§ Mr. WrayTo ask the Secretary of State for the Environment what assessment he has made of the effect of a reduction of 85 per cent. of chlorofluorocarbons by the year 2000 on the time needed for the ozone layer shield to recover completely.
§ Mrs. Virginia BottomleyThe second report of the Department's stratospheric ozone review group, copies of which have been placed in the Library of the House, calculated the reductions of chlorofluorocarbon emissions required to stabilize concentrations of chlorine in the atmosphere. In the case of CFCs 11 and 12, these reductions are 77 per cent. and 85 per cent. respectively. After such reductions, further depletion of the ozone layer would not occur. A complete phase out of CFCs would 347W lead to a slow decrease in atmospheric chlorine concentrations and recovery of the ozone layer. Because of the long atmospheric lifetime of chlorofluorocarbons, however, chlorine concentrations would not return to their 1975 levels until the second half of the next century.
The Government have called for a reduction in luchlorofluorocarbon emissions of at least 85 per cent. as soon as possible, in response to the review group's report. At the Environment Council held on 24 November the United Kingdom proposed that the Community should call for the Montreal protocol to be strengthened by requiring an 85 per cent. reduction of world-wide emissions of chlorofluorocarbons by the turn of the century.