The Unexpected Tech

Chemotherapy For The Planet: Geoengineering As A Solution Of Last Resort

Mount Pinatubo is a volcano in the Philippines that erupted in 1991, spreading 10 million tons of sulfur into the atmosphere. The impact on the local environment was horrific. But scientists later noticed that the acrid cloud deflected 2% of normal sunlight, and reduced worldwide temperatures by 0.5 degrees Celsius (0.9 degrees Fahrenheit). The thinking behind the “Pinatubo Option” is basically to re-enact this natural event: to put thousands of tons of particles into the atmosphere to deflect sunlight, and cool the Earth’s surface.

Ken Caldeira, a Stanford climate scientist says it would be possible to stop most of the global warming each year by releasing tens of kilograms a second into the air. The cost would be low, probably in the few millions of dollars. And the operation could be carried out by an airline-sized fleet of aircraft.

According to his models, it would be possible to offset 90% of the warming change from increased CO2 concentrations, and 70% of the precipitation change, even if emissions doubled. “The basic story is that climate models indicate that the deflection of sunlight will offset most climate change in most of the places, most of the time,” Caldeira says.

Caldeira doesn’t actually endorse the Pinatubo Option, saying it is more like chemotherapy for a cancer patient than a painless cure. But he said it should be considered in an emergency, and that research should continue so that we’re ready if we need it.