Overview
- A peer‑reviewed paper published July 8 in Science Advances used seasonal forecast models to test deliberate cloud brightening on the 1997–98 and 2015–16 El Niño events and found nine months of spraying could nearly halve Niño 3.4 warming in the simulations.
- The method works by spraying fine sea‑salt aerosols into low marine clouds so the clouds hold more, smaller droplets, reflect more sunlight, cool the ocean surface and thereby weaken the wind and ocean feedbacks that drive El Niño.
- The study says the plan is not operational: the modeled mission would need roughly 2,400 spray ships and nozzle output far beyond current technology, so it is a research concept rather than a ready response.
- Models also show clear risks and regional tradeoffs, including earlier or stronger La Niña phases after suppression of El Niño and possible harms to vulnerable regions such as the Horn of Africa from shifted rainfall patterns.
- Authors and funders urge more study and governance work rather than deployment, noting the idea grew from a natural experiment with Australian 2019–20 wildfire smoke and that there are no known field tests or government plans to use the technique on the developing 2026 El Niño.