********************************************************************* *** 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 1980 340.45 341.32 341.19 339.59 338.27 338.32 338.46 338.45 338.59 338.86 339.16 339.77 339.37 1981 341.00 342.05 342.23 340.84 339.10 338.98 338.90 338.46 338.71 339.40 339.94 340.43 340.00 1982 341.16 342.26 342.41 340.82 339.77 339.73 339.35 339.52 339.67 339.47 339.94 340.40 340.38 1983 340.35 341.61 343.36 342.16 340.21 339.60 339.25 339.73 340.02 -99.99 -99.99 -99.99 -99.99 1984 -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 1985 -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 1986 345.32 346.55 346.84 345.62 345.45 346.37 346.35 346.24 346.64 347.14 346.95 346.98 346.37 1987 347.94 348.67 349.36 349.59 348.89 348.40 348.51 349.21 348.36 347.07 348.79 350.27 348.76 1988 350.51 351.21 351.24 349.87 348.96 349.60 350.58 350.86 351.29 350.66 349.07 349.40 350.27 1989 352.05 353.98 353.44 352.02 350.85 351.09 352.04 352.12 352.16 352.14 352.33 353.40 352.30 1990 354.60 355.34 355.19 353.60 352.32 352.76 353.31 352.73 352.23 352.49 352.76 353.22 353.38 1991 354.05 354.59 354.32 353.02 352.85 353.55 353.65 353.67 353.77 354.45 355.16 355.02 354.01 1992 354.91 355.69 356.50 356.09 354.25 352.96 353.92 354.84 354.61 355.00 355.17 355.15 354.92 1993 355.92 356.85 357.77 356.98 354.85 354.27 355.00 355.81 356.33 356.21 356.33 357.14 356.12 1994 357.81 358.26 357.71 355.93 354.67 355.73 356.40 355.54 355.52 356.19 356.77 357.16 356.47 1995 358.30 359.27 359.29 358.56 357.12 356.72 357.38 357.82 357.62 357.78 358.72 358.72 358.11 1996 358.98 360.52 360.30 358.77 358.32 358.48 359.49 360.89 361.08 361.27 362.13 362.32 360.21 1997 362.50 363.70 363.91 362.04 361.32 362.10 362.15 362.03 362.48 363.50 364.32 364.64 362.89 1998 364.88 365.54 366.29 365.63 364.73 364.74 365.29 365.92 365.79 365.35 365.72 366.17 365.50 1999 366.31 367.56 368.28 366.40 365.47 366.20 366.63 366.81 366.98 366.90 366.68 367.32 366.80 2000 368.46 369.95 369.73 367.78 367.03 367.45 367.56 367.29 367.41 368.12 369.02 369.89 368.31 2001 370.92 370.81 369.60 368.64 368.63 369.20 369.81 370.09 370.15 370.36 370.07 370.08 369.86 2002 371.95 373.46 372.86 371.36 370.85 371.68 372.27 372.39 372.50 372.87 373.26 373.71 372.43 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.