The June 12, 1991 eruption column from Mt. Pinatubo.
Credit: U.S. Geological Survey / D. Harlow.

By Lauren Lipuma

It’s nice to get away in mid-March. Especially when you’re leaving the chilly, unpredictable weather of Washington, D.C. for the warm sunshine of the Canary Islands.

I have the pleasure of attending an AGU Chapman Conference this week in Puerto de la Cruz, a small town on the island of Tenerife in the Canary Islands. The Canaries are a small group of volcanic islands just off the coast of Morocco governed by Spain. They’re essentially the Atlantic Ocean’s version of Hawaii.

The focus of this Chapman Conference is the study of stratospheric aerosols: fine particles suspended in air that have made it all the way to the stratosphere, the second layer of Earth’s atmosphere. Aerosols encompass many kinds of particles: dust, soot, smoke, water vapor and various natural and man-made gases.

Stratospheric aerosols are important because they can have big short-term effects on Earth’s climate. Depending on what type of particles they are, aerosols can either absorb or reflect sunlight, effectively warming or cooling Earth’s surface.

Picture of Alaska’s Mt. Redoubt eruption on April 21, 1990. The mushroom-shaped plume rose from avalanches of hot debris (pyroclastic flows) that cascaded down the north flank of the volcano. A smaller, white steam plume rises from the summit crater.
Credit: U.S. Geological Survey / R. Clucas.

Volcanic eruptions are one of the biggest sources of stratospheric aerosols. Eruptions send clouds of ash and smoke and gases like sulfur dioxide high into the atmosphere, where they can block out the sun and cool Earth’s surface. While locally devastating, eruptions of Indonesia’s Mt. Agung in 1963-64, Guatemala’s Fuego volcano in 1974, Mexico’s El Chichon in 1982 and the Philippines’ Mt. Pinatubo in 1991 gave scientists the opportunity to better understand how aerosols disperse in the atmosphere and affect Earth’s climate.

But Earth has not had a major volcanic eruption since Pinatubo in 1991. And since then, the technologies for measuring stratospheric aerosols have evolved rapidly. So over the past three decades, scientists have been able to study the climate effects of smaller aerosol concentrations in unprecedented detail.   

The purpose of this conference is to better understand how aerosols have impacted Earth’s climate since Pinatubo. I’ll be hanging out with the 70 or so researchers here as they discuss new ways of measuring aerosols from satellites and space; how the 2017 wildfires affected the stratosphere; and what kinds of effects aerosols will have on Earth’s climate in the future. And perhaps most importantly: is this volcanically quiet period we’re in normal? Are we overdue for a big eruption? And what would such an eruption do to our climate?

—Lauren Lipuma is AGU’s public information specialist and science writer. She is attending the AGU Chapman Conference on stratospheric aerosols in Tenerife, Spain. Find more of Lauren’s stories from this meeting on The Field and read about research presented at the meeting on GeoSpace. See photos from the conference on AGU’s Instagram. Follow Lauren on twitter at @Tenacious_She.