% Data source is Meinshausen et al., GMD, doi:10.5194/gmd-10-2057-2017, 2017
%      
% Year  xCO2
%       (ppm)
1849.5  284.3200000
1850.5  284.3169999
1851.5  284.4509998
1852.5  284.5979998
1853.5  284.7309998
1854.5  284.8459998
1855.5  284.9409998
1856.5  285.0489998
1857.5  285.2039998
1858.5  285.3689998
1859.5  285.5449998
1860.5  285.7389997
1861.5  285.9329997
1862.5  286.0999997
1863.5  286.2709997
1864.5  286.4419997
1865.5  286.6139996
1866.5  286.7809996
1867.5  286.9549996
1868.5  287.1049996
1869.5  287.2249996
1870.5  287.3549996
1871.5  287.4939995
1872.5  287.6639995
1873.5  287.8599995
1874.5  288.0609995
1875.5  288.2909994
1876.5  288.5199994
1877.5  288.7519994
1878.5  288.9929994
1879.5  289.2209994
1880.5  289.4699993
1881.5  289.7369993
1882.5  290.0189993
1883.5  290.2629992
1884.5  290.5119992
1885.5  290.7969992
1886.5  291.0999992
1887.5  291.4139991
1888.5  291.7629991
1889.5  292.1129991
1890.5  292.4579990
1891.5  292.8159990
1892.5  293.1669989
1893.5  293.4769989
1894.5  293.7909989
1895.5  294.0789989
1896.5  294.3649988
1897.5  294.6459988
1898.5  294.9539987
1899.5  295.2999986
1900.5  295.6749984
1901.5  296.0069980
1902.5  296.3249974
1903.5  296.6539968
1904.5  296.9539963
1905.5  297.2889957
1906.5  297.6619951
1907.5  298.0979945
1908.5  298.5179940
1909.5  298.9359935
1910.5  299.3769929
1911.5  299.8289923
1912.5  300.3529917
1913.5  300.9099911
1914.5  301.4189908
1915.5  301.9369903
1916.5  302.4849897
1917.5  303.0109891
1918.5  303.4489886
1919.5  303.8139883
1920.5  304.2459877
1921.5  304.5999873
1922.5  304.9449868
1923.5  305.2709861
1924.5  305.6299855
1925.5  305.8129850
1926.5  305.9539845
1927.5  306.1769839
1928.5  306.3289833
1929.5  306.4949827
1930.5  306.6199824
1931.5  306.8219821
1932.5  307.0929818
1933.5  307.4019813
1934.5  307.7849806
1935.5  308.2269800
1936.5  309.0119793
1937.5  309.7639786
1938.5  310.2939782
1939.5  310.8509776
1940.5  311.3569769
1941.5  311.8109763
1942.5  312.1719757
1943.5  312.3899752
1944.5  312.4129748
1945.5  312.3849746
1946.5  312.3899740
1947.5  312.4859732
1948.5  312.5209725
1949.5  312.6319721
1950.5  312.8209713
1951.5  313.0139706
1952.5  313.3419700
1953.5  313.7299694
1954.5  314.0949688
1955.5  314.4149680
1956.5  314.6979672
1957.5  314.9919665
1958.5  315.3449659
1959.5  315.8069651
1960.5  316.6249644
1961.5  317.2989638
1962.5  318.0439631
1963.5  318.6499622
1964.5  319.3329614
1965.5  319.8159605
1966.5  320.8799597
1967.5  321.4799589
1968.5  322.3889580
1969.5  323.2509570
1970.5  324.7829559
1971.5  325.3999550
1972.5  327.3489541
1973.5  329.9089531
1974.5  330.7559525
1975.5  330.8269520
1976.5  331.5449510
1977.5  333.3529501
1978.5  335.0099494
1979.5  336.6049484
1980.5  338.7049479
1981.5  340.0589478
1982.5  340.6439474
1983.5  342.2659473
1984.5  344.0079495
1985.5  345.4589538
1986.5  346.9029481
1987.5  348.7749474
1988.5  351.2759329
1989.5  352.8939214
1990.5  354.0729301
1991.5  355.3529349
1992.5  356.2289489
1993.5  356.9249589
1994.5  358.2539622
1995.5  360.2389564
1996.5  362.0049615
1997.5  363.2519618
1998.5  365.9329580
1999.5  367.8449748
2000.5  369.1249800
2001.5  370.6729901
2002.5  372.8349943
2003.5  375.4109950
2004.5  376.9870025
2005.5  378.9070050
2006.5  381.0100070
2007.5  382.6030247
2008.5  384.7390186
2009.5  386.2800190
2010.5  388.7170293