Radical plan to ‘dim’ the Sun among best options to protect Earth from potentially historic El Niño season: scientists

They’re literally proposing we steal its sunshine.

Researchers at UC San Diego have floated a wildly controversial plan to combat the looming super El Niño threat — injecting particles into clouds to turn down the sun. The radical sunscreen proposal was detailed in a study in the journal Science Advances.

“SG (solar geoengineering) could theoretically be leveraged to mitigate extreme events by instead targeting compounding seasonal-to-multiyear events such as El Niño,” wrote the researchers, who were led by UC San Diego climate scientist Kate Ricke.

A graph showing a marine heat wave off the coast of Southern California. NOAA

On Thursday, the National Oceanic and Atmospheric Administration’s Climate Prediction Center forecast an 81% chance that the natural climate pattern, defined by preternaturally warm temperatures on the Pacific Ocean’s surface, would be “very strong” by December.

If true, this so-called super El Niño results in extreme weather events ranging from droughts to downpours and heatwaves. The resultant damages could reportedly cost the global economy trillions of dollars, the UC San Diego researchers declared.

Some researchers have blamed climate change for exacerbating El Niño’s effects; UN chief Antonio Guterres warned that “the world must treat it as the urgent climate warning it is.”

However, “there is no evidence that climate change increases the frequency or intensity of El Niño events,” according to the World Meteorological Association.

Either way, we’re not defenseless against this apocalyptic weather event, or so the scientists say. According to the seemingly far-fetched study, we could mitigate the worst effects of El Niño through various weather alteration measures, including dimming the Sun.

The sun is seen through the haze covering the southern city of Narathiwat on October 23, 2015. AFP via Getty Images

This sci-fi-esque proposition would reportedly involve — not a giant celestial dimmer switch — but rather injecting special aerosols into the Earth’s stratosphere to make clouds over the sea brighter in a method called “marine cloud brightening.” In theory, this would reflect the Sun’s rays back into space, cooling the surface below like intergalactic blackout curtains.

Researchers posited that this form of geoengineering could “theoretically mitigate extremes” in seasonal weather events like El Niño, offering a more targeted and natural alternative to the “forced response to greenhouse gases” pushed by climatologists.

One major concern surrounding this radical plan? To curb “long-term climate risks,” this interstellar sunscreen would have to be deployed “continuously for an indefinite period of time,” according to coauthor and University of Chicago postdoctoral researcher Jessica Wan.

“If we could target natural variability, we could get some of the benefits of geoengineering without having to employ it indefinitely,” she said.

To prove this solar dimmer could work in seasonal bursts, the team built on a 2023 study that found that aerosols given off by bushfire smoke over the Pacific Ocean had caused clouds to brighten, reflecting solar radiation back into space. In turn, this reduced the amount of heat that escaped into the atmosphere.

The UC San Diego researchers specifically simulated what would happen if the sun-blocking method were deployed deliberately in the South East Pacific during the major El Niños that originated in 2015 and 1997.

They found that this could increase cooling and drying effects by 40%.

Of course, the concept of geoengineering has been shaded by many climate scientists, who feel that playing sun god could distract from crucial solutions such as dialing back carbon emissions.

In addition, no one knows the side effects of this solar dimming proposal.

“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,” Texas A&M University professor of atmospheric science Andrew Dessler, who was not involved in the research, told Wired. 

Currently, there are no concrete plans to test this sun-dimming defense on the current El Niño, but Ricke nonetheless feels it’s important to ponder said solution amid looming climate threats.

“We need to understand a lot more, but if there is a way to use this in addition to the risk-reduction tools to mitigate El Niños, why wouldn’t we consider it?” she said.