# oxygen catastrophe

> English word · Noun

## Definitions
1. An event during the oxygenation event of Earth's past, where the level of free oxygen in the environment exceeds the tolerance levels of most extant anaerobic life.
2. Such an event that theoretically occurs elsewhere, away from Earth.

## Etymology
From oxygen + catastrophe. From the accumulation of atmospheric oxygen, which was toxic to the anaerobic organisms existing at the time. This process led to a widespread extinction of those life forms.

## Source
Compiled from Wiktionary via kaikki.org (CC BY-SA). Data vintage: 2026-05-06.
Canonical page: https://plainspell.com/en/word/oxygen-catastrophe