Monthly CO2 Mixing Ratios

Monthly atmospheric CO₂ mixing ratios from Point Barrow, Alaska, U.S.

Background atmospheric CO₂ mixing ratios from individual flask air samples for Point Barrow, Alaska, 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 Point Barrow, Alaska, 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

1971 -99.99 -99.99 -99.99 -99.99 332.20 330.23 323.67 317.70 318.77 322.86 327.31 331.07 -99.99 1972 333.39 334.19 334.12 334.51 335.45 333.28 325.66 319.10 322.05 327.26 330.66 333.46 330.26 1973 334.71 335.40 336.48 336.98 336.55 334.01 327.53 322.22 323.65 328.60 332.08 334.70 331.91 1974 337.01 337.78 337.80 337.59 338.73 338.17 330.53 323.08 323.73 328.95 333.26 335.69 333.53 1975 336.62 336.46 336.39 336.60 336.25 334.57 329.69 324.46 324.97 329.56 333.50 336.28 332.95 1976 337.48 337.89 338.55 338.85 338.10 335.65 329.98 324.76 325.10 329.61 333.11 336.03 333.76 1977 337.67 337.71 338.31 339.41 339.69 337.62 331.50 326.29 327.28 331.01 334.62 337.44 334.88 1978 339.84 341.03 340.96 341.05 340.87 338.93 333.36 327.39 327.70 332.42 337.07 338.97 336.63 1979 340.08 341.29 342.07 342.33 343.20 341.32 333.81 327.38 328.90 334.37 337.66 338.64 337.59 1980 340.93 342.71 343.29 344.32 345.15 342.89 337.27 332.20 332.53 336.96 340.60 342.97 340.15 1981 344.75 345.38 345.44 345.99 346.45 343.86 336.46 330.85 332.60 338.25 342.13 344.40 341.38 1982 345.94 347.19 347.81 347.55 347.64 345.69 339.54 333.30 333.20 338.38 342.34 344.87 342.79 1983 346.58 347.13 347.59 347.88 348.25 346.51 339.86 333.79 333.95 340.42 345.24 347.01 343.68 1984 349.01 350.36 349.94 349.66 350.31 348.36 341.33 335.90 337.47 341.42 344.85 348.12 345.56 1985 349.44 349.34 350.33 351.77 352.13 349.53 343.45 337.24 338.36 343.53 347.32 348.87 346.78 1986 350.74 352.92 353.38 353.07 353.04 350.33 343.97 338.79 341.89 347.49 350.36 352.04 349.00 1987 353.10 353.69 354.10 354.36 354.97 352.87 345.97 340.19 340.91 345.67 349.82 352.65 349.86 1988 355.63 357.05 357.28 357.85 357.64 354.96 348.05 343.12 345.04 350.47 354.96 358.06 353.34 1989 358.93 358.55 359.56 359.93 359.33 358.33 350.80 342.70 345.07 351.57 355.91 359.27 355.00 1990 360.57 361.02 361.61 361.57 361.37 356.70 348.45 344.53 346.86 352.72 356.50 359.73 355.97 1991 361.69 361.63 362.05 362.09 361.80 360.00 353.52 346.78 348.37 354.60 358.48 360.46 357.62 1992 361.77 361.96 362.28 362.70 362.45 360.14 353.92 347.26 348.22 352.68 356.75 360.68 357.57 1993 362.43 362.63 363.27 363.61 363.37 359.55 352.26 347.86 349.77 354.52 358.81 360.99 358.26