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March 2, 2021
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March 2, 2021

Earth’s oxygen-rich atmosphere will probably last for approximately 1 billion years

Dr. Kazumi Ozaki

Dr. Kazumi Ozaki, Assistant Professor at the Department of Environmental Science, Faculty of Science, Toho University, and Japan-U.S. research team from Georgia Institute of Technology have revealed that the future lifespan of Earth’s oxygen-rich atmosphere is approximately one billion years.

Key Points
The team revealed that the Earth’s surface environment will gradually become less oxygenated as a consequence of future solar evolution.
The oxygen concentration in the atmosphere is predicted to decrease significantly after approximately one billion years, making it difficult for oxygen-breathing multicellular organisms to survive.
This is the first clarification that the current highly-oxygenated environment will not be maintained permanently, and it raises an important issue for the search for life beyond our solar system.

Kazumi Ozaki, Assistant Professor at the Department of Environmental Science, Faculty of Science, Toho University, and Japan-U.S. research team from Georgia Institute of Technology have revealed that the future lifespan of Earth’s oxygen-rich atmosphere is approximately one billion years.

Dr. Kazumi Ozaki
Key Points The team revealed that the Earth’s surface environment will gradually become less oxygenated as a consequence of future solar evolution. The oxygen concentration in the atmosphere is predicted to decrease significantly after approximately one billion years, making it difficult for oxygen-breathing multicellular organisms to survive. This is the first clarification that the current highly-oxygenated environment will not be maintained permanently, and it raises an important issue for the search for life beyond our solar system.

Evolution of atmospheric oxygen levels (blue lines) obtained from this study. Gray lines denote results obtained by running the same model ensemble with constant solar luminosity for the future evolution. Phan = Phanerozoic.

Summary
The Earth’s oxygen-rich atmosphere is the most prominent example of how life has a profound effect on the planetary environment. However, the extent to which such an environment will be sustained has not been quantitatively assessed. The research team developed a numerical model that comprehensively considers the processes that define the amount of oxygen in the atmosphere on geological time scales, and conducted numerical experiments to predict future global environmental changes. As a result, it was found that global warming caused by increased solar radiation and a decrease in atmospheric carbon dioxide concentration will lead to a gradual decrease in primary production in the biosphere, resulting in a deoxygenation of the atmosphere and oceans. In particular, it is predicted that there will be a rapid transition to an oxygen-poor state after approximately one billion years, after which it will be difficult for oxygen-breathing multicellular organisms to survive. This is the first quantitative assessment that the current oxygen-rich environment on Earth will not last indefinitely, and is an important result that will have an impact on future plans to explore life outside the solar system. The results of this research were published in the electronic version of Nature Geoscience on March 2.

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