********************************************************************* *** 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 -99.99 -99.99 -99.99 344.00 343.92 343.07 338.60 333.50 333.56 336.99 340.03 342.67 -99.99 1981 344.11 344.86 345.47 345.84 346.69 346.11 339.42 332.57 333.91 338.37 341.34 344.05 341.90 1982 346.09 346.92 347.07 347.23 347.55 345.77 339.91 334.25 333.40 337.22 340.81 344.21 342.54 1983 346.54 347.02 347.51 347.80 347.86 346.44 340.51 334.45 334.97 339.60 344.36 347.47 343.71 1984 349.35 350.14 349.81 349.74 350.16 348.02 342.32 336.75 337.13 341.32 344.97 347.91 345.64 1985 349.26 349.40 350.44 351.44 351.92 349.73 343.96 338.31 338.54 343.07 347.04 349.36 346.87 1986 351.40 352.62 353.04 353.14 353.36 352.09 346.52 340.33 339.83 344.34 348.57 351.45 348.89 1987 353.19 353.07 353.84 354.57 354.58 353.10 347.57 341.37 340.77 345.62 349.92 352.88 350.04 1988 355.61 356.19 356.78 357.54 357.26 355.14 348.88 343.67 345.09 350.24 354.87 359.77 353.42 1989 360.97 359.92 359.55 359.53 359.30 357.64 351.80 345.74 346.09 351.35 355.52 358.91 355.53 1990 359.93 360.59 361.87 361.22 360.55 358.07 351.65 346.57 347.59 351.88 355.36 359.03 356.19 1991 362.54 362.54 361.85 362.26 361.80 359.75 354.13 347.72 348.34 353.22 357.81 360.90 357.74 1992 362.09 361.91 362.05 362.35 362.69 360.56 353.22 347.11 347.77 352.37 357.05 361.07 357.52 1993 362.74 362.13 362.83 363.26 362.98 361.09 353.75 347.63 348.40 353.04 357.69 359.71 357.94 1994 361.54 363.85 364.73 364.30 364.08 362.68 356.66 350.36 350.42 355.49 360.45 363.12 359.81 1995 364.56 366.01 366.81 366.41 365.39 363.69 358.17 352.53 353.52 358.13 362.88 366.50 362.05 1996 366.88 366.52 366.95 367.72 368.47 367.17 361.58 355.29 354.52 359.12 364.00 366.22 363.70 1997 367.65 368.65 368.78 368.84 369.06 -99.99 -99.99 -99.99 -99.99 -99.99 -99.99 -99.99 -99.99 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.