At the conference marking the 20th anniversary of the Montreal Protocol last week, some 191 nations agreed to a faster phaseout of ozone-depleting chemicals than had originally been negotiated in 1987. Hydrochlorofluorocarbons, or HCFCs, emerged in the 1990s as a less-ozone-damaging alternative to CFCs, which did truly nasty things to the ozone layer. But HCFCs also turned out to be a potent greenhouse gas a few thousand times more potent than carbon dioxide. Whoops! However, at the conference last week, developed countries agreed to reduce both production and consumption of HCFCs by 75 percent by 2010, 90 percent by 2015, and finally ending their use in 2020 — 10 years earlier than in the previous agreement. Developing countries, for their part, agreed to cut production and consumption by 10 percent in 2015 and gradually cut down their use until a final phaseout in 2030. Achim Steiner, head of the U.N. Environment Program, said, “It is perhaps the most important breakthrough in an international environment negotiation process for at least five or six years.” Translation: Holy crap, I can’t believe the U.S. actually agreed!

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