[Vision2020] Realclimate.org 4-9-16, NASA's Gavin Schmidt: "The Volcano Gambit"
starbliss at gmail.com
Tue Apr 12 21:12:24 PDT 2016
Excellent and easily comprehensible piece on the mangling of critical
scientific issues in the public sphere, focusing on distortions of science
on emissions from volcanos: chlorine, SO2 and CO2 specifically.
Over and over in discussions on anthropogenic global warming I have heard
the claim that volcanos have emitted more CO2 into the atmosphere since the
industrial revolution than human CO2 emissions.
This is fantastically false!
Vision2020 Post: Ted Moffett
The Volcano Gambit
- Carbon cycle
- Climate Science
- Greenhouse gases
- Instrumental Record
— gavin @ 9 April 2016
Anyone reading pundits and politicians pontificating profusely about
climate or environmental science will, at some point, have come across the
“volcano gambit”. During the discussion they will make a claim that
volcanoes (or even a single volcano) produce many times more pollutant
emissions than human activities. Often the factor is extremely precise to
help give an illusion of science-iness and, remarkably, almost any
pollutant can be referenced. This “volcano gambit” is an infallible sign
that indicates the author is clueless about climate science, but few are
aware of its long and interesting history…
*From Augustine to Mt. St. Helens*
The ur-usage was a legitimate paper in *Science* in July 1980 by
seismologist David Johnston
writing about chlorine emissions in eruptions:
Earlier estimates of the chlorine emission from volcanoes, based upon
evaluations of the pre-eruption magmatic chlorine content, are too low for
some explosive volcanoes by a factor of 20 to 40 or more. Degassing of ash
erupted during 1976 by Augustine Volcano in Alaska released 525 x 106 kg of
chlorine (±40%), of which 82 x 106 to 175 x 106 kg may have been ejected
into the stratosphere as hydrogen chloride [HCl]. This stratospheric
contribution is equivalent to 17 to 36% of the 1975 world industrial
production of chlorine in fluorocarbons.
In the main text, there was also this quote:
[The] eruption of the Bishop Tuff from Long Valley Caldera, California,
700,000 years ago generated 100 km3 of air-fall ash(19). If the magma
degassed 0.25% chlorine (equivalent to Augustine Volcano), this eruption
may have injected 289 x 109 kg of HCl into the stratosphere, equivalent to
about *570 times* the 1975 world industrial production of chlorine in
For context, a big issue at the time was to characterise the budget for
chlorine in the stratosphere, given it’s importance in ozone depletion.
While there is quite a lot of HCl emitted by volcanoes, that form of
chlorine is soluble, and is swiftly rained out, unlike the much less
reactive human-made chlorofluorocarbons (CFCs) which can stay in the
atmosphere from many decades. Multiple studies subsequent to the Johnston
paper confirmed that the volcanic contribution to stratospheric chlorine is
actually very small, but this paper was a genuine attempt to constrain this
term. To summarise, there are two cases mentioned, Augustine (in Alaska,
1976) and the Long Valley Caldera (California, 700,000 yrs ago), with
estimated multiples of 0.17-0.36 and 570 of HCl injection into the
stratosphere compared to the annual industrial source of Cl in CFCs. *[Note
– if anyone has an earlier usage, please let me know]*.
An important volcanic event in 1980 was of course the huge eruption of
Mount St Helens in May of that year. Tragically, the author of the *Science*
paper, David Johnston, an up-and-coming USGS volcanologist, was himself
killed <http://en.wikipedia.org/wiki/David_A._Johnston> in the blast a
couple of months before his paper appeared.
Later that year, in October, President Reagan commented on the eruption,
suggesting that “one little mountain out there [Mt. St. Helens], in these
last several months, has probably released more sulfur dioxide into the
atmosphere than has been released in the last ten years of automobile
driving or things of that kind.” However, while the volcano emitted roughly
2×106 metric tons SO2
emissions from cars were 30 x 106 tons
(out of a total human emission of ~131×106 tons). Reagan was out by a
factor of 150. This was just the beginning of the mangling.
More relevant for the growth of the volcano gambit, these results got more
and more warped in subsequent retellings. For instance, in 1990, Dixy Lee
Ray, the ex-marine biologist and former (Democratic) governor of
Washington, wrote in her book: “The eruption of Mt. St. Augustine in 1976
injected 289 billion kilograms of hydrochloric acid directly into the
stratosphere. That amount is 570 times the total world production of
chlorine and fluorocarbon compounds in the year 1975…. So much is known.”
She mixed up the huge eruption 700,000 years ago, with a much smaller one
in 1976, but it would get worse.
The Johnston paper also became a staple of the folks engaged in rearguard
defenses against the 1989 Montreal Protocol, in particular, the Maduro and
book “Holes in the Ozone Scare” quotes the paper accurately, but ignores
subsequent work ruling out the HCl source for stratospheric chlorine. This
was well discussed by Sherwood Rowland
in a 1993 *Science* commentary which aptly enough was focused on the need
for better scientific communication with the public.
*… to Mt. Pinatubo*
In June 1991, Mt. Pinatubo in the Philippines erupted, and unsurprisingly
became the volcano of choice for the contrarians.
discussed this at various points in 1992 and in his 1993 book. On Nightline
he stated: “it is man-made products which are causing the ozone depletion,
yet Mount Pinatubo has put 570 times the amount of chlorine into the
atmosphere in one eruption than all of man-made chlorofluorocarbons in one
year”. (Note the further confusion attributing the eruption 700,000 yrs to
the one that just happened). In his book “The Way Things Ought To Be”
(1993) Limbaugh stretched the facts still further: “Mount Pinatubo in the
Philippines spewed forth more than a thousand times the amount of
ozone-depleting chemical in one eruption than all the fluorocarbons
manufactured by wicked, diabolical, and insensitive corporations in
history.” He claims he got this information from Dixy Lee Ray’s book, “the
most footnoted, documented book I have ever read.” Which, as noted above
was already garbled. (More discussion on Limbaugh’s errors here
and here <http://web.mit.edu/thistle/www/v9/9.05/9limbaugh.html>).
*From Chlorine to Greenhouse Gases*
The Dixy Lee Ray book turns out to be a major source for disinformation,
though with little evidence anyone read it carefully or looked up the
references. In 2004, the conservative commentator, Jude Wannski mis-remembered
Dixy Lee Ray <http://www.polyconomics.com/memos/mm-041005.htm>: “[the] book
she wrote, Trashing the Planet … debunked a number of myths about the
environment. In it she had the following line: “The eruption of Mt. St.
Helens in 1980 dumped more greenhouse gases into the atmosphere than all
that has been released since the industrial revolution. Volcanoes have been
erupting for millions of years with the same result. If this really
affected climate, don’t you think it would have happened by now?””. This
swaps HCl for greenhouse gases, conflates Mt St. Helens with St Augustine
in her text (which in any case should have been the Long Valley Caldera)…
As environmental concern moved to the impact of global warming on ice
sheets, so disinformers moved the volcanoes accordingly. In 2006, Christopher
Monckton (“the Potty Peer”) said
“In a good year for eruptions, Erebus can put out as much CFCs as Man used
A year later (2007), Martin Durkin in his execrable documentary
<http://www.look-to-the-skies.com/global_warming.htm> that “One volcanic
eruption for example, puts more pollution into the atmosphere than ten
years worth of human activity.” This, despite being totally unspecific
(which pollutant does he think he is referring to?), is of course wrong in
any case. Perhaps he was channeling Reagan?
As in 1992, a new eruption gave rise to a new eruption of the gambit. In
2009, the “Stop Global Cooling” crowd
stated: “Sure, volcanoes like the one spouting off in Alaska right now spew
much more CO2 than humans could ever think of”. Similarly, Congressman Dana
in March of that year added: “Can one huge volcano spew more CO2 into the
atmosphere than all the people? Yes”. Ummm… no.
And yet it goes on. Ian Plimer in another contrarian tome
<http://www.realclimate.org/wiki/index.php?title=Ian_Plimer> included some
even more made up facts: “massive volcanic eruptions (e.g. Pinatubo) emit
the equivalent of a years’ human CO2 emissions in a few days” (p472) and
“Volcanoes produce more CO2 then the world’s cars and industries combined”
(p413). On p217 he claims that while “Mt. Pinatubo . . . released 20
millions tonnes of sulphur dioxide” it also released “very large quantities
of chlorofluorocarbons”, citing Brasseur and Granier (1992)
who don’t say there were any CFCs in the eruption, and even on chlorine,
actually say the opposite: “after the eruption of Mount Pinatubo, the input
of chlorine to the stratosphere was probably small”.
*From Pinatubo to Eyjafjallajökull*
In 2013, it was the turn of Eyjafjallajökull in Iceland to steal the
limelight. Ex-Gov. Mike Huckabee said: “*The volcano that erupted over in
Northern Europe actually poured more CO2 into the air in that single act of
nature than all of humans have in something like the past 100 years.*“.
Senator Lisa Murkowski in 2014 similarly mentioned a volcano she “had heard
in Iceland. “The emissions that are being put in the air by that volcano
are a thousand years’ worth of emissions that would come from all of the
vehicles, all of the manufacturing in Europe,” she said. Huckabee was using
the same point as recently as July 2015: “*a volcano, in one blast, will
contribute more [CO2] than 100 years of human activity*“. A century or a
millennium – who’s counting?
Again this is all patent nonsense – the amount of CO2 emitted by
Eyjafjallajökull was in fact more than 20 times smaller than just European
aviation emissions per day – and the claim was rightly debunked by
at the time.
So let’s recap with a simple graphic charting the use and abuse of these
claims, colour-coded by the degree of wrongness:
To summarise, a speculative paper (that was later contradicted) about HCl
emitted in a volcano 700,000 years ago is the progenitor of statements
related to SO2, CO2, greenhouse gases or just “pollutants” in general, and
has been associated with Mt. Augustine, Mt. St. Helens, Mt. Pinatubo,
Erebus and Eyjafjallajökull, with comparisons to all industrial emissions
in a year, 100 years, or since the industrial revolution, all cars in a
decade, or indeed a thousand years.
The volcano gambit is the universal comparison, untethered to any actual
facts, and look for it to resurface again the next time a big volcano hits
1. D.A. JOHNSTON, "Volcanic Contribution of Chlorine to the
Stratosphere: More Significant to Ozone Than Previously Estimated?",
*Science*, vol. 209, pp. 491-493, 1980.
2. F.S. Rowland, "President's Lecture: The Need for Scientific
Communication with the Public", *Science*, vol. 260, pp. 1571-1576,
3. G. Brasseur, and C. Granier, "Mount Pinatubo Aerosols,
Chlorofluorocarbons, and Ozone Depletion", *Science*, vol. 257, pp.
1239-1242, 1992. http://dx.doi.org/10.1126/science.257.5074.1239
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