Do volcanoes affect weather?

[music fades in]

Welcome to CoreFacts, where we're always short on time, but big on science. I'm Steve Sobieszczyk. Today's question is a good one.

Do Volcanoes Affect Weather?

Yes. For example the June 1991 eruption of Mount Pinatubo was global. Slightly cooler than usual temperatures recorded worldwide and the brilliant sunsets and sunrises have been attributed to this eruption that sent fine ash and gases into the stratosphere, forming a large volcanic cloud that drifted around the world. The sulfur dioxide (SO2) in this cloud -- about 22 million tons -- combined with water to form droplets of sulfuric acid, blocking some of the sunlight from reaching the Earth and thereby cooling temperatures in some regions by as much as 0.5 degrees Celsius. An eruption the size of Mount Pinatubo could affect the weather for a few years.

A similar phenomenon occurred in April of 1815 with the cataclysmic eruption of Tambora Volcano in Indonesia, the most powerful eruption in recorded history. Tambora's volcanic cloud lowered global temperatures by as much as 3 degrees Celcius. Even a year after the eruption, most of the northern hemisphere experienced sharply cooler temperatures during the summer months. In parts of Europe and in North America, 1816 was known as "the year without a summer."

And now you know. Join us every weekday for a new CoreFact. If you'd like to have a question featured on our show, give us an email or phone call. The email address is corefacts@usgs.gov. The phone number is 703-648-5600; and that is a long distance number, so long distance fees do apply.

The USGS CoreFacts is a product of the U.S. Geological Survey, Department of the Interior.

[music fades out]