According to scientists, a significant decrease in oxygen levels would wipe out most life on Earth in about a billion years.
It means the planet will revert to a methane-rich, inhospitable climate close to that of the early Earth.
Researchers from the United States and Japan predicted how our planet’s atmosphere will change as a result of a number of biological, geological, and climate processes.
They discovered that increasing solar brightness has an effect on surface temperatures and photosynthesis, as well as causing rapid deoxygenation of the atmosphere.
“We find that future deoxygenation is an unavoidable consequence of growing solar fluxes,” the researchers wrote in their paper, which was published in the journal Nature Geoscience.
As the sun brightens, surface temperatures will rise and photosynthesis will fall, the scientists say.
This will happen before so-called moist greenhouse conditions appear, where water will irreversibly leak from the Earth’s atmosphere, the research shows.
In addition, the findings suggest that atmospheric oxygen is not a permanent fixture on planets suitable for life.
This could have implications on our search for life elsewhere in the universe.
Before 2.4 billion years ago, our planet’s atmosphere was rich in methane, water vapour,ammonia, and neon gas but it lacked free oxygen.
Free oxygen arrived on Earth in an episode that geologists call the Great Oxygenation Event.
During this period, a group of bacteria living in the oceans known as cyanobacteria started producing significant amounts of oxygen via photosynthesis which changed the atmosphere.
Scientists believe this led to multicellular life on a wide scale but also came with a price of the death of other bacteria that thrive in the absence of free oxygen.
Meanwhile, the new research shows that the Earth’s atmosphere could swing back the other way in the future.
In the hunt for alien-life, logic suggests we should look for oxygenated planets similar to our own.
The oxygenation of the Earth’s atmosphere is widely considered to be a sign of its plants, biosphere and photosynthetic activity.
But the new study suggests that the detection of the Earth’s atmospheric oxygen might only be possible for around two to three tenths of its existence.