Common Climate Questions

Q: Might volcanoes emit more carbon dioxide than human activities?

A: No. The burning of fossil fuels results in several hundred times as much CO2 release as volcanoes each year. Fossil fuel burning results in the emission of approximately 35 gigatons (billion metric tons) of carbon dioxide into the atmosphere per year worldwide. This obviously dwarfs the estimated annual release of carbon dioxide from volcanoes, which is 0.15 to 0.26 gigatons of CO2 per year.

Volcanoes can and do influence global climate in the opposite direction, exerting a cooling influence for a few years, but this is through their injection of sulfate particles into the high reaches of the atmosphere (the stratosphere) during very large and explosive volcanic eruptions that occur sporadically. For example, the four major volcanic eruptions of the 20th Century caused short-term interruptions in the long-term warming trend caused by human induced emissions of heat-trapping gases.