Climate Modification and Volcanoes
The local climate modification discussion is often a cruel one. Parties decide on their positions, dig in and refuse to hear the rants of another side. Lost in the yelling is the simple proven fact that climate modification is a normal fact to some extent. For proof, we need merely look at the materials emitted by volcanoes.
It is an undeniable fact that volcanoes have altered the climate at some point in certain periods. Small explosions don’t have much impact, but large explosions send massive quantities of material and gases into the atmosphere. The gases include carbon dioxide, the ultimate bugaboo greenhouse gas. Ahead of these gases, however, volcanoes can kick out a huge amount of debris and ash which results in the material in the atmosphere blocking out the sun or reducing the warming effect.
Mount St. Helens is the most studied and well known recent eruption. Unless you have been meditating in a cave for the last 20 years, you no doubt know that the volcano exploded on May 18, 1980. The eruption was powerful enough to level everything for 17 miles, immediately turning 10 million trees into fuel. The huge volcanic ash cloud stretched halfway across the United States, but barely had an impact on global temperatures.
In contrast, the eruption of the El Chichon volcano in 1982 had a measurable climate impact. El Chichon is found in Mexico and was a much less significant eruption than Mount St. Helens. Still, the average temperature around the globe cooled by one degree. What scientist learned is that the climate modification impact of volcanoes is extremely dependent on the type of explosion. The materials from Mount St. Helens fell out of the atmosphere quickly, while El Chichon belched enormous amounts of sulfur that remained inside the environment for a much longer time.
One of the issues with environment modification is it occurs over a relatively long period of time. Since we started taking note of the case, we have not had a chance to observe the impact of a major eruption. The things we see in the media is basically small potatoes in comparison to historical eruptions of note. For instance, Mount St. Helens threw almost a half a cubic mile of material into the air. In 1815, a volcano in Indonesia belched 24 cubic miles of material into the atmosphere. Obviously, one can only imagine the impact on the climate of the earth.
Is there a association between climate modification and volcanoes? Undoubtedly. From what we see, in spite of this, the connection is generally of a short duration and not evidence for the increasing temperatures we are seeing currently.