A new study published in the journal Science Advances suggests that a form of solar geoengineering could be used to weaken El Niño events before they grow too strong, potentially reducing their global impact. This matters because this year's El Niño is shaping up to be among the strongest on record, and such events — which raise global temperatures and bring droughts, floods and cyclones — can cause hundreds of billions in economic losses, especially when compounded by fossil-fuel-driven warming. The research reframes geoengineering as a possible regional, targeted intervention rather than a permanent, planet-wide one.

The study, co-authored by climate scientist Katherine Ricke of UC San Diego and Scripps, focused on marine cloud brightening (MCB), which involves spraying seawater into clouds to make them more reflective. As real-world MCB trials remain small, the team modelled the effect using the 2019–2020 Australian bushfires, whose vast smoke output helped trigger a rare "triple-dip" La Niña. Running this model against two historic El Niño events showed the technique could have significantly reduced their magnitude. However, experts including Ricke and Texas A&M's Andrew Dessler caution that the approach is unproven, that models are imperfect, and that real-world deployment could prove a "political nightmare" with unpredictable and potentially dangerous consequences.