For now, life is thriving on our oxygen-rich planet, but Earth wasn’t always like this, and scientists predict that in the future the atmosphere will return to an atmosphere rich in methane and low in oxygen. It will probably only happen in a billion years. But when change comes, it will happen quite quickly, according to a study published in 2021.
This shift will return the planet roughly to its state before the event known as the Great Oxidation Event (GOE) approximately 2.4 billion years ago. At best, the researchers behind the study say, atmospheric oxygen is unlikely to be a permanent feature of inhabited worlds in general; This impacts our efforts to detect signs of life further out in the universe.
“The model predicts that atmospheric deoxygenation will occur with a sharp drop in atmospheric O 2 “Levels reminiscent of the Archaean Earth will most likely be caused by the onset of wet greenhouse conditions in the Earth’s climate system and the significant loss of surface water in the atmosphere,” the researchers explained in their paper.
At this point, it will be the end of the road for humans and many other life forms that need oxygen to get through their days; so let’s hope to figure out how to get off the planet at some point in the next billion years.
To reach their conclusions, the researchers ran detailed models of the Earth’s biosphere, accounting for changes in the Sun’s brightness and the resulting reduction in carbon dioxide levels as gas breaks down due to increased heat levels. Less carbon dioxide means fewer photosynthetic organisms such as plants, resulting in less oxygen.
Scientists had previously predicted that increased radiation from the Sun would wipe out the ocean waters from our planet’s surface in about 2 billion years, but the model, based on an average of just under 400,000 simulations, suggests that oxygen depletion will lead to death. First of all, from life.
“The oxygen drop is very, very extreme,” said Reinhard of the Georgia Institute of Technology. “We’re talking about a million times less oxygen than today.”
What makes the research particularly relevant today is our search for habitable planets outside the solar system. More and more powerful telescopes are coming online, and scientists want to know what to look for in the wealth of data these instruments collect.
To have the best chance of detecting life, we may need to look at biological signatures other than oxygen, the researchers say. Their research is part of NASA’s NExSS (Nexus for Exoplanet System Science) project, which examines the habitability of planets other than our own.
According to calculations by Reinhard and environmental scientist Kazumi Ozaki of Toho University in Japan, Earth’s oxygen-rich, habitable history may last only 20 to 30 percent of the lifespan of the planet as a whole, and microbial life will continue long after we’re gone. will continue to exist.
“The atmosphere after major deoxygenation is characterized by increased methane content and low levels of CO2 and the absence of the ozone layer,” Ozaki said.
“The Earth system will likely be a world of anaerobic life forms.” The study was published on: Natural Geology.
Source: Port Altele
