Effect of Regional Marine Cloud Brightening Interventions on Climate Tipping Elements

Abstract

It has been proposed that increasing greenhouse gas (GHG) driven climate tipping point risks may prompt consideration of solar radiation modification (SRM) climate intervention to reduce those risks. Here, we study marine cloud brightening (MCB) SRM interventions in three subtropical oceanic regions using Community Earth System Model 2 experiments. We assess the MCB impact on tipping element‐related metrics to estimate the extent to which such interventions might reduce tipping element risks. Both the pattern and magnitude of the MCB cooling depend strongly on location of the MCB intervention. We find the MCB cooling effect reduces most tipping element impacts; though differences in MCB versus GHG climate response patterns mean MCB is an imperfect remedy. However, MCB applied in certain regions may exacerbate certain GHG tipping element impacts. Thus, it is crucial to carefully consider the pattern of MCB interventions and their teleconnected responses to avoid unintended climate effects.

Rethinking the Susceptibility‐Based Strategy for Marine Cloud Brightening Climate Intervention: Experiment With CESM2 and Its Implications

“…Latham et al (2008) and Rasch et al (2009) described a methodology in which regions most susceptible to cloud seeding were first identified and MCB deployment was then prioritized solely based on susceptibility. In other MCB studies (Baughman et al, 2012;Haywood et al, 2023;Hill & Ming, 2012;Hirasawa et al, 2023;Jones et al, 2009), deployment of cloud seeding was frequently assumed to be over the stratocumulus regions, for example, the Southeast Pacific, Northeast Pacific, and Southeast Atlantic. With the cloud decks constantly present over these regions, deployment of MCB is likely to induce strong cooling.…”

“…For SAI (MacMartin et al, 2017(MacMartin et al, , 2019(MacMartin et al, , 2022Richter et al, 2022;Tilmes et al, 2018), the injected aerosols become widespread due to the transport processes through atmospheric circulations and thus the induced cooling in general is much more evenly distributed over the globe. With MCB (Haywood et al, 2023;Hill & Ming, 2012;Hirasawa et al, 2023;Jones et al, 2009;Rasch et al, 2009) a global reduction of temperature can also be achieved, however the induced cooling is much more localized around regions where MCB is deployed.…”