Although an international treaty to limit production of ozone-destroying chlorofluorocarbons - better known as CFCs - went into effect on New Year's Day, it may be a case of good intentions failing to keep up with harsh reality.

Indications are that the pact may be ineffective. Plans are already being made to revise the treaty at a March meeting in Britain.Concern about CFCs has been mounting for several years, ever since it was discovered that the chemicals are destroying the ozone layer in the Earth's atmosphere. It is the ozone layer that protects the planet from deadly ultraviolet radiation from space. Increased radiation could markedly raise cancer rates, reduce such vital crops as wheat and rice, damage eyes of certain animals, and cause decay of plastics.

Forty-five nations endorsed the pact in 1987, but only about two dozen - mainly industrialized nations, including the U.S. - have actually signed. The treaty calls for signers to freeze CFC production at 1986 levels, and to cut that production in half by 1998. CFCs are used in industrial cleaners, air conditioners, refrigerators, and many kinds of spray cans, although the latter are no longer manufactured in the U.S.

Unfortunately, the agreement is weak when it comes to developing nations. Few of those less-industrialized countries have signed the pact, and even for those that have, the restrictions on CFC production are less than for industrialized societies.

This doesn't sound too serious, except for the fact that destruction of the ozone layer appears to be more rapid than anyone anticipated when the treaty was being designed.

In 1987, the framers of the pact expected it to limit the rise of CFCs from the present 2.7 parts per billion in the stratosphere to about 5 ppb by 1998. But a September study showed that the concentration is likely to reach 8 ppb by that date.

In addition, the ozone layer has thinned 2.5 percent on a global average and as much as 5 percent in certain places and during certain seasons. Such studies show that more ozone depletion has already occured than the treaty experts thought would happen for another century.

Clearly, it is a problem that must be taken much more seriously. More nations must be vigorously encouraged to join the effort to reduce CFC production. And the industrialized countries must push harder to find substitutes for CFC. This is not something that can be pushed into the background and ignored - at least not without peril.