25 Most CFC's are decomposed by soil bacteria and other terrestrial mechanisms.
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This article is from the Ozone Depletion: Stratospheric Chlorine and Bromine FAQ, by Robert Parson rparson@spot.colorado.edu with numerous contributions by others.
25 Most CFC's are decomposed by soil bacteria and other terrestrial mechanisms.
This argument is based upon a misinterpretation of measurements made by
Khalil and Rasmussen. These scientists did show that some CFC's such
as CFC-11 and CFC-12 (but not CFC-113) were taken up by soils in
Australia [Khalil and Rasmussen 1989] and by rice paddies in China
[Khalil et al. 1990]. However, the amounts that are disposed of in
this way are small compared to the amounts that end up in the
stratosphere. A recent summary [Khalil and Rasmussen 1993] concludes
that out of a total of 9152 Gigagrams (Gg) of CFC-11 produced, only 1
Gg has been removed by soils and 33 Gg reside in the oceans; in
contrast, 1709 Gg have been photolyzed in the stratosphere, 741 Gg are
presently in the stratosphere, and 5360 Gg are in the troposphere.
Most of the remainder is still trapped in foams, aerosols, etc. and
has not yet been released to the atmosphere.
(In contrast, soil bacteria do appear to consume large quantities of
methyl bromide, CH3Br. [Shorter et al.])
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