Is Earth’s Oxygen Running Out? Discover How Long We Have Left with Insights from Scientists | BBC Sky at Night Magazine

Oxygen is essential for life on Earth, but what happens when it runs low? Will we eventually run out? Scientists have looked into different scenarios that could end life as we know it, like climate change, rising carbon dioxide levels, or even an asteroid impact. One troubling thought is the Sun’s future—it will expand in about 6 billion years and could consume our planet.

A recent study highlights a key concern: Earth’s oxygen-rich atmosphere might not last. Researchers, including Kazumi Ozaki from Toho University and Christopher Reinhard from Georgia Tech, modelled future conditions and predicted Earth’s oxygen could diminish within the next billion years.

This study, published in Nature Geoscience, analyzes the complex relationship between the Sun’s brightness, atmospheric changes, and life on Earth. According to Ozaki, “The lifespan of Earth’s biosphere has been discussed based on scientific knowledge about the steady brightening of the Sun.” He mentions that as our planet heats up, carbon dioxide levels could decrease, making it challenging for plants to undergo photosynthesis, ultimately threatening the oxygen supply.

During their simulations, the scientists ran over 400,000 models, adjusting various parameters to examine the possible futures. Their findings suggested that in around a billion years, we may experience “rapid deoxygenation.” This means our atmosphere may revert to conditions similar to those before the Great Oxidation Event, which occurred around 2.5 billion years ago, when single-celled organisms first began producing significant amounts of oxygen.

Once deoxygenation starts, expect an atmosphere rich in methane and low in carbon dioxide, where life will be dominated by anaerobic organisms—those that don’t need oxygen to survive.

This research also has implications beyond Earth. Astronomers search for oxygen when looking for signs of life on other planets, known as biosignatures. However, this study suggests oxygen might only account for 20-30% of Earth’s history. What if extraterrestrial life doesn’t rely on oxygen? This could refine how we search for life beyond our planet.

While Earth’s future is uncertain, understanding the dynamics of our atmosphere helps us appreciate its fragility. Let’s hope that in the meantime, we can prioritize actions that preserve our oxygen-rich environment.

For a deep dive into the research, check out the full paper from Nature Geoscience here.

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