Dust From Mt. Pinatubo Eruption to Offset Global Warming Trend

The explosion of Mt. Pinatubo in the Philippines last June, now believed to be the largest volcanic eruption of the century, filled the skies with enough dust to cool the Earth far more than any effects of global warming might warm it--at least for a few years--according to new findings released Tuesday.

Images from satellites show the Earth girdled by a cloud of light-reflecting volcanic ash and gas, which is whirling around the Equator about 15 miles above the Earth’s surface. The particles reflect sunlight back into space and keep it from striking and heating the Earth.

Scientists at the National Oceanic and Atmospheric Administration, who used polar-orbiting weather satellites to look down on the volcanic cloud, say the dust has begun lowering average temperatures in the tropics by about 4 degrees Fahrenheit.

As the cloud disperses in the fall and spreads its load of sulfuric-acid droplets evenly over all latitudes of the globe, worldwide average temperatures could fall by about 1 degree Fahrenheit, according to NOAA scientist Larry Stowe.

The temperature change is so subtle it will probably not be noticed by most people. But for climate specialists, a 1-degree drop would be more than enough to temporarily offset any effects attributed to global warming.

Many scientists believe that the gradual buildup of “greenhouse gases” from power plants and automobile tailpipes will increase global temperatures by a few tenths of a degree each decade, eventually raising average temperatures by 4 or 5 degrees by the middle of the 21st Century. The Pinatubo eruption could lower temperatures by a full degree in one year.