What Happens If We Start Solar Geo-Engineering—And Then Suddenly Stop?

Volcanoes, nuclear war, and solar geo-engineering.

With a research portfolio that includes all three, Alan Robock is used to thinking about sudden, catastrophic change. A professor of environmental science at Rutgers University, Robock studies the movement of small particles and liquids through Earth’s atmosphere. In that role, he researches some very large and particle-producing events: the sudden extrusion of many tons of sulfur from an erupting volcano, or the global convection of smoke and ash from the firestorms that would follow a nuclear war.

Such a combination of interests—calamities both natural and anthropogenic—make him well-credentialed to study solar geo-engineering, which scientists widely consider to be the most promising technique to slow the increase in