THE statistics are striking: Half the world's rain forests in Latin America, Africa, and Asia have disappeared since World War II. Destruction continues at the rate of 50 to 100 acres a minute, a pace that could wipe out half of what's left by the end of the century. Fortunately, aggressive work by environmentalists in the last two years has alerted the world to the extent of the problem. More must be done, but significant correction efforts are under way.
Rain forests are home to about half of all plant and animal species, many of which have not yet been identified. Many plants are valuable sources of food and pharmaceuticals. The lush vegetation of rain forests also plays an important role in modulating the earth's temperatures; it does it by absorbing some of the considerable amount of carbon dioxide in the atmosphere and, in the process, giving off oxygen. A buildup of too much carbon dioxide traps the sun's heat, contributing to the ``greenhouse effect.''
Certain development efforts, such as uncontrolled logging, the building of new dams, and the conversion of forests to farmland, are at fault. Fueling the push are rapid third-world population growth and developed nations' demands for such items as mahogany tables and cheap beef from cattle raised on cleared forest land. Growing crops on such land has not proved very successful. Nutrients tend to lie near the soil's surface. Light crop yields have encouraged the devastation of still more forest in hopes of a greater economic return.
Many developing nations view rain forest conservation as a luxury they cannot afford. But the choice need not be between preservation and economic progress. The need in some cases is for more intensive development of land already cleared; roads should be improved and ways found to increase crop yields. New ways of using forest resources, such as tapping latex for rubber from wild trees without destroying them in the process, must be found.
The World Bank announced a series of reforms a few months ago. These include an increase in the bank's ecological staff and more attention to the environmental impact of its projects. A group of 35 nongovernmental organizations from 14 nations is pressing for more change from world lenders, such as the advance alerting of citizens in any country where projects are planned and a halt on global investments in large dam projects until the environmental and social costs are weighed. One of the most heartening developments is the increasing involvement in saving rain forests of third-world citizens themselves. Brazil, which has about one-third of the forest total, has some 300 conservation groups. Both Brazil and Costa Rica have put sections of their rain forests under national protection.
Such efforts mark an important beginning. More of the world should now take up the task of preserving a valuable international resource otherwise headed for extinction.