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RESEARCH PAPERSWang, O., Liang, J., Gu, Y., Haywood, J. M., Chen, Y., Fang, C., & Wang, Q. G. (2024). Projected future changes in extreme precipitation over China under stratospheric aerosol intervention in the UKESM1 climate model. Atmospheric Chemistry and Physics, 24(21), 12355-12373. Abstract Extreme precipitation events are linked to severe economic losses and casualties in China every year; hence, exploring the potential mitigation strategies to minimize these events and their changes in frequency and intensity under global warming is of importance, particularly for the populous subregions. In addition to global warming scenarios, this study examines the effects of the potential deployment of stratospheric aerosol injection (SAI) on hydrological extremes in China based on the SAI simulations (G6sulfur) of the Geoengineering Model Intercomparison Project (GeoMIP) by the UK Earth System Model (UKESM1) simulations. G6sulfur is compared with simulations of the future climate under two different emission scenarios (SSP5-8.5 and SSP2-4.5) and a reduction in the solar constant (G6solar) to understand the effect of SAI on extreme precipitation patterns. The results show that under global warming scenarios, precipitation and extreme wet climate events during 2071–2100 are projected to increase relative to the control period (1981–2010) across all the subregions in China. Extreme drought events show a projected increase in southern China. The G6sulfur and G6solar experiments show statistically similar results to those under SSP2-4.5 in extreme precipitation intensities of China in UKESM1. These results are encouraging. The efficacy of SAI in decreasing extreme precipitation events and consecutive wet days is more pronounced than that of G6solar when compared to SSP2-4.5. While both G6sulfur and G6solar show drying at high-latitude regions, which is consistent with our understanding of the spin-down of the hydrological cycle under SRM. Given the limitations of the current model and the small ensemble size, and considering that the hydrological effects are less beneficial than those indicated for temperature, it is recommended that further, more comprehensive research be performed, including using multiple models, to better understand these impacts.
Pavesi, M. (2024). One Atmosphere, Many Metaphysics: The Philosophies of Geoengineering. Authorea Preprints. Abstract Deliberate, large-scale interventions in the Earth’s climate system, collectively known as “geoengineering”, are increasingly being proposed to counteract the worst effects of global warming. Public and scholarly controversies have ensued due to the high risks and high uncertainties that characterise these novel technologies. For all that, geoengineering is currently being evaluated at the highest levels of governance, and a full-scale review by the United Nations is ongoing. To enrich the understanding of geoengineering, the present work reviews the metaphysics behind the main arguments in favour and against geoengineering. Based on the varied conceptions of humans, nature, knowledge, and technical systems, which support their appraisals, proponents and opponents of climate engineering are grouped into four ideal-types: homo naturans, homo faber, homo sapiens, and anthropo-not-seen. In addition to the pro-against geoengineering fissure, a second one is identified: transcendental-instrumental metaphysics.
Kaur, H., Bala, G., & Seshadri, A. K. (2024). Climate response to interhemispheric differences in radiative forcing governed by shortwave cloud feedbacks. Environmental Research: Climate. Abstract Understanding the climate response to interhemispheric differences in imposed radiative forcing is crucial for solar radiative modification (SRM) investigations. While previous studies have shown that climate sensitivity to solar insolation changes imposed in the northern versus the southern hemisphere is different, the underlying mechanisms remain unclear. In this study, we investigate the climate response to three different radiative forcing scenarios: globally uniform radiative forcing, radiative forcing imposed only in the northern hemisphere, and radiative forcing confined only to the southern hemisphere. We find that the climate sensitivity is larger when forcing is imposed only in the southern hemisphere. To explain the mechanisms for this, we estimate climate feedbacks using the radiative kernel approach. We find that albedo and Planck feedbacks are insensitive to hemisphere of forcing, and the larger climate sensitivity to the southern hemispheric radiative forcing is primarily due to differences in shortwave cloud feedbacks. Additionally, we examine impacts of interhemispheric differences in radiative forcing on tropical circulation, planetary albedo, and land/sea warming contrast. Our results clearly demonstrate how the Intertropical Convergence Zone (ITCZ) moves into the hemisphere where the radiative forcing is larger without maintaining a symmetric planetary albedo. Overall, our study provides insights into climate system responses to interhemispheric differences in radiative forcing caused by forcing agents such as aerosols from volcanic eruptions and human activities, and land cover changes, in addition to solar geoengineering.
WEB POSTS
UPCOMING EVENTSGood COP, Bad COP: a post-COP29 assessment | 27 November 2024
Solar Geoengineering Events Calendar
PODCASTSDirect climate cooling overview - Baiman | Reviewer 2 does Geoengineering  | Direct climate cooling overview - Baiman Reviewer 2 does geoengineering 1:03:32 |
"Ron Baiman discusses his expansive paper summarising all known SRM and other direct climate cooling techniques https://academic.oup.com/oocc/article/4/1/kgae014/7731760 Plus his letter to the International Maritime Organization https://academic.oup.com/oocc/article/4/1/kgae008/7706251"
YOUTUBE VIDEOSCan we geo-engineer our way out of climate change? with Gernot Wagner | MHTV Podcasts "Jason talks to Gernot Wagner about geo-engineering, and whether it's a feasible way forward."
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