Earth will become unhabitable due to oxygen loss, not asteroid strike

It is assumed that the end of the world would occur either due to an asteroid impact or to the Sun engulfing Earth. However, the scientific community indicates a much quieter and more gradual scenario in the very long term.

According to various studies, the real risk is that the atmosphere will become unsuitable for life long before the planet physically fades. This process would be driven by the Sun’s natural evolution, which makes it hotter as it ages. It is not a visible change on a human scale, but it is accumulative over billions of years.

According to a NASA scientific review, Earth could become uninhabitable for complex life forms in just over 1 billion years.

In the faraway future, the Sun will ultimately expand into a red giant in about 5 billion years. Yet problems could occur much earlier due to a feedback loop: Earth’s rising temperature causes more water to evaporate, and increased water vapor further accelerates warming, leading to a runaway greenhouse effect. NASA confirms that the end of life on Earth has a projected date, and the cause won’t be an asteroid impact.

A study in Nature Geoscience, led by Kazumi Ozaki from Toho University and Christopher Reinhard from Georgia Tech, used climate and chemical models to simulate Earth’s future.

After around 400,000 simulations, they found that the oxygen-rich atmosphere might last another 1.1 billion years. The key finding is the sequence of changes: the model indicates that a significant loss of oxygen may happen before Earth loses a substantial amount of its water to space.

This means that the atmosphere could become unbreathable even before the planet is fully dehydrated.

Another 2024 paper, led by Keming Zhang (University of California, San Diego), estimates that Earth would remain habitable “for around another billion years” before the oceans disappear completely.

Researchers emphasize that these scenarios are on extremely distant time scales and are unrelated to current warming, which has causes other than solar activity.