Dimming the Sun Would Help Lower the Risks of El Niño

New Delhi, India Jul 8, 2026 ALN: This year’s El Niño is shaping up to be among the strongest on record, and it’s set to create chaotic weather around the world. This climatic phenomenon, characterized by the periodic warming of sea surface temperatures in the central and eastern Pacific Ocean, has far-reaching impacts on global weather patterns. El Niño events can lead to severe droughts in some areas while causing intense rainfall and flooding in others, disrupting agricultural production, water supply, and leading to economic losses.

A new study suggests that there could be a way to mitigate some of the impacts of future El Niños and global warming: dimming the sun. This concept, while ambitious, is rooted in the growing urgency to address climate change and its associated risks. As the planet continues to warm due to human activities, particularly the burning of fossil fuels, the frequency and intensity of extreme weather events are expected to increase. As such, innovative solutions to climate-related challenges are being explored.

El Niño develops naturally in the tropical Pacific every few years, caused by weakened trade winds that push heat from the ocean toward the coast of South America. This shift not only raises global temperatures but also alters precipitation patterns, leading to droughts in regions like Australia and the American Southwest, while causing heavy rainfall and flooding in places like the southeastern United States and parts of South America. The economic implications of a strong El Niño can be staggering, with estimates suggesting potential losses in the hundreds of billions of dollars across various sectors, including agriculture, fisheries, and disaster response.

The new study argues that deflecting solar energy could cool the ocean and help moderate El Niño events before they become too strong, staving off the worst impacts. This approach aligns with broader discussions in the field of climate science regarding solar geoengineering, which encompasses various techniques aimed at reflecting a portion of sunlight back into space to counteract global warming. By potentially reducing the intensity of El Niño events, this strategy could provide a much-needed buffer against the adverse effects of climate change.

“El Niño is one of these things where something happens in the tropical Pacific, and then it rearranges the way the entire global atmosphere is holding energy that year,” says Katherine Ricke, a coauthor of the study published Wednesday in the journal Science Advances and a climate scientist at UC San Diego and the Scripps Institution of Oceanography. “It’s an ultimate pressure point in the climate system.” This perspective underscores the interconnectedness of global climate systems and the cascading effects that a single event like El Niño can have on weather patterns worldwide.

Ricke and her coauthors looked at using marine cloud brightening, or MCB, as a way to dim the sun in the Pacific. The technique entails spraying seawater into marine clouds to enhance the clouds’ reflectivity. By increasing the albedo, or reflectivity, of clouds, MCB could help cool the ocean surface beneath them. While some pilot projects and randomized controlled trials have tested the technique’s efficacy, they’ve only been on very small scales, making it difficult to assess its potential effectiveness on a larger scale.

MCB is one of a few different solar geoengineering methods intended to reflect sunlight back into space. Other methods, like using planes to inject aerosols into the stratosphere, can only work globally. However, MCB has the potential to be a regional cooling solution, which may be more manageable and less controversial than global approaches. The idea of targeting specific climatic events rather than attempting to cool the entire planet could appeal to policymakers and scientists who are wary of the broader implications of large-scale geoengineering.

To get around the lack of MCB experiments, researchers looked at a recent natural phenomenon that mimicked it: the catastrophic 2019-2020 Australian bushfire season. More than 10,000 bushfires raged across the country, producing almost 1 million metric tons of smoke. This represents one of the largest inputs of smoke into the stratosphere that humans have observed with satellite technology. The smoke particles acted similarly to the proposed MCB technique, reflecting sunlight and altering atmospheric conditions.

While the effects of this massive amount of smoke were complex, previous research shows it helped trigger a rare triple-dip La Niña—the opposite phase of El Niño—thanks in part to reflective particles in the smoke. This event, Ricke says, enabled her and her coauthors to finally address a question they’d had for years about whether regional interventions can help relieve the pressure events like El Niño put on the global climate system. The researchers created a model based on the MCB effects of the Australian bushfires and ran it against two different historic El Niño events to observe its effects. The modeling showed that lowering the amount of sunlight reaching the Pacific’s surface would have significantly reduced the magnitude of those El Niño events and their global impact.

Geoengineering techniques have traditionally been viewed as a method to cool the entire planet, acting as a counterbalance to humans’ use of fossil fuels—albeit an extremely controversial one. Critics of geoengineering argue that these techniques may distract from the urgent need to reduce greenhouse gas emissions and could lead to a false sense of security. The new study makes the case that some forms of geoengineering would be better used to target regional events, like El Niño. Doing so has the potential to avoid—or at least lower the risk—of the compounding effects of El Niño piled on top of rising temperatures due to human activity.

“The idea of having to sustain geoengineering indefinitely gives a lot of people pause—we all understand that cooperation at that magnitude would be hugely complicated in the world we live in,” Ricke says. “This is a totally different way to think about geoengineering.” The notion of regional geoengineering could open new avenues for research and policy discussions, particularly in light of the increasing frequency of extreme weather events linked to climate change.

Geoengineering techniques like using planes to inject aerosols into the stratosphere—or even more fantastical ideas like space mirrors—have been met with skepticism from scientists, policymakers, and the public. This skepticism primarily stems from concerns about their unpredictability—altering the weather can come with a lot of unintended consequences—and their potential to create political instability. For example, if one region were to implement a geoengineering project that inadvertently affected weather patterns in another region, it could lead to conflicts over resources and blame for adverse outcomes. It’s likely even a regionalized approach like the one proposed in the new study would run into the same issues, but it appears to be scientifically feasible—or at least worth further study.

“The thesis seems quite reasonable,” Andrew Dessler, a professor of atmospheric science at Texas A&M University, says of the Scripps study. However, Dessler warns that actually executing something like this would be “a political nightmare,” resulting in conflict or war if something goes wrong in what would be a worst-case scenario. The complexities of international cooperation on such initiatives cannot be overstated, especially as nations grapple with their own climate challenges and priorities.

“These models are imperfect, and there's the possibility that you'll create an unpredicted problem that is worse than the problem you're trying to solve,” Dessler says. “I think this is a really interesting paper, and I learned a few things reading it, but I certainly would not say that this is a great idea and we should implement it.” This cautionary stance reflects a broader sentiment in the scientific community regarding the need for thorough research and consideration before pursuing geoengineering strategies.

Ricke agrees: “There’s a lot of things we need to figure out from models before trying it in the real world,” she says. Still, she emphasizes that this research could prove crucial for the future if humanity fails to address fossil fuel pollution. “The reason people do research on solar geoengineering is because we might end up in a world where we need it.” As the climate crisis continues to escalate, the exploration of innovative solutions, including geoengineering, may become increasingly relevant in discussions about how to safeguard the planet's future.