Climate Change - page 3 Volcanoes and ClimateWhen some volcanoes
erupt, they send gases up into the stratosphere. Emitted sulfur
dioxide is converted into sulfate aerosols, which are tiny
suspended particles that circle the globe and reduce the amount
of solar radiation that reaches the Earth. Although the actual
volcanic activity may only last several days, the impacts on
climate can last for a few years, which is the time it takes for
the aerosols to fall out of the stratosphere. The eruption of
Mount Pinatubo in the Philippines in June 1991 sent about 20
million tons of sulfur dioxide and ash as high as 20 miles into
the Earth's atmosphere. The Pinatubo sulfur dioxide cloud was
the largest stratospheric disturbance observed since the advent
of Earth-observing satellite imagery in the 1970s. Following the
eruption, global temperatures decreased by as much as 0.5
degrees C (about 1 degree F) in late 1992. In addition, sulfate
aerosols emitted during the eruption interacted with human-made
chlorofluorocarbons