*Subscribe to the Solar Geoengineering Updates Newsletter here:* 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> *WEEKLY SUMMARY (29 JANUARY - 04 FEBRUARY 2024) <https://substack.com/app-link/publications/1346479/drafts/cb9b3cfc-a516-4367-b3ab-f864ca032617?publication_id=1346479&post_id=140935232&utm_source=post-email-title&utm_campaign=email-post-title&isFreemail=false>**Links to recent scientific papers, web posts, upcoming events, job opportunities, podcasts, and event recordings, etc. on Solar Radiation Management Technology.* ------------------------------ RESEARCH PAPERSSimulated responses and feedbacks of permafrost carbon under future emissions pathways and idealized solar geoengineering scenarios <https://iopscience.iop.org/article/10.1088/1748-9326/ad2433>
Chen, Y., Moore, J. C., & Ji, D. (2024). Simulated responses and feedbacks of permafrost carbon under future emissions pathways and idealized solar geoengineering scenarios. *Environmental Research Letters*.*Abstract*The carbon-rich northern high-latitude permafrost is a potential climate tipping point. Once triggered, its thawing and release of carbon dioxide and methane might unleash devastating and irreversible changes in the Earth's climate system. We investigate the response of permafrost under three Shared Socioeconomic Pathways (SSP) with no mitigation (SSP5-8.5), moderate mitigation (SSP2-4.5) and delayed mitigation (SSP5-3.4-OS), and three solar geoengineering scenarios applied to each experiment to prevent global warming from exceeding 2 oC above pre-industrial. The long-term negative emissions in SSP5-3.4-OS preserves much more frozen soil than SSP5-8.5, but shows nearly as much permafrost carbon loss this century as SSP2-4.5 due to its mid-century temperature overshoot. Solar geoengineering to meet the 2 oC target above pre-industrial effectively suppresses permafrost thawing and reduces subsequent carbon release from the soil. However, the carbon emission from permafrost still continues after the temperature is stabilized, due to the decomposition of thawed permafrost carbon. More solar insolation reduction is required to compensate the positive permafrost carbon feedback, which exerts greater impacts on the efficiency of solar geoengineering under a scenario with strong climate policy and lower carbon emissions. A simple and realistic aerosol emission approach for use in the Thompson–Eidhammer microphysics scheme in the NOAA UFS Weather Model (version GSL global-24Feb2022) <https://gmd.copernicus.org/articles/17/607/2024/> Li, H., Grell, G. A., Ahmadov, R., Zhang, L., Sun, S., Schnell, J., & Wang, N. (2024). A simple and realistic aerosol emission approach for use in the Thompson–Eidhammer microphysics scheme in the NOAA UFS Weather Model (version GSL global-24Feb2022). *Geoscientific Model Development*, *17*(2), 607-619.*Abstract*A physics suite under development at NOAA's Global Systems Laboratory (GSL) includes the aerosol-aware double-moment Thompson–Eidhammer microphysics (TH-E MP) scheme. This microphysics scheme uses two aerosol variables (concentrations of water-friendly aerosol (WFA) and ice-friendly aerosol (IFA) numbers) to include interactions with some of the physical processes. In the original implementation, WFA and IFA depended on emissions derived from climatologies. In our approach, using the Common Community Physics Package (CCPP), we embedded modules of sea-salt emissions, dust emissions, and biomass-burning emissions, as well as of anthropogenic aerosol emissions, into the Unified Forecast System (UFS) to provide realistic aerosol emissions for these two variables. This represents a very simple approach with no additional tracer variables and therefore very limited additional computing cost. We then evaluated a comparison of simulations using the original TH-E MP approach, which derives the two aerosol variables using empirical emission formulas from climatologies (CTL) and simulations that use the online emissions (EXP). Aerosol optical depth (AOD) was derived from the two variables and appears quite realistic in the runs with online emissions when compared to analyzed fields. We found less resolved precipitation over Europe and North America from the EXP run, which represents an improvement compared to observations. Also interesting are moderately increased aerosol concentrations over the Southern Ocean from the EXP run, which invigorate the development of cloud water and enhance the resolved precipitation in those areas. This study shows that a more realistic representation of aerosol emissions may be useful when using double-moment microphysics schemes. Modeling the contribution of secondary aerosols on aerosol scattering ensemble: a comparative analysis of the scattering abilities of different aerosol species <https://opg.optica.org/oe/fulltext.cfm?uri=oe-32-3-4614&id=545962> Arreyndip, N. A., & Joseph, E. (2024). Modeling the contribution of secondary aerosols on aerosol scattering ensemble: a comparative analysis of the scattering abilities of different aerosol species. *Optics Express*, *32*(3), 4614-4626.AbstractAtmospheric transport processes and conditions can cause primary aerosols to interact, giving rise to secondary aerosols with unique chemical and physical properties. These new species of aerosols can potentially influence the light-scattering properties of the aerosol ensemble and thus the climate system in ways that are not yet fully understood. In this study, the effects of different aerosol types on the scattering of incident solar radiation are modeled and the contribution of secondary aerosols to the aerosol scattering ensemble is highlighted. Using the discrete dipole approximation method, the scattering properties of freshwater droplets, sea salts (liquid, dry, and wet solids), ice crystals, clay minerals, clay particles coated with a thin film of water and sea salt droplets, black carbon (BC), and a complex particle of clay, sea salt, and BC with sulphate coating are calculated and compared. The calculations assume a spherical particle shape model for marine aerosols, a distorted cube for wet salts and ice, and a distorted ellipse with an induced surface roughness length for terrestrial aerosols at a size parameter of x=5 and a wavelength range of 400 to 750 nm. The results show that tiny ice crystals trapped in freshwater droplets are the most efficient atmospheric scatterers, followed by sea salt droplets, while BC absorbs the most compared to other aerosols studied. On average, the atmospheric interaction between marine and terrestrial aerosols is able to enhance atmospheric light scattering and polarisation by aerosols compared to terrestrial aerosols. This study suggests that the scenario in which there are many freshwater aerosols in the atmosphere can be very healthy for the Earth’s system compared to other aerosols. Therefore, we suggest that when formulating the radiative properties of aerosols in climate models, the scenarios of dominant freshwater aerosols and the contribution of secondary aerosols should not be ignored. The results presented here may be useful in the fields of Geoengineering and Aerosol-cloud microphysics. Radiative effect of thin cirrus clouds in the extratropical lowermost stratosphere and tropopause region <https://acp.copernicus.org/articles/24/1213/2024/> Spang, R., Müller, R., & Rap, A. (2024). Radiative effect of thin cirrus clouds in the extratropical lowermost stratosphere and tropopause region. *Atmospheric Chemistry and Physics*, *24*(2), 1213-1230.*Abstract*Cirrus clouds play an important role in the radiation budget of the Earth; nonetheless, the radiative effect of ultra-thin cirrus clouds in the tropopause region and in the lowermost stratosphere remains poorly constrained. These clouds have a small vertical extent and optical depth and are frequently neither observed even by sensitive sensors nor considered in climate model simulations. In addition, their short-wave (cooling) and long-wave (warming) radiative effects are often in approximate balance, and their net effect strongly depends on the shape and size of the cirrus particles. However, the CRyogenic Infrared Spectrometers and Telescopes for the Atmosphere instrument (CRISTA-2) allows ultra-thin cirrus clouds to be detected. Here we use CRISTA-2 observations in summer 1997 in the Northern Hemisphere midlatitudes together with the Suite Of Community RAdiative Transfer codes based on Edwards and Slingo (SOCRATES) radiative transfer model to calculate the radiative effect of observed ultra-thin cirrus. Using sensitivity simulations with different ice effective particle size and shape, we provide an estimate of the uncertainty in the radiative effect of ultra-thin cirrus in the extratropical lowermost stratosphere and tropopause region during summer and – by extrapolation of the summer results – for winter. Cloud top height and ice water content are based on CRISTA-2 measurements, while the cloud vertical thickness was predefined to be 0.5 or 2 km. Our results indicate that if the ice crystals of these thin cirrus clouds are assumed to be spherical, their net cloud radiative effect is generally positive (warming). In contrast, assuming aggregates or a hexagonal shape, their net radiative effect is generally negative (cooling) during summer months and very likely positive (warming) during winter. The radiative effect is in the order of ±(0.1–0.01) W m−2 for a realistic global cloud coverage of 10 %, similar to the magnitude of the contrail cirrus radiative forcing (of ∼ 0.1 W m−2). The radiative effect is also dependent on the cloud vertical extent and consequently the optically thickness and effective radius of the particle size distribution (e.g. effective radius increase from 5 to 30 µm results in a factor ∼ 6 smaller long- and short-wave effects, respectively). The properties of ultra-thin cirrus clouds in the lowermost stratosphere and tropopause region need to be better observed, and ultra-thin cirrus clouds need to be evaluated in climate model simulations. *Avoiding atmospheric anarchy: Geoengineering as a source of interstate tension <https://journals.sagepub.com/doi/10.1177/27538796231221597>* Morrissey, W. (2024). Avoiding atmospheric anarchy: Geoengineering as a source of interstate tension. *Environment and Security*, *0*(0).AbstractIdealized climate modeling of geoengineering, notably including stratospheric aerosol injection, routinely frames the practice as the provision of a global public good in the absence of geopolitical context. This study argues that the situation of geoengineering governance within individual state governments combined with the technology’s substantial, unforeseeable consequences present a potential security dilemma that heightens tensions between states and risks conflict, including potential environmental catastrophe. Initially, there is a brief overview of geoengineering technology and the associated concerns before highlighting four elements of the technology that potentially generate interstate tension: the potential for independent action, low costs, ambiguity surrounding deployment, and the possibility of counter-geoengineering. This is followed by a discussion of four speculative geoengineering scenarios intended to illustrate the complexity of potential geoengineering impacts on states’ strategic thinking and risks associated with solar geoengineering. The article outlines four scenarios derived by isolating the availability of counter-geoengineering and the controllability of geoengineering as drivers for contesting strategic climate outcomes. The scenarios emphasize possible geopolitical tensions that could emerge under geoengineering, encouraging further study of potential geoengineering efforts within international security. <https://acp.copernicus.org/articles/24/1213/2024/> <https://acp.copernicus.org/articles/24/1213/2024/> ------------------------------ WEB POSTSThe Solar Geoengineering Updates Newsletter (January'2024) (Solar Geoengineering Updates) Solar Geoengineering Updates The Solar Geoengineering Updates Newsletter (January'2024) <https://solargeoengineeringupdates.substack.com/p/the-solar-geoengineering-updates-18e?utm_source=substack&utm_campaign=post_embed&utm_medium=email> Read more <https://solargeoengineeringupdates.substack.com/p/the-solar-geoengineering-updates-18e?utm_source=substack&utm_campaign=post_embed&utm_medium=email> 4 days ago · Andrew Lockley It is time to draw down carbon dioxide but shut down moves to play God with the climate <https://theconversation.com/it-is-time-to-draw-down-carbon-dioxide-but-shut-down-moves-to-play-god-with-the-climate-220422> (The Conversation)Solar geoengineering could start soon if it starts small <https://www.technologyreview.com/2024/02/05/1087587/solar-geoengineering-could-start-soon-if-it-starts-small/> (MIT Technology Review)Geoengineering may slow Greenland ice sheet loss, finds modeling study <https://phys.org/news/2024-01-geoengineering-greenland-ice-sheet-loss.html> (Phys.Org) imageHow solar geoengineering is clouding issues of tribal consent <https://www.hcn.org/issues/56.2/indigenous-affairs-how-solar-geoengineering-is-clouding-issues-of-tribal-consent> (High Country News)Could a Giant Parasol in Outer Space Help Solve the Climate Crisis? <https://www.nytimes.com/2024/02/02/climate/sun-shade-climate-geoengineering.html> (The New York Times)Looking back on 2023 at the Degrees Initiative <https://www.degrees.ngo/looking-back-on-2023-at-the-degrees-initiative/> (The Degrees Initiative) <https://www.technologyreview.com/2024/02/05/1087587/solar-geoengineering-could-start-soon-if-it-starts-small/> ------------------------------ OPEN LETTER CALLAmplifying Youth Voices For The Governance Of Solar Radiation Modification <https://www.srmyouthwatch.org/open-letter-call> (SRM Youth) ------------------------------ JOB OPPORTUNITYResearch Fellow in Solar Geoengineering at University College London | Deadline: 10 March 2024 <https://www.ucl.ac.uk/work-at-ucl/search-ucl-jobs/details?jobId=19955&jobTitle=Research+Fellow+in+Solar+Geoengineering> *“We are seeking to appoint a research fellow position in Solar Geoengineering, to be held in the Department of Earth Sciences at UCL. The Horizon Europe-funded project ‘Conditions for Responsible Research of SRM – Analysis, Co-Creation, and Ethos (Co-Create)’ aims to support the development of possible new research governance arrangements for solar geoengineering in the European Union.**The post is available for 18 months in the first instance and collaborations will span several UK and European universities and several disciplines.**The postdoctoral researcher will play a central role in the scientific and technical evaluation of solar geoengineering and proposed field tests as part of this interdisciplinary project. The postdoctoral researcher will also help organize an international workshop focused on potential field tests of solar geoengineering, bringing together researchers with plans for such field tests.”* ------------------------------ *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* ------------------------------ YOUTUBE VIDEOSHow 2023 Broke Our Climate Models with Neil deGrasse Tyson & Gavin Schmidt | StarTalk <https://www.youtube.com/watch?v=CHJKKsOHtAk> *“Why were climate models so wrong about 2023? Neil deGrasse Tyson learns about why 2023 was hotter than we expected it to be and what effects need to be factored into future climate modeling with climatologist at NASA Goddard Institute, Gavin Schmidt.”* Regional Dialogue 2024 - Day 01- Session II | Institute of Regional Studies <https://www.youtube.com/watch?v=MqHZ7DaFcoU> *“DSG's Hassaan Sipra joined the IRSIslamabad Annual Regional Dialogue 2024 on Crafting Climate Commitments: Next Phase of Regional NDCs, where he provided insights on SG as potential coping strategies and adaptation measures for the South Asia to consider.”* ------------------------------ -- You received this message because you are subscribed to the Google Groups "geoengineering" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/geoengineering/CAHJsh9-J3mXHK0vAWRvSxgK7v4axsTL6UBk0zFZHQoBNduV2Tw%40mail.gmail.com.
