The first US outdoor test of a solar geoengineering technology was conducted in San Francisco Bay. A device sprayed a fine mist of aerosol particles to simulate brightening clouds and reflecting sunlight.
The machine, developed over several years, aims to spray salt aerosols into the atmosphere to alter cloud composition and cool the Earth. The immediate goal was to test its ability to consistently spray the correct size aerosols outdoors.
This research is driven by the urgency of addressing global warming. The ongoing burning of fossil fuels makes it increasingly difficult to limit warming to the target of 1.5 degrees Celsius above pre-industrial levels. Solar geoengineering is being explored as a potential intervention strategy.
If the current test is successful, the next phase would involve attempting to modify clouds directly over the Earth's oceans.