The Benefits Of Hurricanes

Each summer and fall, the severe tropical storms known as hurricanes become a major meteorological peril for inhabitants of the Eastern and Gulf Coast states. In 1970 the winds, rains and floods of Hurricane Celia killed eleven and caused some $454 million in damage in Texas alone. Two years later, Hurricane Agnes brought even greater devastation, killing 118 people and leaving over $3 billion in damage. In a continuing effort to prevent -or at least minimize -such disasters, the Federal Government has been sponsoring Project Stormfury, which was designed to study the formation of the complex storms and find ways of controlling them.

Daredevil Assaults. This year the Administration's budget cutters have decided to suspend the most dramatic aspect of Stormfury's work: the efforts to reduce the devastating power of hurricanes by "seeding" them with silver iodide crystals, spread by planes flying directly into the storm. Such daredevil aerial assaults, which in at least one case -1969's Hurricane Debbie -apparently succeeded in temporarily reducing wind velocities by as much as 30%, will not be resumed before the summer of 1976. Then Stormfury's pilots will try their seeding skills on typhoons, the Pacific version of hurricanes.

Though disappointed by the reduced allocations, the hurricane hunters do not find the halt entirely unwelcome. In fact, meteorologists are beginning to believe that tropical storms may more than offset the damage they cause by the good they do. Scientists already know that in such places as Japan, India, Southeast Asia -even in the southeastern portion of the U.S. -tropical storms provide up to 25% of available rainfall. If this vital precipitation were ever cut off by man's interference with such storms, the results might be ruinous for farmers, industry and drinking-water supplies. Now many meteorologists are becoming convinced that tropical storms have an even more significant and less understood role: they may well be a crucial factor in maintaining the planet's heat balance, which is essential to the well-being of all life.

Because the sun's rays strike it more directly, the earth's equatorial zone heats up more than either polar region. If some of this heat were not transported away from the tropics, average equatorial temperatures would probably begin to rise dangerously. Fortunately, the earth has some handy mechanisms for carrying heat from the tropics toward the poles. Perhaps a third of this heat is distributed by ocean currents. The rest is transported by movement of the atmosphere. A large portion of this atmospheric heat -the exact percentage is unknown -is picked up from the sea by tropical storms.

The process is only partly understood. Apparently formed when a low-pressure area develops over warm tropical waters, the newborn storm system is fed by evaporation from the sea. Helped by the whirling winds in the area (which move in a counterclockwise direction in the Northern Hemisphere and clockwise in the Southern), the rate of evaporation gradually increases. As the water vapor rises from the sea, it cools, condenses and releases enormous amounts of heat into the atmosphere. The heat, in turn, causes more evaporation and condensation, further fueling the brewing storm like the updraft in a chimney. As the winds build and the tropical storm edges away from its birthplace, it releases enormous stores of heat. In a full-fledged hurricane, which has winds of 75 m.p.h. or more, as much energy may be released in a single day as by the detonation of 400 20-megaton hydrogen bombs.

Warmer and Warmer. What would happen if man ever interfered drastically with this process? Meteorologist Francis K. Davis, who is dean of Drexel University's College of Science in Philadelphia, warns of some frightening consequences. Unable to shake off their heat, he says, the tropics might become warmer and warmer. Simultaneously, the polar regions would slowly become colder. Eventually, both areas would expand, relentlessly shrinking the thickly populated temperate zones between them.

Davis foresees another possible horror. If they were prevented by man's technology from releasing their heat through tropical storms, the equatorial seas might warm up until their huge store of heat would be released in the form of super hurricanes that could make their present-day counterparts seem as mild as a summer downpour.

Davis acknowledges that his terrifying scenarios are based on a large quotient of guesswork. Meteorologists may not ever achieve enough mastery over hurricanes to affect the earth's heat balance. Still, the warning echoes a theme that is finding widening support among thoughtful scientists: man must learn much more about nature's most elemental forces before he tampers with them.

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