Geoengineering Potential to Mitigate Extreme El Niño Events Explored

As the world braces for a potentially devastating “super” El Niño event, researchers at UC San Diego’s Scripps Institution of Oceanography are exploring an unconventional strategy: targeted geoengineering to moderate its catastrophic impacts. This emerging scientific inquiry focuses on marine cloud brightening—a technique that involves increasing the reflectivity of clouds over oceans to reduce incoming solar heat and potentially inhibit the atmospheric dynamics that intensify El Niño.

The concept gained traction following the 2019-2020 Australian “Black Summer” bushfires, which released vast amounts of aerosols into the atmosphere. These particles acted similarly to geoengineering agents by brightening clouds above the southeastern Pacific Ocean, reflecting more sunlight back to space, and fostering conditions akin to a natural La Niña, which counters El Niño’s warming effects. Scientists observed that this phenomenon contributed significantly to altering global weather patterns, offering a real-world proof of concept.

Building on this natural experiment, climate scientists Kate Ricke and Jessica Wan utilized sophisticated seasonal forecasting models to simulate the effects of deliberately deploying marine cloud brightening during the onset of historic El Niño events, particularly those in 1997 and 2015. Their computational simulations indicate that early intervention with cloud brightening in the central Pacific could notably dampen El Niño’s intensity, enhancing cooling and drying effects by over 40%, and thereby reducing the extreme weather risks associated with these events.

The study, published in Science Advances, underscores a promising shift in geoengineering research—from long-term climate modification strategies to short-term, event-targeted interventions. Unlike ongoing global solar radiation management schemes that demand continuous deployment and carry substantial socio-political risks, this approach aims for time-limited application to mitigate specific, high-risk natural climate disturbances.

Despite its potential, the idea remains controversial. Geoengineering has historically sparked concerns about unintended ecological consequences and governance challenges. However, Ricke, Wan, and co-author John Fasullo—whose prior work on bushfire aerosol impacts validated key aspects of this study—argue that carefully calibrated marine cloud brightening could become a valuable adjunct to existing disaster mitigation tools such as flood control infrastructure. The economic stakes are significant; previous El Niño events have caused damage amounting to trillions of dollars globally.

While there are currently no plans to deploy this intervention against the brewing 2026 El Niño, the research encourages policy-makers and scientists to consider geoengineering not as a panacea for climate change, but as a tactical tool for reducing the severity of predictable, cyclic climate crises. The team highlights the necessity for further studies to understand potential risks and refine deployment strategies.

This investigation redefines geoengineering’s role in climate science, suggesting that precise, temporary alterations in natural variability may provide a pragmatic pathway to risk reduction without the sustained socio-technical burdens of global climate intervention.