Suspended ash particles are concentrated in distinct layers in the photo on the right. This banded appearance provides evidence of aerosols suspended in the atmosphere.

Aerosols gradually fall back to Earth. While they are suspended in the atmosphere, they block some of the sunlight and heat that would otherwise reach Earth's surface. A slight decrease in global temperatures followed Mount Pinatubo's eruption.

12. Describe one way you might test the idea that Mount Pinatubo's eruption was responsible for this instance of global cooling. Explain your answer.