In 1987 an international protocol was signed at Montreal, in which signatory countries declared their intention to cut CFC production and consumption in half by the end of the century. The Montreal Protocol is remarkable for the fact that it constitutes an anticipatory response to global change. Although held up by many as a model for those working on other global environmental issues, in its initial form this international agreement left much to be desired: it did not cover a range of chemicals (for example, methyl chloroform, carbon tetrachloride) whose effects are similar to those of CFCs; it allowed developing countries to actually increase their use of CFCs; it offered minimal assistance to governments seeking to reduce the use of CFCs within their own jurisdictions; it provided little guidance on compliance; and it did not succeed in drawing in key players like China and India. But the pressure of worldwide public opinion, driven by dramatic recurrences of sharp yearly reductions in ozone over Antarctica and by a growing scientific consensus concerning the dangers of ozone depletion, led to a renegotiation of the protocol that has strengthened its provisions in a number of areas. Under a series of amendments to the Montreal Protocol negotiated in London in 1990, CFCs and halons are to be phased out by the year 2000, and methyl chloroform and carbon tetrachloride have been added to the list of chemicals to be eliminated. The creation of an international fund to assist developing countries in switching to alternatives to CFCs has persuaded China and India to say they will join the agreement.

Nevertheless, the new provisions do not solve all the problems associated with ozone depletion. CFCs already in the atmosphere are expected to cause significant reductions in stratospheric ozone over a period of several decades. There is no guarantee that the chemicals developed as substitutes for CFCs will prove benign over the long run (CFCs themselves were thought to have ideal properties when they were introduced in the 1930s). Hydro-chlorofluorocarbons (HCFCs) and hydrohalocarbons (HFCs), prominent among the candidates to be used as substitutes for CFCs, have already provoked opposition from those concerned about their potential contribution to the greenhouse effect. That opposition makes prospective producers such as DuPont reluctant to invest heavily in facilities needed to initiate large-scale production of the chemicals (Holusha, 1990a, b). Still, the international response to the problem of ozone depletion has been note-

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