Transcripts of HFCs-FINAL1920PRORES_lowres

A new NASA study takes a closer look at a group of chemicals once thought to be harmless to Earth's ozone layer. Hydrofluorocarbons, or HFCs, are synthetic chemicals found in common household items like refrigerators and air conditioners. They were created to replace chlorofluorocarbons, a group of ozone-depleting chemicals found to cause the ozone hole over Antarctica. But NASA scientists now reveal that HFCs also contribute to ozone depletion. HFCs were thought to be "ozone-friendly" because they don"t contain chlorine atoms, which destroy ozone molecules. Our study is the first to show that as HFC levels increase, they'll have a weak but measurable effect on the ozone layer. HFCs trap heat in the atmosphere, raising temperatures. In the stratosphere, which contains the protective ozone layer, this warming speeds up chemical reactions that deplete ozone. Atmospheric concentrations of these chemicals are currently growing around 7 percent a year and are projected to be over 17 times higher by 2050. Using a NASA computer model, the scientists simulated the impact of HFCs on the ozone layer. They found that HFCs will reduce global ozone levels by 0.035% by the year 2050. The ozone depletion that we calculated was small, but about 100 times larger than a previous estimate. Studies show an increase in HFC levels will affect more than the ozone layer. HFCs are strong greenhouse gases that contribute to the warming of the planet. By the year 2050, their contribution to global warming could be as large as 20 percent that of carbon dioxide. Now that we better understand the impacts of these particular greenhouse gases on the ozone layer, our next step is to study how these chemicals contribute to other changes in Earth's climate and the environment.