NOAA · Global Monitoring Laboratory

Atmospheric CO₂ Concentration

Monthly mean carbon-dioxide concentration measured at Mauna Loa, Hawaii — the longest continuous record of atmospheric CO₂ (the "Keeling Curve"). The saw-tooth is the seasonal breathing of Northern-Hemisphere plant life; the smooth line removes it.

The Keeling Curve

Monthly mean & seasonally adjusted trend, parts per million

The seasonal cycle

Average monthly deviation from the trend — CO₂ falls each Northern summer as plants grow

Atmospheric CO₂ Concentration — PublicChartsMonthly atmospheric CO₂ from NOAAAtmospheric CO₂ ConcentrationThe Keeling CurveThe seasonal cycleMonthly mean carbon-dioxide concentration measured at Mauna Loa, Hawaii — the longest continuous record of atmospheric CO₂ (the "Keeling Curve"). The saw-tooth is the seasonal breathing of Northern-Hemisphere plant life; the smooth line removes it.Monthly mean & seasonally adjusted trend, parts per millionAverage monthly deviation from the trend — CO₂ falls each Northern summer as plants grow