At that time, humanity and most other forms of life that rely on oxygen for survival will have almost no chance of surviving on Earth.
Currently, life is thriving on our oxygen-rich planet. However, this “beautiful” period will not last forever. Instead, Earth’s atmosphere is expected to revert to a methane-rich state with low oxygen levels in the future, according to a study published in the journal Nature Geoscience.
According to the research, this may not occur for another billion years or longer. But when this event happens, it will occur quite rapidly. This shift will return our Blue Planet to a state similar to that before the event known as the Great Oxidation Event (GOE), which took place approximately 2.4 billion years ago.
At that time, humanity and most other forms of life that rely on oxygen for survival will have almost no chance of surviving on Earth. In other words, humanity will need to find a way to leave Earth at some point within the next billion years.
In one billion years, Earth will not run out of oxygen.
To reach their conclusions, researchers ran detailed models of the Earth’s biosphere, taking into account the changing brightness of the Sun and the corresponding reduction in carbon dioxide levels, which are broken down due to rising temperatures. Less carbon dioxide means fewer photosynthetic organisms (such as plants), which will lead to less oxygen.
Scientists have previously predicted that increased radiation from the Sun will cause oceans to “evaporate” from the surface of our planet within about two billion years. However, this latest model—which has run nearly 400,000 simulations—indicates that the reduction of oxygen on Earth will first lead to the extinction of all life.
Earth scientist Chris Reinhard from the Georgia Institute of Technology told New Scientist: “The drop in oxygen is very, very serious. We’re talking about oxygen levels being around one million times lower than today.”
According to calculations by expert Reinhard and environmental scientist Kazumi Ozaki from Toho University, Japan, the period during which life flourishes thanks to Earth’s oxygen-rich atmosphere may only constitute 20-30% of the total lifespan of the Blue Planet.
However, microbial life will persist long after humanity is gone.
“The atmosphere after the Great Deoxygenation Event will be characterized by high methane levels, low CO2, and no ozone layer. Earth may become a world of anaerobic life forms,” Ozaki noted.
Remarkably, this latest research also greatly aids us in the search for habitable planets beyond our Solar System. With powerful telescopes coming into operation en masse, scientists want to know what they should be looking for in the vast amounts of data these devices are collecting.
Specifically, oxygen in the atmosphere may not be a prerequisite in the search for new habitats for humanity, due to the relatively short duration that a planet can be rich in this gas. Instead, we need to hunt for other biological signs beyond oxygen to have the best chance of discovering life-supporting sites in the universe.
