Despite rumors and arguments to the contrary, greenhouse gas emissions from volcanoes comprise less than one percent of those generated by today's human endeavors.
Image: Lyn Topinka, courtesy U.S. Geological Survey
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Dear EarthTalk: Could it really be true that a single large volcanic eruption launches more greenhouse gases into the atmosphere than the amount generated by all of humanity over history?
-- Steve Schlemmer, London, England
This argument that human-caused carbon emissions are merely a drop in the bucket compared to greenhouse gases generated by volcanoes has been making its way around the rumor mill for years. And while it may sound plausible, the science just doesn’t back it up.
According to the U.S. Geological Survey (USGS), the world’s volcanoes, both on land and undersea, generate about 200 million tons of carbon dioxide (CO2) annually, while our automotive and industrial activities cause some 24 billion tons of CO2 emissions every year worldwide. Despite the arguments to the contrary, the facts speak for themselves: Greenhouse gas emissions from volcanoes comprise less than one percent of those generated by today’s human endeavors.
Another indication that human emissions dwarf those of volcanoes is the fact that atmospheric CO2 levels, as measured by sampling stations around the world set up by the federally funded Carbon Dioxide Information Analysis Center, have gone up consistently year after year regardless of whether or not there have been major volcanic eruptions in specific years. “If it were true that individual volcanic eruptions dominated human emissions and were causing the rise in carbon dioxide concentrations, then these carbon dioxide records would be full of spikes—one for each eruption,” says Coby Beck, a journalist writing for online environmental news portal Grist.org. “Instead, such records show a smooth and regular trend.”
Furthermore, some scientists believe that spectacular volcanic eruptions, like that of Mt. St. Helens in 1980 and Mt. Pinatubo in 1991, actually lead to short-term global cooling, not warming, as sulfur dioxide (SO2), ash and other particles in the air and stratosphere reflect some solar energy instead of letting it into Earth’s atmosphere. SO2, which converts to sulfuric acid aerosol when it hits the stratosphere, can linger there for as long as seven years and can exercise a cooling effect long after a volcanic eruption has taken place.
Scientists tracking the effects of the major 1991 eruption of the Philippines’ Mt. Pinatubo found that the overall effect of the blast was to cool the surface of the Earth globally by some 0.5 degrees Celsius a year later, even though rising human greenhouse gas emissions and an El Nino event (a warm water current which periodically flows along the coast of Ecuador and Peru in South America) caused some surface warming during the 1991-1993 study period.
In an interesting twist on the issue, British researchers last year published an article in the peer reviewed scientific journal Nature showing how volcanic activity may be contributing to the melting of ice caps in Antarctica—but not because of any emissions, natural or man-made, per se. Instead, scientists Hugh Corr and David Vaughan of the British Antarctic Survey believe that volcanoes underneath Antarctica may be melting the continent’s ice sheets from below, just as warming air temperatures from human-induced emissions erode them from above.
CONTACTS: U.S. Geological Survey, www.usgs.gov; Carbon Dioxide Information Analysis Center, cdiac.esd.ornl.gov; British Antarctic Survey, www.antarctica.ac.uk.
EarthTalk is produced by E/The Environmental Magazine. GOT AN ENVIRONMENTAL QUESTION? Send it to: EarthTalk, c/o E/The Environmental Magazine, P.O. Box 5098, Westport, CT 06881; submit it at: www.emagazine.com/earthtalk/thisweek/, or e-mail: earthtalk@emagazine.com. Read past columns at: www.emagazine.com/earthtalk/archives.php.
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16 Comments
Add CommentThat's a real tricky interactive graphic SciAM has provided for us: Two identical pictures you can click "one after the other." Oh, the wonder of it all!
Reply | Report Abuse | Link to thisOtherwise - this article is great, very good to see the anti-hoax, anti-urban-legend crew is on the job!
I have a math question from this article: The statement that volcanoes generate 200 million tons of CO2 yearly compared to 24 billion tons of output for humans means that humans generate (2400 million / 200 million) = 12 times more CO2 than volcanoes.
Reply | Report Abuse | Link to thisBut then the following statement is: "Greenhouse gas emissions from volcanoes comprise less than 1% of those generated by today's human endeavors."
So my question is, since when does 1/12th of something also equal 1/100th of the same thing? Come on, people, it's about credibility for Science HERE!
24 billion would be 24000 million. Divide by 200 million, you get 120x more CO2 than volcanoes, not 12x. This works out to0.83% by my math....
Reply | Report Abuse | Link to thisHmm, are you using the British "million" "billion" -? That would explain it - because as far as my American math is concerned: 1 billion (1,000,000,000) is one thousand millions. (1,000,000)
Reply | Report Abuse | Link to thisOh YEAH! I just noticed the article begins with a question from a fellow in London, England. Sorry, but we can only have one nation's math at one time in one article in this American magazine. (Just kidding.) ;-)
24,000,000,000 / 200,000,000 = 120, not 12. Be careful, most Chinese made American calculators don't have enough digits to enter 24 billion.
Reply | Report Abuse | Link to this200 million is 0.2 billion, right? 24 / 0.2 = 120. 0.2 / 24 = 0.0083, or 0.83%.
No no no no no way am I going to let this pass. BuckSkin, you just came in here complaining about SciAm's standards of credibility based on a math problem that you obviously spent no more than two seconds thinking about, since you messed up a single decimal point.
Reply | Report Abuse | Link to thisCompared with included sanctimony about 'credibility' - it really was a hilariously self-inflated pratfall, all by itself.
But it's the appeal to 'British billions' as an explanation and the attempt to turn this right back into a criticism of the magazine again - that's what turns this ordinary pratfall into a magnificent self-lampoon.
I can't wait for Part 3, in which BuckSkinMan will lay claim an entire alternate field called 'BuckSkin mathematics', and allege ethnic discrimination on the part of Scientific American for not recognising his own unique personal cultural belief that 24 billion = 2400 million.
Whoa! Let's not get overwrought here. If I'm mistaken, I'll admit it. I still think that there's a question involved and I may be mistaken but - in my response - you can see that I noticed the probable cause. It was "fair" for me to jokingly point out what appeared to be the use of two different numbering systems. Which I still believe to be true.
Reply | Report Abuse | Link to thisI've always had the impression that the British numbering system counted "one million" as a million millions. In the U.S. we count "one million" as a thousand millions.
You can see that here: <http://www.mazes.com/numberingsystems.html#british>
So, in the British system, our "billion" is their "milliard."
While their "billion" is our "trillion" (their billion is 1 thousand times greater than the American version - an extra three zeros).
Notice: the article doesn't show the numerical value, it says "24 billion."
If referring to the British system, that's 24,000,000,000,000 - 24 trillion in our system.
And of course you got it wrong: 2,400 million in the American system is 2.4 billion, not 24 billion. :-)
kcaldwel,
Reply | Report Abuse | Link to thisI initially got confused - by the difference between the British and American numbering systems. You're right though to say, "be careful."
Good point about our common calculators. If I'd just knocked off "all possible zeroes" and divided 200 million by 24,000 million, I'd have arrived at 0.083 like you did!
OOOPS! NOW I've really screwed up - meant to type .0083!!
Reply | Report Abuse | Link to thisThe 20% increase in CO2 over the last 200 years amounts to an overall increase of 0.006% to a total CO2 concentration of 0.036%. Even with a rudimentary knowledge of chemistry it's apparent that there is no way in hell that such trace amounts of ANY greenhouse gas can affect world-wide climate to the extent we're led to believe. But Scientific American has pushed this idea to rediculous extremes. It's sensationalized and very poor science at its worst. Shameful! A.Lipkin, Ph.D. neoguru@aol.com
Reply | Report Abuse | Link to thisneoguru, what's your Ph.D in? Please say it's not in an earth science.
Reply | Report Abuse | Link to thisIf people believed your stance then they'd also have to believe that we shouldn't even exist in the first place. That 20% increase you casually mention means that whatever effect existed before hand is now magnified by a factor of 1.2, in delicately balanced systems (you'd be a fool not to consider the atmosphere-biosphere relationship delicate) that is highly significant.
Denying the greenhouse effect is a highly precarious position to assume.
Ian
neoguru, what's your Ph.D in? Please say it's not in an earth science.
Reply | Report Abuse | Link to thisIf people believed your stance then they'd also have to believe that we shouldn't even exist in the first place. That 20% increase you casually mention means that whatever effect existed before hand is now magnified by a factor of 1.2, in delicately balanced systems (you'd be a fool not to consider the atmosphere-biosphere relationship delicate) that is highly significant.
Denying the greenhouse effect is a highly precarious position to assume.
Ian
I agree with neoguru, and I think that it is irresponsible for anybody to mis-lead the population about the global warming myth. It is scandalous enough that goverments are pushing it for their own agenda's.
Reply | Report Abuse | Link to thisUse scientific notation and you will have no problems.
Reply | Report Abuse | Link to this24 billion = 24 x 10^9
200 million = 200 x 10^6
Rewrite both:
2.4 x 10^10
2.00 x 10 ^8
Then, divide 2.4 by 2.00, then add on (10-8 = 2) as your exponent on the x 10.
You get: 1.2 x 10^2... or 120, which is about 1.0. That means that the human emission is 120 times greater than volcanic. Or, in other words, volcanic emission is about 1% that of human emission, as the article says.
And this is with American billions and American millions = one billion = 1000 millions.
Seriously guys. Basic math and science here...
does it even help?
Reply | Report Abuse | Link to thisI HATE THIS.. DOENT HELP...
Reply | Report Abuse | Link to this