Diminished efficacy of regional marine cloud brightening in a warmer world

[Geoengineering News]

https://www.nature.com/articles/s41558-024-02046-7

Authors

Jessica S. Wan, Chih-Chieh Jack Chen, Simone Tilmes, Matthew T. Luongo, Jadwiga H. Richter & Katharine Ricke 

Nature Climate Change (2024)Cite this article

21 June 2024

Citations: Wan, J.S., Chen, CC.J., Tilmes, S. et al. Diminished efficacy of regional marine cloud brightening in a warmer world. Nat. Clim. Chang. (2024). https://doi.org/10.1038/s41558-024-02046-7

Abstract

Marine cloud brightening (MCB) is a geoengineering proposal to cool atmospheric temperatures and reduce climate change impacts. As large-scale approaches to stabilize global mean temperatures pose governance challenges, regional interventions may be more attractive near term. Here we investigate the efficacy of regional MCB in the North Pacific to mitigate extreme heat in the Western United States. Under present-day conditions, we find MCB in the remote mid-latitudes or proximate subtropics reduces the relative risk of dangerous summer heat exposure by 55% and 16%, respectively. However, the same interventions under mid-century warming minimally reduce or even increase heat stress in the Western United States and across the world. This loss of efficacy may arise from a state-dependent response of the Atlantic Meridional Overturning Circulation to both anthropogenic warming and regional MCB. Our result demonstrates a risk in assuming that interventions effective under certain conditions will remain effective as the climate continues to change.

Source: Nature Climate Change