CO2 concentration derived using Zhacos data Time(MyBP) CO2(ppm) 35.00 335.1 35.25 334.3 35.75 308.2 36.25 335.8 36.75 344.0 37.25 350.2 37.75 379.9 38.25 389.6 38.75 400.5 39.25 436.7 39.75 460.7 40.25 491.6 40.75 452.7 41.25 511.5 41.75 560.9 42.25 487.0 42.75 542.3 43.25 562.3 43.75 553.9 44.25 524.0 44.75 540.0 45.25 585.7 45.75 632.7 46.25 698.8 46.75 727.2 47.25 819.0 47.75 850.3 48.25 869.6 48.75 981.4 49.25 934.4 49.75 994.9 50.25 1057.7 50.75 1133.6 51.25 1155.7 51.75 1017.4 52.25 1037.0 52.75 1054.6 53.25 969.0 53.75 861.6 54.25 890.1 54.75 984.7 55.25 833.0 55.75 794.1 56.25 760.8 56.75 697.6 57.25 657.5 57.75 637.5 58.25 590.9 58.75 581.9 59.25 660.1 59.75 663.6 60.25 745.5 60.75 742.1 61.25 724.0 61.75 734.5 62.25 721.4 62.75 650.3 63.25 614.1 63.75 734.6 64.25 711.8 64.75 742.4 65.25 636.9 65.75 624.4