Right now, life is thriving on our oxygen-rich planet, but Earth hasn’t always been this way – and scientists have speculated that in the future, the atmosphere will return to one that’s rich in methane and low in oxygen.
It probably won’t happen for another billion years or so. The study suggests that when change comes, it will happen fairly quickly.
This transformation will return the planet to the state it was in before what is known as the Great Oxidation Event (GOE) about 2.4 billion years ago.
Moreover, the researchers behind the new study say that oxygen in the atmosphere is unlikely to be a permanent feature of habitable worlds in general, which has implications for our efforts to uncover signs of life in the universe.
“The model predicts that oxygen is removed from the atmosphere, with atmospheric oxygen drastically reduced to levels reminiscent of Ancient land, Likely before the onset of humid greenhouse conditions in the Earth’s climate system and before the substantial loss of surface water from the atmosphere, “the researchers write in Published paper.
At this point it will be the end of the road for humans and most other life forms that depend on oxygen to get through today, so let’s hope to figure out how to exit the planet at some point in the next billion years.
To reach their conclusions, the researchers conducted detailed models of Earth’s biosphere, taking into account changes in the sun’s brightness and a corresponding decrease in carbon dioxide levels, as the gas breaks down by increasing heat levels. Reduced carbon dioxide means fewer photosynthesizing organisms like plants, which results in less oxygen.
Scientists previously expected that increased radiation from the sun would wipe ocean water off the surface of our planet Within about 2 billion years, But the new model – based on an average of just under 400,000 simulations – says that reducing oxygen will kill life first.
“The decline in oxygen is very extreme,” said Earth scientist Chris Reinhard of the Georgia Institute of Technology. new world. “We’re talking about a million times less oxygen than there is today.”
What makes the study particularly relevant today is our search for habitable planets outside the solar system.
Increasingly powerful telescopes are coming online, and scientists want to be able to know what to look for in the data packages these tools collect.
Researchers say it is likely that we need to look for other biomarkers besides oxygen to have the best chance of discovering life. Studying them is part of NASA NExSS (Nexus for Exoplanet System Science), which researches the habitability of planets other than ours.
According to the calculations made by Reinhard and ecologist Kazumi Ozaki of Toho University in Japan, the Earth’s habitable, oxygen-rich history could end up in only 20-30 percent of the life of the planet as a whole – and microbial life would carry. To exist long after we are gone.
“The atmosphere is characterized by high levels of methane, low levels of carbon dioxide, and no significant oxygen removal Ozone Layer, “he says Ozaki. “It is possible that the Earth system is a world of anaerobic life.”
The research has been published in Natural Earth Sciences.