Life on Earth is inextricably linked to oxygen. After the Great Oxidation Event, which occurred about 2.4-2.0 billion years ago, this element became the basis for sustaining life in most organisms to this day. But will it always be in our atmosphere? A study published in Nature Geoscience provides an unexpected answer: in a billion years, the planet will lose oxygen, making it unsuitable for most forms of life. That is, four billion years before our Sun begins to die and turn into a red giant.
The end of the oxygen era
Kazumi Ozaki of Toho University and Christopher Reinhard of the Georgia Institute of Technology have created a computer model to trace the future of Earth’s atmosphere. After 400,000 simulations, they concluded: oxygen will remain in the atmosphere for about another billion years. After that, there will be “rapid deoxygenation” – the atmosphere will be deprived of oxygen, which will be displaced by other gases.
Why will this happen?
The main factor is the evolution of the Sun. Over time, the star will grow brighter, causing CO₂ levels to decrease due to intense weathering of the rocks. Without enough carbon dioxide, photosynthesis will stop, and with it, the production of oxygen. The planet will overheat, the oceans will vaporize, and the atmosphere will fill with methane. Only anaerobic bacteria like those that existed on the early Earth before the Oxygen catastrophe will survive.
Search for salvation
This research is changing the approach to the search for extraterrestrial civilizations. Oxygen is considered a key “biosignature” – an indicator of life on exoplanets. However, the work shows: the oxygen atmosphere is only a temporary phase (20-30% of Earth’s history). Astronomers should look for other markers, such as methane or organic compounds, so they don’t miss worlds where life has already passed or has not yet reached the “oxygen phase.”
Is it worth worrying about?
Fortunately, the threat is not urgent: a billion years is an extremely long time. But the discovery is a reminder of the vulnerability of our world. “This is not only a prediction of Earth’s future, but also a key to understanding how planetary systems in the universe evolve,” Ozaki emphasizes.
Hence, the end of the oxygen era is inevitable, but for now we can only appreciate the uniqueness of our planet’s “blue period”.
We previously reported on how Venus’ atmosphere was actively losing carbon and oxygen.
According to skyatnightmagazine.com
