A study proposes to tackle the 'Superman' with geoengineering: increasing the brightness of marine clouds could weaken it

A new study proposes using geoengineering to counteract the effects of the so-called "Super El Niño," suggesting that increasing the brightness of marine clouds could weaken this powerful climate phenomenon. As forecasts warn of the arrival of what might be the strongest El Niño event in history, some scientists are exploring potentially radical solutions. In a paper published on Wednesday in the journal Science Advances, two researchers from the Scripps Institution of Oceanography, Kate Ricke and Jessica Wan, suggest mitigating the global impacts caused by the extreme warming of Pacific waters through a geoengineering intervention: creating marine clouds that reflect more sunlight and act as a countermeasure. El Niño is a natural climate phenomenon characterized by the anomalous and persistent warming of surface waters in the Pacific Ocean, which disrupts atmospheric and weather patterns across much of the planet. Geoengineering refers to altering the climate through technological interventions, such as injecting aerosols into the atmosphere to increase cloud brightness—a strategy surrounded by controversy due to the unpredictability of its consequences. Inspired by massive wildfires To develop their idea, Ricke and Wan were inspired by the effects of large-scale wildfires in Australia during 2019 and 2020. In that "natural experiment," smoke rising from these fires was laden with reflective aerosols that interacted with clouds and increased the amount of solar radiation reflected back into space. This reduced the amount of heat reaching the lower atmosphere, which in turn fueled the formation of La Niña—an anomalous cooling of the equatorial Pacific waters—that emerged in 2020. "That was the key breakthrough that made this a viable research question," says Ricke. "Without that opportunity for validation, I don't think our findings would have been as credible." In this new study, supported by the National Science Foundation (NSF), NASA, the U.S. Department of Energy, and NOAA, the scientists conducted simulations to explore what would happen if an intentional increase in marine cloud brightness had been applied in the southeastern and central Pacific during major El Niño events that occurred in 1997 and 2015. The results suggest that such an intervention would have lessened the impact of these El Niño events and led to cooling. They conclude that policymakers should consider real geoengineering plans targeting the natural variability of these phenomena in the future, so that continuous and sustained intervention is not required—one of the major drawbacks and concerns associated with this strategy. "We need to understand much more, but if there is a way to use this to mitigate El Niño, why not consider it?" asks Ricke. The lead researcher acknowledges she often aligns with scientists who advocate caution when discussing geoengineering, but believes this case is different. In her view, geoengineering could be used for specific El Niño events like the one currently forming, unlike broader geoengineering plans that require international cooperation to manage over years or decades. "One of the greatest social concerns surrounding geoengineering is that, if we use it to reduce long-term climate risks, we must implement it continuously and indefinitely," adds Wan. "If we could harness natural variability, we might gain some of the benefits of geoengineering without having to employ it indefinitely."