explains the importance of measuring a CO 2 concentration of 400 parts per million at the observatory that his father, Charles Keeling, set up. Catherine Brahic: The Mauna Loa Observatory in ...

Record global carbon dioxide concentrations surpass 400 parts per million in March 2015. ScienceDaily . Retrieved June 2, 2025 from www.sciencedaily.com / releases / 2015 / 05 / 150507084211.htm ...

For the first time in human history, the concentration of carbon dioxide in the atmosphere has reached 400 parts per million (ppm). The arrival at this threshold represents a powerful symbol of ...

On Thursday, scientists at a research facility on top of the Mauna Loa volcano in Hawaii reported that average daily levels of carbon dioxide in the atmosphere surpassed 400 parts per million ...