07 Mar Study reveals that the planet’s oxygen could be depleted
The Earth’s atmosphere, which today is rich in oxygen and allows life, could change within a billion years, with a predominance of methane and low levels of oxygen, which would remind us of what the planet was like in its beginnings, according to a study published by Nature Geoscience on Wednesday.
The research, led by Kazumi Osaki of the Japanese University of Toho and Christopher T. Reinhard of the US space agency NASA, suggests that atmospheric oxygen is not permanent in habitable worlds, which has implications for the search for life in other Earth-like planets.
One of the factors that suggests planetary life is a detectable and oxygen-rich atmosphere, like the one on our planet Earth, which leads to the existence of plants and photosynthesis. “For many years, the lifespan of the Earth’s biosphere has been debated on the basis of scientific knowledge about the constant brightness of the sun and the global carbonate-silicate geochemical cycle.
One of the corollaries of such a theoretical framework is a continuous decrease in atmospheric CO2 levels and global warming on geological time scales. In fact, it is generally thought that the Earth’s biosphere will come to an end in the next 2 billion years due to the combination of overheating and a shortage of CO2 for photosynthesis. If true, it can be expected that atmospheric O2 levels will also eventually decline in the distant future. However, it is not clear exactly when and how this will occur, “says Kazumi Ozaki. So the team modeled Earth’s systems, including climate, biological and geological processes, to examine the timescale of current atmospheric conditions on our planet.
According to the publication, essential random variables were used in probability theories, based on a technique known as stochastic modeling. This model of the Earth system was applied 400,000 times to obtain samples to simulate climatic and biogeochemical processes, the result of the investigation indicated that an oxygen-rich atmosphere “will probably persist for another billion years”, before rapid deoxygenation does. reminiscent of the Earth before the Great Oxidation Event, which means large increases in methane and consequently the disappearance of the atmosphere, leading to the extinction of humanity and life as we know it, since they could only be sustained anaerobic life forms.
The original atmosphere of the Earth contained very little oxygen, but that began to change about 2.5 billion years ago when levels increased during the Great Oxidation, which marked a milestone in the history of the planet, allowing, with the passage of millions of years, the development of biological forms. The authors suggest that the detection of atmospheric oxygen on Earth could be possible only during 20-30% of the planet’s life and consider that future deoxygenation will be “an inevitable consequence of the increase” of solar fluxes.
If the same happens on other planets, the study indicates, then additional biosignatures are needed in the search for extraterrestrial life.
Will we have a way to extend the life span of our oxygen? Or can we generate an environmental conscience that allows us future subsistence? Time will tell us if we can reverse it or if this oxidation process will accelerate, but the future of our planet is not looking good at all for now.