MLO monthly measured CO2 annual year mean 1Qavg 1Qto1Qincrease 2yrAvgIncrease 3yrAvgIncrease Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 1958 315.70 317.45 317.51 317.24 315.86 314.93 313.20 312.43 313.33 314.67 1959 315.98 316.237 315.58 316.48 316.65 317.72 318.29 318.15 316.54 314.80 313.84 313.33 314.81 315.58 1960 316.91 316.997 0.760 316.43 316.98 317.58 319.03 320.04 319.59 318.18 315.90 314.17 313.83 315.00 316.19 1961 317.64 317.710 0.713 0.737 316.89 317.70 318.54 319.48 320.58 319.77 318.57 316.79 314.99 315.31 316.10 317.01 1962 318.45 318.723 1.013 0.863 0.829 317.94 318.55 319.68 320.57 321.02 320.62 319.61 317.40 316.25 315.42 316.69 317.70 1963 318.99 319.223 0.500 0.757 0.742 318.74 319.07 319.86 321.38 322.25 321.48 319.74 317.77 316.21 315.99 317.07 318.35 1964 319.62 320.107 0.883 0.692 0.799 319.57 320.01 320.74 321.84 322.26 321.89 320.44 318.69 316.70 316.87 317.68 318.71 1965 320.04 320.257 0.150 0.517 0.511 319.44 320.44 320.89 322.14 322.17 321.87 321.21 318.87 317.81 317.30 318.87 319.42 1966 321.37 321.537 1.280 0.715 0.771 320.62 321.60 322.39 323.70 324.08 323.75 322.38 320.36 318.64 318.10 319.78 321.03 1967 322.18 322.623 1.087 1.183 0.839 322.33 322.50 323.04 324.42 325.00 324.09 322.54 320.92 319.25 319.39 320.73 321.96 1968 323.05 323.203 0.580 0.833 0.982 322.57 323.15 323.89 325.02 325.57 325.36 324.14 322.11 320.33 320.25 321.32 322.89 1969 324.62 324.683 1.480 1.030 1.049 324.00 324.42 325.63 326.66 327.38 326.71 325.88 323.66 322.38 321.78 322.86 324.12 1970 325.68 325.990 1.307 1.393 1.122 325.06 325.98 326.93 328.13 328.08 327.67 326.34 324.69 323.10 323.06 324.01 325.13 1971 326.32 326.673 0.683 0.995 1.157 326.17 326.68 327.17 327.79 328.93 328.57 327.36 325.43 323.36 323.56 324.80 326.01 1972 327.46 327.383 0.710 0.697 0.900 326.77 327.63 327.75 329.72 330.07 329.09 328.04 326.32 324.84 325.20 326.50 327.55 1973 329.68 329.470 2.087 1.398 1.160 328.55 329.56 330.30 331.50 332.48 332.07 330.87 329.31 327.51 327.18 328.16 328.64 1974 330.19 330.513 1.043 1.565 1.280 329.35 330.71 331.48 332.65 333.19 332.20 331.07 329.15 327.33 327.28 328.31 329.58 1975 331.13 331.377 0.863 0.953 1.331 330.73 331.46 331.94 333.11 333.95 333.42 331.97 329.95 328.50 328.37 329.38 330.78 1976 332.03 332.553 1.177 1.020 1.028 331.56 332.74 333.36 334.74 334.72 333.98 333.08 330.68 328.96 328.72 330.16 331.62 1977 333.84 333.603 1.050 1.113 1.030 332.68 333.17 334.96 336.14 336.93 336.17 334.89 332.56 331.29 331.28 332.46 333.60 1978 335.41 335.620 2.017 1.533 1.414 334.94 335.26 336.66 337.69 338.02 338.01 336.50 334.42 332.36 332.45 333.76 334.91 1979 336.84 337.033 1.413 1.715 1.493 336.14 336.69 338.27 338.82 339.24 339.26 337.54 335.72 333.97 334.24 335.32 336.82 1980 338.76 338.770 1.737 1.575 1.722 337.90 338.34 340.07 340.93 341.45 341.36 339.45 337.67 336.25 336.14 337.30 338.29 1981 340.12 340.490 1.720 1.728 1.623 339.29 340.55 341.63 342.60 343.04 342.54 340.82 338.48 336.95 337.05 338.57 339.91 1982 341.48 341.820 1.330 1.525 1.596 340.93 341.76 342.77 343.96 344.77 343.88 342.42 340.24 338.38 338.41 339.44 340.78 1983 343.15 342.577 0.757 1.043 1.269 341.57 342.79 343.37 345.40 346.14 345.76 344.32 342.51 340.46 340.53 341.79 343.20 1984 344.87 344.937 2.360 1.558 1.482 344.21 344.92 345.68 347.37 347.78 347.16 345.79 343.74 341.59 341.86 343.31 345.00 1985 346.35 346.600 1.663 2.012 1.593 345.48 346.41 347.91 348.66 349.28 348.65 346.90 345.26 343.47 343.35 344.73 346.12 1986 347.61 347.503 0.903 1.283 1.642 346.78 347.48 348.25 349.86 350.52 349.98 348.25 346.17 345.48 344.82 346.22 347.49 1987 349.31 349.153 1.650 1.277 1.406 348.73 348.92 349.81 351.40 352.15 351.58 350.21 348.20 346.66 346.72 348.08 349.28 1988 351.69 351.570 2.417 2.033 1.657 350.51 351.70 352.50 353.67 354.35 353.88 352.80 350.49 348.97 349.37 350.42 351.62 1989 353.20 353.527 1.957 2.187 2.008 353.07 353.43 354.08 355.72 355.95 355.44 354.05 351.84 350.09 350.33 351.55 352.91 1990 354.45 354.903 1.377 1.667 1.917 353.86 355.10 355.75 356.38 357.38 356.39 354.89 353.06 351.38 351.69 353.14 354.41 1991 355.70 356.027 1.123 1.250 1.486 354.93 355.82 357.33 358.77 359.23 358.23 356.30 353.97 352.34 352.43 353.89 355.21 1992 356.54 357.173 1.147 1.135 1.216 356.34 357.21 357.97 359.22 359.71 359.44 357.15 354.99 353.01 353.41 354.42 355.68 1993 357.21 357.703 0.530 0.838 0.933 357.10 357.42 358.59 359.39 360.30 359.64 357.45 355.76 354.14 354.23 355.53 357.03 1994 358.96 359.170 1.467 0.998 1.048 358.36 359.04 360.11 361.36 361.78 360.94 359.51 357.59 355.86 356.21 357.65 359.10 1995 360.97 361.007 1.837 1.652 1.278 360.04 361.00 361.98 363.44 363.83 363.33 361.78 359.33 358.32 358.14 359.61 360.82 1996 362.74 363.280 2.273 2.055 1.859 362.20 363.36 364.28 364.69 365.25 365.06 363.69 361.55 359.69 359.72 361.04 362.39 1997 363.88 364.033 0.753 1.513 1.621 363.24 364.21 364.65 366.49 366.77 365.73 364.46 362.40 360.44 360.98 362.65 364.51 1998 366.84 366.283 2.250 1.502 1.759 365.39 366.10 367.36 368.79 369.56 369.13 367.98 366.10 364.16 364.54 365.67 367.30 1999 368.54 369.157 2.873 2.562 1.959 368.35 369.28 369.84 371.15 371.12 370.46 369.61 367.06 364.95 365.52 366.88 368.26 2000 369.71 369.970 0.813 1.843 1.979 369.45 369.71 370.75 371.98 371.75 371.87 370.02 368.27 367.15 367.18 368.53 369.83 2001 371.32 371.693 1.723 1.268 1.803 370.76 371.69 372.63 373.55 374.03 373.40 371.68 369.78 368.34 368.61 369.94 371.42 2002 373.45 373.457 1.763 1.743 1.433 372.70 373.37 374.30 375.19 375.93 375.69 374.16 372.03 370.92 370.73 372.43 373.98 2003 375.98 375.843 2.387 2.075 1.958 375.07 375.82 376.64 377.92 378.78 378.46 376.88 374.57 373.34 373.31 374.84 376.17 2004 377.70 378.093 2.250 2.318 2.133 377.17 378.05 379.06 380.54 380.80 379.87 377.65 376.17 374.43 374.63 376.33 377.68 2005 379.98 379.830 1.737 1.993 2.124 378.63 379.91 380.95 382.48 382.64 382.40 380.93 378.93 376.89 377.18 378.54 380.31 2006 382.09 382.280 2.450 2.093 2.146 381.58 382.40 382.86 384.80 385.22 384.24 382.65 380.60 379.04 379.33 380.35 382.02 2007 384.02 384.010 1.730 2.090 1.972 383.10 384.12 384.81 386.73 386.78 386.33 384.73 382.24 381.20 381.37 382.70 384.19 2008 385.83 386.040 2.030 1.880 2.070 385.78 386.06 386.28 387.33 388.78 387.99 386.61 384.32 383.41 383.21 384.41 385.79 2009 387.64 387.970 1.930 1.980 1.897 387.17 387.70 389.04 389.76 390.36 389.70 388.24 386.29 384.95 384.64 386.23 387.63 2010 390.10 390.230 2.260 2.095 2.073 388.91 390.41 391.37 392.67 393.21 392.38 390.41 388.54 387.03 387.43 388.87 389.99 2011 391.85 392.117 1.887 2.073 2.026 391.50 392.05 392.80 393.44 394.41 393.95 392.72 390.33 389.28 389.19 390.48 392.06 2012 394.06 393.980 1.863 1.875 2.003 393.31 394.04 394.59 396.38 396.93 395.91 394.56 392.59 391.32 391.27 393.20 394.57 2013 396.74 396.823 2.843 2.353 2.198 395.78 397.03 397.66 398.64 400.02 398.81 397.51 395.39 393.72 393.90 395.36 397.03 2014 398.81 398.740 1.917 2.380 2.208 398.04 398.27 399.91 401.51 401.96 401.43 399.27 397.18 395.54 396.16 397.40 399.08 2015 401.01 400.823 2.083 2.000 2.281 400.18 400.55 401.74 403.35 404.15 402.97 401.46 399.11 397.82 398.49 400.27 402.06 2016 404.41 404.013 3.190 2.637 2.397 402.73 404.25 405.06 407.60 407.90 406.99 404.59 402.45 401.23 401.79 403.72 404.64 2017 406.76 406.853 2.840 3.015 2.704 406.36 406.66 407.54 409.22 409.89 409.08 407.33 405.32 403.57 403.82 405.31 407.00 2018 408.72 408.753 1.900 2.370 2.643 408.15 408.52 409.59 410.45 411.44 410.99 408.90 407.16 405.71 406.19 408.21 409.27 2019 411.66 411.723 2.970 2.435 2.570 411.03 411.96 412.18 413.54 414.86 414.16 411.97 410.18 408.76 408.75 410.48 411.98 2020 414.24 414.230 2.507 2.738 2.459 413.61 414.34 414.74 416.45 417.31 416.60 414.62 412.78 411.52 411.51 413.12 414.26 2021 416.45 416.637 2.407 2.457 2.628 415.52 416.75 417.64 419.05 419.13 418.94 416.96 414.47 413.30 413.93 415.01 416.71 2022 418.56 418.760 2.123 2.265 2.346 418.19 419.28 418.81 420.23 420.99 420.99 418.90 417.19 415.95 415.78 417.51 418.95 2023 419.47 tabs 9 17 27 43 59 75 83 91 99 107 115 123 131 139 147 155 163