“The real difficulty about vulcanism is not to see how it can start, but how it can stop.” ~ Sir Harold Jeffreys
Two primary things affect the weather on Earth: the sun and volcanoes.
Throughout history large volcanic reactions have had a major impact upon Mankind and the climate. Volcanoes have created islands and plunged them beneath the sea; they have forced mass migration and caused mass death, and many have changedat least temporarilythe climate of the entire planet.
Ken Caldeira, an earth scientist at Stanford University, California, and member of Britain’s prestigious Royal Society working group on geo-engineering, explains that “dust sprayed into the stratosphere in volcanic eruptions is known to cool the Earth by reflecting light back into space.”
That simple process has led to the starvation of whole nations in the past. Volcanic gases and dust suspended in the atmosphere cool the Earth to a point where the growing seasons significantly shorten and crops cannot reach maturity.
Whether Iceland’s Eyjafjallajokull glacier volcano continues to erupt and perhaps spark off the neighboring volcano, Katla, remains to be seen. The weather on Earth has already been affected and two erupting Icelandic volcanoes will significantly increase and accelerate climate cooling.
The late Cornell University professor, astronomer Carl Sagan, used the consequences of a large volcanic eruption’s impact on global cooling as part of his theoretical model for the frightening prospect of a nuclear winter. He presented his idea in the acclaimed television series,”The Nuclear Winter” that explored the devastating physical and chemical effects even a limited nuclear war would have upon the earth’s biosphere and lifeforms.
Vulcanologist’s, ecologists, meteorologists, oceanographers and agricultural scientists are all closely monitoring the volcano and waiting to see what it will do next.
Agricultural scientists are particularly concerned. They point to the longer term effects toxic plumes create on the food chain, including global cooling. The scientists cite the Tambora eruption in Sumbawa Island, Indonesia during 1815 that released megatons of sulfur into the atmosphere. The gases and particulates resulted in a significant drop of mean temperatures throughout the Northern Hemisphere and precipitated disruptions in the fishing industry, the loss of entire crops, and the outbreak of famines in parts of continental Europe.
While the Tambora eruption was bad, the Karakatoa explosion of 1883 threw so much debris into the air that 1884 became known throughout the Northern Hemisphere as “the year without a summer.” Besides providing for spectacular sunsets during a handful of years following its eruption, the massive long term cooling of Earth lasted much longer than that. A 2006 article in Nature revealed that Krakatoa’s mighty eruption cooled that atmosphere and the oceans for almost a century.
All volcanoes release water, CO2 and sulfur dioxide into the atmosphere—as well as millions of tons of rock in the form of microscopic ash. This debris, carried by stratospheric winds (including the jet stream), encircles the globe.
Although at present the world’s meteorologists predict only minor effects on the climate, a gigantic plume like the one created by the Icelandic volcano has saturated the upper atmosphere with aerosols that become a white haze acting like a mirror reflecting sunlight back into space. When that occurs, the process of cooling begins, as explained by Caldeira at Stanford.
When Laki—another Icelandic volcano erupted with cataclysmic force destroying almost everything on Iceland during 1783, Europe was thrown into the deep freeze.
As it happened, the United States’ Ambassador to France, Benjamin Franklin, saw the connection between the volcanic eruption and the abrupt cool down across Europe. He wrote that the sun’s “effect of heating the Earth was exceedingly diminished. Hence the surface was early frozen. Hence the first snows remained on it unmelted. Hence the air was more chilled. Hence perhaps the winter of 1783-84 was more severe than any that had happened for many years.”
So far, the force of the Eyjafjallajokull glacier eruption does not equal that of the Philippine’s Mt. Pinatubo eruption of 1991. That plume cooled the entire planet for almost a year.
Unless the Icelandic eruption intensifies or Katla also begins erupting—the worst climate effects would be no more than a relatively cool European summer.
