| Links to recent scientific papers, web posts, upcoming events, job opportunities, podcasts, and event recordings, etc. on Solar Radiation Management Technology.RESEARCH PAPERSWei, J., Ren, T., Yang, P., DiMarco, S. F., & Huang, X. (2023). Sensitivity of Arctic surface temperature to including a comprehensive ocean interior reflectance to the ocean surface albedo within the fully coupled CESM2. Journal of Advances in Modeling Earth Systems, 15(12), e2023MS003702.AbstractAlmost all current climate models simplify the ocean surface albedo (OSA) by assuming the reflected solar energy without the ocean interior contribution. In this study, an improved ocean surface albedo scheme is incorporated into the Community Earth System Model version 2 (CESM2) to assess the sensitivity of Arctic surface temperature to including ocean interior reflectance to the OSA. Fully coupled CESM2 simulations with and without ocean interior reflectance are subsequently performed, we focus on the analysis of Arctic surface temperature responses. Incorporating ocean interior reflectance increases absorbed solar radiation and warms the ocean, enhancing seasonal heat storage and release across the Arctic Ocean, and increasing sea ice reduction and positive climate feedbacks that elevates Arctic surface temperature. Seasonal variations in air-surface temperature differences induce changes in turbulent heat flux patterns, concurrently modifying dynamic advection and moisture processes that affect boundary layer humidity and low clouds, especially in winter. Based on partitioning physical processes in the thermodynamic energy equation, surface air warming is induced primarily through positive heating anomalies of vertical advection, latent heat release, and longwave radiative forcing. Through an examination of the surface energy budget, skin temperature warming is driven predominantly by increased downward longwave radiation, positive surface albedo feedback in summer, and increased conductive heat transport from the ocean particularly in winter. Significant effects of ocean interior reflectance on the Arctic Ocean, including sea surface warming and sea ice reduction, justify the importance of ocean interior reflectance in climate models for better understanding of ongoing Arctic climate changes.
Minière, A., von Schuckmann, K., Sallée, J. B., & Vogt, L. (2023). Robust acceleration of Earth system heating observed over the past six decades. Scientific Reports, 13(1), 22975.AbstractGlobal heating of the Earth system is unequivocal. However, detecting an acceleration of Earth heating has remained elusive to date, despite suggestive evidence of a potential increase in heating rates. In this study, we demonstrate that since 1960, the warming of the world ocean has accelerated at a relatively consistent pace of 0.15 ± 0.05 (W/m2)/decade, while the land, cryosphere, and atmosphere have exhibited an accelerated pace of 0.013 ± 0.003 (W/m2)/decade. This has led to a substantial increase in ocean warming, with a magnitude of 0.91 ± 0.80 W/m2 between the decades 1960–1970 and 2010–2020, which overlies substantial decadal-scale variability in ocean warming of up to 0.6 W/m2. Our findings withstand a wide range of sensitivity analyses and are consistent across different observation-based datasets. The long-term acceleration of Earth warming aligns qualitatively with the rise in CO2 concentrations and the decline in aerosol concentration during the same period, but further investigations are necessary to properly attribute these changes.
Alice Florence Wells, Matthew Henry, Ewa M. Bednarz, et al. Identifying climate impacts from different Stratospheric Aerosol Injection strategies in UKESM1. ESS Open Archive . December 27, 2023.AbstractStratospheric Aerosol Injection (SAI) is a proposed method of climate intervention aiming to reduce the impacts of human-induced global warming by reflecting a portion of incoming solar radiation. Many studies have demonstrated that SAI would successfully reduce global-mean surface air temperatures, however the vast array of potential scenarios and strategies for deployment result in a diverse range of climate impacts. Here we compare two SAI strategies - a quasi- equatorial injection and a multi-latitude off-equatorial injection - simulated with the UK Earth System Model (UKESM1), both aiming to reduce the global-mean surface temperature from that of a high-end emissions scenario to that of a moderate emissions scenario. Both strategies effectively reduce global mean surface air temperatures by around 3°C by the end of the century; however, there are significant differences in the resulting regional temperature and precipitation patterns. We compare changes in the surface and stratospheric climate under each strategy to determine how the climate response depends on the injection location. In agreement with previous studies, an equatorial injection results in a tropospheric overcooling in the tropics and a residual warming in the polar regions, with substantial changes to stratospheric temperatures, water vapour and circulation. However, we demonstrate that by utilising a feedback controller in an off-equatorial injection strategy, regional surface temperature and precipitation changes relative to the target can be minimised. We conclude that moving the injection away from the equator minimises unfavourable changes to the climate, calling for a new series of inter-model SAI comparisons using an off-equatorial strategy.
Glade, I., Hurrell, J. W., Sun, L., & Rasmussen, K. L. (2023). Assessing the impact of stratospheric aerosol injection on US convective weather environments. Earth's Future, 11(12), e2023EF004041.AbstractContinued climate warming, together with the overall evaluation and implementation of a range of climate mitigation and adaptation approaches, has prompted increasing research into proposed solar climate intervention methods, such as stratospheric aerosol injection (SAI). SAI would use aerosols to reflect a small amount of incoming solar radiation away from Earth to stabilize or reduce future warming due to increasing greenhouse gas concentrations. Research into the possible risks and benefits of SAI relative to the risks from climate change is emerging. There is not yet, however, an adequate understanding of how SAI might impact human and natural systems. For instance, little to no research to date has examined how SAI might impact environmental conditions critical to the formation of severe convective weather over the United States (US). This study uses ensembles of Earth system model simulations of future climate change, with and without hypothetical SAI deployment, to examine possible future changes in thermodynamic and kinematic parameters critical to the formation of severe weather during convectively active seasons over the US Results show that simulated forced changes in thermodynamic parameters are significantly reduced under SAI relative to a climate change (SSP2-4.5) world, while simulated changes in kinematic parameters are more difficult to distinguish. Also, unforced internal climate variability is likely to significantly modulate the projected forced climate changes over large regions of the US.
Morgenstern, O. (2023). Using historical temperature to constrain the climate sensitivity and aerosol-induced cooling. EGUsphere, 2023, 1-23.AbstractThe most recent generation of climate models that has informed the 6th Assessment Report (AR6) of IPCC is characterized by the presence of several models with anomalously large equilibrium climate sensitivities (ECSs) relative to the previous generation. Partly as a result, AR6 did not use any direct quantifications of ECSs based on 4xCO2 simulations and relied on other evidence when assessing the Earth’s actual ECS. Here I use the historical observed global-mean surface air temperature and simulations produced under the Detection and Attribution Model Intercomparison Project to constrain the ECS and historical aerosol-related cooling. Based on 15 largely independent models I obtain an average adjusted ECS of 3.4±0.8 K (at 68 % confidence), which is very consistent with the AR6 estimate. Furthermore, importantly I find that the optimal cooling due to anthropogenic aerosols consistent with the observed temperature record should on average be about 34±31 % of what these models simulate, yielding a multi-model-mean, global-, and annual-mean aerosol-related cooling for 2000–2014, relative to 1850–1899, of -0.19±0.14 K (at 68 % confidence), when these models simulate on average -0.63±0.28 K. For 12 models the reduction in aerosol-related cooling equals or exceeds 50 %. There is a correlation between the models’ ECS and their aerosol-related cooling, whereby large-ECS models tend to be associated also with large aerosol-related cooling. The results imply that a large reduction of the aerosol-related cooling, along with a more moderate adjustment of the greenhouse-gas related warming, for most models would bring the historical global mean temperature simulated by these models into better agreement with observations.
Vattioni, S., Luo, B., Feinberg, A., Stenke, A., Vockenhuber, C., Weber, R., ... & Chiodo, G. (2023). Chemical impact of stratospheric alumina particle injection for solar radiation modification and related uncertainties. Geophysical Research Letters, 50(24), e2023GL105889.AbstractCompared to stratospheric SO2 injection for climate intervention, alumina particle injection could reduce stratospheric warming and associated adverse impacts. However, heterogeneous chemistry on alumina particles, especially chlorine activation via , is poorly constrained under stratospheric conditions, such as low temperature and humidity. This study quantifies the uncertainty in modeling the ozone response to alumina injection. We show that extrapolating the limited experimental data for ClONO2 + HCl to stratospheric conditions leads to uncertainties in heterogeneous reaction rates of almost two orders of magnitude. Implementation of injection of 5 Mt/yr of particles with 240 nm radius in an aerosol-chemistry-climate model shows that resulting global total ozone depletions range between negligible and as large as 9%, that is more than twice the loss caused by chlorofluorocarbons, depending on assumptions on the degree of dissociation and interaction of the acids HCl, HNO3, and H2SO4 on the alumina surface.
Chang, C. H., & Hosseinpour, F. (2023). Relationships between Aerosols and Marine Clouds during the “Godzilla” Dust Storm: Perspective of Satellite and Reanalysis Products. Atmosphere, 15(1), 13.AbstractIn June 2020, a record-breaking Saharan dust storm, known as the “Godzilla” extreme event, caused significant dust transport from the Sahara Desert across the Atlantic Ocean to the United States. Based on satellite observations, the magnitude of aerosol optical depth (AOD) has consistently remained highest over the Atlantic Ocean for the past 18 years. This study uses satellite observations (including MODIS and CALIOP) and MERRA-2 reanalysis products to investigate the relationships between dust and marine clouds. During this extreme event, the concentration of AOD exhibits a synchronous anomaly with the cloud fraction (CF). Principal components analysis (PCA) results show that the enhanced temperature and specific humidity near the surface contribute the most to cloud development over the tropical Atlantic Ocean. Despite the reduced sensitivity of CF to aerosols, the semi-direct effect of dust can still play a crucial role during this extreme dust storm. We found that the presence of absorbing aerosols above the cloud layers warms the air, accompanied by an enhancement of surface moisture, thereby benefiting low-level cloud coverage.
WEB POSTSWe Can Already Stop Climate Change If We Want To (Uncharted Territories) Uncharted TerritoriesThe 2023 UN Climate Change Conference (“COP28”) finished last month with many promises that obscure a key fact: We could easily stop climate change right now if we wanted. If we don't do it, it's just because we don't really want to. Here's how we could do it, in 3 steps… a day ago · 126 likes · 61 comments · Tomas Pueyo
THESIS
JOB OPPORTUNITY“The University of Chicago’s Climate Systems Engineering initiative ( David Keith) and Climate Extremes Theory and Data Group (PI: Pedram Hassanzadeh) are looking for a highly motivated postdoctoral fellow to work on developing AI-based weather emulators and hybrid models for solar geoengineering including different climate conditions (CO2 levels, aerosol loading, etc.). A particular focus is on understanding changes in the characteristics of extreme weather events. The projects involves a multidisciplinary collaboration among experts in climate science, scientific ML, and climate modeling.”
YOUTUBE VIDEOSChris Vivian Ocean Geoengineering HPAC | Robbie Tulip  “In this discussion with the Healthy Planet Action Coalition, Dr Chris Vivian addresses a range of methods of ocean cooling, with focus on the relation between iron fertilization and ocean gyres, and overall governance of marine geoengineering. His slides are available at https://www.healthyplanetaction.org/”
DEADLINES | |
