A new study has proposed that artificially brightening clouds over the Pacific Ocean could help tame extreme El Niño events, but researchers caution that such geoengineering carries significant risks and unintended consequences.
How cloud brightening works
The technique, known as marine cloud brightening, involves spraying salt particles into low-lying clouds to make them more reflective. This would bounce more sunlight back into space, cooling the ocean surface and potentially dampening the temperature spikes that drive El Niño.
According to the study published in the journal Nature Climate Change, targeting clouds in specific regions of the Pacific could reduce the intensity of extreme El Niño events by up to 50%. The researchers used climate models to simulate the effects of cloud brightening on El Niño Southern Oscillation (ENSO) cycles.
Potential side effects
However, the same models showed that the intervention could disrupt rainfall patterns in other parts of the world. For example, it might weaken the monsoon in South Asia and lead to drier conditions in the Amazon. “The risk of unintended side effects is substantial,” said lead author Dr. Sarah Johnson from the University of Washington. “We need to carefully weigh the benefits against the potential for causing harm elsewhere.”
El Niño events are associated with severe weather worldwide, including droughts in Australia and floods in South America. The study suggests that cloud brightening could mitigate these impacts, but only if implemented with caution and international cooperation.
Geoengineering debate
The research adds to the ongoing debate about geoengineering as a tool for climate change mitigation. Some experts argue that it offers a temporary solution while emissions are reduced, while others warn that it could distract from the need to cut greenhouse gases. “Cloud brightening is not a substitute for reducing carbon emissions,” Johnson emphasized. “It’s a potential emergency measure that comes with its own set of risks.”
The study was funded by the U.S. National Science Foundation and the European Research Council. Further research is needed to assess the feasibility and safety of large-scale implementation.
