The chlorine part of CFC refrigerants can reduce ozone. Hydrochlorofluorocarbons (HCFCs) can also damage ozone. Newer Hydrofulorocarbon (HFC) refrigerants do not have chlorine in them and do not reduce ozone in the atmosphere. Most refrigerants also increase global warming because they are powerful greenhouse gasses. These refrigerants increase global warming thousands of times more than carbon dioxide (CO).