Math & science · 1958

Keeling curve

Continuous measurements on Mauna Loa show atmospheric CO2 rising every year.

Charles David Keeling's record began at about 315 ppm and passed 420 ppm in the 2020s. It is the longest direct record of human change to the atmosphere.

See it in the living tree Wikipedia

Arcs above join it to what it stood on, arcs below to what it led to. The bar places this stretch on the tree's whole timeline.

What it built on 2

Greenhouse effect quantified 1896
Spectroscopy 1859

What it led to 1

Gigatonne-scale carbon removal ~2045

Related measurements

The dashed line marks when it first worked.

CO2 emissions Latest: 39B t (2025) Source: Our World in Data

Fossil fuel consumption Latest: 144k TWh (2025) Source: Our World in Data