How atmospheric CO2 has risen since 1959

Atmospheric CO₂ at Mauna Loa has risen in every decade since measurements began in 1959, and it has risen faster in each successive decade — the record bends upward rather than following any straight line.

Measured CO₂ at Mauna LoaConstant-rate line drawn from the baseline

Move the baseline forward and the average rate of rise measured from it goes up, not down. That is the arithmetic signature of acceleration: recent decades cannot be described by the same slope that fits the early record.

Year to measure the rise from1990

Year to read the record at2025

Increase in CO₂ since the baseline year72.9 ppm

Average rise per year since the baseline year2.08 ppm/yr

Amount above the pre-industrial level147.4 ppm

Year 450 ppm is reached at the average rate since the baseline2036

Atmospheric CO2 concentration, Mauna Loa annual mean, NOAA Global Monitoring Laboratory retrieved 2026-07-27 · Public domain

Interactive artifact by Delineo