Ever wondered how much longer Earth will provide us with the vital oxygen we need before it faces a catastrophic decline? It’s not the most comforting thought, but researchers from Toho University have dedicated their efforts to exploring this very question, and their findings are worth noting.
Kazumi Ozaki, an Assistant Professor at Toho University, alongside Christopher Reinhard, an Associate Professor at Georgia Institute of Technology, have published their research in Nature Geoscience. They delve into the future evolution of Earth’s atmosphere and offer insights into the expected duration of our planet’s oxygen-rich environment.
Previous assessments have suggested that Earth’s biosphere may end in 2 billion years due to overheating and a shortage of CO2 necessary for photosynthesis, according to Ozaki, as reported by BBC Sky At Night.
The scientist elaborated: “For many years, the lifespan of Earth’s biosphere has been discussed based on scientific knowledge about the steady brightening of the Sun and global carbonate-silicate geochemical cycle.” This theoretical framework indicates a gradual decrease in atmospheric CO2 levels and global warming over geological time.
“It’s generally thought Earth’s biosphere will come to an end in 2 billion years due to the combination of overheating and CO2 scarcity for photosynthesis,” Ozaki noted. “If true, one can expect atmospheric O2 levels will also eventually decrease in the distant future. However, it remains unclear exactly when and how this will occur.”
After conducting their own research, Ozaki and Reinhard arrived at a different conclusion with a notably shorter timeline.
Following their analysis, they discovered that our oxygen-abundant atmosphere might deplete approximately twice as fast as previously anticipated, within one billion years.
While it means we have another billion years ahead, the notion of an eventual end is daunting. To reach their conclusions, the researchers developed a computer model of Earth, simulating climate and biochemical processes. Given the numerous possible variables over time, they ran the simulation over 400,000 times, altering model components each run to gather a diverse array of outcomes.
The researchers predict that ‘rapid deoxygenation’ will occur after one billion years, transforming our atmosphere back to a state similar to pre-Great Oxidation Event Earth, which occurred 2.5 billion years ago.
Ozaki further explained: “The atmosphere after the great deoxygenation is characterised by an elevated methane, low-levels of CO2, and no ozone layer. The Earth system will probably be a world of anaerobic life forms.”
The study not only projects when oxygen might deplete on Earth but also reveals that our planet’s oxygenated phase may constitute only a small fraction of its entire history, potentially as little as 20–30 percent.