As the spectacular eruption of Eyjafjoell volcano in Iceland brings most transcontinental air travel between Europe and North America to a screeching halt, the question arises out here in the blogosphere: what effect will the eruption have on global climate?
The short answer is none, or very little, or who knows?
According to the U.S. Geological Survey, the worlds volcanoes emit about 200 million tons of CO2 annually on average. The EPA estimates that in 2006, human activity accounted for 28 trillion metric tons of CO2 emissions. Despite the dramatic impact the Iceland volcano, it’s emission are fairly small, only spewing an estimated one million metric tons of CO2. All told, volcanic activity probably equals only about 0.7% of anthropogenic sources of greenhouse gas emissions.
Fortunately, large-scale eruptions are relatively rare, at least on the scale of human lifetimes. But the downside to that is that scientists don’t get a lot of opportunities to study the formation of other invisible gases, such as sulphur dioxide, formed along with the great plume of ash in volcanic eruptions, or where those gases may eventually end up in the atmosphere.
When sulfur dioxide mixes with water, aerosols, or fine particulates, of sulfuric acid is produced that can reflect back sunlight into space when those aerosols reach the stratosphere, so despite the addition of greenhouse gases from volcanoes, large eruption can have a short-term cooling effect on climate, such as after the significantly larger 1991 Mount Pinatubo eruption in the Philippines, that cooled the planet for about a year.
Mount Pinatubo sent approximately 200 megatons of sulfur dioxide into the atmosphere. By contrast, the Iceland eruption has thus far only shot out 0.004 megatons. Also, Pinatubo is located in the lower latitudes, considered the “sweet spot” for a volcano to have a global climate effect, as the ejected gases more easily spread across latitudes. Even if the gases ejected from the Iceland eruption do reach the stratosphere, they likely will not spread to other latitudes.
Also, in regard to short-term emissions and climactic effects, the grounding of thousands of airplanes in Europe has temporarily reduced anthropogenic greenhouse gas emissions.
So to answer the question a bit more definitively what effect the Eyjafjoell volcano will have on global climate, I say, “not much“.
Of course, that’s little comfort for the stranded passenger languishing at Heathrow, waiting to go home.
How do you pronounce it?Beats me.
Image credit: Huffington Post