New research by scientists has suggested that the Earth may return to a low-oxygen high-methane atmosphere in around 1-billion-years-time, much like it was long before life formed on the blue planet.
The research also suggests that planets only hold oxygen-rich environments for a fraction of their life span, indicating that alien life may be less common in the universe than some models suggest.
The scientists came to their conclusions after running computer simulation programs of Earth's biosphere which factored in changes such as the heat of the Sun and CO2 levels. They believe that as the Sun heats, it will result in falling CO2 levels, which means less plant life, and therefore less oxygen. The scientists also believe that the oceans may be stripped from the Earth's surface in 2 billion years. This will however happen after falling oxygen levels have eliminated all life on Earth.
The paper states:
"The model projects that a deoxygenation of the atmosphere, with atmospheric O2 dropping sharply to levels reminiscent of the Archaean Earth, will most probably be triggered before the inception of moist greenhouse conditions in Earth's climate system and before the extensive loss of surface water from the atmosphere."
Earth scientist Chris Reinhard, from the Georgia Institute of Technology, adds:
"The drop in oxygen is very, very extreme. We're talking around a million times less oxygen than there is today."
Earth formerly had a low oxygen methane-rich environment up to 2.5 billion years ago when the 'great oxidation event' occurred which allowed living beings to thrive and colonise every inch of the planet we know today. If the projections in the new research are correct it could mean Earth will only have a habitable atmosphere for 20% to 30% of its entire existence.
The research was part of a study by the NExSS (Nexus for Exoplanet System Science) project. The project is designed to examine the future nature of our planet and the viability of life on other planets, including the viability of humans to move to other planets.
[h/t: science alert]
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