********************************************************************* *** 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 1976 -99.99 -99.99 334.05 335.74 336.37 334.64 331.41 328.89 328.55 330.06 331.87 332.56 -99.99 1977 333.70 334.42 334.90 336.82 337.85 336.48 334.76 332.79 330.84 331.00 332.88 334.37 334.23 1978 335.60 336.66 337.59 338.34 339.38 338.99 335.91 332.70 331.34 332.56 334.42 335.56 335.75 1979 337.05 338.57 339.31 339.88 341.14 340.10 336.60 334.28 333.23 334.35 336.84 337.27 337.39 1980 -99.99 -99.99 -99.99 -99.99 -99.99 -99.99 339.95 337.03 335.48 336.47 338.08 339.25 -99.99 1981 340.99 341.80 342.22 343.37 343.86 342.51 339.62 337.26 336.58 337.71 339.10 340.12 340.43 1982 341.54 342.75 343.48 344.22 344.61 343.20 340.53 338.20 336.60 337.46 339.48 340.94 341.08 1983 341.94 343.38 344.69 345.57 346.03 345.05 342.70 339.18 338.16 339.93 341.56 342.85 342.59 1984 344.10 345.19 346.18 347.50 347.92 346.66 343.76 340.51 340.18 341.43 342.89 344.58 344.24 1985 345.73 346.45 347.28 348.36 349.60 348.59 345.78 342.60 341.16 342.66 344.69 346.16 345.76 1986 347.18 347.62 348.41 349.39 350.00 349.23 346.66 344.43 343.26 343.75 345.88 347.48 346.94 1987 348.93 349.40 349.89 351.25 352.33 351.31 348.18 345.88 344.92 345.81 347.94 349.51 348.78 1988 350.77 351.85 352.72 354.04 354.85 353.76 351.46 348.38 347.49 349.34 350.54 351.88 351.42 1989 352.84 353.11 354.41 356.28 356.46 355.06 352.44 349.98 349.25 350.15 352.00 353.79 352.98 1990 354.71 355.76 356.47 357.18 357.44 355.72 353.55 351.73 350.36 351.11 353.27 354.94 354.35 1991 355.81 356.69 357.82 359.34 359.82 357.97 355.60 352.70 351.54 352.81 354.42 355.85 355.86 1992 357.56 358.41 358.76 359.49 359.93 358.20 355.79 353.46 351.89 352.95 354.99 356.36 356.48 1993 357.76 358.94 359.15 359.95 360.98 359.74 356.99 353.39 352.13 353.74 355.80 357.95 357.21 1994 359.78 361.22 361.60 361.31 361.67 360.57 358.14 355.83 354.53 355.77 358.17 359.90 359.04 1995 361.02 361.96 363.07 364.16 364.00 362.51 360.02 357.32 356.75 358.69 359.99 360.95 360.87 1996 362.37 363.61 364.37 364.72 365.51 365.14 362.47 360.03 358.44 358.87 361.08 364.03 362.55 1997 364.72 364.45 365.16 366.62 367.51 366.06 363.55 360.73 359.00 360.10 363.48 366.30 363.97 1998 366.87 367.96 369.46 369.56 369.20 367.86 366.52 364.09 362.01 364.00 366.49 367.88 366.83 1999 369.48 369.98 370.73 371.74 371.95 370.21 367.11 364.08 363.33 365.22 367.36 368.69 368.32 2000 369.68 370.61 372.02 373.01 373.33 372.53 369.16 366.26 366.00 367.13 368.67 369.99 369.87 2001 371.72 372.44 372.46 373.99 374.89 373.50 370.76 368.44 367.46 368.52 370.79 372.18 371.43 2002 373.36 374.51 375.50 376.45 376.11 374.47 372.59 370.08 369.10 371.10 373.04 375.23 373.46 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.