The Earth has a date with death. Not the kind of death you imagine, though: the one where everything explodes and ends in a bang. No, it will be a death by suffocation. Slow, inexorable, scientifically predictable. In a billion years, the Earth's atmosphere will lose all its oxygen and we, along with almost everything alive today, will no longer be here. They calculated it Kazumi Ozaki e Chris Reinhard, two researchers who dared to ask an uncomfortable question: how long will the air we breathe last? The answer is chilling (and fascinating).
The Sun ages and condemns us all
The mechanism is simple. As the Sun ages, it becomes brighter and hotter. This extra heat will evaporate more carbon dioxide from the atmosphere, breaking down CO2 molecules. Less carbon dioxide means less photosynthesis, and less photosynthesis means goodbye oxygen.. It's a chain reaction that will cause oxygen levels to drop a million times lower than they are today.
The authors of the study, published in Nature Geoscience, they used complex models that simulate climate, biology and geology for over 400.000 different scenarios. The result is always the same: in 1,08 billion years (plus or minus 140 million), atmospheric oxygen will drop below 1% of current levels.
The Future Without Oxygen? A Return to the Primordial Past
This transformation will return Earth to the conditions of the Archean Eon, when the planet had an atmosphere rich in methane and devoid of free oxygen. Back then, about 4 billion years ago, life was limited to single-celled organisms that did not need to breathe. The Oxygen Catastrophe 2,4 billion years ago had changed everything, allowing the evolution of complex life forms. But the future holds a catastrophe in reverse.
“We're talking about about a million times less oxygen than there is today,” he explained. Reinhard. No plants, no animals, no humans. Only anaerobic bacteria that will thrive in a methane-dominated atmosphere.
Why the discovery changes extraterrestrial research
This research has enormous implications for the hunt for life in the universe. If atmospheric oxygen only characterizes 20-30% of a planet's life, Search only for oxygen in exoplanets could cause us to miss many opportunities. The researchers suggest expanding the search to other biomarkers.
The most disturbing thing? All this is inevitable. It is not climate change or human pollution, but the normal aging of our solar system. It is written in stellar physics, as inescapable as gravity.
Besides, you know, organisms without oxygen already exist.
As we have pointed out, nature has already experimented with life without oxygen. The parasite Henneguya Salminicola lives peacefully without breathing, proving that evolution always has hidden cards to play.
The time we have left
In the meantime, I hope you appreciated the approach to the news. Surely you will read it elsewhere with some headline like “help!11!1 The oxygen is running out!”: what you won't do for a click.
But, between you and me, a billion years may seem like an eternity, but in geological terms it is the blink of an eye. For comparison, complex life on Earth It appeared precisely in this time frame.
The search for Ozaki of Toho University e Reinhard of the Georgia Institute of Technology reminds us of an uncomfortable truth: Nothing lasts forever, not even the air we breathe.. But at least we know now, and we have a lot of (human) time to think about it. If we can stick around for another billion years, that is.
