Latest news with #Ozaki
NDTV
7 days ago
- Science
- NDTV
Earth Will Lose Its Oxygen: Scientists Warn Of A Rapid Countdown
A recent study reveals that Earth's oxygen-rich atmosphere, vital for complex life, is expected to last approximately one billion more years. Increasing solar radiation will reduce atmospheric carbon dioxide, impairing photosynthesis and leading to a sharp decline in oxygen levels. The study that was published in Nature Geoscience said that this deoxygenation could occur rapidly, rendering Earth inhospitable to most life forms. The findings also suggest oxygen may not be a permanent biosignature on habitable planets, impacting the search for extraterrestrial life. "For many years, the lifespan of Earth's biosphere has been discussed based on scientific knowledge about the steady brightening of the sun and the global carbonate-silicate geochemical cycle. One of the corollaries of such a theoretical framework is a continuous decline in atmospheric CO2 levels and global warming on geological timescales. Indeed, it is generally thought that Earth's biosphere will come to an end in the next 2 billion years due to the combination of overheating and CO2 scarcity for photosynthesis. If true, one can expect that atmospheric O2 levels will also eventually decrease in the distant future. However, it remains unclear exactly when and how this will occur," environmental scientist Kazumi Ozaki from Toho University in Japan said when the study was published. To examine how Earth's atmosphere will evolve in the future, Ozaki and Christopher Reinhard, Associate Professor at Georgia Institute of Technology, constructed an Earth system model which simulates climate and biogeochemical processes. Because modelling future Earth evolution intrinsically has uncertainties in geological and biological evolutions, a stochastic approach was adopted, enabling the researchers to obtain a probabilistic assessment of the lifespan of an oxygenated atmosphere. Ozaki ran the model more than 400 thousand times, varying the model parameters, and found that Earth's oxygen-rich atmosphere will probably persist for another one billion years before rapid deoxygenation renders the atmosphere reminiscent of early Earth before the Great Oxidation Event around 2.5 billion years ago. "The atmosphere after the great deoxygenation is characterised by elevated methane, low levels of CO2, and no ozone layer. The Earth system will probably be a world of anaerobic life forms," says Ozaki. Earth's oxygen-rich atmosphere represents an important sign of life that can be remotely detected. However, this study suggests that Earth's oxygenated atmosphere would not be a permanent feature and that the oxygen-rich atmosphere might only be possible for 20-30% of the Earth's entire history as an inhabited planet. Oxygen (and photochemical byproduct, ozone) is the most accepted biosignature for the search for life on exoplanets, but if we can generalise this insight to Earth-like planets, then scientists need to consider additional biosignatures applicable to weakly oxygenated and anoxic worlds in the search for life beyond our solar system.
Arab Times
02-06-2025
- Science
- Arab Times
Study predicts oxygen collapse will end most life on Earth in a billion years
JAPAN, June 2: Earth's atmosphere, currently rich in oxygen and capable of supporting complex life, won't remain this way forever. Scientists predict that in about a billion years, the planet will undergo a dramatic shift — returning to a state rich in methane and extremely low in oxygen, similar to conditions before the Great Oxidation Event (GOE) roughly 2.4 billion years ago. Although this transformation is far off, when it begins, the change will happen relatively quickly, according to a 2021 study by environmental scientist Kazumi Ozaki of Toho University in Japan and Earth scientist Chris Reinhard of the Georgia Institute of Technology. 'For many years, the lifespan of Earth's biosphere has been discussed based on scientific knowledge about the steadily brightening Sun and global carbonate-silicate geochemical cycles,' said Ozaki. 'One consequence of this framework is a steady decline in atmospheric CO₂ and eventual global warming over geological timescales.' Using detailed models of Earth's biosphere — factoring in the Sun's increasing luminosity and corresponding drops in atmospheric CO₂ — the researchers determined that lower carbon dioxide levels will lead to fewer photosynthesizing organisms. This would significantly reduce the production of oxygen, ultimately pushing atmospheric oxygen levels to a point roughly a million times lower than today. 'The drop in oxygen is very, very extreme,' Reinhard told New Scientist. 'We're talking around a million times less oxygen than there is today.' According to the study, this atmospheric shift is likely to occur before Earth reaches a "moist greenhouse" state, where water vapor dominates the upper atmosphere and the planet begins to lose its surface water. This means that oxygen-dependent life will likely die out long before Earth becomes too hot for oceans to exist. Despite its long timeline, the study has pressing implications for astrobiology. The findings suggest that atmospheric oxygen may not be a permanent feature of habitable planets. This challenges the current focus on oxygen as a key biosignature in the search for life on exoplanets. The research, part of NASA's NExSS (Nexus for Exoplanet System Science) project, highlights the importance of considering alternative biosignatures in the hunt for extraterrestrial life. 'The atmosphere after the great deoxygenation will be characterized by high methane, low CO₂, and no ozone layer,' said Ozaki. 'Earth will likely become a world dominated by anaerobic life forms.' According to the team's models—based on nearly 400,000 simulations—the oxygen-rich phase of Earth's habitable era may represent only 20 to 30 percent of the planet's total lifespan. While human and other oxygen-dependent life will eventually vanish, microbial life adapted to low-oxygen conditions is expected to persist long after.
India.com
14-05-2025
- Science
- India.com
Trees will turn to ash..., scientists say life on Earth will end sooner than expected, oxygen will vanish in...
Researchers from Japan's Tohoku University have made a striking new prediction about the future of Earth based on simulations run on a supercomputer. According to their study, oxygen on our planet might disappear in about one billion years. Without oxygen to breathe, life as we know it won't be able to survive, leading to the eventual end of life on Earth. The scientists used NASA's planetary climate models to conduct their research. Interestingly, earlier studies had predicted that Earth's oxygen would last for two billion more years, but this new analysis shortens that timeline significantly. The study focused on how Earth's atmosphere might change over time. For this, the team ran around 400,000 simulations. The results showed that as the Sun continues to age, it will get hotter. This increased heat will have serious effects on Earth's climate. Higher temperatures will cause water to evaporate more quickly, surface temperatures will rise, and Earth's carbon cycle which helps keep plants alive will weaken. As a result, plants will start to die off, stopping the production of oxygen. Eventually, the atmosphere will become filled with methane instead of oxygen. This future Earth will look very similar to what it was like before oxygen first appeared in the atmosphere, a time known as the 'Great Oxidation Event.' Titled 'The Future Lifespan of Earth's Oxygenated Atmosphere' , the research suggests that our planet's oxygen-rich atmosphere may only last for another 1 billion years. According to Kazumi Ozaki, an assistant professor from Japan who led the study, scientists have long debated how long Earth's biosphere (the zone of life) might survive. These discussions have been based on various factors like the Sun's brightness and Earth's long-term geochemical carbon-silicate cycles. Ozaki explained that one major outcome of these models is a steady drop in atmospheric CO2 levels over time. Combined with increasing heat, this could eventually lead to conditions where photosynthesis, the process plants use to make oxygen, can no longer occur. In simple words, Earth may become too hot and low on oxygen much sooner than we thought — and that could bring the end of life as we know it.
