ENVIRONMENT

The Rising Curve

1958 CE

History · Contemporary · Holocene · Meghalayan

In 1958, on the slope of Mauna Loa, Charles David Keeling began measuring carbon dioxide in clean Pacific air, precisely and without interruption. Within two years he had seen the planet breathe, CO2 falling each northern summer as forests inhale, and, in Antarctica, a slight but steady rise. The curve has climbed from 315 parts per million toward 430, the plainest record of humanity's mark on the whole atmosphere, and the emblem of Earth monitoring itself.

Why it matters

Climate models, treaties and targets all refer back to 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 long view of this whole timeline 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 had reported both the seasonal swing of the northern hemisphere 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