This road map could help us decide whether to deploy solar geoengineering

Solar geoengineering, also called stratospheric aerosol injection (SAI), is a proposed method to counteract climate change by releasing reflective particles into the stratosphere—the second layer of Earth’s atmosphere, above where weather occurs.

These particles would mimic the cooling effect of volcanic eruptions by reflecting sunlight back into space, potentially lowering global temperatures.

Scientists have studied SAI for half a century, but major uncertainties remain about its effectiveness and potential side effects.

A San Francisco nonprofit called Reflective, founded in late 2023, aims to fill these knowledge gaps by funding research and publishing a detailed road map for experiments and studies.

Reflective has raised over $20 million and provided $4 million to dozens of research groups.

The organization does not advocate for deploying SAI but argues that more research is needed to make informed decisions about its use.