Bloomberg: The U.S. plans a second stab at a greenhouse-gas proposal, arguing that carbon trading isn’t the best way to eliminate hydrofluorocarbon-23, an industrial waste product that traps 11,700 times as much heat as carbon dioxide. The Montreal Protocol, signed in 1987 after scientists discovered a hole in the earth’s ozone, could be a vehicle for saving hundreds of millions of dollars now spent via emissions trading, said Dan Reifsnyder, the official responsible for ozone protection at the …