A reader chimes in with a question regarding the CO2 output of volcanoes. Normally we discourage our readers from asking questions, but we will indulge you just this once, because the answer was (to us) a little surprising.
Turns out volcanoes release quite a bit of CO2, although the numbers are small in comparison the amount created each year by human activities. One conservative estimate puts the amount of CO2 released every year by volcanoes at about 150-200 million tons (which you could offset with about 10 million Utility TerraPasses — anyone? Anyone?). This is a big number, but the amount created by humans every year is about 150 times bigger.
Another online source says that volcanoes produce about 3% of global CO2 emissions. That number, though significantly higher, is still small in comparison to man-made emissions.
Other fun volcano emissions facts:
- Vulcanologists measure volcano emissions by taping sensors to the front of a helicopter and flying it into active craters. That is so freaking cool.
- Despite the large amount of greenhouse gases coming out of volcanoes, volcanic activity is thought, on balance, to cause global cooling (cf. dinosaurs, extinction of).
- CO2 emissions from volcanoes can reach concentrations high enough to be deadly. Because CO2 is heavier than oxygen, it has a tendency to settle in depressions. Although the gas itself isn’t toxic, it can cause asphyxiation at high enough concentrations. Pliny the Elder supposedly succumbed to CO2 asphyxiation after lying on the ground near Pompeii.
- You think we were making up that bit about Pliny the Elder? There are areas near popular California ski resorts where you are discouraged from digging or lying face-down on the ground. You were warned.