GETTING 92 governments to agree on anything, let alone on an environmental rule affecting dozens of industries, surely ranks as one of the more improbable feats of the season. But it happened last week in London, where they set a total ban on chlorofluorocarbons. At first the White House refused to join it, but to his great credit, President Bush changed his mind. The reasons for this extraordinary success deserve careful attention, for other kinds of environmental protection are going to require similar international consensus.

Three years ago in the Montreal Protocol the industrial countries committed themselves to cut the use of chlorofluorocarbons -- CFCs -- in half by 1998. Since then an inundation of extremely ominous data has warned that the Montreal schedule wasn't fast enough and didn't include enough of the world. At London the rich countries committed themselves to a total ban by the year 2000 and the poor ones by a decade later. Both, incidentally, have the ability to achieve the ban well ahead of those deadlines and ought to push along faster. Under the agreement, the rich countries will also provide the technology and money to help the poor countries adapt. India and China are apparently going to ratify the agreement, immensely expanding its scope.

One ingredient of this achievement was good science. It was the discovery that CFCs had eaten a huge hole in the ozone layer over the Antarctic -- with its implication of increased danger of skin cancers as the hole widened to more heavily populated parts of the planet -- that forced the negotiations to speed up.

But there was another essential ingredient as well. Advancing technology provided less threatening substitutes for CFCs. For that, credit goes to the chemical industry in general and to Du Pont in particular. CFCs are widely used for refrigeration and many other things. At first it looked as though a ban would be immensely disruptive and costly. Now, thanks to much good work in the laboratory, it appears that the substitutes will be more efficient than the compounds they replace.

Global warming will probably be the next environmental question requiring this kind of worldwide answer. Once again, there will be progress only if there is a sound scientific base and only if there are substitute technologies that can reduce emissions of carbon dioxide without great impacts on standards of living. Getting 92 governments to agree on environmental action is never going to be simple. But the London agreement shows that it can be done -- and done more effectively than most of the world thought possible.