EARTH × ATMOSPHERE

When the Earth Made Too Much Oxygen

~2.44 to 2.02 billion years ago

Proterozoic · Paleoproterozoic · Siderian

For four hundred million years after oxygen first entered the air, the ocean buried organic carbon on a scale never seen since. Every carbon atom buried instead of being left to rot leaves an oxygen atom behind, so all that burial reads as a surge of oxygen far beyond anything that followed. Marine limestone from this interval carries the isotopic mark, the largest shift of its kind in the entire record.

Why it matters

If it happened worldwide, the first oxygenation did not edge upward; it overshot, to levels the planet would not see again for a billion and a half years.

Dating & uncertaintyDisputed

The largest carbon isotope excursion known, and among the most contested. A Bayesian reconstruction of the global record dates it from 2445 to 2018 million years ago with a peak at 2130; other work finds the strength of the signal depends on water depth, which would make it a set of local excursions rather than one global event. What hangs on the answer is how high oxygen actually rose.

Sources

  1. Edmonson et al. (2026), PNAS · Timing and magnitude of the Lomagundi-Jatuli carbon isotope excursion
  2. Hodgskiss & Sperling (2023), Annual Review of Earth and Planetary Sciences · Deconstructing the Lomagundi-Jatuli carbon isotope excursion
  3. Prave et al. (2021), Journal of the Geological Society · The grandest of them all: the Lomagundi-Jatuli Event and Earth's oxygenation

Earth history as one day

11:04:2912 h 56 min before midnight

if Earth’s 4.54 billion years were compressed into a single day

See it on the timeline