Stratospheric Aerosol Injection (SAI) Research and Commercial Deployment

suspended and commercial deployment ongoing

Stratospheric Aerosol Injection (SAI) is a solar geoengineering project aimed at cooling the planet by spraying reflective particles into the stratosphere to dim the sun and reduce global temperatures. The project includes research experiments such as Harvard University's SCoPEx, which planned to release calcium carbonate particles from a weather balloon to study their behavior in the upper atmosphere. Although the SCoPEx experiment was suspended and later shut down due to political objections, commercial startups like Make Sunsets and Stardust Solutions are actively deploying or planning to deploy SAI technologies by launching weather balloons carrying sulphur dioxide into the stratosphere to sell cooling credits or geoengineering capabilities.