Superfact 125: Volcanoes emit about 0.2 to 0.6 billion metric tons of carbon dioxide per year globally. Our burning of fossil fuels and industrial activities release more than 35 billion metric tons annually. Human emissions are roughly 60 to 100 times greater than all global volcanic output combined. Thus, volcanoes are not the cause of the current rapid global warming.
Have you ever seen claims on social media such as “a single volcanic eruption release as much CO2 as all of humanity has to date? Or 100 times as much? Or 10,000 times as much? As Snopes explains this is of course nonsense. I’ve seen this kind of claim many times and I’ve seen in the comment sections that a lot of people fall for them. That makes me wonder about people’s critical thinking skills as well as Facebook’s alleged fact checking.
As the super-fact above states, volcanoes emit about 0.2 to 0.6 billion metric tons of carbon dioxide per year globally. Our burning of fossil fuels and industrial activities release more than 35 billion to 38 metric tons annually. Thus, volcanoes emit only a small fraction of CO2 compared to what we do burning fossil fuels. Which also means that volcanoes are not the cause of the current rapid global warming. You can read more about this here, or here, or here, or here.
The graph above compares human carbon emissions (green line) with carbon emissions from volcanic eruptions (purple line). Human carbon emissions (the burning of fossil fuels and cement production) correspond to 35 billion metric tons annually while volcanic emissions are less than one ton annually. The graph is based on data from the Carbon Dioxide Information Analysis Center (CDIAC) at the DOE’s Oak Ridge National Laboratory and Burton et al., 2013.
Since so many people so quickly believe the disinformation, this fact should be surprising to a lot of people, and it is kind of important. Therefore, I consider it a super fact.
How do Volcanoes Affect Climate?
The emissions from volcanoes and their effect on climate are complicated. A large volcanic eruption can result in a lot of carbon emissions during a short period of time, but that typically does add up to being substantial in comparison to our annual anthropogenic carbon emissions. However, volcanic emissions include other gases that are not greenhouse gases, particularly Sulphur dioxide, which acts like an aerosol reflecting sunlight. This results in a more noticeable effect, but it is not a warming effect, but a cooling effect.
Long story short, when a volcano has a massive explosion, it shoots sulfur dioxide gas high up into the stratosphere, it mixes with water to make tiny liquid drops that reflect sunlight away from Earth. This causes global temperatures to drop for one to three years. In addition, to some global cooling volcanic eruptions can deplete Earth’s Ozone layer. However, as mentioned the amount of carbon dioxide released from volcanic eruptions is negligible compared to our emissions from burning fossil fuels.
How did Volcanoes Affect Climate in the past?
It has been proposed that intense volcanic release of carbon dioxide in the deep geologic past did cause global warming back then, and possibly some mass extinctions. This is a topic of scientific debate. However, whether these eruptions caused global warming or not, their intensity and the circumstances under which they happened were much different from today. Unlike the single eruptions that cool the Earth with ash and sulfur today, these rare ancient eruptions were giant outpourings that lasted hundreds of thousands of years, or millions of years, and overwhelmed the planet’s natural carbon cleanup systems. Instead of coming from a single mountain peak, the magma poured out of giant cracks, or fissures, in the earth.
The Permian-Triassic extinction or the Paleocene-Eocene Thermal Maximum (PETM) 56 million years ago is thought to possibly have been such an event. It could also have been that volcanic eruptions caused the sudden release of methane hydrates from ocean sediments.
A Couple of Videos and Links
The video below is a short one-minute overview of the causes behind global warming.
The video below from NASA is a bit longer, 13 minutes, but it gives a more detailed overview. Click here to see the page from where this is coming from.
Conclusion
This is my third post in the series about natural causes of climate change that we know are not the cause of the current rapid global warming / climate change (I use both words interchangeably). The fact that no known natural cause for climate change can explain the current rapid global warming is just one small piece of the evidence. However, it is a piece that people tend to get stuck on a lot. You often hear claims such as “climate has always changed”. “I think it is a natural cause”.
Unlike the sun and orbital cycles carbon emissions from erupting volcanoes would warm the lower atmosphere while cooling the upper atmosphere, just like our burning of fossil fuels does, and the warming would distribute in time and geography in a similar way. However, we know that the carbon emissions from volcanoes are relatively tiny compared to the emissions from the burning of fossil fuels. In addition, isotope studies show that the origin of the greenhouse gases added to the atmosphere are from burning fossil fuels. This is referred to as the isotopic footprint. These two reasons are how we know that it cannot be volcanoes that are causing the current rapid warming. Here is an additional long list of answers to common questions and objections to human caused global warming.
Other super facts related to global warming
- Global Warming is Happening and is Caused by us
- The Hockey Stick Graph is not Wrong
- Scientists Agree that Global Warming is happening and that we are the Cause
- Climate change worsens wildfires in the US
- Without carbon dioxide the Earth would freeze
- IPCC Did Not Backtrack on Global Warming Being Human Caused
- Orbital Cycles are not the Cause of the current Global Warming
- The Sun is not the Cause of the current Global Warming
To see the other Super Facts click here
Super Facts 
Another excellent article in your series.
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Thank you so much Peter / Craigavad
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Good to know that volcanoes only emit a small fraction CO2 compared to what we do burning fossil fuels, as it’s not always portrayed this way in the media. Intriguing that Sulphur dioxide creates a cooling effect; I didn’t know that!
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Yes in fact the Mount Pinatubo eruption in 1991, which was a large eruption, lowered average global temperatures by about 0.5°C (0.9°F). This temporary cooling effect lasted for nearly two years, spanning from 1992 through 1993. However, the long term warming effect from the carbon dioxide emissions were too small to be estimated.
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Lets get the obvious out of the way first
That makes me wonder about people’s critical thinking skills as well as Facebook’s alleged fact-checking.
These are both grossly overstated. Most people have no critical thinking skills.
Now, I’m no genius, but it seems logical that a volcano couldn’t have had much impact, since volcanoes have been around forever and we’re only now seeing signs of climate change. That is my simple way of looking at it.
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Thank you Kevin. That is a good observation. I did not mention this, but there is a natural carbon cycle. There are continuous carbon emissions from various sources and then carbon dioxide is continously absorbed but slowly. Our emissions from burning fossil fuels are extra that is too large and fast so it builds up. It takes about a 1,000 years to fully be re-absorbed. I think my illustration of the glass bath tubs with a faucet and the drain in my post “High Wet-bulb Temperatures the Mass Killer in Heat Waves” illustrates this. Normally the faucet and the drain are in balance. That is the carbon cycle that volcanoes are part of. Now the faucet is running too fast due to our human emissions.
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I found your post truly informative.
In Italy, Mount Etna, on the island of Sicily, has been erupting for days. Fortunately, it hasn’t caused much damage: it’s simply a fabulous spectacle.
However, Catania airport was forced to close for several days due to Etna’s eruptive activity.
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Thank you so much Luisa. I can imagine that is fabulous spectacle. When we visited Costa Rica we saw a continuously erupting volcano, the Arenal volcano. From below the mountain you could see a littlt bit of red lava and hot rocks falling and the smoke. Like mount Etna it was a tourist attraction. If it started getting too active they evacuated, which had only happened once in recent history.
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Sadly, people often chose to follow the path of least resistance which includes taking the view that human activity is causing global warming. Accepting that human activities are causing global warming would require action to be taken to stop this situation. It is easier to be ignorant.
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Thank you Robbie. I assume that in your first sentence you meant “…..which includes taking the view that human activity is NOT causing global warming. ” You are right doing something about it seems inconvenient. Another aspect about it is that the fossil fuel industry succeeded in making it a political talking point. Once an opinion on a topic has become a political talking point people will get dismissive and stubborn. It no longer matters what the science and evidence says.
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You only need to look at photos of any large Asian city to see that nothing is being done to slow down emissions from vehicle traffic.
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Yes vehicles are becoming more common in Asia. However, there’s been some progress. According to the University of Chicago, China has replaced a lot of cars with EVs lately, and renewables such as wind and solar and batteries has replaced a significant amount of coal (not enough but some) and therefore pollution in China has been reduced by 43% over the last ten years, resulting in Chinese life expectancy increasing by 2.2 years. One of my graphs in my post “The Unfolding Solar Power Boom“. I might make a post about this.
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Great information Thomas, hopefully your message is getting out to those who need to read it. Maggie
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Thank you so much Maggie. I really appreciate it.
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I fact checked you (because that’s how I am!) and Grok agrees with you.
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Thank you so much Jacqui for doing that. If I get it wrong I want to know.
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Very interesting, I didn’t even know volcanos emitted carbon dioxide.
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Thank you Pooja. I am glad you saw this before you saw the false claims on social media saying they emit much more than humans.
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Wow a great comprehensive post with so many great videos and info I’ll come back to! Hoping we can get a handle on it💕
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Thank you so much for your kind words Cindy. I agree I am also hoping we can get a handle on it
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Fascinating explanation of how volcanoes can both cool the planet in the short term and, under very different conditions, contribute to warming over geological timescales. The contrast between brief explosive eruptions and vast ancient volcanic outpourings really puts today’s climate processes into perspective. I had an idea that humans are far more destructive than volcanones, but your numbers were shocking.
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Thank you so much Patricia. Yes volcanoes emit a tiny amount of carbon compared to us (except for the massive million year eruptions 250 million years ago). Despite that a lot of social media posts claim the opposite and a lot people fall for the deception.
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