Atmospheric CO2 Soars to Million-Year High: Human Impact Confirmed
In May 2025, measurements at Hawaii’s Mauna Loa Observatory revealed a record-high average atmospheric carbon dioxide concentration of 430.2 ppm, a 3.5 ppm increase from the previous year. This surpasses the 400 ppm threshold, previously considered unimaginable, and signifies the highest level in millions of years, attributed to human fossil fuel consumption. The data, collected by Scripps Institution of Oceanography and NOAA, continues a long-term record illustrating the escalating impact of greenhouse gases on the planet’s climate and ecosystems. These measurements, integrated into the Global Greenhouse Gas Reference Network, provide crucial information for policymakers addressing climate change.
John Q. Hosedrinker