Comparison of different greenhouse gases Co2 CH4 CFC-11 CFC-12 N20 Concentration ppm ppt ppt ppb Preindustrial(<1800)280 0.80 0 288 Current 3701.74268 484 314 Atmospheric lifetime 50-10010 5 130 114 (y) Per molecule of radiative forcing 23 400015,800296 relative to co2Comparison of different greenhouse gases CO2 CH4 CFC-11 CFC-12 N2O Concentration Preindustrial (<1800) Current ppm 280 370 ppm 0.8 1.74 ppt 0 268 ppt 0 484 ppb 288 314 Atmospheric lifetime (yr) 50-100 10 45 130 114 Per molecule of radiative forcing relative to CO2 1 23 4,000 15,800 296