Most of life on Earth will be EXECUTED in a billion years as a result of an extreme dip in oxygen levels, scientists warn
- Researchers from Japan and the US have modeled the future of Earth’s atmosphere
- The increasing brightness of the sun affects surface temperatures and photosynthesis
- This will cause rapid atmospheric deoxygenation in about a billion years
- The finding has implications for the way we look for habitable planets elsewhere
An extreme dip in atmospheric oxygen levels will wipe out most of life on Earth in a billion years, a study has predicted.
Researchers from Japan and the US have modeled how our planet’s atmosphere will change in the light of various biological, climatic and geological processes.
Deoxygenation will result from the sun’s increasing energy flow as it brightens, increasing surface temperatures and reducing photosynthesis.
They found that in about a billion years, deoxygenation will return the atmosphere to an inhospitable, methane-rich compound – one reminiscent of early Earth.
This fate, they added, will occur before the advent of so-called humid greenhouse conditions in which water will leak irreversibly from the planet’s atmosphere.
The findings suggest that airborne oxygen is not a permanent part of habitable planets, which has implications for our search for life on other worlds.
An extreme dip in atmospheric oxygen levels will wipe out most of life on Earth in a billion years, a study has predicted. Pictured: The decrease in oxygen that the team predicted
Before 2.4 billion years ago, the Earth’s atmosphere was rich in methane, ammonia, water vapor, and the noble gas neon, but lacked free oxygen.
This was introduced in an episode geologists call the Great Oxygenation Event, in which cyanobacteria living in the oceans began to produce significant amounts of oxygen through photosynthesis, radically altering the atmosphere.
This influx of oxygen has been attributed to paving the way to broadly support multicellular life, although this also came with a price – the death of many anaerobic bacteria, in what is believed to be Earth’s first mass extinction .
The new findings suggest that Earth’s atmosphere could swing the other way in the future – and potentially give the world back to anaerobic microorganisms.
“We discover that future deoxygenation is an inevitable consequence of increasing solar fluxes,” the research duo wrote in their paper.
“The precise timing is modulated by the exchange flux of reducing power between the mantle and the ocean-atmosphere crust system.”
“Our results suggest that the planetary carbonate-silicate cycle will lead to terminally CO2-restricted biospheres and rapid atmospheric deoxygenation.”
The oxygenation of the atmosphere is generally seen as an indication of the Earth’s current biosphere, plants and photosynthetic activity. Therefore, the logic goes, we should look for similar oxygen-rich worlds in our pursuit of extraterrestrial life.
However, the findings suggest that – from the point of view of a hypothetical distant alien observer – detection of atmospheric oxygen on Earth may only be possible for about two to three-tenths of our planet’s lifespan.
If this is also true of other planets, the researchers argue, we may need to adjust our search for life elsewhere in the universe to look for additional biosignatures that indicate life persists beyond a planet’s oxygen-rich period.
The full findings of the study are published in the journal Nature Geoscience.
WHAT IS THE FERMI PARADOX?
The Fermi Paradox wonders why, given the estimated 200 billion to 400 billion stars and at least 100 billion planets in our galaxy, there have been no signs of extraterrestrial life.
The contradiction is named after its creator, the Italian physicist Enrico Fermi.
He first asked the question in 1950.
Fermi believed it was too extraordinary that no alien signal or engineering project should be detected in the universe yet – despite its vast expanse.
Fermi concluded that there must be a barrier limiting the emergence of intelligent, self-aware, technologically advanced space colonizing civilizations.
This barrier is also referred to as the ‘large filter’.
The Italian physicist Enrico Fermi invented the so-called Fermi Paradox in the 1950s. It examines why there is no sign of extraterrestrial life, despite the 100 billion planets in our galaxy
If the main obstacle preventing the colonization of other planets is not in our past, then the barrier that humanity’s prospects for reaching other worlds must lie in our future, scientists have theorized.
Professor Brian Cox believes that the advancements in science and engineering that a civilization needs to conquer the stars will eventually lead to their destruction.
He said: ‘One solution to the Fermi paradox is that it is not possible to run a world that has the power to self-destruct and that needs global collaborative solutions to prevent that from happening.
“The growth of science and technology may inevitably outpace the development of political expertise, leading to disaster.”
Other possible explanations for the Fermi Paradox include that no other intelligent species have emerged in the universe, intelligent alien species exist – but lack the necessary technology to communicate with Earth.
Some believe that the distance between intelligent civilizations is too great to allow for any form of two-way communication.
If two worlds are several thousand light years apart, it is possible that one or both civilizations have died out before a dialogue can be established.
The so-called Zoo hypothesis claims that intelligent extraterrestrial life exists, but deliberately avoids any contact with life on Earth to allow its natural evolution.