Which volcano erupted in 1991 and caused measurable global cooling?

Mount Pinatubo erupted in 1991 and caused measurable global cooling.

Pinatubo is a stratovolcano on Luzon in the Philippines. Its June 1991 eruption was the second-largest volcanic eruption of the twentieth century and the largest to affect a densely populated area in modern times. Scientists successfully forecast the eruption, allowing the evacuation of tens of thousands of people.

The eruption injected approximately 17 million tonnes of sulfur dioxide into the stratosphere. That gas became sulfate aerosol, which reflected some sunlight and lowered global average temperatures by roughly 0.5 degrees Celsius for about one to two years. The eruption also created a large caldera at the summit.

Heavy monsoon rains later remobilized ash and pumice into lahars, which continued damaging communities and infrastructure. The eruption is often confused with Mount St. Helens because both produced major explosive events, but Pinatubo’s climate impact was especially significant because of the amount of sulfur dioxide reaching the stratosphere.