• Question: How much pollution does a volcano produce?

    Asked by megansaurus to Davie, Gemma, James P, James V, Nuala on 28 Jun 2012.
    • Photo: James Verdon

      James Verdon answered on 28 Jun 2012:

      Hi megansaurus,
      Volcanoes can produce a lot of pollution when they erupt. Sometimes, if volcanoes emit a lot of sulphuric gasses they can lead to acid rain. The Skaftá volcano in Iceland erupted in 1793, releasing lots of toxic gasses that killed a lot of people, as well as poisoning the land so that nothing could grow. About 50% of livestock on Iceland died, and 25% of the population died in the resulting famine. The effects were felt all over Western Europe.

      The ash and dust the volcanoes can emit can also have severe environmental effects. The dust clouds from large volcanoes can partially block out the sun, reducing temperatures and stopping crop growth. For example, when Tambora erupted in 1815, we had what is called the year without summer, because of all the volcanic dust blocking the sun’s rays. Crops failed all over the world, leading to famines.

      Also, volcanoes can emit lots of CO2. The emission rates are smaller than the emission rates from fossil fuels, so we know that volcanoes are not causing the current rate of global warming. But they can build up over time if rates of volcanism increase. For example, in the Cretaceous, when the dinosaurs lived, rates of volcanism were higher, creating more CO2 in the atmosphere. This lead to increased temperatures, so much so that there was barely any ice at the poles at all.

      So yes, absolutely, volcanoes can produce a lot of pollution!

    • Photo: Gemma Purser

      Gemma Purser answered on 28 Jun 2012:

      Hi megasaurus,

      Volcanoes do produce alot of pllution like James Verdon has explained but if you compare volcanoes to us humans they dont produce that much pollution (if we think about carbon dioxide) at all!

      The seconded biggest eruptions that occured in the last century was Mount Pinatubo, it erupted in 1991, in the philippines. It emitted 0.05 giga tonnes of carbon dioxide. Humans pollute our planet by burning fossil fuels and releasing 35 giga tonnes per year into the atmosphere. That means for volcanoes to match the same amount of carbon dioxide we are putting into the air there would have to be 700 eruptions like mount Pinatubo every year!! Thats alot of big volcanic eruptions!

      Another big volcanic eruption was Mount St Helens, it erupted in 1980, in the USA. It produced 0.01 giga tonnes of carbon dioxide during the eruption that lasted for days. It only takes 2.5 hours for the activities of humans burning fuels to match what it took nature days to acheive.

      It kind of makes you think what is worse for our planet…..volcanoes or humans?

    • Photo: James Pope

      James Pope answered on 28 Jun 2012:

      Hi megansaurus,

      The sullphur dioxide pollution (that cause the formation of sulphuric gasses and acid rain) that some volcanoes emit can cause a cooling of the climate, so the eruption of Mt Pinatubo that Gemma mentioned is known to have cooled the global climate by 0.2°C (which is about the rate of global warming we see in about 8 years) for about a year, so it is quite a big impact. It was eruptions like this that started the idea of geo-engineering of the climate (manmade cooling by puting sulphur dioxide into the Stratosphere to cancel out the greenhouse gases!).