Scientists warn that most life on Earth will be extinct within a billion years due to an extreme drop in oxygen levels
- Researchers from Japan and the US have shaped the future of the Earth’s atmosphere
- Rising sunshine brightness will affect surface temperatures and photosynthesis
- It will cause rapid atmospheric deoxygenation within about a billion years
- The finding has implications for how we look for habitable planets elsewhere
An extreme drop in atmospheric oxygen levels will wipe out most of life on Earth in a billion years, a study predicted.
Researchers from Japan and the US have modeled how the atmosphere of our planet will change in the light of different biological, climatic and geological processes.
Detoxification will be due to the increasing flow of energy from the sun as it brightens, increases surface temperatures and decreases photosynthesis.
They found that in about one billion years, detoxification would return the atmosphere to an inhospitable, methane – rich composition – one reminiscent of the early earth.
This fate, they added, will occur before the arrival of so-called humid greenhouse conditions in which water will irreversibly leak out of the planet’s atmosphere.
The findings suggest that atmospheric oxygen is not a permanent structure of habitable planets, which has implications for our search for life in other worlds.
An extreme drop in atmospheric oxygen levels will wipe out most of life on Earth in a billion years, a study predicted. Pictured: the oxygen drop the team predicted
2.4 billion years ago, the Earth’s atmosphere was rich in methane, ammonia, water vapor, and noble gas neon, but it did not have oxygen.
It was introduced in an episode that geologists call the Great Oxygenation Event, during which cyanobacteria that live in the oceans begin to produce significant amounts of oxygen via photosynthesis, thus radically altering the atmosphere.
This supply of oxygen is attributed to the fact that it paved the way to support multicellular life on a large scale, although it also had a cost – the death of many anaerobic bacteria, which was presumably the Earth’s first mass extinction.
The new findings suggest that the atmosphere in the Earth’s future may fluctuate the other way around – possibly giving the world back to anaerobic microorganisms.
“We find that future detoxification is an inevitable consequence of increasing solar currents,” the research duo wrote in their paper.
“Its exact timing is modulated by the alternating current between the mantle and the ocean-atmosphere crust system.”
“Our results suggest that the planetary carbonate silicate cycle will tend to eventually cause CO2-restricted biospheres and rapid atmospheric detoxification.”
The oxygenation of the atmosphere is usually seen as an indication of the current biosphere, plants and photosynthetic activity of the Earth. Therefore, according to logic, we must look for similar oxygen-rich worlds in our search for extraterrestrial life.
However, the findings suggest that the detection of atmospheric oxygen on Earth will only be possible for about two to three tenths of the life of our planet – from the point of view of a hypothetical distant alien observer.
If this also applies to other planets, the researchers argue, we may have to adjust our search for life elsewhere in the universe to look for additional biosignatures, indicating life that continues outside the oxygen-rich period of a planet. .
The full findings of the study were published in the journal Nature Geoscience.
WHAT IS THE FERMI PARADOX?
The Fermi paradox questions why, given the estimated 200 to 400 billion stars and at least 100 billion planets in our galaxy, there were no signs of alien life.
The contradiction is named after its creator, the Italian physicist Enrico Fermi.
He first posed the question in 1950.
Fermi felt that it was too unusual for a single extraterrestrial signal or engineering project to be detected in the universe, despite its large scale.
Fermi concluded that there must be an obstacle limiting the rise of intelligent, self-conscious, technologically advanced space-colonizing civilizations.
This barrier is sometimes called the ‘Large filter’.
The Italian physicist Enrico Fermi invented the so-called Fermi Paradox in the 1950s. It explores why there is no sign of alien life, despite the 100 billion planets in our galaxy
If the greatest obstacle that prevents the colonization of other planets is not in our past, the barrier that humanity’s prospects to reach other worlds must stop in our future, scientists have theoretically stated.
Professor Brian Cox believes that advances in science and engineering that require a civilization to begin conquering 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 destroy itself and that needs global collaborative solutions to prevent it.
“It may be that the growth of science and engineering necessarily outweighs the development of political expertise, leading to disaster.”
Other possible explanations for the Fermi paradox include that there were no other intelligent species in the universe, that intelligent alien species are there – but they do not have the necessary technology to communicate with the earth.
Some believe that the distances between intelligent civilizations are too great to allow any form of two-way communication.
If two worlds are separated by thousands of light years, it is possible that one or both civilizations will die out before a dialogue can take place.
The so-called zoo hypothesis claims that intelligent alien life is there, but deliberately avoids contact with life on earth to enable natural evolution.