Annual Greenhouse Gas Concentrations -N2O and CH4 Modified for GCM Input Years Concentration YEAR CO2_(ppm) N2O_(ppb) CH4_(ppb) CFC-11(ppt) CFC-12_(ppt) CFC-X_(ppt) 1850 285.00 281.51 984.62 .00 .00 .00 1851 285.20 281.51 986.40 .00 .00 .00 1852 285.39 281.52 988.12 .00 .00 .00 1853 285.59 281.52 989.90 .00 .00 .00 1854 285.79 281.53 991.67 .00 .00 .00 1855 285.98 281.53 993.44 .00 .00 .00 1856 286.18 281.54 995.20 .00 .00 .00 1857 286.38 281.54 996.96 .00 .00 .00 1858 286.58 281.54 998.72 .00 .00 .00 1859 286.77 281.55 1000.47 .00 .00 .00 1860 286.97 281.55 1002.28 .00 .00 .00 1861 287.17 281.56 1004.03 .00 .00 .00 1862 287.37 281.56 1005.83 .00 .00 .00 1863 287.57 281.57 1007.62 .00 .00 .00 1864 287.77 281.58 1009.36 .00 .00 .00 1865 287.96 281.58 1011.15 .00 .00 .00 1866 288.16 281.59 1012.93 .00 .00 .00 1867 288.36 281.59 1014.71 .00 .00 .00 1868 288.56 281.60 1016.55 .00 .00 .00 1869 288.76 281.61 1018.32 .00 .00 .00 1870 288.96 281.62 1020.09 .00 .00 .00 1871 289.16 281.62 1021.92 .00 .00 .00 1872 289.36 281.63 1023.68 .00 .00 .00 1873 289.56 281.64 1025.49 .00 .00 .00 1874 289.76 281.65 1027.30 .00 .00 .00 1875 289.96 281.66 1029.11 .00 .00 .00 1876 290.16 281.67 1030.92 .00 .00 .00 1877 290.36 281.68 1032.72 .00 .00 .00 1878 290.56 281.69 1034.51 .00 .00 .00 1879 290.76 281.70 1036.30 .00 .00 .00 1880 290.96 281.71 1038.15 .00 .00 .00 1881 291.16 281.72 1039.93 .00 .00 .00 1882 291.36 281.73 1041.77 .00 .00 .00 1883 291.56 281.74 1043.61 .00 .00 .00 1884 291.76 281.76 1045.44 .00 .00 .00 1885 291.96 281.77 1047.26 .00 .00 .00 1886 292.17 281.78 1049.08 .00 .00 .00 1887 292.37 281.80 1050.90 .00 .00 .00 1888 292.57 281.81 1052.71 .00 .00 .00 1889 292.77 281.82 1054.58 .00 .00 .00 1890 292.97 281.84 1056.39 .00 .00 .00 1891 293.17 281.85 1058.25 .00 .00 .00 1892 293.38 281.87 1060.04 .00 .00 .00 1893 293.58 281.89 1061.89 .00 .00 .00 1894 293.78 281.91 1063.74 .00 .00 .00 1895 293.98 281.92 1065.58 .00 .00 .00 1896 294.19 281.95 1067.42 .00 .00 .00 1897 294.39 281.96 1069.31 .00 .00 .00 1898 294.59 281.99 1071.14 .00 .00 .00 1899 294.80 282.01 1072.96 .00 .00 .00 1900 295.00 282.03 1074.84 .00 .00 .00 1901 295.35 282.05 1076.89 .00 .00 .00 1902 295.69 282.08 1078.98 .00 .00 .00 1903 296.04 282.10 1081.07 .00 .00 .00 1904 296.39 282.13 1083.10 .00 .00 .00 1905 296.73 282.15 1085.18 .00 .00 .00 1906 297.08 282.18 1087.26 .00 .00 .00 1907 297.43 282.21 1089.38 .00 .00 .00 1908 297.78 282.24 1091.45 .00 .00 .00 1909 298.13 282.27 1093.51 .00 .00 .00 1910 298.48 282.30 1095.62 .00 .00 .00 1911 298.83 282.34 1097.72 .00 .00 .00 1912 299.18 282.37 1099.82 .00 .00 .00 1913 299.53 282.41 1101.92 .00 .00 .00 1914 299.88 282.44 1104.00 .00 .00 .00 1915 300.23 282.48 1106.09 .00 .00 .00 1916 300.59 282.52 1108.22 .00 .00 .00 1917 300.94 282.56 1110.35 .00 .00 .00 1918 301.29 282.60 1112.42 .00 .00 .00 1919 301.65 282.65 1114.54 .00 .00 .00 1920 302.00 282.70 1116.65 .00 .00 .00 1921 302.30 282.74 1118.81 .00 .00 .00 1922 302.59 282.79 1120.92 .00 .00 .00 1923 302.89 282.84 1123.07 .00 .00 .00 1924 303.19 282.90 1125.16 .00 .00 .00 1925 303.49 282.95 1127.30 .00 .00 .00 1926 303.79 283.01 1129.44 .00 .00 .00 1927 304.09 283.07 1131.57 .00 .00 .00 1928 304.39 283.13 1133.75 .00 .00 .00 1929 304.69 283.19 1135.87 .00 .00 .00 1930 304.99 283.26 1138.04 .00 .00 .00 1931 305.29 283.33 1140.21 .00 .00 .00 1932 305.59 283.40 1142.36 .00 .01 .00 1933 305.89 283.48 1144.52 .00 .02 .00 1934 306.19 283.56 1146.67 .00 .06 .00 1935 306.49 283.63 1148.81 .00 .11 .00 1936 306.79 283.72 1151.00 .01 .19 .00 1937 307.09 283.80 1153.19 .01 .34 .00 1938 307.39 283.89 1155.37 .02 .47 .00 1939 307.70 283.99 1157.54 .02 .66 .00 1940 308.00 284.08 1159.71 .03 .88 .00 1941 308.38 284.18 1161.88 .04 1.17 .00 1942 308.77 284.28 1164.09 .05 1.45 .00 1943 309.16 284.39 1166.25 .06 1.84 .00 1944 309.54 284.50 1168.45 .08 2.64 .00 1945 309.93 284.62 1170.65 .09 3.59 .00 1946 310.32 284.74 1172.89 .12 4.38 .00 1947 310.70 284.86 1175.07 .17 5.32 .00 1948 311.09 284.99 1177.26 .29 6.47 .00 1949 311.48 285.13 1179.48 .46 7.68 .00 1950 311.87 285.27 1181.71 .72 9.30 .00 1951 312.26 285.40 1185.38 1.07 10.98 .00 1952 312.65 285.56 1189.05 1.60 12.69 .00 1953 313.04 285.71 1192.74 2.26 14.83 .00 1954 313.43 285.87 1196.43 3.06 17.09 .00 1955 313.82 286.04 1200.15 4.05 19.74 .00 1956 314.21 286.21 1203.86 5.28 22.90 .00 1957 314.61 286.40 1207.60 6.54 26.29 .00 1958 314.85 286.60 1213.00 7.60 29.62 .00 1959 315.67 286.82 1220.31 8.88 33.61 .00 1960 316.54 286.99 1227.58 10.71 38.14 .00 1961 317.18 287.21 1234.79 12.93 43.06 .00 1962 317.88 287.43 1241.96 15.82 48.90 .00 1963 318.48 287.69 1249.08 19.26 55.56 .00 1964 319.03 287.90 1256.15 23.36 63.33 .00 1965 319.58 288.16 1263.18 27.84 71.99 .00 1966 320.90 288.42 1270.17 32.97 81.83 .00 1967 321.61 288.73 1277.12 38.74 92.89 .00 1968 322.29 288.99 1284.03 45.35 105.04 .00 1969 323.44 289.29 1290.90 53.20 118.52 .00 1970 324.70 289.59 1297.73 61.73 133.04 .00 1971 325.55 289.89 1304.52 71.10 148.42 .00 1972 326.54 290.24 1311.28 82.05 165.51 .00 1973 328.47 290.58 1318.00 94.47 184.55 .00 1974 329.24 290.92 1324.69 107.48 204.36 .00 1975 330.18 291.27 1331.34 117.99 220.95 .00 1976 331.17 291.61 1337.96 129.33 237.06 .70 1977 332.73 292.00 1344.55 139.81 255.24 2.80 1978 334.52 292.38 1351.11 148.54 271.37 6.30 1979 336.02 292.81 1357.63 157.62 286.55 11.20 1980 337.90 292.89 1364.13 166.60 300.33 17.50 1981 339.29 293.40 1370.59 175.26 320.35 25.20 1982 340.18 293.83 1377.03 183.64 337.10 34.30 1983 341.90 294.09 1383.44 192.71 354.32 44.80 1984 343.45 294.43 1389.82 201.45 365.83 56.70 1985 344.85 294.51 1396.18 213.27 387.35 70.00 1986 346.22 294.94 1401.66 223.64 409.40 84.70 1987 347.92 294.85 1406.29 234.80 427.29 100.80 1988 350.12 295.10 1410.90 245.38 446.64 118.30 1989 351.67 295.91 1416.34 255.79 462.83 137.20 1990 352.96 296.12 1420.50 262.20 477.53 157.50 1991 354.12 296.46 1424.66 267.48 490.75 179.20 1992 355.25 297.01 1428.81 270.60 505.92 202.30 1993 356.01 297.05 1429.22 271.94 518.93 226.80 1994 357.57 297.26 1432.12 272.22 528.71 252.70 1995 359.49 297.55 1434.18 271.65 534.54 280.00 1996 361.15 297.81 1434.59 270.81 540.37 308.00