In 1988, President Reagan signed the Montreal Protocol, which banned CFC refrigerants like Freon in air conditioners and refrigerators. The chlorofluorocarbons were the cause of a giant hole in the ozone layer, which has been shrinking ever since the ban. Unfortunately, the chemicals that replaced CFCs – hydrofluorocarbons or HFCs – have their own major problem: they are a seriously bad greenhouse gas, far worse than carbon dioxide. Last fall, an international agreement was reached by over 170 countries to reduce and eventually replace HFCs, which included 100 developing countries like China and India where air conditioning use is growing fastest.
