********************************************************************* *** 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 1978 332.11 332.44 333.03 333.11 333.30 334.12 334.77 335.06 335.11 334.93 334.79 334.73 333.96 1979 334.47 334.08 333.90 333.96 334.23 334.50 334.88 335.72 336.63 337.07 336.74 336.04 335.19 1980 -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 1981 336.97 336.88 336.99 337.33 337.71 338.01 338.39 338.83 339.10 339.10 338.97 338.63 338.08 1982 338.29 338.20 338.31 338.63 339.01 339.34 339.64 340.06 340.44 340.51 340.42 340.13 339.42 1983 339.71 339.42 339.41 340.01 340.60 340.89 341.41 342.01 342.16 342.16 342.16 342.13 341.01 1984 341.88 341.49 341.55 341.82 341.95 342.14 342.60 343.41 343.97 343.85 343.79 343.62 342.67 1985 343.03 342.79 342.79 342.86 343.12 343.53 344.12 344.83 345.05 345.10 345.15 344.85 343.94 1986 344.53 344.26 344.26 344.51 344.59 344.67 -99.99 -99.99 -99.99 -99.99 -99.99 -99.99 -99.99 1987 345.02 345.37 345.72 346.08 346.76 347.10 347.23 347.72 348.04 348.05 347.90 347.79 346.90 1988 347.90 348.29 349.15 349.49 349.45 349.58 349.70 350.15 350.81 350.76 350.46 350.08 349.65 1989 349.64 349.66 350.00 350.11 350.18 350.94 352.02 352.31 352.09 351.97 351.80 351.43 351.01 1990 350.65 350.21 350.72 351.19 351.52 351.92 352.41 353.11 353.32 353.11 352.96 352.70 351.99 1991 352.32 352.24 352.35 352.58 352.89 353.24 353.62 353.97 354.20 354.24 354.16 353.81 353.30 1992 353.23 353.04 353.19 353.49 353.89 354.27 354.77 355.10 355.36 355.52 355.19 354.81 354.32 1993 354.37 354.04 354.19 354.62 354.84 354.88 355.31 355.97 356.27 356.31 356.26 355.92 355.25 1994 355.41 355.39 355.62 355.85 356.02 355.93 356.17 356.96 357.34 357.43 357.36 356.88 356.36 1995 356.57 356.67 356.93 357.52 358.03 358.10 358.26 358.78 359.30 359.50 359.39 358.77 358.15 1996 358.29 358.45 358.72 358.95 359.30 359.55 359.92 360.48 360.77 360.85 360.64 360.15 359.67 1997 359.91 359.78 359.83 360.48 360.85 361.00 361.49 361.87 362.00 362.09 362.01 361.97 361.11 1998 361.92 361.84 362.11 362.63 363.21 363.89 364.40 364.78 365.12 365.16 365.02 364.84 363.74 1999 364.68 364.67 364.77 365.05 365.46 365.71 365.97 366.30 366.60 366.86 366.79 366.45 365.78 2000 366.02 365.99 366.20 366.34 366.57 366.79 367.13 367.58 367.71 367.72 367.68 367.44 366.93 2001 367.16 367.10 367.25 367.73 368.20 368.35 368.76 369.40 369.76 370.01 370.02 369.67 368.62 2002 369.33 369.20 369.38 369.80 370.16 370.59 371.18 371.63 371.96 372.11 371.97 371.69 370.75 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.