Pacific cloud brightening could weaken El Nino, but models reveal risks for Europe and Asia

Scientists are exploring the possibility of altering Pacific clouds to potentially weaken a powerful climate event called an El Niño. An El Niño brings heatwaves, floods, and droughts worldwide, and is made worse by human-induced climate change. The idea is to artificially brighten clouds over the Pacific Ocean to counteract this effect.

Researchers used computer models to test this concept and found that it worked best when started early in the El Niño cycle, around June, and continued through February. The model showed that this intervention could reverse many of the temperature and rainfall changes typically associated with an El Niño. However, the technology for such cloud brightening is not yet ready on a large scale.

It would require spraying sea salt from around 2,400 ships to achieve the desired effect. Even if the technology is developed, there are potential downsides. The models suggest that this approach could cause warming in Europe and Asia, which might not be desirable. Moreover, the long-term effects of repeatedly using marine cloud brightening to suppress El Niños are unknown.

While some critics argue that geoengineering could create a "moral hazard" by giving polluters a free pass to continue emitting greenhouse gases, the lead researcher believes it's necessary to explore such options given the current climate situation.