Global Warming Potentials (IPCC Second Assessment Report) Species Chemical formula Lifetime (years) Global Warming Potential (Time Horizon) 20 years 100 years 500 years Carbon dioxide CO2 variable § 1 1 1 Methane * CH4 12±3 56 21 6.5 Nitrous oxide N2O 120 280 310 170 HFC-23 CHF3 264 9100 11700 9800 HFC-32 CH2F2 5.6 2100 650 200 HFC-41 CH3F 3.7 490 150 45 HFC-43-10mee C5H2F10 17.1 3000 1300 400 HFC-125 C2HF5 32.6 4600 2800 920 HFC-134 C2H2F4 10.6 2900 1000 310 HFC-134a CH2FCF3 14.6 3400 1300 420 HFC-152a C2H4F2 1.5 460 140 42 HFC-143 C2H3F3 3.8 1000 300 94 HFC-143a C2H3F3 48.3 5000 3800 1400 HFC-227ea C3HF7 36.5 4300 2900 950 HFC-236fa C3H2F6 209 5100 6300 4700 HFC-245ca C3H3F5 6.6 1800 560 170 Sulphur hexafluoride SF6 3200 16300 23900 34900 Perfluoromethane CF4 50000 4400 6500 10000 Perfluoroethane C2F6 10000 6200 9200 14000 Perfluoropropane C3F8 2600 4800 7000 10100 Perfluorobutane C4F10 2600 4800 7000 10100 Perfluorocyclobutane c-C4F8 3200 6000 8700 12700 Perfluoropentane C5F12 4100 5100 7500 11000 Perfluorohexane C6F14 3200 5000 7400 10700