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*WEEKLY SUMMARY (06 NOVEMBER - 12 NOVEMBER 2023)* ------------------------------ *DEADLINES**Call for Proposals-Grants for social science research on solar radiation modification | Deadline: 13 December 2023 <https://link.sbstck.com/redirect/406a123d-1524-41ec-b2b9-486abcf28cdf?j=eyJ1IjoiMjJrMHl3In0.wQQsFypG52typ8FI2nhnJ8eUoUIIkdCkuhmzxNYKtgE>* ------------------------------ *RESEARCH PAPERS*Change in wind energy potential under Solar Radiation Modification—Conference Paper <https://gfzpublic.gfz-potsdam.de/pubman/faces/ViewItemFullPage.jsp?itemId=item_5017452_1> Baur, S., Terray, L., Séférian, R., & Sanderson, B. M. (2023). Change in wind energy potential under Solar Radiation Modification. In *XXVIII General Assembly of the International Union of Geodesy and Geophysics (IUGG)*. GFZ German Research Centre for Geosciences.*Abstract*Solar Radiation Management (SRM) is increasingly being discussed as a hypothetical policy tool to reduce global and regional temperatures to supplement conventional carbon mitigation measures. A crucial part of the net-zero transition is the shift to renewable energy (RE) resources. Here, we analyze the change in technical wind energy potential under solar- and sulfate-forced SRM. Simulated output from the Earth System Model CNRM-ESM2-1 for scenario-based experiments (GeoMIP G6 and ScenarioMIP output) are used for the assessment. Preliminary results indicate some regional and global differences in potential wind RE production capacity between solar-forced SRM, sulfur-forced SRM and climate change without SRM for relevant regions and seasons. This study gives an indication as to how RE capacity, and therefore the potential to limit decarbonisation rates, may be affected by SRM deployment. Substantial Radiative Warming by an Inadvertent Geoengineering Experiment from 2020 Fuel Regulations <https://www.researchsquare.com/article/rs-3490826/v1> Yuan, T., Song, H., Oreopoulos, L., Wood, R., Bian, H., Breen, K., ... & Platnick, S. (2023). Substantial Radiative Warming by an Inadvertent Geoengineering Experiment from 2020 Fuel Regulations.AbstractHuman activities affect the Earth’s climate through modifying the composition of the atmosphere, which then creates radiative forcing that drives climate change 1. The warming effect of anthropogenic greenhouse gases has been partially balanced by the cooling effect of anthropogenic aerosols 2. In 2020, fuel regulations abruptly reduced the emission of sulfur dioxide from international shipping by more than 80%3 and created an inadvertent geoengineering experiment4,5 with global scale. Here we show the regulation leads to a radiative forcing of 0.12 Wm-2 averaged over the global ocean using a combination of modeling and satellite data. The forcing is estimated to effectively double the warming rate of global mean temperature in this decade with strong spatiotemporal heterogeneity. The warming effect contributes 50% to the measured increase in planetary heat uptake since 2020. The radiative forcing also has strong hemispheric contrast of 0.12 Wm-2 and contributes to the measured hemispheric contrast in absorbed solar radiation, which has important implications for precipitation patterns. Our result suggests marine cloud brightening may be a viable geoengineering method in temporarily cooling the climate. High sensitivity of summer temperatures to stratospheric sulfur loading from volcanoes in the Northern Hemisphere <https://www.pnas.org/doi/10.1073/pnas.2221810120> Burke, A., Innes, H. M., Crick, L., Anchukaitis, K. J., Byrne, M. P., Hutchison, W., ... & Wilson, R. (2023). High sensitivity of summer temperatures to stratospheric sulfur loading from volcanoes in the Northern Hemisphere. *Proceedings of the National Academy of Sciences*, *120*(47), e2221810120.*Abstract*The 540s, 1450s, and 1600s represent three of the five coldest decades in the Common Era (CE). In each of these cases, the cause of these cold pulses has been attributed to large volcanic eruptions. However, the provenance of the eruption and magnitude of the volcanic forcing remains uncertain. Here, we use high-resolution sulfur isotopes in Greenland and Antarctic ice cores measured across these events to provide a means of improving sulfur loading estimates for these eruptions. In each case, the largest reconstructed tree-ring cooling is associated with an extratropical eruption, and the high-altitude stratospheric sulfate loading of these events is substantially smaller than previous estimates (by up to a factor of two). These results suggest an increased sensitivity of the reconstructed Northern Hemisphere summer temperature response to extratropical eruptions. This highlights the importance of climate feedbacks and processes that amplify and prolong the cooling signal from high latitudes, such as changes in sea ice extent and ocean heat content. Spaces of anthropogenic CO2 emissions compatible with planetary boundaries <https://www.researchsquare.com/article/rs-3402213/v1> Bossy, T., Gasser, T., Ciais, P., Tanaka, K., Lecocq, F., & Bousquet, P. (2023). Spaces of anthropogenic CO2 emissions compatible with planetary boundaries.*Abstract**The concept of planetary boundaries delineates the Earth system’s limits within which humanity can sustainably prosper.**Here, we introduce a new modelling framework to translate four climate-related boundaries: global warming, ocean acidification, sea level rise, and Arctic sea ice melt. Using a reduced-form model, we map a range of anthropogenic CO2 emissions and removals pathways consistent with the boundaries, optionally adding solar radiation management (SRM) measures to the picture. Our framework estimates safety levels as probabilities to stay within the boundaries considering the physical uncertainty of the Earth system.**If CO2 emissions peak in 2030, net-zero CO2 is reached in 2100, CDR deployment capacity is 10 PgC per year, and SRM is not allowed, remaining within the global warming boundary is ensured with a safety level of 66%. This level is 50% for the sea level rise or the Arctic sea ice boundary; it is 26% for the ocean acidification boundary. When all four boundaries are considered together, it drops to only 12%, indicating a complex interplay of planetary boundaries in determining the safety level.**Our results suggest a need to assess planetary boundaries holistically to develop sustainable future strategies.* Aerosol-Induced Closure of Marine Cloud Cells: Enhanced Effects in the Presence of Precipitation <https://egusphere.copernicus.org/preprints/2023/egusphere-2023-2416/> Christensen, M. W., Wu, P., Varble, A. C., Xiao, H., & Fast, J. D. (2023). Aerosol-Induced Closure of Marine Cloud Cells: Enhanced Effects in the Presence of Precipitation. *EGUsphere*, *2023*, 1-35.*Abstract*The Weather Research Forecasting (WRF) V4.2 model is configured within a Lagrangian framework to quantify the impact of aerosols on evolving cloud fields. Simulations employing realistic meteorological boundary conditions are based on 10 case study days offering diverse meteorology during the Aerosol and Cloud Experiments in the Eastern North Atlantic (ACE-ENA). Cloud and aerosol retrievals in observations from aircraft measurements, ground-based Atmosphere Radiation Measurement (ARM) data at Graciosa Island in the Azores, and A-Train and geostationary satellites are in good agreement with the simulations. Higher aerosol concentration leads to suppressed drizzle and increased cloud water content. These changes lead to larger radiative cooling rates at cloud top, enhanced vertical velocity variance, and increased vertical and horizontal wind speed near the base of the lower-tropospheric inversion. As a result, marine cloud cell area expands, narrowing the gap between shallow clouds and increasing cloud optical thickness, liquid water content, and the top-of-atmosphere outgoing shortwave flux. While similar aerosol effects are observed in lightly to non-raining clouds, they tend to be smaller by comparison. These results show a strong link between cloud cell area expansion and the radiative adjustments caused by liquid water path and cloud fraction changes. These adjustments scale by 74 % and 51 %, respectively, relative to the Twomey effect. Given the limitations of traditional global climate model resolutions, addressing mesoscale cloud-state transitions at kilometer-scale resolutions or higher should be of utmost importance in accurately quantifying aerosol radiative forcing. Injection strategy – a driver of atmospheric circulation and ozone response to stratospheric aerosol geoengineering <https://acp.copernicus.org/articles/23/13665/2023/> Bednarz, E. M., Butler, A. H., Visioni, D., Zhang, Y., Kravitz, B., & MacMartin, D. G. (2023). Injection strategy–a driver of atmospheric circulation and ozone response to stratospheric aerosol geoengineering. *Atmospheric Chemistry and Physics*, *23*(21), 13665-13684.*Abstract*Despite offsetting global mean surface temperature, various studies demonstrated that stratospheric aerosol injection (SAI) could influence the recovery of stratospheric ozone and have important impacts on stratospheric and tropospheric circulation, thereby potentially playing an important role in modulating regional and seasonal climate variability. However, so far, most of the assessments of such an approach have come from climate model simulations in which SO2 is injected only in a single location or a set of locations.Here we use CESM2-WACCM6 SAI simulations under a comprehensive set of SAI strategies achieving the same global mean surface temperature with different locations and/or timing of injections, namely an equatorial injection, an annual injection of equal amounts of SO2 at 15∘ N and 15∘ S, an annual injection of equal amounts of SO2 at 30∘ N and 30∘ S, and a polar strategy injecting SO2 at 60∘ N and 60∘ S only in spring in each hemisphere.We demonstrate that despite achieving the same global mean surface temperature, the different strategies result in contrastingly different magnitudes of the aerosol-induced lower stratospheric warming, stratospheric moistening, strengthening of stratospheric polar jets in both hemispheres, and changes in the speed of the residual circulation. These impacts tend to maximise under the equatorial injection strategy and become smaller as the aerosols are injected away from the Equator into the subtropics and higher latitudes. In conjunction with the differences in direct radiative impacts at the surface, these different stratospheric changes drive different impacts on the extratropical modes of variability (Northern and Southern Annular modes), including important consequences on the northern winter surface climate, and on the intensity of tropical tropospheric Walker and Hadley circulations, which drive tropical precipitation patterns. Finally, we demonstrate that the choice of injection strategy also plays a first-order role in the future evolution of stratospheric ozone under SAI throughout the globe. Overall, our results contribute to an increased understanding of the fine interplay of various radiative, dynamical, and chemical processes driving the atmospheric circulation and ozone response to SAI and lay the foundation for designing an optimal SAI strategy that could form a basis of future multi-model intercomparisons. <https://www.researchsquare.com/article/rs-3402213/v1> ------------------------------ REPORTSSolar geoengineering research & governance-Policy brief <https://www.woodwellclimate.org/solar-geoengineering-research-governance/>Draft decision: Stratospheric aerosol injection and protection of the ozone layer (ver 1) <https://ozone.unep.org/meetings/thirty-fifth-meeting-parties/contact-groups/informal-discussions-stratospheric-aerosol-injection/> (United Nations Environment Program)The Solar Geoengineering Ecosystem: Key Actors Across the Landscape of the Field, Wil Burns & Shuchi Talati (November 2023) <https://sgdeliberation.org/publications/the-solar-geoengineering-ecosystem-key-actors-across-the-landscape-of-the-field/> <https://sgdeliberation.org/wp-content/uploads/2023/11/DSG-FCEA-Landscape-Report_Final.pdf> ------------------------------ MEETING SUMMARY REPORTA New Era for the Geoengineering Model Intercomparison Project (GeoMIP) <https://climate.envsci.rutgers.edu/pdf/GeoMIP13ExeterBAMS.pdf> <https://climate.envsci.rutgers.edu/pdf/GeoMIP13ExeterBAMS.pdf> ------------------------------ *UPCOMING EVENTS**104th Annual Meeting by American Meteorological Society <https://ams.confex.com/ams/104ANNUAL/meetingapp.cgi/Program/1743> | 28 January 2024 - 01 February 2023**Climate Engineering (GRS) <https://www.grc.org/climate-engineering-grs-conference/2024/>| 17-18 February 2024**GRC Climate Engineering 2024 <https://www.grc.org/climate-engineering-conference/2024/>| 18-23 February 2024* ------------------------------ PODCASTSC2GTalk: Should Global South scientists engage in solar radiation modification research? with Inés Camilloni | Carnegie Climate Governance Initiative (C2G) <https://www.carnegiecouncil.org/media/series/c2g/global-south-scientists-solar-radiation-modification-research> *“It is important for scientists from the Global South to be engaged in research and discussions around solar radiation modification (SRM) because its potential impacts would affect everyone, says Inés Camilloni from the University of Buenos Aires. Researchers need to consider the risks of SRM against the risks of a dangerously warming planet. More research is needed, because the world currently does not know enough to make informed decisions.**Dr. Camilloni is currently associate professor at the Department of Atmospheric and Oceanic Sciences of the University of Buenos Aires, senior researcher of the National Scientific and Technical Research Council at the Center for Atmosphere and Ocean Research (CIMA) in Argentina, and vice-chair of the Intergovernmental Panel on Climate Change Working Group 1.”* Climate Now Debates: Solar Radiation Management (SRM) | Climate Now Climate Now Debates: Solar Radiation Management (SRM) Climate Now 1:10:34 <https://podcasts.apple.com/us/podcast/climate-now-debates-solar-radiation-management-srm/id1565404483?i=1000633972266&uo=4> *“Geoengineering refers to the intentional intervention in Earth processes for the purpose of mitigating climate change. A controversial topic, geoengineering is typically divided into two categories: carbon dioxide removal and solar radiation management. This second category, also known as SRM, made headlines this summer when the White House released a report that “opened the door” to future research on the topic.**In principle, SRM includes any technology that could be used to reflect some of the sun’s energy from the Earth in order to decrease the amount of associated heating, effectively cooling the planet. And while the study of SRM has mostly been limited to the lab and to date no large-scale experiments have been conducted, more people are calling for the idea to be explored further as global warming increases. At the same time, others are saying the door needs to remain shut, as the potential for unintended political, societal and ecological side effects are just too great.**To help us understand why - why is SRM being considered, and why are people concerned that it is being considered, Climate Now brought together five experts – Professors Frank Biermann (Utrecht Univ.), David Keith (Univ. Chicago), Chukwumerije Okereke (Alex Ekwueme Federal Univ. Ndufu-Alike, Nigeria), Jennie Stephens (Northeastern Univ.), and Claudia Wieners (Utrecht Univ.) – to debate the merits and risks of examining SRM as a possible climate solution.”* ------------------------------ YOUTUBE VIDEOS*C2GTalk: Should Global South scientists engage in solar radiation modification research? | *C2G Carnegie Climate Governance Initiative <https://www.youtube.com/watch?v=E2kZdRlU8_Q> *“It is important for scientists from the Global South to be engaged in research and discussions around SRM, because its potential impacts would affect everyone, says Inés Camilloni from the University of Buenos Aires. Researchers need to consider the risks of SRM against the risks of a dangerously warming planet. More research is needed, because the world currently does not know enough to make informed decisions.”* *Webinar 24 | Solar Radiation Management with Harmattan over Southern West Africa | Meteorological Virtual Seminar Series Ghana* <https://www.youtube.com/watch?v=cRrXXjuSbEk> *“Solar geoengineering is often discussed as a means to mitigate the impacts and injustice of climate change by reducing its magnitude. However, climate response to Solar Radiation Management simulation at a regional scale remains uncertain. In addition, the potential effects of geoengineering on temperature levels during the harmattan season in West Africa are not well understood. This study aims to project how geoengineering could impact harmattan temperatures by comparing current temperature trends under moderate and high greenhouse gas emissions scenarios (Representative Concentration Pathways 4.5 and 8.5) with and without geoengineering. The findings suggest that if geoengineering deployment cools the tropics during the harmattan season, it could potentially increase the discomfort caused by the cold and dry conditions that persist during the harmattan season, especially for those who are not accustomed to the cold. Additionally, the study indicates that geoengineering could offset the projected harmattan temperature reduction that may occur by 2070 without intervention. These results highlight the importance of considering the potential regional trade-offs that could arise from implementing geoengineering strategies to offset warming during the harmattan season in West Africa.”* Climate Now Debates: Solar Radiation Management (SRM) | Climate Now <https://www.youtube.com/watch?v=qpgfTcZYZNc> *“Geoengineering refers to the intentional intervention in Earth processes for the purpose of mitigating climate change. A controversial topic, geoengineering is typically divided into two categories: carbon dioxide removal and solar radiation management. This second category, also known as SRM, made headlines this summer when the White House released a report that “opened the door” to future research on the topic.”* Solar Radiation Modification Youth Watch Launch Event at Climate Week NYC | SRM Youth Watch <https://www.youtube.com/watch?v=Blk7-xo-TV4> *“The Solar Radiation Modification Youth Watch (SRM YW) launch event aims to bring together young people to discuss the need for strengthening governance around solar radiation modification (SRM) whilst introducing and launching the SRM YW platform.”* *A virtual event: Global Dialogue on Climate Cooperation and Governance | C2G Carnegie Climate Governance Initiative* <https://www.youtube.com/watch?v=Ss1faZoAx7A> *“A virtual event between the Institute for Sustainable Development Goals, Tsinghua University (TUSDG), Center for Industrial Development and Environmental Governance, Tsinghua University (CIDEG), and Carnegie Climate Governance Initiative (C2G).”* ------------------------------ -- You received this message because you are subscribed to the Google Groups "geoengineering" group. 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