The explosion of the Mt. Pinatubo volcano on June 15, 1991, was the largest
volcanic eruption the world had seen in nearly a century. In addition to
the widespread destruction that the volcano wrought on the Philippine
island of Luzon, Mt. Pinatubo’s impact was felt around the world.

Global average temperatures cooled for more than a year after the eruption
due to the massive injection of dust and gases into the upper atmosphere.
With the Mt. Pinatubo eruption, the global effects of volcanoes on climate
were captured in detail for the first time by a suite of Earth-observing

“By combining satellite information with other measurements from airplanes
and the Earth’s surface, we were able to monitor the Pinatubo impact on the
upper atmosphere for many years after the eruption,” said Phil Russell of
NASA Ames Research Center, located in California’s Silicon Valley. “We
measured the initial increase in particle sizes and the subsequent return
to pre-eruption values many years later.”

Russell and other scientists who were involved in many of these
trailblazing studies are available for interviews.

A Global Pall of Dust and Aerosols. Pinatubo pumped so much volcanic ash
and gas into the upper reaches of the atmosphere that the normal levels of
stratospheric aerosols increased by more than 20 times, leading to a
short-lived global cooling. Interview Phil Russell, NASA Ames Research
Center, Moffett Field, CA; telephone John Bluck at 650/604-5026 or
650/604-9000 to schedule interviews with Russell; e-mail

A Temporary Global Cooling. Global warming was halted – at least
temporarily – by the aerosol cloud from the eruption, which lowered global
average temperatures by half a degree through 1992. NASA climate modelers
precisely predicted this volcano-induced cooling – a powerful demonstration
of the capability of these computer simulations. Contact: James Hansen,
NASA Goddard Institute for Space Studies, New York, NY, telephone,
212/678-5500; e-mail

Ozone Levels Drop Worldwide. The protective ozone layer in the upper
atmosphere weakened for more than a year as the result of gases injected
into the stratosphere by the eruption. NASA’s Total Ozone Mapping
Spectrometer (TOMS) instrument tracked the decline and eventual recovery
from start to finish. Contact: Jay Herman, NASA Goddard Space Flight
Center, Greenbelt, MD; telephone, 301/614-6039; e-mail

A Shift in the Weather and Winds. The eruption also caused changes in
regional weather patterns. Climate models showed that Pinatubo produced a
shift in wind patterns in the North Atlantic that lead to a
warmer-than-usual winter in Europe in 1991-92. Contacts: Gavin Schmidt,
Columbia University and NASA Goddard Institute for Space Studies, New York,
NY; telephone 212/678-5627; e-mail Drew Shindell,
NASA Goddard Institute for Space Studies, New York, NY; telephone,
212/678-5561; e-mail

Mudflows: A Continuing Hazard. The millions of tons of ash and rock that
blanketed the flanks of Mt. Pinatubo created dangerous rivers of mud during
the annual rainy season. Scientists are keeping an eye on this shifting
natural hazard with airborne and space sensors. Contact: Peter
Mouginis-Mark, University of Hawaii, Honolulu; telephone, 808/956-3147;

A New View of the Swirling Atmosphere. The Mt. Pinatubo eruption was a
unique natural experiment that unveiled movements in the atmosphere that
scientists had never seen before. As satellites tracked volcanic aerosols
moving around the globe, researchers saw movements through the troposphere
into the stratosphere for the first time. Contact: Chip Trepte, NASA
Langley Research Center, Hampton, VA; telephone, 757/864-5836; e-mail

Visualizations of Mt. Pinatubo and several of these global climate effects
will be broadcast on NASA TV on Wednesday, June 13 at 1 2 noon, 3:00 p.m.
and 6:00 p.m., EDT. NASA TV is broadcast on the GE2 satellite, which is
located on Transponder 9C, at 85 degrees West longitude, frequency 3880.0
MHz, audio 6.8 MHz.