There appears to be a large number of people who are under the impression that Volcanos release ozone-depleting CFC's into the atmosphere. What's more is that they believe a single eruption expels more CFC's into the atmosphere than all the CFC's used by mankind since they were first discovered and used in aerosol cans and other industrial and consumer applications.

The prominent global warming denier Christopher Monckton makes the claim, as referenced here:

Another, which I’m trying to find data for, is the volcanic activity of Mount Erebus, Antarctica’s active volcano. In a good year for eruptions, Erebus can put out as much CFCs as Man used to.

Do volcanos release ozone depleting chlorofluorocarbons?

  • Evidence of notability?
    – user5341
    Commented Sep 2, 2015 at 3:28
  • I fear we are attacking a strawman. Yes, Monckton may have reported volcanoes spewed CFCs, but it seems he means to refer to HCl, rather than CFC. Proving that volcanos don't spew CFC doesn't undermine the wider point of whether the ozone depletion problem is largely from volcanic sources.
    – Oddthinking
    Commented Sep 2, 2015 at 16:32
  • That's a different question Oddthinking, but I believe it can also be answered if someone cares to ask. I focused below on the question that was asked.
    – Mark
    Commented Sep 2, 2015 at 18:22

1 Answer 1



A study was published in 2006 specifically looking for CFCs and other halogenated compounds in volcanic plumes. The study involved collecting gas samples while flying over fumaroles emitting volcanic gases. The samples were analyzed and CFCs were found above the detection limit, but were not volcanic in origin. As the abstract states:

However, these compounds occur in the fumarole gases in relative proportions characteristic for ambient air.

This atmospheric fingerprint can be explained by variable amounts of air entering the porous volcanic edifices and successively being incorporated into the fumarolic gas discharges.

The conclusion states

Our results suggest that the investigated volcanoes do not constitute a significant natural source for CFCs, HFCs, HCFCs, halons, CF4, SF6 and NF3.

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