To paraphrase that famous remark about the weather, everyone talks about the ozone layer, but no one does anything about it. Though evidence has mounted that man-made compounds called chlorofluorocarbons (CFCs) are destroying the screen of ozone-enriched air that helps shield the earth from the sun's dangerous radiation, the world's nations have been slow to develop a consensus on how to cope with the problem.
Last week the world, or at least a part of it, finally did something. At a conference in Montreal sponsored by the United Nations Environment Program, 24 countries signed a milestone accord that promised to halve...