Briefs · Frontier Science
The air now holds 432 parts per million of carbon dioxide
The annual carbon dioxide peak has reached 432 parts per million. That is the highest in the record, and the record began in 1958.
Scripps measured a May monthly average of 432.00 ppm at Mauna Loa, up 1.8 ppm from 430.2 ppm in May 2025. NOAA’s independent measurement, 432.3 ppm, rose by the same 1.8 ppm. Two instruments, one verdict.
The first reading, taken by Charles David Keeling on 29 March 1958, was 313 ppm. His son Ralph Keeling, who now directs the Scripps CO2 Program, put it plainly: “Atmospheric CO2 has continued its relentless rise… I wish we had better news.”
Relentless is the right word. The curve has never once, in 68 years, taken a year off.
Conclusion: 432 is not a number, but rather a direction, and it is pointing the wrong way, fast and furious.
Read the original at Scripps Institution of Oceanography / UC San Diego
Summary in our own words. The original belongs to its publisher.