Earth's Oxygen Demise Predicted in a Billion Years: Implications for Life Beyond

A study published in Nature Geoscience predicts Earth's atmosphere will lose its oxygen in approximately one billion years, rendering the planet uninhabitable for current life forms. Led by environmental scientist Kazumi Ozaki, the research utilized 400,000 simulations to analyze atmospheric gas evolution. The findings indicate a future atmosphere dominated by methane, with a progressive decline and eventual disappearance of oxygen, mirroring conditions of the Archean Eon. The primary driver of this deoxygenation is the Sun's evolution. As it ages, its increasing temperature will reduce atmospheric carbon dioxide. This reduction will eliminate photosynthetic organisms, the primary oxygen producers, disrupting the atmospheric balance. Currently, oxygen comprises 21% of Earth's atmosphere, supporting complex life. The study emphasizes that this composition is not permanent, and deoxygenation is an inevitable consequence of solar luminosity changes and atmospheric chemistry. This discovery impacts the search for extraterrestrial life. NASA's NExSS project suggests that oxygen should not be the sole indicator of habitability. Exoplanets lacking oxygen may still harbor undiscovered life forms.