Earth’s atmosphere will eventually lose its ability to support life, with oxygen levels collapsing in about one billion years, according to new research by NASA’s Nexus for Exoplanet System Science and Japan’s Toho University.
The study, led by Kazumi Ozaki and Christopher Reinhard, used large-scale simulations to model how Earth’s atmosphere will evolve as the Sun gradually warms over time. As the Sun brightens, carbon dioxide molecules will begin to break down, depriving plants of the CO₂ needed for photosynthesis. Without photosynthesis, oxygen production will cease.
This chain reaction would wipe out plants and animals, leaving only anaerobic microorganisms capable of living without oxygen. The ozone layer would also vanish, exposing the planet to high levels of solar radiation.
Scientists say the atmospheric shift will also coincide with rising methane levels, making the air more toxic and accelerating the extinction of complex life. In time, Earth will resemble the barren world it was billions of years ago.
While this change is projected to take place far in the future, researchers say it offers important lessons about planetary habitability and the fragility of life-supporting systems. “Even the planet we take for granted as perfectly habitable is temporary in cosmic terms,” the study notes.
The findings also help astronomers refine their search for life on exoplanets by understanding how long oxygen-rich atmospheres can last.
Though no immediate threat exists for humanity, scientists stress that the research underscores the importance of planetary stewardship and offers a stark reminder of the interdependence of Earth’s systems.
