Atmospheric CO2 Breaks 430 PPM Record at Mauna Loa

In May 2025, atmospheric carbon dioxide (CO2) levels surpassed 430 parts per million (ppm) for the first time on record, marking the highest concentration since measurements began over 65 years ago. This milestone was reported by scientists from both the Scripps Institution of Oceanography and NOAA's Global Monitoring Laboratory, based on data collected at the Mauna Loa Observatory in Hawaii, a key global benchmark site for monitoring CO2. The increase of around 3.5 ppm from the previous year continues the long-term upward trend documented since 1958, famously represented by the Keeling Curve, initially established by Charles David Keeling and now maintained by his son, Ralph Keeling. Elevated CO2 levels contribute significantly to global warming by trapping heat in the atmosphere, which exacerbates extreme weather events such as heatwaves, droughts, wildfires, and flooding, and also leads to ocean acidification that harms marine life. Despite challenges like the 2022 Mauna Loa volcanic eruption, scientists have maintained continuous monitoring using backup systems to ensure data continuity. Experts warn that these rising CO2 concentrations pose serious environmental and health risks, underscoring the urgent need for action to mitigate climate change.