So the more affluent nations should pay poorer countries to stop exploiting the world's tropical rain forests and start preserving them, should they?

At first, the suggestion may sound like just another attempt on the part of less developed countries to pass the buck for their own short-sightedness and irresponsibility.But it's harder to dismiss the proposal now that some hard-headed business leaders have added their voices to those of the many conservationists who have long supported it.

A few days ago the Asian Development Bank devoted much of its annual report to a warning that deserves more attention than has been accorded to most previous reports about the alarmingly rapid depletion of the rain forests.

Noting that the depletion is so rapid that Asia could run out of tropical hardwoods in less than 40 years, the ADB pointedly added:

"It is not reasonable to expect developing nations, many of which are among the world's poorest countries, to limit or divert scarce resources for the alleviation of global environmental problems."

Actually, the bank could have made a much stronger case than it did for getting the industrialized nations to pour billions of dollars into saving the rain forests. For example:

- Every second, one acre of rain forest is wiped out. In a year, that amounts to an area the size of New York state. Already, half of the Earth's tropical forests have been burned, bulldozed and obliterated.

- The loss of rain forests contributes to global warming, or the "greenhouse effect." Such warming, if not checked, could by the middle of the next century change weather patterns enough to cause coastal flooding around the world and produce serious economic disruptions.

- Of 3,000 plants with cancer-fighting properties, 70 percent of them grow in the rain forests, which also produce other medications and food products.

- Tropical deforestation wipes out 17,000 species of plants and animals a year - species that exist nowhere else. That's 48 species made extinct each day, or two an hour.

Clearly, the entire world has a stake in the preservation of the rain forests. The rich countries have an especially great responsibility in this effort because they have helped in a big way to cause the problem by relocating factories that produce toxic, forest-destroying substances to developing nations with low labor costs.

Though it will be expensive to save the rain forests, just letting them continue to vanish would be even more costly. The more affluent nations should lead the way in this conservation effort not out of charity but as an act of enlightened self-interest.