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CFCs do not destroy the ozone layer

From bullshitopedia
CFCs do not destroy the ozone layer
FALSE
"Chlorofluorocarbons (CFCs) used in aerosol sprays, refrigerators and air conditioners do not damage the ozone layer; natural sources such as volcanoes release far more chlorine, and the ozone hole is natural or exaggerated."
Domain Science & Environment
Tactic Statistical & Evidentiary Distortion
Propaganda Technique
Era Historical
First seen 1974
Origin Chemical industry responses to the 1974 Molina–Rowland hypothesis, later revived by commentators and writers opposing the Montreal Protocol in the early 1990s
Last reviewed 2026-10-27
Further reading: books on Science & Environment

The claim that CFCs do not destroy the ozone layer was made by chemical manufacturers in the 1970s and revived by commentators in the early 1990s as governments phased out the chemicals. Chlorofluorocarbons were widely used as refrigerants, aerosol propellants and foam-blowing agents. In 1974 chemists Mario Molina and F. Sherwood Rowland showed that CFCs could reach the stratosphere and release chlorine that destroys ozone, the layer that shields life from harmful ultraviolet radiation. The discovery of the Antarctic ozone hole in 1985 and subsequent atmospheric measurements confirmed their findings. The 1987 Montreal Protocol phased out CFCs, and the ozone layer is now slowly recovering. Molina, Rowland and Paul Crutzen received the 1995 Nobel Prize in Chemistry for this work.

The claim

Industry representatives initially argued that the theory was speculative and unproven and that restricting CFCs would be costly and premature. In the early 1990s some commentators and writers argued that volcanoes, such as Mount Erebus in Antarctica, and sea spray released far more chlorine than human activities, that ozone levels fluctuated naturally, and that the ozone hole was a natural phenomenon or a scare.

Origin

CFCs, developed in the 1930s, were prized because they were stable, non-toxic and non-flammable. Their stability meant they did not break down in the lower atmosphere but drifted up to the stratosphere, where ultraviolet light breaks them apart, releasing chlorine atoms. A single chlorine atom can destroy many thousands of ozone molecules. When Molina and Rowland published their findings in Nature in 1974, the CFC industry was worth billions of dollars.

What the evidence shows

  • The ozone hole. In 1985 scientists of the British Antarctic Survey, Joseph Farman, Brian Gardiner and Jonathan Shanklin, reported large springtime losses of ozone over Antarctica. Later research showed that polar stratospheric clouds greatly accelerate chlorine's destructive effect.
  • Direct measurements. Aircraft measurements in 1987 showed that, inside the ozone hole, levels of chlorine monoxide, a product of chlorine destroying ozone, rose as ozone fell, a pattern that provided strong evidence of the mechanism.
  • Volcanoes. Most chlorine released by volcanoes is in water-soluble forms that are washed out by rain before reaching the stratosphere. Measurements show that the great majority of chlorine in the stratosphere comes from human-made compounds. The rise in stratospheric chlorine closely followed the rise in CFC production.
  • Recovery. After the Montreal Protocol phased out CFCs, concentrations of ozone-depleting substances in the atmosphere began to fall. A 2022 scientific assessment for the World Meteorological Organization and UN Environment Programme projected that the ozone layer over Antarctica would return to 1980 levels around 2066, and elsewhere sooner. This recovery, following the reduction of CFCs, is further evidence that they were the cause.

Policy

The Montreal Protocol, agreed in 1987 and strengthened several times, phased out the production of CFCs and other ozone-depleting substances. In 2009 it became the first treaty in UN history to achieve universal ratification. It is often cited as the most successful international environmental agreement. Because CFCs are also potent greenhouse gases, the phase-out also slowed climate change.

Why it persists

Doubts about ozone depletion are now rarely heard, but the episode is studied because the arguments used against CFC regulation, that the science was uncertain, that natural sources were larger and that action was too costly, closely resemble those later used against action on climate change. In some cases the same individuals were involved in both campaigns.

Lessons for readers

  • Industry statements that a hazard is "unproven" deserve scrutiny when large profits are at stake.
  • Check whether natural sources actually reach the place where the damage occurs.
  • A predicted recovery after a cause is removed strengthens evidence for that cause.
  • International cooperation can solve global environmental problems.
  • Watch for recurring arguments used to delay action on different issues.

See also

Sources

  • Mario J. Molina and F. S. Rowland, "Stratospheric sink for chlorofluoromethanes: chlorine atom-catalysed destruction of ozone," Nature 249 (1974).
  • J. C. Farman, B. G. Gardiner and J. D. Shanklin, "Large losses of total ozone in Antarctica reveal seasonal ClOx/NOx interaction," Nature 315 (1985).
  • World Meteorological Organization, Scientific Assessment of Ozone Depletion: 2022.
  • Naomi Oreskes and Erik M. Conway, Merchants of Doubt (Bloomsbury, 2010).
  • Nobel Prize in Chemistry 1995, press release, Royal Swedish Academy of Sciences.
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