SHOULD COAL BE THE major fuel of the future?

President Carter thinks so, but there are many problems down that path. Some of the difficulties have been illuminated in legislative debates over clean air, strip mining, slurry pipelines, and benefits for victims of black-lung disease. But these problems are dwarfed by one which a committee of the National Academy of Sciences has just warned about. According to that panel, long-term reliance on fossil fuels, coal, oil and natural gas could change the elimate of the globe within the next 200 years, with "adverse, perhaps even catastrophic" effects.

The trouble is that fossil fuels, when burned, release carbon dioxide. This builds up in the atmosphere and functions there much like glass in a greenhouse, letting the sun's rays in but keeping heat from radiating out. Since 1860, as the world has become more industrialized, carbon dioxide levels in the air have gone up 11.5 to 13.5 per cent. The NAS panel found that if the world's populations and the use of fossil fuels, primarily coal, keep growing as generally assumed, atmospheric carbon dioxide concentrations could double by the year 2050 and increase several fold by the year 2150.

The consequences sound like a disaster-movie script.By 2150, the average temperature in the "global greenhouse" could be raised 6 degrees Centigrade (11 degrees Fahrenheit). The oceans would get warmer. Polar ice would melt. Sea levels might rise as much as 20 feet. Marine life would be disrupted. Rainfall patterns around the world would change, with drastic and unpredictable effects on deserts and semi-arid zones. Temperate zones would shift toward the poles: Iowa's corn belt might wind up in Canada. The effects on world food supplies would be enormous, nearly irreversible and possibly disastrous.

Scientific concern about the "greenhouse effect" is not new. The NAS panel's warning though, is the first to carry the cachet of the nation's official scientific establishment. Emphasizing that its forecasts are very tentative, the panel called for a major national effort to learn more about climatic processes and "assess the seriousness of the matter." Certainly such a program should be gotten under way. In the meantime, as the panel's chairman said, it may be "perfectly all right" from this perspective to rely heavily on coal for the next few decades. But policy-makers should not bank on that - and should start thinking very seriously about long-range, large-scale alternatives to fossil fuels. The NAS report is a timely reminder that every energy option has its costs, and that the policy decisions of the next several decades could affect the world in unintended ways for a millenium or more.