2026-07-08 カリフォルニア大学サンディエゴ校（UCSD）
＜関連情報＞
- https://today.ucsd.edu/story/could-geoengineering-work-to-tamp-down-super-el-ninos
- https://www.science.org/doi/10.1126/sciadv.adx3012
- https://www.science.org/doi/10.1126/sciadv.adg1213
海洋雲の集中的な明るさがその後のエルニーニョ現象を弱める Targeted marine cloud brightening weakens subsequent El Niño
Jessica S. Wan, John T. Fasullo, Nan Rosenbloom, Chih-Chieh Chen, and Katharine Ricke
Science Advances Published:8 Jul 2026
DOI:https://doi.org/10.1126/sciadv.adx3012
Abstract
Extreme events are often attributable to the compounding effects of anthropogenic warming and natural variability. Marine cloud brightening (MCB), a solar geoengineering proposal to reduce long-term warming, could theoretically mitigate extremes by instead targeting seasonal-to-multiyear phenomena, such as El Niño–Southern Oscillation (ENSO). Yet the effectiveness of regional MCB to deliberately modify ENSO has not been tested. By exploiting the 2019–2020 Australian wildfire opportunistic experiment, we demonstrate that the “natural” cloud brightening and ensuing La Niña–like response can be reproduced by simulating MCB in the southeast Pacific. We then explore how MCB modifies the 1997–1998 and 2015–2016 El Niño events. MCB initiated during the El Niño growth phase disrupts the Bjerknes feedbacks that normally amplify El Niño conditions, but those effects weaken after MCB is terminated. Only the earliest and longest interventions restore neutral ENSO conditions and weaken teleconnections. Weakening El Niño can result in unintended consequences including an earlier La Niña following the targeted El Niño, although early and short interventions may counter these effects. Our results support the consideration of climate variability and teleconnections as targets in solar geoengineering research.
CESM2における、最近のオーストラリアの森林火災に対する熱帯太平洋の複数年にわたる冷却反応 A multiyear tropical Pacific cooling response to recent Australian wildfires in CESM2
John T. Fasullo, Nan Rosenbloom, and Rebecca Buchholz
Science Advances Published:10 May 2023
DOI:https://doi.org/10.1126/sciadv.adg1213
Abstract
The climate response to biomass burning emissions from the 2019–2020 Australian wildfire season is estimated from two 30-member ensembles using CESM2: one of which incorporates observed wildfire emissions and one that does not. In response to the fires, an increase in biomass aerosol burdens across the southern hemisphere is simulated through late 2019 and early 2020, accompanied by an enhancement of cloud albedo, particularly in the southeastern subtropical Pacific Ocean. In turn, the surface cools, the boundary layer dries, and the moist static energy of the low-level flow into the equatorial Pacific is reduced. In response, the intertropical convergence zone migrates northward and sea surface temperature in the Niño3.4 region cools, with coupled feedbacks amplifying the cooling. A subsequent multiyear ensemble mean cooling of the tropical Pacific is simulated through the end of 2021, suggesting an important contribution to the 2020–2022 strong La Niña events.
