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Did You Know: Volcanoes and Climate Change

Did you know that volcanic eruptions can cool Earth's atmosphere? Using imagery and data from the 1991 eruption of Mt. Pinatubo as an example, this segment shows addresses the misconception that volcanic eruptions are a cause of global warming by explaining how sulfur dioxide aerosols cause cooling. 


Produced by the Space Telescope Science Institute’s Office of Public Outreach in collaboration with the NASA Earth Observatory (
Story adapted from Image of the Day post by the NASA Langley Research Center Aerosol Research Branch:

  • Eruption of Mt. Pinatubo, Philippines, June 1991: U.S. Geological Survey

  • Spread of Dust and Sulfur Dioxide, Mt. Pinatubo, 1991: Mt. Pinatubo Particle Model (NASA/Goddard Space Flight Center Scientific Visualization Studio

  • Side-by-side Comparison of amount of light blocked before, soon after, and 2.5 years after the eruption: Stratospheric Aerosol and Gas Experiment II (SAGE II) instrument, Earth Radiation Budget Satellite (ERBS)

  • Effect of volcanic aerosols on global average air temperature: NASA’s Goddard Institute for Space Studies (GISS)

Written by Margaret Carruthers
Designed by Dani Player
Music courtesy of Associated Production Music LLC 


Text, Did You Know? Volcanoes and Climate Change.
A mushroom cloud of smoke and debris erupts on the horizon, viewed from a distant village with puffy white clouds in between. Volcanic eruptions can cool Earth's atmosphere. Volcanic eruptions spew ash and gases high into the atmosphere. Some of the gases, like sulfur dioxide, form tiny particles called aerosols.
A map of the Earth. Mt. Pinatubo Particle Model. Over time, air currents spread the sulfur dioxide and other volcanic aerosols throughout the atmosphere and around the globe. A strip of rainbow shoots west from the Philippines and spreads out after crossing Africa, gradually spiraling around the globe and diffusing across the map. Sulfur dioxide aerosols block sunlight, preventing it from reaching the surface. This causes the ground and the air above the ground to cool.
Diagrams contrast the planet's atmosphere before the eruption versus after, showing the amount of light blocked by aerosols, with blue indicating less light blocked or clear, and red at the other end of a full color spectrum indicating more light blocked, or hazy. Most of the atmosphere is blue, or clear before the eruption. 2 to 3 months after the eruption, the are closest to the tropics is red, and progresses to yellow and green by the north pole, with only the Antarctic still blue. Then 2 and 1/2 years after the eruption the planet is mostly green, or about midway on the spectrum. The overall effect of a major volcanic eruption is several years of lower-than-average global temperatures. A graph charts volcanic eruptions against temperatures, with sharp dips right after eruptions.