CORRECTION & APOLOGY: Planes or Volcano?

Tuesday, April 20th, 2010

We got our figures wrong on the CO2 emissions of Icelandic volcano Eyjafjallajoekull. Badly wrong.

So we want to apologise.

We pride ourselves on good data and solid information. Despite detailed research and feedback from Icelandic vulcanologists, our figures were out by a magnitude of ten.

The volcano is emitting 150,000 tons of CO2 per day, not 15,000 tons. (source)

The post was always intended as an open question. Our hope was to get the information refined and corrected. Naively, we didn’t expect the graphic to go super-viral.

We’re sorry for any confusion, annoyance and distrust this error may have caused.

We’ll do better next time.


p.s. Thanks for our great commenters and community for feeding back and correcting us.

Here’s the corrected visual:

Planes vs Volcano? What's emitting the most CO2

Here’s the data:
And the original post:

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Show Comments ( )

  • Darkoneko

    Wow, that’s quite a bit of ratio change –

    no one’s is “mistake free”, so please don’t feel too bad about it and keep up the good work :)

  • Morgan

    Based on your UPDATE 3 text, shouldn’t the estimated volcanic emissions be something more like 225,000 tons? You mention that your source estimated that it is “emitting between “150,000 and 300,000″ tons of CO2 a day”

    Just wondering.

  • Hannah

    Everyone makes mistakes, we’re all only human after all!

    Beautifully written apology. Good for you.

    You have a wonderful website, please keep up the good work!

  • Carlos

    Why don’t you add up the European plus American plus Asian aviation industry? The total aviation industry may be up to four times larger than the European. We have airplanes flying everyday while volcanos eruptions are very rare!!

  • Akseli

    Is this only CO-2 or CO2-equivalents?
    br, Akseli Koskela, Finland

    [CO2 - David]

  • Florian

    Thanks for being honest and open about it! That is what counts.

  • Dan

    Shouldn’t the black triangle be corrected to read 56,465 tons? Still an improvement.

  • Kim

    Your source states ’150-300,000 tonnes of CO2 daily’ yet you go for 150,000, why did you chose the lower figure? Wouldn’t it make more sense to pick a figure somewhere between the two and make it very clear that it’s an estimate so rough as to be almost useless?

    It looks like you had an agenda before you produced the graphic and that unfortunately reality got in the way.

  • Claire

    that’s trully making a difference … thanks for the correction. (I noticed the ‘red-faced’ tag :) )

  • Micheal Lunny

    So it takes 32 days for the volcano to emit the same amount of CO2 as two weeks of air travel.

    Still good returns.

  • bshaftoe

    Hey! This graph has been used by a TV news program in a spanish channel, la Sexta. Like 20 minutes ago.

  • Kabri Ali

    Credit where it is due for the correction. It would be interesting to know whether better sources are available for aviation emissions than The Independent and the BBC, neither of which are noted for their neutrality on environmental issues.

    Has this taken into account the increased amount of car and ship usage, both of which are less efficient / environmentally friendly methods of transport than air travel? This would add considerably more CO2 to the volcano’s effect than is represented above.

    UK aviation has a roadmap in place to cut CO2 emissions – – but by their very nature the impact of volcanic eruptions cannot be addressed in a similar manner.

  • Brad

    The human beings on the planet emit about six million tons per day, just to put that into perspective. Source:

  • Jorge

    OK, but what would be the scenario if the emmissions of aternative transport were added to the picture? We’re seing extra trains, we’re seing loads of extra buses and trucks, sending people here and there all over Europe. Would the volcano still be “eco-friendly” with all that data added?

  • Derek

    So, we are roughly even either way:
    without volcano: 344,109 tons
    with volcano: 150,000 + (344,109 – 206,465) = 287,644 tons

    If I estimate the incremental ground travel caused by the volcano to be 10% of the emissions by the canceled flights, that would be 20,646 tons. Add this to the ‘with volcano’ line above, and the comparison is even closer.

    PS: Dave, I like the way you handled the error. Great work on your site overall.

  • stijnm

    Ah, a refresh solved it :)


  • Leonardo

    Yeah right! Good returns, lets save the planet, bla bla bla… You guys probably are stucked in an airport to have free time for write this crap.

  • BoringCommenter

    And yes, you’re using the lower estimate for the airline industry as well. But that isn’t comparable, because that’s a much more precise estimate. If I have no idea if it’s going to rain tomorrow, my lower bound would be zero. Comparing that to the average rainfall doesn’t mean there’s a drought.

  • Joe Sokohl

    You’re missing a data point–at what financial cost to Europe & the rest of the world does this CO2 savings result in? How many businesses will fail? How many workers will become unemployed? How will taxes rise to accommodate the newly (and unexpectedly) unemployed?

    One metric says the aviation industry ALONE is losing $200 million per day…$1.7B a week. While there might be some long, long-term financial savings, the impact is disastrous economically. Though some hotels have increased prices (and, thus, revenue) to gouge the stranded passengers, they will begin running out of stuff. So will other businesses–replacement parts can’t come from Japan to fix your Honda that went into the shop before this environmental incident began, as well.

    So this is interesting…but I’m not sure how significant it is.

  • Leo Murray

    Whoah! The figure given by the Durham Uni earth scientist is at great variance with the figure given to me directly by Dr. Thorvaldur Thordarson at the university of Edinburgh, who is in fact a vulcanologist with published research on volcanic gases and climate change, and who was involved in measuring the emissions of THIS volcano – not some other ‘nearby’ volcano – during its eruption in March. At that time, measurements showed that the volcano was emitting 10-15,000 tonnes of CO2 per day. Your first figure was right – please don’t apologise. The sources in this news story disagree – by a factor of ten – with the experts who are actually working on emissions from Icelandic volcanoes. Have a word with them before you go eating your hats.
    Lovely bit of work btw

  • Matt

    Thanks for the update, David. Do you happen to know any info on how much Sulphur Dioxide the volcano is emitting as compared to airplanes? All your source info only has CO2.

  • Michel

    So your article is still as disingenuous as your initial error. The source you quote talks to two experts, one who estimated 150K and one who estimate 300K. Quite a huge difference in estimations (which calls into question the accuracy of their guesses). You, of course, chose to run with the smaller of the two and fail to even mention the other figures. I’ll give you one small point for at least linking to the source. Which is better than the source article itself. The source article says that with these emissions it would be ranked 47th as a polluter, but never mentions which number they went with.

  • Mr Eyjafjallajoekull

    CO2 is entirely harmless, and it causes no measurable global warming, despite the incessant propaganda emitted by the tax grabbers.

    For honest, reliable, beautiful information, check out the Winner of the Best Science site in the most recent Weblog Awards.

    And speaking of “super viral,” has gone from zero to well over 30,000,000 hits in just three years. Why? Because it uses verifiable facts to counteract the incessant misinformation drumbeat about “carbon” (by which the scientific illiterates mean beneficial carbon dioxide).

    We are made of carbon. We exhale carbon dioxide. And CO2 is an extremely minor trace gas comprising only a tiny 0.00039 of the atmosphere. Water vapor has a huge effect on temperature compared with CO2. But the government can’t tax water vapor.

    And CO2 has been almost twenty times higher in the past, for millions of years at a time, without causing “runaway global warming.” In fact, during geologic eras with high CO2, the planet has plunged into Ice Ages.

    The carbon scare is being perpetrated for money. If Cap & Trade passes, every U.S. family will be forced to pay about $16,000 a year more in taxes, because CO2 is emitted not only by transportation, heating and electrical generation, but by making fertilizers, plastics, and most manufacturing.

    CO2 is harmless. It is beneficial. And for every 34 CO2 molecules emitted naturally by the planet, humans emit only one. That is the truth. Don’t let the kleptocrats scare you into opening your wallet for them.

  • fd

    I still don’t understand what information is contained here – aligning the triangles the way you have makes it very hard to compare the quantities/volumes – and why the strange space between the two red triangles? I can’t even tell if the leftmost red triangle is the aviation industry including the cancellations or not. You’ve presented 3 and only 3 numbers in a giant graphic and rendered them impossible to compare visually.

    This is the worst kind of ‘infoviz’ – where information is obscured in an attempt to be flashy and clever. you should be disappointed.

  • RJ

    Big question is if the cancelled flight are truly cancelled or if the airline industry will increase their flights in the weeks to come, which decreases ‘the Eyjafjallajoekull-effect’. My guess is the latter, but not to the full extent that all cancelled flights are equal to the increase in flights in the weeks to come. What do you think?

  • Jonathan Sundqvist

    Something that would be utterly interesting is how much CO2 is released by the all the people traveling in something else rather than by airplane. People still travel you know. Will the impact of the volcano + alternative traveling still be less than with airplane?

  • Alice

    You’re still ignoring the fact that many people will travel at some point, either by plane once they can or car or train now. There are estimates that the people traveling by other methods are using the same carbon per passenger mile, so we’ve really not saved anything at all.

    Plus it ignores the bigger picture. The volcano is spewing Sulfur Dioxide and steam, more so than the planes would.

  • Gary Hladik

    The CO2 estimate is for the “European Aviation Industry” which was never completely shut down and I understand is currently operating at about 50% capacity. People who can’t fly now are switching to CO2-generating surface transportation or deferring travel temporarily. Europe seems to be paying quite a high price in disaster and economic dislocation for a temporary and trivial (at best) drop in plant food production.

  • Peter H

    This shows how infographics and their preparation carry an emotive weight. When you publish a striking graphic it looks authoritative and carries intention. It was a good graphic, but its comparison is more of a damp squib rather than a big bang now.

  • Matthew

    How do you calculate the 206,465 saved?

    [60% of flights cancelled = 60% of CO2 emitted = 206K. Thanks! David]

  • jim

    We still love you.

  • Graney

    But what about the environmental damage done by the huge amounts of SO2 being emitted?
    Or the affect on albedo effect by the ash cloud vs. the same by aircraft contrails?
    Everyone is obsessing about just one environmental factor of planes vs. volcanoes, CO2 emissions, and conveniently ignoring others that have disastrous affects on the environment.
    The ratio of CO2 to SO2 for a plane is roughly 10,000:3 (for every 10000 Tons of CO2 they emit 3 Tons of SO2)
    This means that the Volcano is pumping out a horrendous 30,000 Tons of SO2, using your 5:1 ratio, and planes pump out 103 Tons of SO2, using your CO2 figure for planes stated above and the ratio of 10,000:3.
    [Source for plane CO2/SO2 omissions:
    Unfortunately, the science behind the environmental impact of volcanoes and planes is not easily comparable.
    And a simple graphic, no-matter how sexy and convincing it may be, only scratches the surface of a very complex set of variables.
    I guess this is the inherent risk of visualizing such data.
    That in trying to give a complex situation some visual meaning, you end up oversimplifying it so much that people take away naive conclusions.

  • Bernard F. Gilday

    Afraid your figures are skewed somewhat…

    I accept your CO2 figures, but you are hiding the SO2 and CH4 figures. Sulphur Dioxide and Methane are much more harmful than Carbon Dioxide to Global Warming…..

    Bernard Gilday

    [Not hiding, just focusing on CO2 to answer the question. Thanks! David]

  • Simon Phipps

    Thanks for the correction. Any idea how much more the volcano is emitting than usual? I think it would be good to indicate the change from the norm (maybe with a dark red core to the volcano triangle indicating normal, non-eruption emissions) and not just the total amount.

  • ctd

    Sometimes it takes an incorrect assertion to elicit the correct information – and that’s OK, so long as the truth wins out.

  • Adam

    What about the neighbouring volcano that always goes off after?

    Its alot bigger.

  • JER0ME

    Is there any analysis of the increased use of other modes of transport that almost certainly emit more CO2 per mile? And the almost certain increase in injuries and fatalities due to the use of these much less safe modes of transport?

    I recall studies claiming that the grounding of ‘planes over the US after Sept 11 probably caused and increase in CO2 emissions and probably more deaths than the original attack did.

  • Daniel

    Isn’t this still wrong?

    European aviation industry emissions: 344k tons
    Volcano: 150k tons

    Cancelling 60% of Europe’s flights = less 206k tons, leaving the plane emissions at 344 – 206 = 138k

    Total emissions = 150k from Volcano + 138 = 288k, total saved = 56k tons.

  • imajoebob

    Luckily the most provocative point is still true: this is reducing the daily CO2 accumulation.

    Of course, it doesn’t tell us about the amount of methane (CH4) added to the atmosphere (nor is there any expectation). Since methane is a more “efficient” greenhouse gas, I’d guess this negates any supposed reduction of CO2.

  • Geri

    Hey your only human!

  • Alain Jobardot

    Yes, but how much we did not saved ?

    Billions of tons every year, without counting other billions of tons of toxic substances and products and million of new human: we reach the 7 billions…

    What’s a real shame for this stupid animal so called human.

  • Spelling is beautifu

    “Icelandic vulcanologists” – they have Star Trek fans too?
    I wonder, however, what their expertise is in Volcanoes.

    (For the humour impaired – it is volcanologist – with an O. Pretty easy really, it has the word “volcano” in it.)

    [I think Vulcanologist is an accepted form of volcano specialist - - Thanks! David]

  • Jussi

    There have been many great graphics on this site, but I think this on is a good “don’t do this” type of example of one of Edward Tufte’s principles of infographic design: “Don’t present in a graphic what can be efficiently presented in a table”. The whole picture delivers only three numbers.

  • Ian Jones

    You haven’t adjusted the downwrd pointing triangle, this should be much smaller.
    This is a piddly little eruption, if you check the data when Mt Pinutobo erupted it emitted 80 to 234 million tonnes of CO2 is a few days!

  • Aqui_c

    Recognizing an error tells a lot about you!
    Thanks for this new infograph!

  • Bill Hartree


    Please re-read the Breitbart website again. Nowhere does it refer to actual observations of the Eyjafjallajoekull eruption. It quotes less than a sentence of Colin MacPherson’s email – in itself a cause for suspicion, but from this cryptic snippet it is still clear that he is saying that the 150,000 tonne figure might be true if the eruption is similar to an earlier eruption of another, unnamed, Icelandic volcano. As for the 300,000 tonne figure this is described as “an upper limit”, not an estimate. Moreover it is not based on any measurements actually done on Eyja f.j.

    By contrast the 15,000 tonne figure is based on actual measurements done on 1st/2nd April 2010 during the course of the Eyja f.j. eruption. In actual fact Nicole has over-estimated the 15,000 tonne figure; 10,000 is a better estimate. It’s because CO2 has a lower molecular weight: I can expand on this if you wish.

    In summary:

    15,000 / 10,000 tonne is based on observational evidence,
    150,000 tonne is based on a speculative model.

    I suggest you go with the former

  • Amy

    Hi there!

    I love your site and that you’re big enough to stand up and announce a mistake. Brava, you.

    If you want to create more infographics on this topic, it’s worth adding the sulphur dioxide emissions because while planes put out almost none, the volcano puts out a LOT. And that stuff is super toxic.

    This blog post is where I read about it – and the author is kinda bitchy, unwarrantedly, but he does have a point when he sticks to facts:

    BTW – thanks for linking to Every Time Zone! It’s such a thrill to see something I designed linked by one of my absolute favorite blogs :)

  • Sam

    Daniel is right. either the graphic is wrong, or it’s misleading. It seems to imply a net reduction of 206k tons, when in fact the net reduction is 56k tons.

  • guaj

    could you please give the actual co2 figure.150/300ths is a big gap it could be more?

  • Michael R.

    A couple of comments: One, Volcanic dust lingers in the atmosphere for months, blocking sunlight and reducing the sun’s warming effect. Global temps always drop with increased volcanic activity. Two, Jets emit more than just CO2. Unburned hydrocarbons are much more potent greenhouse gasses than CO2, and jet hydrocarbons are ejected into the upper atmosphere where they do much more damage than ground-level emissions.