ambience: Volcanic Eruption
Weâ€™re listening to the sounds of a volcanic eruption. Besides spewing out molten lava and hot plumes of gas, volcanoes may also have a profound affect on the worldâ€™s climate. Iâ€™m Jim Metzner and this is the Pulse of the Planet.
â€œIn order for a volcano to have an effect on climate, it has to be explosive, so that it gets its particles and gases high enough into the atmosphere so that theyâ€™ll stay around for awhile.â€
Alan Robock is an associate professor of meteorology at the University of Maryland.
â€As far as the effect on global climate, you need an eruption which puts sulfur gases into the stratosphere. When that happens, the sulfur gases are converted to sulfate particles, which are tiny white particles which can last for several years in the stratosphere.â€
â€These clouds of sulfuric acid reflect sunlight and scatter it back into space, reducing the amount of sunlight which reaches the ground, and so it gets colder. And after large eruptions, it can get cold for quite a while.â€
According to Professor Robock, large, explosive eruptions can lower global temperatures for more than a year. Smaller eruptions can have a drastic, short-term effect on local climate, by filling the air with large particles of volcanic ash. Thatâ€™s what happened in the state of Washington, when Mount St. Helens erupted in 1980.
â€In Yakima, Washington, the temperature was constant for 15 hours. It didnâ€™t matter whether it was day or night, because there was so much dust in the atmosphere, that it completely insulated the ground from outer space. And it was so dark the street lights came on during the day time.â€
Pulse of the Planet is presented by DuPont, makers of better things for better living.