Science Questions

How much pollution does a volcano produce?

Sun, 15th Jun 2008

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Darwin Teague asked:

How much pollution does a volcano produce? I’ve heard that a volcanoes spew out as much pollution as all the cars that have ever been put on Earth combined but how much pollution does a volcano produce when it erupts?


We asked our guest Marie Edmonds:

Marie- This is a very good question and it gives me an opportunity to dispel some of the myths about volcanoes and global warming and pollution. Volcanoes emit CO2 and SO2: carbon dioxide and sulphur dioxide are the main gases that might be construed to cause global warming or pollution. Volcanoes emit around 100,000,000 tonnes of CO2 a year. Compare that to man-made emissions of CO2 which comes to about 30,000,000,000 tonnes of CO2 per year*. So volcanoes emit around 1/300th of CO2 that we do and are therefore insignificant in terms of global warming. Sulphur dioxide on the other hand, volcanoes emit around a tenth of the anthropogenic emissions of SO2. That forms regional smog.

Chris- Isn’t there a benefit of sulphur dioxide in that it reflects heat back in to space? In fact it cools down the Earth so volcanoes are quite good in that respect because they keep us cooler than we otherwise would be.

Marie- Yes. There has been some research in the last few years that suggests very large eruptions such as Pinatubo in 1991. That eruption emitted about 20 megatonnes of SO2 into the stratosphere. Eruptions such as those which happen once every decade in fact have slowed down global warming a little bit. Without those eruptions we’d actually see the effects of global warming much more now than we do.

[*Value correct for 2008-10]


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What you've heard is true.

Beside particulate (ash and other particles), volcanoes can release enormous quantities of gases, including the following pollutants:
H2O water vapor
CO2 carbon dioxide
SO2 sulfur dioxide
H2S hydrogen sulfide
CO carbon monoxide
HCl hydrogen chloride
HF hydrogen flouride

Even non-explosive basaltic volcanoes (Hawaii, Iceland) can release damaging quantities of pollutants in the form of "vogâ", or volcanic smog.  The Hawaii volcano observatory has recently issued warnings for sulfur dioxide emissions and restricted access to areas around Kilauea.  The 1783 Icelandic basalt eruption resulted in emission of over 100 tons of SO2 in less than 8 months- killing humans, livestock and damaging crops in both Iceland and Europe.  Gas emissions during the eruption of the Siberian traps may have caused the great Permian extinction 250 million years ago.  Volcanic SO2 emissions can range up to 10 million tonnes per day.
Bass, Mon, 16th Jun 2008

Krakatoa is a volcanic island in the Sunda Strait between Java and Sumatra in Indonesia.

See also:
Krakatoa immence volano

The best known eruption culminated in a series of massive explosions on August 26-27, 1883.

The combined effects of pyroclastic flows, volcanic ashes and tsunamis had disastrous results in the region.

The official death toll recorded by the Dutch authorities was 36,417 and many settlements were destroyed, including Teluk Betung and Ketimbang in Sumatra, and Sirik and Semarang in Java.

The eruption also produced erratic weather and spectacular sunsets throughout the world for many months afterwards, as a result of sunlight reflected from suspended dust particles ejected by the volcano high into Earth's atmosphere.

This worldwide volcanic dust veil acted as a solar radiation filter, reducing the amount of sunlight reaching the surface of the earth.

In the year following the eruption, global temperatures were lowered by as much as 1.2 degrees Celsius on average.

Weather patterns continued to be chaotic for years, and temperatures did not return to normal until 1888..

For more information about the topic Krakatoa, read the full article at, or see the following related articles:
Alan McDougall, Mon, 7th Jul 2008

I think the biggest source of water pollution is Industries. Who are releasing large amount of hazardous waste into our water resources. In order to do proper treatment of this waste water consultant like must be contacted harmonsmith, Thu, 4th Jun 2009

Well you would say that, wouldn't you, Mr. SPAM. Don_1, Thu, 4th Jun 2009

The largest volcanic eruption since the rise of modern humans, Homo sapiens, is the great eruption of Toba, in Sumatra, about 71,000 years ago. It produced some 2800 cubic kilometers of ash and may have reduced the world's human population to only 10,000. The eruption of Toba is hypothesized by some scientists to have decimated the early human inhabitants of S Asia. The eruption lasted perhaps two weeks, but the ensuing "volcanic winter" resulted in a decrease in average global temperatures by 3 to 3.5 degrees Celsius for several years.

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AlexSmith, Tue, 9th Jun 2009

i love this it has helped me soo much :) thanks p.s. i love josh s carl lane, Mon, 1st Mar 2010

Who is Marie Edmonds and what are her qualifications? Her reply sounds just as generalized and unsubstantiated as the origonal "myth". Zim, Sat, 17th Apr 2010

How much pollution does a volcano produce?

That's a very good question that I too wonder. How the he** do you measure a ash cloud constantly erupting from a volcano? Shining lasers on it? measuring the light shining through it? "Accurate forecasts of the amount of ash expected to fall in a given area are difficult to produce. Ash fall amounts depend on the character of the eruption (duration, cloud height, grain size distribution, water content) and the prevailing winds, all factors that can change rapidly and are difficult to measure accurately."

Take a look here too.  yor_on, Mon, 19th Apr 2010

I thought this put things into context quite nicely... Mazurka, Tue, 20th Apr 2010

For Zim, this would  be her, then:
Her publications list is linked from that page.
As to her qualifications, I can't immediately find her CV online, but I guess if you actually wanted to know you could e-mail her and ask.
rosy, Tue, 20th Apr 2010

Here is an interesting

Volcano emitting 150-300,000 tonnes of CO2 daily

Extrapolating from what?
Where do they get their numbers?

This are the only numbers I know off?

Institute of Earth Sciences. 

Eyjafjallajokull eruption. 

yor_on, Tue, 20th Apr 2010

Zim, I'm astonished that you have the audactiy to question anyone's qualifications when you can't even spell original correctly! Martin, Sun, 12th Dec 2010

Martin, it's funny that you pointed out somebody's mistake when you also made one when you spelled audacity. It's a typo, get over it. I'm also curious who this Marie is. jm, Tue, 8th Feb 2011

Why-oh-why is it so hard to decide? Dr Edmonds says volcanoe emit around 100,000,000 tonnes of CO2 a year. The US Geological Society says Volcanoes release more than 130 million tonnes of CO2 into the atmosphere every year. says that the British Geological Survey (the Grauniad's link doesn't work) says it has been estimated that subaerial volcanism releases around 300 Mt/yr CO2. Who do we believe? ..maybe even the nutters who are in denial! Mike. Mike, Fri, 4th Nov 2011

How many BTUs of heat does the erupting volcano emit per day? Everything I have read only talks about gases and not at all about temperature that is being released how many BTUs does matter also. Dennis Malkin, Tue, 11th Oct 2016

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