compared with greenhouse gas scenarios. The models show significantly cooler Amundsen Sea waters and lower heat content at 300-600 m under SAI than with either solar dimming or the SSP5-8.5 unmitigated greenhouse gas scenarios. However, the heat content increases under all scenarios compared with present day suggesting that although vulnerable ice shelves would continue to thin, the rate would be lower for SAI even with SSP5-8.5 specified greenhouse gases, than for the moderate (SSP2-4.5) scenario. The simulations here use climate interventions designed for global temperature targets; interventions targeted at preserving the frozen high latitudes have also been proposed that might be expected to produce bigger local effects, but potentially deleterious impacts elsewhere. Considering the huge disruptions to society of ice sheet collapse, more research on avoiding them by intervention technology is a moral imperative. Exploring the impacts of changes in solar radiation on ecohydrological variables <https://meetingorganizer.copernicus.org/EGU24/EGU24-7258.html> Wang, Y., Meili, N., & Fatichi, S. (2024). *Exploring the impacts of changes in solar radiation on ecohydrological variables* (No. EGU24-7258). Copernicus Meetings. *Abstract* Several geoengineering projects are designed to modify solar radiation to limit global warming. These changes in solar radiation can have impacts on ecohydrological systems which are poorly quantified. In this study, CMIP6 outputs were used to calculate sensitivities of global and local near-surface meteorological variables to solar radiation changes. These sensitivities were applied to the currently observed climate to perturb meteorological variables in response to changes in solar radiation. These new conditions were used as inputs to a mechanistic ecohydrological model (T&C) to analyze the partitioning and changes in energy and water fluxes and the response of vegetation productivity in different biomes and climates. Specifically, we run two simulation scenarios to understand the solar radiation impacts on ecohydrological systems. The first scenario focuses only on changes in solar radiation, while the second scenario considers the combined effects of solar radiation changes and its climate feedback. The results show that, in the absence of climate feedback, changes in solar radiation are mainly reflected in changes in sensible heat, with less impact on the hydrological cycle, and vegetation productivity is positively and linearly correlated with changes in solar radiation. When climate feedback is included, the effects on latent heat and hydrologic variables are more pronounced, and the response of vegetation productivity to negative and positive solar radiation changes tend to be asymmetric. These results provide a basis for how land-surface processes could respond to regional brightening and dimming and future solar geoengineering programs. ------------------------------ WEB POSTSPermitting for mCDR and mSRM <https://www.epa.gov/ocean-dumping/permitting-mcdr-and-msrm> (US EPA)When is ignorance the best strategy? (Plan A+) Plan A+ When is ignorance the best strategy? <https://peteirvine.substack.com/p/when-is-ignorance-the-best-strategy?utm_source=substack&utm_campaign=post_embed&utm_medium=email> Researchers, and the societies they serve, generally believe that it is better to know something than to not know it. There are exceptions, though. Some knowledge is dangerous because it unlocks dangerous capabilities. The secrets of the nuclear bomb were closely, if unsuccessfully, guarded by the USA for obvious reasons. Similarly, there is great conce… Read more <https://peteirvine.substack.com/p/when-is-ignorance-the-best-strategy?utm_source=substack&utm_campaign=post_embed&utm_medium=email> 12 days ago · 2 likes · Pete Irvine Divisive Sun-dimming study at Harvard cancelled: what’s next? <https://www.nature.com/articles/d41586-024-00876-1> (Nature)Thinking fast and slow about SRM (Plan A+) Plan A+ Thinking fast and slow about SRM <https://peteirvine.substack.com/p/thinking-fast-and-slow-about-srm?utm_source=substack&utm_campaign=post_embed&utm_medium=email> Humans are not naturally neutral and objective truth seekers. We're capable of complex, rational thought, but it seems this capability evolved to solve problems and persuade others, rather than to pursue the truth. How will our tendency towards reactive and motivated reasoning play out when it comes to thinking about Solar Radiation Management… Read more <https://peteirvine.substack.com/p/thinking-fast-and-slow-about-srm?utm_source=substack&utm_campaign=post_embed&utm_medium=email> 6 days ago · 1 like · 1 comment · Pete Irvine Brief Reflections On The SCOPEX Advisory Committee And Implications For Research Governance <https://sgdeliberation.org/brief-reflections-on-the-scopex-advisory-committee-and-implications-for-research-governance/> (DSG)Roll The Dice To Save The Arctic? <https://globalclimaterisks.org/insights/beyond-quick-fixes/roll-the-dice-to-save-the-arctic/> (Global Climate Risks) ------------------------------ PODCASTWarm pool & SAI - Günther | Reviewer 2 does geoengineering Warm pool & SAI - Günther Reviewer 2 does geoengineering 1:27:19 <https://podcasts.apple.com/us/podcast/warm-pool-sai-g%C3%BCnther/id1529459393?i=1000650436323&uo=4> "Moritz Günther tries valiantly to get @geoengineering1 to understand the atmospheric dynamics of SAI's impacts on the warm pool, but it's rather like watching him trying to train a baboon to use Photoshop - there's some engagement, and the occasional flash of comprehension before it all gets too much for him. Günther, M., Schmidt, H., Timmreck, C., and Toohey, M.: Why does stratospheric aerosol forcing strongly cool the warm pool?, EGUsphere [preprint], https://doi.org/10.5194/egusphere-2024-429, 2024." ------------------------------ *UPCOMING EVENTS**Solar Radiation Modification, Clouds, Aerosols, and their Impacts on the Biosphere and Earth System | EGU General Assembly <https://meetingorganizer.copernicus.org/EGU24/session/49142> | 18 April 2024**Fourteenth GeoMIP Workshop | Ithaca, USA <https://climate.envsci.rutgers.edu/GeoMIP/2024.html> | 10-12 July 2024* Solar Geoengineering Events Calendar <https://teamup.com/ks64mmvtit583eitxx> *GUIDELINES:**Sync selected events to your default calendar in these simple steps:**1) Click on the event you want to sync.**2) Tap the menu icon (three vertical lines) at the top left.**3) Choose 'Share.'**4) Pick your default calendar.**5) Save the event.* *Sync the entire Teamup Calendar to your default calendar with these simple steps:**1) Tap the menu icon (three vertical lines) at the top right.**2) Choose 'Preferences.'**3) Click 'iCalendar Feeds.'**4) Copy the URL shown for 'Solar Geoengineering Events / SRM Deadlines.'’**5) Paste the URL into your default calendar settings.**6) Click 'Subscribe' or 'Add Calendar.'**For more detailed instructions, visit: https://calendar.teamup.com/kb/subscribe-to-teamup-icalendar-feeds/ <https://calendar.teamup.com/kb/subscribe-to-teamup-icalendar-feeds/>* *You can directly sync all Solar Geoengineering events to your default calendars by pressing the link below:* Sync SG Events to your Default Calendars <https://ics.teamup.com/feed/ks64mmvtit583eitxx/0.ics> <https://substackcdn.com/image/fetch/f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F9179304a-0442-40cd-b8ed-974bcdacfa51_720x477.jpeg> ------------------------------ -- You received this message because you are subscribed to the Google Groups "geoengineering" group. 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