June 15, 1991, felt like Armageddon in the Philippines. Twenty-five years ago today, Mount Pinatubo erupted in the country’s north, blowing a cloud into the sky that would cast its shadow over the entire planet.
Considered the strongest terrestrial volcanic eruption in the past 100 years, the nearly 5,000 foot volcano had been dormant for over five centuries. Then, over the course of four days, Pinatubo spewed 10 billion tons of gas-charged magma and aerosols into the air.
The resulting haze cooled Earth by 0.9 F (0.5 C), according to the US Geological Survey. Though one degree is imperceptible to human skin, the U.S. National Academy of Sciences (pdf, p. 5) explains that a single-digit increase in the earth’s temperature can have dramatic effects: at 200-400% more land burned by wildfire; a 15% decrease in sea ice, and up to a 15% decrease in agricultural crop yield. Pinatubo’s eruption also temporarily enlarged the earth’s ozone hole.
A strong typhoon amplified Pinatubo’s effect, bringing heavy rains and winds that blew a cloud of fine ash to the capital Manila, some 56 miles (90 km) southeast. The cloud from Pinatubo later traveled the globe for three weeks, disrupting at least 17 commercial flights. It also caused colorful sunsets worldwide, as the Baltimore Sun explains.
Oxford University volcanologist David Pyle says that Pinatubo has become fertile ground for research, that may one day lead to a deeper understanding of volcanic activity. “Pinatubo is a fantastic case study, and there are still developing hypotheses based on observations of Pinatubo,” Pyle said to Live Science.
Today, Mt. Pinatubo has become a tourist attraction, especially for adventurous mountain climbers. A deep blue and green lake on the summit formed after the blast is a popular hiking destination.
Yesterday, June 14, a new Mt. Pinatubo museum was inaugurated in the province of Pampanga in memory of the historic event that shaped the fate of local towns and—for a year—the climate of the entire planet.