Global Mean N2O Mixing Ratios (ppb) --------------------------------------------------------------------------------- Observations --------------------------------------------------------------------------------- Data Data Data Source Year MixR. Year MixR. Source Year MixR. Source Year MixR. --------------------------------------------------------------------------------- Ice- 1850 275.4 1900 279.8 1950 289.0 2000 315.55 Core 1851 275.5 1901 279.9 1951 289.2 2001 316.34 Data 1852 275.6 1902 280.0 1952 289.4 2002 317.00 1853 275.7 1903 280.1 1953 289.7 2003 317.66 1854 275.8 1904 280.2 1954 289.9 2004 318.25 1855 275.9 1905 280.3 1955 290.1 2005 319.03 1856 276.0 1906 280.4 1956 290.4 2006 319.99 1857 276.1 1907 280.5 1957 290.6 2007 320.64 1858 276.2 1908 280.7 1958 290.8 2008 321.57 1859 276.3 1909 280.8 1959 291.1 2009 322.23 1860 276.4 1910 281.0 1960 291.4 2010 323.11 1861 276.5 1911 281.1 1961 291.7 2011 324.17 1862 276.6 1912 281.3 1962 291.9 2012 325.00 1863 276.7 1913 281.5 1963 292.2 2013 325.91 1864 276.8 1914 281.6 1964 292.6 2014 327.03 1865 276.9 1915 281.8 1965 293.0 2015 328.13 1866 277.0 1916 282.0 1966 293.4 2016 328.92 1867 277.1 1917 282.2 1967 293.8 2017 329.77 1868 277.2 1918 282.5 1968 294.2 2018 330.88 1869 277.3 1919 282.7 1969 294.7 2019 331.86 1870 277.4 1920 282.9 1970 295.2 1871 277.4 1921 283.2 1971 295.7 1872 277.5 1922 283.4 1972 296.2 1873 277.6 1923 283.6 1973 296.8 1874 277.7 1924 283.8 1974 297.4 1875 277.8 1925 284.0 1975 298.0 1876 277.8 1926 284.2 1976 298.6 1877 277.9 1927 284.5 1977 299.4 1878 278.0 1928 284.6 ------ 1978 300.03 1879 278.1 1929 284.8 NOAA 1979 300.91 1880 278.2 1930 285.0 ESRL 1980 301.04 1881 278.3 1931 285.1 GMD 1981 301.95 1882 278.4 1932 285.3 comb- 1982 303.16 1883 278.5 1933 285.5 ined 1983 303.75 1884 278.6 1934 285.7 1984 304.70 1885 278.7 1935 285.9 1985 305.26 1886 278.8 1936 286.1 1986 306.43 1887 278.9 1937 286.3 1987 306.07 1888 278.9 1938 286.4 1988 306.65 1889 279.0 1939 286.6 1989 307.90 1890 279.1 1940 286.7 1990 308.71 1891 279.2 1941 286.9 1991 309.33 1892 279.3 1942 287.1 1992 309.89 1893 279.4 1943 287.3 1993 310.15 1894 279.4 1944 287.5 1994 310.78 1895 279.5 1945 287.8 1995 311.06 1896 279.5 1946 288.0 1996 311.89 1897 279.6 1947 288.3 1997 312.73 1898 279.7 1948 288.5 1998 313.54 1899 279.7 1949 288.8 1999 314.56 ---------------------------------------------------------------------------------