Global Mean CH4 Mixing Ratios (ppb) ---------------------------------------------------------------------------------- ---------------- Observations Altern. Scenario ---------------------------------------------------------------------------------- ---------------- Data Source Year MixR Year MixR. Year MixR. Year MixR. Year MixR. ---------------------------------------------------------------------------------- ---------------- Ethe- 1850 791. 1900 879. 1950 1147. 2000 1751.64 2000 1751.6 ridge 1851 792. 1901 883. 1951 1155. 2001 1749.84 2001 1756.6 et al. 1852 794. 1902 887. 1952 1163. 2002 1751.51 2002 1761.2 Table 2 1853 795. 1903 891. 1953 1173. 2003 1755.89 2003 1765.4 1854 797. 1904 896. 1954 1182. 2004 1755.75 2004 1769.3 1855 798. 1905 900. 1955 1192. 2005 1752.87 2005 1772.7 1856 799. 1906 905. 1956 1202. 2006 1753.45 2006 1775.8 1857 801. 1907 909. 1957 1213. 2007 1760.40 2007 1778.5 1858 802. 1908 914. 1958 1224. fl,ml+sp2008 1766.16 2008 1780.8 1859 804. 1909 919. 1959 1235. fl,ml+sp2009 1772.41 2009 1782.7 1860 805. 1910 924. 1960 1247. is,mlo 2010 1777.70 2010 1784.3 1861 807. 1911 928. 1961 1259. 2011 1785.4 1862 808. 1912 933. 1962 1272. 2012 1786.2 1863 810. 1913 938. 1963 1285. 2013 1786.6 1864 811. 1914 944. 1964 1298. 2014 1786.6 1865 813. 1915 949. 1965 1312. 2015 1786.2 1866 815. 1916 955. 1966 1326. 2016 1785.4 1867 816. 1917 960. 1967 1340. 2017 1784.2 1868 818. 1918 966. 1968 1355. 2018 1782.7 1869 819. 1919 972. 1969 1370. 2019 1780.8 1870 821. 1920 978. 1970 1386. 2020 1778.4 1871 823. 1921 983. 1971 1401. 2021 1775.7 1872 824. 1922 989. 1972 1417. 2022 1772.7 1873 826. 1923 995. 1973 1433. 2023 1769.2 1874 827. 1924 1001. 1974 1449. 2024 1765.3 1875 829. 1925 1007. 1975 1465. 2025 1761.1 1876 831. 1926 1013. 1976 1481. 2026 1756.5 1877 832. 1927 1019. 1977 1497. 2027 1751.5 1878 834. 1928 1025. 1978 1514. 2028 1746.1 1879 835. 1929 1031. 1979 1530. 2029 1740.3 1880 837. 1930 1036. 1980 1547. 2030 1734.1 1881 839. 1931 1042. 1981 1567. 2031 1727.6 1882 841. 1932 1047. 1982 1586. 2032 1720.6 1883 843. 1933 1053. 1983 1606. 2033 1713.3 1884 845. 1934 1058. Dlugo- 1984 1625.38 2034 1705.6 1885 846. 1935 1063. kencky 1985 1638.06 2035 1697.5 1886 848. 1936 1068. Global 1986 1650.47 2036 1689.0 1887 850. 1937 1073. Means 1987 1662.74 2037 1680.2 1888 852. 1938 1078. 1988 1672.85 2038 1670.9 1889 854. 1939 1083. 1989 1683.84 2039 1661.3 1890 856. 1940 1088. 1990 1693.35 2040 1651.3 1891 858. 1941 1094. 1991 1703.98 2041 1640.9 1892 861. 1942 1099. 1992 1713.96 2042 1630.1 1893 863. 1943 1104. 1993 1715.30 2043 1618.9 1894 865. 1944 1109. 1994 1720.60 2044 1607.4 1895 867. 1945 1115. 1995 1727.55 2045 1595.4 1896 870. 1946 1120. 1996 1729.70 2046 1583.1 1897 872. 1947 1127. 1997 1733.09 2047 1570.4 1898 874. 1948 1133. 1998 1743.39 2048 1557.3 1899 877. 1949 1140. 1999 1750.97 2049 1543.8 ---------------------------------------------------------------------------------- 2050 1530.0 ----------------