Este artículo muestra los esfuerzos de Irving Langmuir, premio Nobel de química por sus trabajos en química de superficies, quien a partir de investigaciones sobre métodos para evitar la formación de hielo en alas de aviones en vuelo durante la IIda GM, pensó que “sembrando” nubes tanto con hielo seco como con ioduros podía iniciar anticipadamente precipitaciones y de esa manera evitar o reducir los daños que ocasionaban las tormentas. Ya muerto Langmuir, durante la guerra de Vietnam, EEUU pensó en utilizar esta metodología para incrementar el nivel de lluvias de los monzones típicos de la zona con el fin de provocar inundaciones que impidiesen el uso de las rutas logísticas del Viet Cong. Esta operación se llamó Proyecto Popeye y resultó en “sembrar” nubes con ioduro de plata desde 1967 a 1972 con dudosos resultados prácticos. Hoy dicho tipo de operación está prohibido por la convención ENMOD, que prohíbe la modificación del medio ambiente con fines militares.
The chemist Irving Langmuir had already won a Nobel Prize, but he’d never screamed in delight during an experiment before. It was November 13, 1946. He was standing in a control tower at the Schenectady, New York, airport, watching a small prop plane go buzzing overhead. Fourteen thousand feet above him, his assistant was leaning out the plane’s window, tossing pellets of dry ice into a cloud. Seconds later, the cloud “began to writhe as if in torment,” one witness recalled. Within five minutes, the cloud had disappeared, transformed into rain. Even before the plane landed, he raced off to telephone a reporter. Mankind, he shouted into the receiver, had finally learned to control the weather.
In his day job, Langmuir studied surface chemistry at General Electric Labs in upstate New York. In contrast to most corporate labs, at GE he had a free hand to research whatever he fancied, and during World War II, he began studying the buildup of ice on airplane wings. This led to a series of field studies at nearby Mount Washington, in New Hampshire. The mountain often produced mists of “supercooled” water that, despite registering far below 32 degrees Fahrenheit, refused to freeze into ice. This Schrödinger’s cat–like indeterminacy—how could water not freeze below its freezing point?—intrigued Langmuir, and he wanted to know more.
To help with the work, he engaged an assistant named Vincent Schaefer. Schaefer started his experiments by commandeering a $240 open-top GE freezer ($3,000 today). He lined it with black velvet so he could see any ice crystals that formed, then huffed into the cold air to introduce moisture, which became supercooled. Yet week after week, no matter how he varied the conditions in the freezer, the water in his breath never condensed into ice.