Day 011 - 12 Jul 94 - Page 32


     
     1        stabilize chlorine at present levels would require large
              cutbacks in CFC emissions; for example, 85% in the case of
     2        CFC12."
              A.   Yes
     3
         Q.   At the bottom of the page, paragraph 11,
     4
              "Man-made chlorofluorocarbons are responsible for the
     5        Antarctic ozone depletions, and are implicated in the
              reductions of ozone observed in the mid- latitude Northern
     6        Hemisphere.  The current terms of the Montreal Protocol,
              whilst reducing emissions of some of these substances,
     7        still permit their concentrations in the atmosphere to
              increase.  Unless emissions are reduced very much further
     8        as a matter of urgency, it is likely that more severe
              depletion of stratospheric ozone will occur.  The only way
     9        to prevent further depletion, and to allow the atmosphere
              to recover, is to phase out production of the major man
    10        made carriers of chlorine and bromine to the
              stratosphere."
    11        A.   Yes.
 
    12   Q.   Is this right: SORG was taking a rather more urgent view
              of the matter than the Montreal Protocol signatories had
    13        done?
              A.   Yes.
    14
         Q.   Can we turn to page 46 of this report.  I am afraid I have
    15        to use the internal numbering.  This is still in the 1988
              one.  Page 504.  Here we find, Professor Duxbury, a
    16        description of the process of ozone depletion potential
              which was the standard, or the yardstick, by which the
    17        effects of these substance was measured in those days.
              A.   Yes.
    18
         Q.   "Each of these source gases will have a different
    19        efficiency for removing ozone in the stratosphere, known
              as its Ozone Depletion Potential (ODP). For convenience,
    20        ODP is defined relative to that of CFC- 11 which is
              therefore, by definition, equal to 1.0) and depends on:
    21
              1.  The atmospheric lifetime of the molecule; longer
    22        lifetimes correspond with higher ODPs mainly because more
              can be transferred to the stratosphere before
    23        decomposition;
 
    24        2.  The number of halogen atoms liberated when broken down
              in the stratosphere; more halogens lead to a greater ODP"
    25
              Is that a correct statement? 
    26        A.   Yes. 
  
    27   Q.   "3. The particular halogen atom; fluorine does not lead to
              ozone depletion at all but bromine has a much greater
    28        effect on ozone than chlorine, atom for atom."
 
    29        Is that correct?
              A.   Yes.
    30
         Q.   For example, CFC- 12 has a long lifetime (139 years) and

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