# The Greenhouse Effect of Volcanoes **URL:** \ **Category:** Factual Questions\ **Created:** [June 28, 2008, 3:30am UTC](https://boards.straightdope.com/t/the-greenhouse-effect-of-volcanoes/454541 "2008-06-28T03:30:11Z")\ **Posts on this page:** 10\ **Page:** 1
**Author:** ![KarlGauss](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/karlgauss/32/3713_2.png) [@KarlGauss](https://boards.straightdope.com/u/KarlGauss)\ **Post date:** [June 28, 2008, 3:30am UTC](https://boards.straightdope.com/t/the-greenhouse-effect-of-volcanoes/454541/1 "2008-06-28T03:30:11Z")
When [Mount Pinatubo](http://en.wikipedia.org/wiki/Mount_Pinatubo) erupted in 1991, it spewed more greenhouse gases into the atmosphere than had been added to it by human activity since the Industrial Revolution began in the mid-19th century. In other words, the potential greenhouse effect of that _single_, albeit large, volcanic eruption exceeded mankind’s entire greenhouse gas production over the last 150 years! Given that this one, natural, short-term production and atmospheric injection of greenhouse gases was greater than humanity’s total contribution since about 1850, and especially since this phenomenon will recur again and again, what possible benefit can be obtained by reducing our greenhouse production by, say, 20 percent? In the grand scheme of things, it’s irrelevant. (I chose to put this in GQ even there may not be a specific factual answer for my question. I hoped by placing it in GQ that I could avoid the emotion-based responses that so often characterize questions about things like the effect of humanity on the climate. I do hope the mods will give me some leeway here - thanks!). ---
**Author:** ![Colibri](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/colibri/32/1841_2.png) [@Colibri](https://boards.straightdope.com/u/Colibri)\ **Post date:** [June 28, 2008, 5:00am UTC](https://boards.straightdope.com/t/the-greenhouse-effect-of-volcanoes/454541/2 "2008-06-28T05:00:00Z")
[QUOTE=KarlGauss] When [Mount Pinatubo](http://en.wikipedia.org/wiki/Mount_Pinatubo) erupted in 1991, it spewed more greenhouse gases into the atmosphere than had been added to it by human activity since the Industrial Revolution began in the mid-19th century. In other words, the potential greenhouse effect of that _single_, albeit large, volcanic eruption exceeded mankind’s entire greenhouse gas production over the last 150 years! [/QUOTE] Cite? Can you provide the specific amounts of greenhouse gases you believe were ejected by Pinatubo vs those produced by human activity in the past 150 years? ---
**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\ **Post date:** [June 28, 2008, 5:28am UTC](https://boards.straightdope.com/t/the-greenhouse-effect-of-volcanoes/454541/3 "2008-06-28T05:28:57Z")
This says that humans produce 150x the amount of CO2 that volcanoes do: [http://www.geology.sdsu.edu/how\_volcanoes\_work/climate\_effects.html](http://www.geology.sdsu.edu/how_volcanoes_work/climate_effects.html) ---
**Author:** ![Colibri](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/colibri/32/1841_2.png) [@Colibri](https://boards.straightdope.com/u/Colibri)\ **Post date:** [June 28, 2008, 5:41am UTC](https://boards.straightdope.com/t/the-greenhouse-effect-of-volcanoes/454541/4 "2008-06-28T05:41:14Z")
I’m having trouble finding an authoritative cite for the amount of carbon dioxide produced by Mount Pinatubo, but what I have have so far suggests the total amount was much less than even a single year’s production by humans. In any case the rate at which carbon dioxide accumulated in the atmosphere [slowed in the two years after the eruption](http://www.gsfc.nasa.gov/topstory/20011210co2absorb.html), pretty much impossible if Pinatubo ejected massive amounts of it. Pinatubo produced large amounts of sulphur dioxide, but that isn’t a greenhouse gas. **Karl** , where are you getting your information from? So far I have only found your allegation on a few right-wing websites with no supporting documentation. ---
**Author:** ![Fubaya](https://avatars.discourse-cdn.com/v4/letter/f/c2a13f/32.png) [@Fubaya](https://boards.straightdope.com/u/Fubaya)\ **Post date:** [June 28, 2008, 5:51am UTC](https://boards.straightdope.com/t/the-greenhouse-effect-of-volcanoes/454541/5 "2008-06-28T05:51:37Z")
And the CO2 that comes from volcanoes are part of the natural carbon cycle. It is basically CO2 that has been absorbed from the atmosphere and though different processes ends up coming out of volcanoes (if there are any geologists in the room, don’t nitpick, I’m trying to keep this simple and short). This what no one ever talks about in regards to global warming, we’re not just putting a greenhouse gas in the atmosphere, we’re disrupting numerous natural cycles such as the carbon cycle, and with unpredictable results. Volcanoes release between 130-230 million metric tons of CO2 per year, humans release over 27 billion metric tons per year: > **[List of countries by carbon dioxide emissions](https://en.wikipedia.org/wiki/List_of_countries_by_carbon_dioxide_emissions)** > > This is a list of sovereign states and territories by carbon dioxide emissions due to certain forms of human activity, based on the EDGAR database created by European Commission and Netherlands Environmental Assessment Agency released in 2018. The following table lists the 1990, 2005 and 2017 annual CO2 emissions estimates (in megatonnes of CO2 per year) along with a list of calculated emissions per km2 (in tonnes of CO2 per year) and emissions per capita (in tonnes of CO2 per year). > The dat... > **[Carbon dioxide](https://en.wikipedia.org/wiki/Carbon_dioxide#In_the_Earth.27s_atmosphere)** > > .mw-parser-output .ib-chembox{border-collapse:collapse;text-align:left}.mw-parser-output .ib-chembox td,.mw-parser-output .ib-chembox th{border:1px solid #a2a9b1;width:40%}.mw-parser-output .ib-chembox td+td{width:60%} > Carbon dioxide is a chemical compound with the chemical formula .mw-parser-output .template-chem2-su{display:inline-block;font-size:80%;line-height:1;vertical-align:-0.35em}.mw-parser-output .template-chem2-su\>span{display:block;text-align:left}.mw-parser-output sub.template-che... ---
**Author:** ![KarlGauss](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/karlgauss/32/3713_2.png) [@KarlGauss](https://boards.straightdope.com/u/KarlGauss)\ **Post date:** [June 28, 2008, 4:10pm UTC](https://boards.straightdope.com/t/the-greenhouse-effect-of-volcanoes/454541/6 "2008-06-28T16:10:20Z")
Thanks for your responses and sorry for the delay. The cite I’m basing my statement on is found [here](http://pubs.giss.nasa.gov/docs/1992/1992_Hansen_etal.pdf). It is cited in [this full text article (pdf)](http://www.pas.rochester.edu/~douglass/papers/2004GL022119_Pinatubo.pdf) in the introduction under point number 7. James Hansen, the senior author, is a highly respected NASA scientist with a [publication list](http://pubs.giss.nasa.gov/authors/jhansen.html) that includes articles in both Nature and in Science. So, I consider him an authority. Have I misinterpreted things? ---
**Author:** ![KarlGauss](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/karlgauss/32/3713_2.png) [@KarlGauss](https://boards.straightdope.com/u/KarlGauss)\ **Post date:** [June 28, 2008, 4:42pm UTC](https://boards.straightdope.com/t/the-greenhouse-effect-of-volcanoes/454541/7 "2008-06-28T16:42:41Z")
I should have pointed out that the key statement in the primary paper is found in the first paragraph of the discussion ---
**Author:** ![Colibri](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/colibri/32/1841_2.png) [@Colibri](https://boards.straightdope.com/u/Colibri)\ **Post date:** [June 28, 2008, 4:51pm UTC](https://boards.straightdope.com/t/the-greenhouse-effect-of-volcanoes/454541/8 "2008-06-28T16:51:55Z")
[QUOTE=KarlGauss] Have I misinterpreted things? [/QUOTE] Yes, very much so. You seem to be confusing greenhouse gases with aerosols. Hansen’s article doesn’t indicate that Pinatubo produced a large amount of greenhouse gases. Instead it produced a large amount of aerosols, which have the opposite effect on climate by reflecting sunlight. From the second article you linked to: > [@](#): > > The Pinatubo volcano climate event (June 15, 1991) dominated all other forcings during its occurrence. As Hansen et al. [1992] said: this dramatic climate event had the potential to ‘‘. . .[exceed] the accumulated forcing due to all anthropogenic greenhouse gases added to the atmosphere since the industrial revolution began’’. . . and should ‘‘provide an acid test for global climate models.’’ The forcing produced by Pinatubo through aerosols was a cooling effect that ran counter to the warming effect of anthropogenic greenhouse gases. However, as the second article concludes, the effect is short-term: > [@](#): > > In summary, we have shown that Hansen’s hope that the dramatic Pinatubo climate event would provide an ‘‘acid test’’ of climate models has been fulfilled, although with an unexpected result. The effect of the volcano is to reveal a short atmospheric response time, of the order of several months, leaving no volcano effect in the pipeline, and a negative feedback to its forcing. ---
**Author:** ![KarlGauss](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/karlgauss/32/3713_2.png) [@KarlGauss](https://boards.straightdope.com/u/KarlGauss)\ **Post date:** [June 28, 2008, 5:13pm UTC](https://boards.straightdope.com/t/the-greenhouse-effect-of-volcanoes/454541/9 "2008-06-28T17:13:59Z")
Ah! I should have realized. Thank you for setting me straight. ---
**Author:** ![jshore](https://avatars.discourse-cdn.com/v4/letter/j/b5e925/32.png) [@jshore](https://boards.straightdope.com/u/jshore)\ **Post date:** [June 28, 2008, 5:46pm UTC](https://boards.straightdope.com/t/the-greenhouse-effect-of-volcanoes/454541/10 "2008-06-28T17:46:13Z")
You can see the dip in the global temperatures around 1992 that was due to the Mt. Pinatubo eruption [here](http://www.cru.uea.ac.uk/cru/info/warming/).