Pinatubo Demonstrates Solar Geoengineering Potential

The 1991 Mount Pinatubo eruption put large amounts of sulfur dioxide into the stratosphere and cooled the planet by nearly 1°F for about two years, demonstrating that injecting aerosols into the stratosphere (solar geoengineering) could prevent some warming—using far less material than would be needed near the surface because stratospheric aerosols stay for one to two years and don't directly harm human health.