********************************************************************* *** Atmospheric Carbon Dioxide Mixing Ratios from the *** *** NOAA CMDL Carbon Cycle Cooperative Global Air Sampling *** *** Network, 1968-2002 *** *** *** *** March 2005 *** *** *** *** Source: Thomas J. Conway *** *** Pieter P. Tans *** *** NOAA Climate Monitoring and Diagnostics Laboratory *** *** 325 Broadway *** *** Boulder, Colorado, U.S.A. *** ********************************************************************* Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Ann 1969 -99.99 -99.99 -99.99 -99.99 -99.99 -99.99 -99.99 322.90 321.36 320.71 322.01 323.78 -99.99 1970 325.13 325.54 325.69 326.58 327.67 327.30 326.12 324.90 322.96 322.54 323.88 325.38 325.31 1971 -99.99 -99.99 -99.99 -99.99 -99.99 -99.99 -99.99 -99.99 -99.99 -99.99 -99.99 -99.99 -99.99 1972 -99.99 -99.99 -99.99 -99.99 -99.99 -99.99 -99.99 -99.99 -99.99 -99.99 -99.99 -99.99 -99.99 1973 -99.99 -99.99 -99.99 -99.99 -99.99 -99.99 -99.99 -99.99 -99.99 -99.99 -99.99 -99.99 -99.99 1974 -99.99 -99.99 -99.99 -99.99 -99.99 -99.99 -99.99 -99.99 -99.99 -99.99 -99.99 -99.99 -99.99 1975 -99.99 -99.99 -99.99 -99.99 -99.99 -99.99 -99.99 -99.99 -99.99 -99.99 -99.99 -99.99 -99.99 1976 -99.99 -99.99 -99.99 -99.99 -99.99 -99.99 332.39 330.95 329.71 329.33 330.57 332.05 -99.99 1977 332.79 333.14 334.00 335.69 336.48 336.02 334.69 332.38 330.73 330.59 331.63 333.65 333.48 1978 335.24 335.82 336.79 337.80 338.02 337.59 336.02 333.97 332.27 332.25 333.19 334.58 335.30 1979 336.08 337.01 338.44 338.99 338.90 338.96 337.63 335.42 333.91 334.34 335.61 336.94 336.85 1980 338.78 340.07 341.37 342.73 342.87 341.59 339.22 337.10 336.60 336.57 337.55 339.17 339.47 1981 340.39 341.85 342.92 343.50 343.40 342.00 340.27 338.56 337.22 337.38 338.86 340.04 340.53 1982 340.92 341.92 342.85 343.57 343.54 342.69 341.25 338.77 337.07 337.43 338.98 340.44 340.79 1983 341.74 342.18 342.85 344.85 345.84 345.09 343.29 340.94 339.59 339.73 340.85 342.48 342.45 1984 343.84 344.41 345.37 346.78 347.24 346.61 344.91 342.66 341.18 341.55 342.74 343.77 344.26 1985 344.44 345.37 346.73 347.77 348.44 347.97 345.99 343.92 342.66 342.70 343.77 345.17 345.41 1986 345.96 346.40 347.59 349.17 349.79 348.85 346.84 345.07 343.76 343.61 345.24 346.72 346.58 1987 347.28 348.00 349.14 350.61 351.57 351.06 349.40 347.28 346.23 346.53 347.95 349.25 348.69 1988 350.10 351.31 352.34 353.40 354.09 353.59 352.24 350.06 348.61 348.94 349.97 351.29 351.33 1989 352.53 352.98 353.79 355.22 355.92 355.30 353.64 351.03 349.38 349.82 351.45 352.63 352.81 1990 353.77 354.89 355.70 356.58 357.03 356.26 354.25 352.17 351.09 351.31 352.83 354.55 354.20 1991 355.09 355.87 357.33 358.59 359.24 358.27 355.86 353.81 352.31 352.46 353.80 355.40 355.67 1992 356.57 357.13 358.07 359.10 359.79 359.20 356.84 354.95 353.60 353.40 354.44 355.81 356.58 1993 356.65 357.23 358.08 359.38 360.33 359.60 357.67 355.22 353.62 354.04 355.39 356.88 357.01 1994 358.08 358.70 359.52 360.83 361.52 360.55 358.80 356.81 355.18 355.34 357.24 359.33 358.49 1995 360.04 360.62 361.80 362.74 363.46 363.14 361.22 359.02 357.89 358.01 359.40 360.79 360.68 1996 361.86 362.96 363.96 364.57 365.12 364.93 363.33 360.97 359.14 359.23 360.80 361.91 362.40 1997 362.92 363.70 364.71 366.35 366.45 365.30 363.90 361.98 360.35 360.57 362.38 364.02 363.55 1998 365.11 365.89 366.98 368.49 369.23 368.82 367.56 365.61 364.13 364.15 365.62 367.49 366.59 1999 368.26 368.52 369.67 370.79 370.79 370.34 369.05 366.86 365.06 365.38 366.78 368.32 368.32 2000 369.56 370.08 370.82 371.75 371.87 371.38 369.94 367.98 366.81 367.09 368.34 369.59 369.60 2001 370.57 371.54 372.69 373.64 374.09 373.22 371.21 369.32 368.13 368.30 369.95 371.44 371.18 2002 372.17 372.95 373.94 374.79 375.50 375.49 374.03 371.36 369.69 370.49 372.44 373.67 373.04 Monthly measurements are reported in parts per million (ppm) and are directly traceable to the WMO CO2 mole fraction scale. Annual values are the arithmetic means of the 12 monthly values.