This year’s El Niño is shaping up to be one of the strongest on record. That means weather will go haywire and a massive slug of heat will likely send the global average temperature to new records.
While there’s not much we can do at this point but prepare for the effects, a group of researchers has an audacious—and highly controversial—proposal for future El Niños: Dim the sun over the Pacific to cool things down.
If it sounds out there, well, it is. Solar geoengineering has been a fringe idea for years in the climate world. But with damage from global warming getting worse and the world still hooked on fossil fuels, it’s getting renewed attention from researchers.
Most efforts have focused on global attempts to cool the planet using planes to inject reflective particles high in the stratosphere. But the new study proposes a regional approach to cool the Pacific specifically through a technique called marine cloud brightening. It’s exactly what it sounds like: spraying tiny particles in the atmosphere that can make clouds brighter.
There have been only small-scale experiments using the technique. To get around that data limitation, researchers used a natural proxy. The 2019-2020 Australian bushfires pumped smoke across the Pacific, which effectively did the same thing as marine cloud brightening.
Models show reflecting some of the incoming sunlight could indeed weaken El Niño. In a warmer future, that may come in handy. But it may also come with unintended consequences and requires vastly more research.
“There’s a lot of things we need to figure out from models before trying it in the real world,” says Katharine Ricke, a co-author of the study and a scientist at UC San Diego and the Scripps Institution of Oceanography.
Of course, there’s one way to lower the background temperature that we know would work, and without adverse consequences: winding down our use of fossil fuels.
Read Molly Taft’s piece from Climate Desk partner Wired on this sounds-like-sci-fi idea.
—Brian Kahn
