New record for largest 12-month gain in carbon dioxide concentration ever observed The monthly average concentration of carbon dioxide in the atmosphere measured at NOAA’s Mauna Loa Observatory in March 2024 was 4.7 parts per million (ppm) higher than that recorded in March 2023, setting a new record and revealing the increasing pace of CO2 addition to the atmosphere by … Continue reading Largest Year–Over-Year Gain in Keeling Curve Set in March