Paul VoosenFor years, the controversial idea of solar geoengineering—lofting long-lived reflective particles into the upper atmosphere to block sunlight and diminish global warming—has been theoretical.
It’s starting to get real: Today, after much technical and regulatory wrangling, Harvard University scientists are proposing a June 2021 test flight of a research balloon designed to drop small amounts of chalky dust and observe its effects.
This first flight would not inject the particles; it would only be a dry run of the steerable balloon and instruments needed to study chemical reactions in the stratosphere, the calm, cold layer more than 10 kilometers up.