Monthly CO2 Mixing Ratios

Monthly atmospheric CO₂ mixing ratios from Key Biscayne, Florida, U.S.

Background atmospheric CO₂ mixing ratios from individual flask air samples for Key Biscayne, Florida, U.S. Only measurements satisfying the data selection criteria fro background measurements are plotted. Consecutive background measurements are joined by lines. Background measurements interrupted by non-background measurements are not joined by lines.

Monthly atmospheric CO₂ mixing ratios for Key Biscayne, Florida, U.S., expressed in parts per million (ppm) and reported in the Scripps Institution of Oceanography X93 manometric mole fraction scale. Annual values were calculated by CDIAC for years with complete records. Missing values are denoted by -99.99.

Year Jan Feb Mar April May June July Aug Sept Oct Nov Dec Ann

1972 -99.99 -99.99 -99.99 -99.99 -99.99 -99.99 -99.99 -99.99 -99.99 -99.99 -99.99 330.45 -99.99 1973 330.77 331.50 332.65 334.04 334.28 332.69 330.65 328.09 326.94 327.84 329.24 330.65 330.78 1974 332.17 333.15 333.84 -99.99 -99.99 -99.99 -99.99 -99.99 -99.99 -99.99 -99.99 -99.99 -99.99 1975 -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 1976 -99.99 -99.99 -99.99 335.33 335.45 334.22 332.19 330.55 329.44 329.76 331.38 333.40 -99.99 1977 335.02 335.84 336.40 336.83 336.77 336.12 334.81 333.22 332.05 333.08 335.01 336.56 335.14 1978 337.83 338.63 339.31 339.84 339.73 337.99 335.21 332.66 332.15 333.77 335.86 337.61 336.72 1979 339.02 340.03 341.14 342.02 341.35 339.56 337.69 335.58 334.59 335.73 337.66 339.30 338.64 1980 341.03 342.16 342.87 343.40 342.66 341.17 339.81 337.81 336.30 337.23 339.49 341.00 340.41 1981 342.21 343.28 344.13 344.88 345.32 344.69 343.16 340.36 337.76 338.29 341.05 342.10 342.27 1982 342.62 343.65 344.47 345.19 344.58 343.16 340.94 337.31 336.13 338.16 340.15 341.77 341.51 1983 343.58 344.65 345.14 345.86 346.70 346.33 343.87 340.89 339.69 340.31 341.51 343.58 343.51 1984 345.82 346.24 346.89 348.03 348.05 347.02 344.84 342.51 341.14 342.15 344.48 346.07 345.27 1985 346.69 347.64 349.01 349.75 349.25 348.30 346.61 343.40 341.95 343.82 346.28 347.93 346.72 1986 348.94 349.54 350.15 350.83 350.65 349.47 348.00 345.23 343.32 344.46 347.04 348.95 348.05 1987 349.61 351.24 352.66 352.63 352.19 351.52 350.25 348.49 347.14 347.81 350.00 351.49 350.42 1988 352.39 352.88 354.10 355.37 354.98 353.91 352.31 350.08 349.26 350.45 352.43 353.67 352.65 1989 353.83 354.10 355.23 356.23 356.67 355.90 353.98 352.39 351.90 352.46 354.24 355.52 354.37 1990 355.78 356.51 357.51 358.77 359.16 357.59 355.02 352.07 351.66 354.84 356.32 355.88 355.93 1991 356.13 357.76 359.50 359.53 359.05 358.21 355.99 353.59 352.14 352.72 355.04 357.91 356.46 1992 359.06 358.71 359.22 360.98 360.66 357.79 355.54 353.68 353.71 355.64 356.56 356.90 357.37 1993 357.86 359.36 361.99 362.61 359.67 358.81 360.68 358.21 353.25 353.60 356.33 357.93 358.36