As scientists warn that the coming Super El Niño could be the worst in recorded history, one group of researchers has proposed a drastic solution. Scientists say that dimming the sun could shield up to 75 per cent of the world's oceans from sweltering heatwaves. In turn, that could help prevent the buildup of hot water in the Equatorial Pacific, which is 'fuelling' the most extreme El Niño cycle in 140 years. The controversial method, known as stratospheric aerosol injection, involves pumping vast clouds of tiny sulphur–based particles into the air. These aerosol particles hang in the upper atmosphere for years, reflecting some of the sun's energy back out into space. According to computer simulations, this could keep global warming within safe levels and dramatically cut the severity and length of marine heatwaves. However, this extreme geoengineering technique is highly controversial, and even the researchers aren't sure what the consequences would be. Co–author Professor Phoebe Zarnetske, of Michigan State University, warns: 'There's very little known about the ecological impacts.' To prevent marine heatwaves from forming, researchers have proposed using Stratospheric Aerosol Injection (SAI) to curb Earth's warming.

In their study, the researchers simulated what would happen to the world's oceans in a 'business as usual' scenario and compared it to a situation in which geoengineering is used. If nothing is done and the world continues on its current path, marine heatwaves will get hotter and longer in 97 per cent of the world's oceans. But if SAI is used to cap global warming at 1.5°C (2.7°F) above the pre–industrial average, about a quarter of the ocean will be shielded from worsening heat waves. In a more aggressive scenario, in which climate change is held back to 1°C (1.8°F), heatwaves will be cooler in 76 per cent of the ocean and shorter in 80 per cent of locations.

The regions that benefited the most in the simulations were the tropical Atlantic, the Indian Ocean, the Arctic Ocean and the South Atlantic Ocean. However, the researchers warn that the benefits are not evenly distributed, and some key areas would still be left unprotected. Even in the most aggressive geoengineering scenario, the North Atlantic, Tropical Pacific, and parts of the Southern Ocean will still see worsening heatwaves if emissions don't fall. These are, unfortunately, some of the key areas in which El Niño weather patterns can be influenced by and drive marine heatwaves.

Lead author Dr Lala Kounta, of Michigan State University, says: 'The geography of protection is deeply unequal.' El Niño is part of a naturally occurring weather cycle called the El Niño–Southern Oscillation, which shifts between hot and cool phases every two to seven years. During the El Niño part of the cycle, warm waters that build up in the Pacific spread out and raise the Earth's average surface temperature. While the cycle itself is natural, scientists have warned that a massive ocean heatwave in the Pacific is driving unusually high intensity.

This heatwave spans 9,000 miles (14,500 km) and has been forming in the Pacific since the end of 2025. At the same time, there is another marine heatwave stretching from Papua New Guinea to the Californian coast, where temperatures have been up to 3°C (5.4°F) above average. Dr Mariana Bernardi Bif and Dr Franz Philip Tuchen, of the University of Miami, warned in an article for the Bulletin of the Atomic Scientists: 'As ocean waters warm in the North Pacific with the marine heatwave, the reduction of the winds can also impact the equator, meaning that extreme events might be helping initiate the conditions necessary for an El Niño.

'And because the equatorial warming affects the North Pacific, the unprecedented 2026 El Niño might amplify the duration of the North Pacific marine heatwave, with serious consequences for people, wildlife, and Earth’s climate.' While the new study suggests dimming the sun could help to prevent another Super El Niño in the future, the researchers caution that the key remains curbing global emissions. Professor Zarnetske added: 'It's not a substitute for reducing emissions; reducing emissions is still the priority and is the most effective action to mitigate climate change.' What's more, previous studies have raised concerns about the side effects of dimming the sun.

A study conducted by Columbia Climate School found that Stratospheric Aerosol Injection could wreak havoc on global weather patterns. If the aerosols were released in the polar regions, they would likely disrupt tropical monsoon systems, which could have an effect on sea levels, they found. Meanwhile, releases concentrated in equatorial regions could affect the jet stream and disrupt atmospheric circulation patterns that conduct heat towards Earth's poles. Dr Ying Chen, an expert on cloud brightening from the University of Birmingham who was not involved with the study, previously told the Daily Mail: 'Change the solar radiation heating at one place, may lead to change of atmospheric pattern in other places.'