When volcanoes erupt, a large amount of material from the Earth’s interior, including extraordinary amounts of carbon dioxide, are released into the atmosphere. Image credit: European Geosciences Union.

How much CO2 does a single volcano emit?

Some say it’s more than all of humanity emits in a year. But people say a lot of things. What does the science say?

“One volcano puts out more toxic gases — one volcano — than man makes in a whole year. And when you look at this ‘climate change,’ and when you look at the regular climate change that we all have in the world, we have warm and we have cooling spells.” -John Raese

Every volcanic eruption that occurs on planet Earth is full of pollutants. Not just ash and dust, mind you, but also carbon dioxide: one of the strongest greenhouse gases on our planet. In the largest cases, a single volcanic plume, lasting only hours, might add many millions of tons of carbon dioxide to the atmosphere. Could it be the case, then, that individual volcanoes add more carbon dioxide to our atmosphere than human activity does? To find the answer, we’ve got to look to the scientific data.

The Earth as viewed from a composite of NASA satellite images from space in the early 2000s. Image credit: NASA / Blue Marble Project.

As viewed from space, it’s immediately clear that the Earth is a truly living planet, distinct from every other known world in the Solar System. With continents, liquid oceans, icecaps, changing cloud patterns…