ENVIRONMENT

The Rising Curve

1958 CE

History · Contemporary · Holocene · Meghalayan

In 1958, on the slope of Mauna Loa, Charles David Keeling started measuring carbon dioxide in clean Pacific air, precisely and without interruption. Within two years he saw the planet breathe, CO2 falling each northern summer as forests inhale, and beneath the breathing, a steady rise. The curve has climbed from 315 parts per million toward 430, the firmest single piece of evidence of humanity's effect on the global atmosphere, and the emblem of Earth monitoring itself.

Why it matters

Every climate model, treaty and target stands on this line: not a theory but a measurement, repeated for two-thirds of a century. The curve taught a general lesson too, that some discoveries creep rather than flash, emerging from patient monitoring that is perpetually hard to fund and impossible to replace. The deep-time perspective of this whole frise ends at this graph: the atmosphere now changes on a human calendar.

Dating & uncertainty

Charles David Keeling began continuous carbon dioxide measurements at Mauna Loa in 1958, and within two years reported both the breathing of the seasons and a small but persistent increase in Antarctica. The measurement has run ever since, through funding crises, and stands among the most consequential data series ever collected.

Sources

1. Keeling (1960), Tellus · The concentration and isotopic abundances of carbon dioxide in the atmospheredoi:10.3402/tellusa.v12i2.9366
2. Nisbet (2007), Nature · Earth monitoring: Cinderella sciencedoi:10.1038/450789a
3. Scripps Institution of Oceanography · The Keeling Curve. Institutional source: keelingcurve.ucsd.edu, accessed 2026-08-30.

Our species’ history as one day

23:59:4118.7 s before midnight

if the 315,000 years of Homo sapiens were compressed into a single day