Carbon dioxide levels in the atmosphere just hit a ‘depressing’ new record
These data come from the National Oceanic and Atmospheric Administration’s Mauna Loa Observatory, which may soon be shut down because of proposed government budget cuts
Carbon dioxide levels in the atmosphere have reached a new peak in April, averaging 431 parts per million (ppm), according to data from the Mauna Loa Observatory of the National Oceanic and Atmospheric Administration in Hawaii.
Greenhouse gases like carbon dioxide are measured by the number of molecules per million molecules of air, expressed as ppm.
Zachary Labe, a climate scientist from Climate Central, a nonprofit focused on climate change research, describes this record as “depressing” but not unexpected.
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“It’s just another sign that carbon dioxide continues to increase in our atmosphere as our planet continues to warm,” he says. “For many climate scientists, this is just ‘here it is again, another record in the wrong direction.’”
Labe explains that atmospheric CO2 peaks in April each year as decaying plants release greenhouse gases after winter. Some of this CO2 is absorbed by plants during the growing season. However, NOAA’s data indicates a concerning trend of steadily rising CO2 levels.
The Mauna Loa Observatory has been monitoring atmospheric CO2 longer than any other U.S. facility. It began recording CO2 levels in 1958 when April levels were under 320 ppm.
This record comes as the observatory’s funding is under threat. A budget proposal on NOAA’s website for the 2027 fiscal year, starting in October 2026, suggests cuts to several climate monitoring facilities, including Mauna Loa.
Other methods, like analyzing gas bubbles trapped in ice cores, allow climatologists to trace atmospheric carbon levels back hundreds of thousands of years. NOAA’s analyses indicate that pre-industrial CO2 levels were 280 ppm or less. Even during warmer interglacial periods, CO2 levels seemed to peak at around 300 ppm.
Despite the continued rise in atmospheric CO2, U.S. emissions decreased in 2023 and 2024, though this was reversed in 2025, partly due to increased electricity demand from artificial intelligence data centers.
Still, Labe believes there is hope as the adoption of renewable energy sources like solar and wind grows.
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