Between earth and sky

By the turn of the twentieth century, the American search for new frontiers led not West but toward a golden age of technology. The invention of the telephone, the electric light bulb, the airplane, and numerous other achievements of science and engineering inspired a faith that technology would always improve the human condition. This same confidence would fuel the drive for "better living through chemistry" that produced chlorofluorocarbons - or CFCs. Spanning six decades, the story of CFCs vividly portrays the unintended consequences of technological progress and the ongoing struggle to contain the threat to the global environment. The invention of chlorofluorocarbons in 1928 by General Motors scientist Thomas Midgley, Jr., was celebrated as a boon to humanity: CFCs made possible both the mass proliferation of air conditioning and refrigeration.^ By the 1950s CFCs had found further applications: as propellants in aerosol spray cans, in the manufacture of Styrofoam, and as vital industrial solvents. Then, in 1974, after millions of tons of CFCs had been released into the Earth's atmosphere, two scientists at the University of California demonstrated that these same "safe" wonder