How do volcanoes affect the atmosphere and climate Volcano World Oregon State University
There are two things to think about. The first is how the weather near an erupting volcano is being affected. The second is how large eruptions will affect the weather/climate around the world. I think more people are worried about the second issue than the first.
The main effect on weather right near a volcano is that there is often a lot of rain, lightning, and thunder during an eruption. This is because all the ash particles that are thrown up into the atmosphere are good at attracting/collecting water droplets. We don’t quite know exactly how the lightning is caused but it probably involves the particles moving through the air and separating positively and negatively charged particles.
Another problem in Hawai’i involves the formation of vog, or volcanic fog. The ongoing eruption there is very quiet, with lava flowing through lava tubes and then into the ocean. Up at the
vent is an almost constant plume of volcanic fume that contains a lot of sulfur dioxide. This SO2 combines with water in the atmosphere to form sulfuric acid droplets that get carried in the trade winds around to the leeward side of the Big Island. The air quality there has been really poor since the eruption started in 1983 and they are getting pretty tired of it.
As for the world-wide affects of volcanic eruptions this only happens when there are large explosive eruptions that throw material into the stratosphere. If it only gets into the troposphere it gets flushed out by rain.
The effects on the climate haven’t been completely figured out. It seems to depend on the size of the particles (again mostly droplets of sulfuric acid). If they are big then they let sunlight in but don’t let heat radiated from the Earth’s surface out, and the net result is a warmer Earth (the famous Greenhouse effect). If the particles are smaller than about 2 microns then they
block some of the incoming energy from the Sun and the Earth cools off a little. That seems to have been the effect of the Pinatubo eruption where about a 1/2 degree of cooling was noticed around the world. Of course that doesn’t just mean that things are cooler, but there are all kinds of effects on the wind circulation and where storms occur.
An even more controversial connection involves whether or not volcanic activity on the East Pacific Rise (a mid-ocean spreading center) can cause warmer water at the surface of the East Pacific, and in that way generate an El Nino. Dr. Dan Walker here at the University of Hawai’i has noticed a strong correlation between seismic activity on the East Pacific Rise (which he presumes indicates an eruption) and El Nino cycles over the past ~25 years.
Just a bit of the article. One might also look at what the USGS has to say on the effects of volcanos. Compared to what we are putting out, volcanos put out less than 1% of the CO2 that we generate from the burning of fossil fuels. That was not always the case. In several short periods of the Earth's geological history, great basalt floods, like the Siberian Traps, put out enough CO2 to cause a rapid and very large climate change that included acidification of the oceans. And there was a major extinction event. In the case of the Siberian Traps, that event resulted in the extinction of over 95% of the species then existing.
Today, even the effects of a Tambora sized eruption are only going to less than a decade. Whereas the effects of adding 40% more CO2, 250% more CH4, and industrial gases that have no natural analog, are going to last for centuries.
