On June 15, 1991, Mount Pinatubo in the Philippines blew its top in an eruption of staggering proportions. It sent an ash cloud 28 miles high, filling surrounding valleys with deposits 660 feet thick and destroying almost every bridge within 18 miles. Over 800 people lost their lives.
The volcano also ended up affecting humans all over the world. Its aerosols circled the Earth, reducing direct sunlight by 21 percent. Which got scientists thinking: Wouldn’t it be nice if we could fight global climate change by reproducing this process, spraying our own aerosols in the stratosphere to bounce light back into space and cool off the Earth? It’s known as geoengineering, specifically “solar radiation management,” and while it sounds a bit bonkers, researchers are seriously studying the possibility of such a drastic campaign — including potential effects on everything from hurricanes to ecosystems.