********************************************************************* *** 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 1979 -99.99 -99.99 339.32 339.83 340.05 339.73 338.46 336.95 335.40 334.57 335.88 338.00 -99.99 1980 339.20 340.13 340.83 341.61 342.58 342.43 341.24 339.83 337.99 337.13 338.35 339.25 340.05 1981 340.36 342.47 343.47 343.53 343.58 343.24 341.82 339.65 338.09 338.64 339.92 340.31 341.26 1982 341.46 342.97 343.22 343.43 343.92 343.08 341.30 338.34 336.55 337.58 338.94 340.28 340.92 1983 341.35 342.42 343.49 344.66 345.87 345.76 344.40 342.08 339.87 340.04 341.25 342.19 342.78 1984 343.43 344.43 345.08 346.33 347.18 346.85 345.86 344.33 342.31 341.98 343.00 343.92 344.56 1985 344.59 345.64 347.27 347.95 347.96 347.69 346.88 345.75 343.84 343.75 345.12 346.30 346.06 1986 347.62 348.11 348.55 349.84 350.64 349.89 347.77 345.65 344.58 344.81 346.18 347.23 347.57 1987 348.43 349.58 350.35 351.48 352.57 352.36 350.83 348.43 347.21 347.21 348.13 349.58 349.68 1988 350.81 352.12 353.07 353.77 354.47 354.08 352.95 352.17 351.03 349.76 349.99 351.10 352.11 1989 352.89 354.64 355.24 355.98 356.75 356.23 354.55 351.35 349.44 350.59 352.16 352.99 353.57 1990 354.33 355.58 356.32 356.75 357.25 357.24 354.28 350.38 350.28 351.81 352.97 354.48 354.31 1991 356.31 357.31 357.62 358.24 358.92 358.70 357.08 355.09 353.31 352.90 353.67 354.97 356.18 1992 356.01 357.22 358.30 358.86 359.80 359.23 357.11 354.93 352.89 352.77 354.26 355.99 356.45 1993 357.25 357.86 358.23 359.10 359.75 358.98 356.96 353.38 352.37 354.07 355.60 356.97 356.71 1994 358.24 359.37 360.15 360.63 360.93 360.52 359.32 357.67 355.40 355.10 356.74 357.77 358.49 1995 359.91 361.88 362.29 362.73 363.04 362.82 361.87 359.22 357.22 357.54 359.14 360.43 360.67 1996 361.77 363.06 363.92 364.37 364.90 364.65 363.00 361.77 360.49 359.37 360.40 361.98 362.47 1997 363.05 364.05 364.95 365.95 366.57 365.84 363.89 361.77 360.74 361.07 362.27 364.01 363.68 1998 365.54 366.42 367.20 368.58 369.27 368.55 367.37 366.10 364.36 364.28 365.48 366.60 366.65 1999 367.67 368.18 369.06 370.26 370.47 369.58 368.13 366.68 365.51 365.34 366.51 367.93 367.94 2000 368.60 368.98 369.88 371.09 371.61 371.10 369.86 368.36 367.68 367.34 367.86 369.20 369.30 2001 370.09 371.31 372.60 373.58 373.72 372.18 370.47 369.91 368.93 368.15 369.63 371.38 371.00 2002 372.58 373.41 374.45 375.38 375.71 375.01 373.08 372.16 370.91 370.33 372.33 373.71 373.26 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.