FORTUNATELY, a new global determination to stem depletion of the fragile layer of ozone circling the earth comes at the very moment when new research underscores the need. An aircraft expedition into the stratosphere over Antarctica last month found that the amount of ozone protecting that part of the planet from the sun's damaging ultraviolet rays was at the lowest level ever recorded, down 55 percent since 1979. The frigid climate of the South Pole is a factor in the particularly swift loss of ozone there; but the expedition also confirmed that chemicals play a major role. High levels of chlorine monoxide, a byproduct of chlorofluorocarbons (CFCs), were reported; chlorine reacts with ozone, breaking it down. Unlike other pollutants, CFCs can stay in the atmosphere up to 150 years; as long as they are in use, they accumulate.
CFCs, used as coolants in refrigerators and air conditioners, as blowing agents in foam packaging and insulation, and in aerosol sprays, are man-made chemical compounds. Mankind is thus in a strong position to do something about them.
The United States, Canada, and Scandinavian countries have banned the use of CFCs in aerosol sprays. McDonald's Corporation plans to phase out containers made with CFCs in the US.
But much more must be done. Better ways of disposing of discarded cooling units must be found. So must a substitute for CFCs; the chemical industry hopes to produce one within five years.
Another effort that should help was the signing last month in Montreal by 24 industrial nations of an international protocol, a decade in the drafting, to protect the ozone layer; it should be promptly ratified.
The US, not always a pioneering force when it comes to protecting the environment, deserves credit for its leadership in pressing for the accord. The first international attempt to control an air pollutant, the accord, which could easily become a model for others, aims to cut world emission of CFCs in half by 1999. It is a good agreement but should be stronger: The US Environmental Protection Agency says an immediate 85 percent reduction is needed to stabilize the ozone layer. Wisely, a global review of the pact at which standards could be upgraded has been set for 1990.
Meantime, nations could move on their own to make more-stringent and rapid reductions. The EPA is expected to produce its recommendation by December.
The lesson in dealing with such pollutants is as basic as learning to tidy up one's room or office after strewing things around. The planet we inhabit should be basically an orderly, smoothly functioning place. Human beings have an obligation to future generations to improve it or at least leave it the way they found it. Cutting back on the production of CFCs is a step in the right direction.