A power outage has prevented communications from Mauna Loa Observatory for several days. Continued inclement weather has delayed repairs. Keelingcurve.ucsd.edu

Communication temporarily down. Keelingcurve.ucsd.edu

Communication down 01-Jan-2026

Baseline reading not available, data too variable 31-Dec-2025 keelingcurve.ucsd.edu

427.94 parts per million (ppm) CO2 in air 29-Dec-2025 keelingcurve.ucsd.edu

428.19 parts per million (ppm) CO2 in air 28-Dec-2025 keelingcurve.ucsd.edu

428.29 parts per million (ppm) CO2 in air 27-Dec-2025 keelingcurve.ucsd.edu

428.15 parts per million (ppm) CO2 in air 26-Dec-2025 keelingcurve.ucsd.edu

427.79 parts per million (ppm) CO2 in air 25-Dec-2025 keelingcurve.ucsd.edu

427.27 parts per million (ppm) CO2 in air 24-Dec-2025 keelingcurve.ucsd.edu

427.34 parts per million (ppm) CO2 in air 23-Dec-2025 keelingcurve.ucsd.edu

426.98 parts per million (ppm) CO2 in air 22-Dec-2025 keelingcurve.ucsd.edu

Baseline reading not available, data too variable 21-Dec-2025 keelingcurve.ucsd.edu

426.95 parts per million (ppm) CO2 in air 20-Dec-2025 keelingcurve.ucsd.edu

Baseline reading not available, data too variable 19-Dec-2025 keelingcurve.ucsd.edu

426.77 parts per million (ppm) CO2 in air 18-Dec-2025 keelingcurve.ucsd.edu

426.84 parts per million (ppm) CO2 in air 17-Dec-2025 keelingcurve.ucsd.edu

426.85 parts per million (ppm) CO2 in air 16-Dec-2025 keelingcurve.ucsd.edu

426.83 parts per million (ppm) CO2 in air 15-Dec-2025 keelingcurve.ucsd.edu

426.40 parts per million (ppm) CO2 in air 14-Dec-2025 keelingcurve.ucsd.edu

426.76 parts per million (ppm) CO2 in air 13-Dec-2025 keelingcurve.ucsd.edu

426.96 parts per million (ppm) CO2 in air 12-Dec-2025 keelingcurve.ucsd.edu

427.03 parts per million (ppm) CO2 in air 11-Dec-2025 keelingcurve.ucsd.edu

427.11 parts per million (ppm) CO2 in air 10-Dec-2025 keelingcurve.ucsd.edu

427.04 parts per million (ppm) CO2 in air 09-Dec-2025 keelingcurve.ucsd.edu

426.99 parts per million (ppm) CO2 in air 08-Dec-2025 keelingcurve.ucsd.edu

426.91 parts per million (ppm) CO2 in air 07-Dec-2025 keelingcurve.ucsd.edu

427.05 parts per million (ppm) CO2 in air 06-Dec-2025 keelingcurve.ucsd.edu

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426.75 parts per million (ppm) CO2 in air 04-Dec-2025 keelingcurve.ucsd.edu

426.77 parts per million (ppm) CO2 in air 03-Dec-2025 keelingcurve.ucsd.edu

Baseline reading not available, data too variable 02-Dec-2025 keelingcurve.ucsd.edu

Baseline reading not available, data too variable 01-Dec-2025 keelingcurve.ucsd.edu

Baseline reading not available, data too variable 30-Nov-2025 keelingcurve.ucsd.edu

426.48 parts per million (ppm) CO2 in air 28-Nov-2025 keelingcurve.ucsd.edu

Baseline reading not available, data too variable 27-Nov-2025 keelingcurve.ucsd.edu

426.01 parts per million (ppm) CO2 in air 25-Nov-2025 keelingcurve.ucsd.edu

426.01 parts per million (ppm) CO2 in air 24-Nov-2025 keelingcurve.ucsd.edu

426.64 parts per million (ppm) CO2 in air 23-Nov-2025 keelingcurve.ucsd.edu

Baseline reading not available, data too variable 22-Nov-2025 keelingcurve.ucsd.edu

Baseline reading not available, data too variable 21-Nov-2025 keelingcurve.ucsd.edu

425.82 parts per million (ppm) CO2 in air 20-Nov-2025 keelingcurve.ucsd.edu

425.90 parts per million (ppm) CO2 in air 19-Nov-2025 keelingcurve.ucsd.edu

426.15 parts per million (ppm) CO2 in air 18-Nov-2025 keelingcurve.ucsd.edu

426.48 parts per million (ppm) CO2 in air 17-Nov-2025 keelingcurve.ucsd.edu

426.32 parts per million (ppm) CO2 in air 16-Nov-2025 keelingcurve.ucsd.edu

426.46 parts per million (ppm) CO2 in air 15-Nov-2025 keelingcurve.ucsd.edu

427.55 parts per million (ppm) CO2 in air 14-Nov-2025 keelingcurve.ucsd.edu

426.57 parts per million (ppm) CO2 in air 13-Nov-2025 keelingcurve.ucsd.edu

426.31 parts per million (ppm) CO2 in air 12-Nov-2025 keelingcurve.ucsd.edu