Washington Post: The 1991 eruption of Mount Pinatubo, a volcano in the Philippines, blasted enough fine particles and sulfur dioxide gas into the atmosphere to envelop the Earth in a high-altitude cloud for the better part of two months. When scientists checked in 1992, they determined that the cloud had deflected enough sunlight to cool the planet by about 1 degree.
Now, with the planet warming inexorably and the threat of long-term climate change looming, some experts are wondering whether the time may have...