The Israeli-U.S. startup Stardust Solutions announced last week that it raised $60 million in venture capital in its latest funding round – the largest venture investment to date for a for-profit company developing solar geoengineering technology, particularly injection of reflective particles into the stratosphere.
Advocates of solar geoengineering are dismayed. But why are they surprised?
Read this blog post which is based on discussions within the initiative for an International Non-Use Agreement on Solar Geoengineering and has been written with contributions from Heleen Bruggink, Sean Low, Aarti Gupta, Frank Biermann, Kevin Surprise, Florian Rabitz, Rakhyun E. Kim, Mike Hulme, Peter Newell, Raymond Pierrehumbert, Louis Kotzé, Margaretha Wewerinke-Singh and Jennie C. Stephens. Views expressed here do not necessarily represent all signatories of the open letter calling for a non-use agreement.
Mike Hulme, 13 November 2025
