Line graph that plots the monthly average atmospheric carbon dioxide concentrations in parts per million from four locations: Mauna Loa, Hawaii (1958 to 2024); La Jolla, California (1957 to 2024); Point Arena, California (1999 to 2011); and Trinidad Head, California (2002 to 2017).

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Chart: OEHHA Indicators of Climate Change in California (updated 2025)Source: NOAA and Scripps Institute of OceanographyGet the dataCreated with Datawrapper