AP Explains: What the new global climate agreement means
JOHANNESBURG — Experts say cutting hydrofluorocarbons, or HFCs, is the fastest way to reduce global warming. The United States, the world’s second-worst polluter, is among the countries that want to quickly phase out the use of HFCs, and now it is bound to take the earliest action, starting by 2019. Here’s a look at what it all means.
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HOW WE GOT HERE: THE OZONE LAYER
In 1987, countries alarmed by the discovery of a huge hole in the ozone layer over Antarctica signed a treaty known as the Montreal Protocol to eventually end the use of chlorofluorocarbons, which at the time were used in refrigerators and aerosols such as hair spray. HFCs were introduced to replace them, and scientists realized only later that while they don’t harm the ozone layer, they have a strong effect on global warming. Their ability to trap the heat radiating off the Earth is hundreds or thousands of times more potent than that of carbon dioxide. HFCs, which are used in air conditioners, refrigerators and insulating foams, have become the latest target as the world tries to reduce global warming. They have been called the world’s fastest-growing climate pollutants, though less plentiful than carbon dioxide, as more people in developing countries buy appliances.