Question

In 1991 an event occurred which changed the Earth's albedo temporarily - what was that event?

Answer 1

It was the Pinatubo eruption

Answer 2

The event was volcanic eruption.

The second largest volcanic eruption took place in June 1991. The volcanic eruption took place in the Mount Pinatubo (a chain of volcanoes along the Luzon arc) on the island of Luzon in the Philippines. After the millions of tons of sulfur dioxide were discharged into the atmosphere, resulting in a decrease in the temperature worldwide over the next few year.