Posted on 10/15/2021 12:33:25 PM PDT by Red Badger
For now, life is flourishing on our oxygen-rich planet, but Earth wasn't always that way – and scientists have predicted that, in the future, the atmosphere will revert back to one that's rich in methane and low in oxygen.
This probably won't happen for another billion years or so. But when the change comes, it's going to happen fairly rapidly, the study from earlier this year suggests.
This shift will take the planet back to something like the state it was in before what's known as the Great Oxidation Event (GOE) around 2.4 billion years ago.
What's more, the researchers behind the new study say that atmospheric oxygen is unlikely to be a permanent feature of habitable worlds in general, which has implications for our efforts to detect signs of life further out in the Universe.
"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," wrote the researchers in their published paper.
At that point it'll be the end of the road for human beings and most other life forms that rely on oxygen to get through the day, so let's hope we figure out how to get off the planet at some point within the next billion years.
To reach their conclusions, the researchers ran detailed models of Earth's biosphere, factoring in changes in the brightness of the Sun and the corresponding drop in carbon dioxide levels, as the gas gets broken down by increasing levels of heat. Less carbon dioxide means fewer photosynthesizing organisms such as plants, which would result in less oxygen.
Scientists have previously predicted that increased radiation from the Sun would wipe ocean waters off the face of our planet within about 2 billion years, but the new model – based on an average of just under 400,000 simulations – says the reduction in oxygen is going to kill off life first.
"The drop in oxygen is very, very extreme," Earth scientist Chris Reinhard, from the Georgia Institute of Technology, told New Scientist earlier this year. "We're talking around a million times less oxygen than there is today."
What makes the study particularly relevant to the present day is our search for habitable planets outside of the Solar System.
Increasingly powerful telescopes are coming online, and scientists want to be able to know what they should be looking for in the reams of data these instruments are collecting.
It's possible that we need to be hunting for other biosignatures besides oxygen to have the best chance of spotting life, the researchers say. Their study is part of the NASA NExSS (Nexus for Exoplanet System Science) project, which is investigating the habitability of planets other than our own.
According to the calculations run by Reinhard and environmental scientist Kazumi Ozaki, from Toho University in Japan, the oxygen-rich habitable history of Earth could end up lasting for just 20-30 percent of the planet's lifespan as a whole – and microbial life will carry on existing long after we are gone.
"The atmosphere after the great deoxygenation is characterized by an elevated methane, low-levels of CO2, and no ozone layer," said Ozaki. "The Earth system will probably be a world of anaerobic life forms."
The research has been published in Nature Geoscience.
A version of this article was first published in March 2021.
If true, which I doubt, it would be caused by dropping CO2.
I would have to disagree. Above 15,000 feet, the atmosphere is still approximately 80% nitrogen and 20% oxygen.
Climate Change!... someday.
Exercise in stupidity! Long before a billion years from now, technology will be able to stabilize atmospheric oxygen.
Therefor our oxygen ocean is only 15,000 feet deep.
You, of all people, should know that.
More than half of all atmospheric oxygen is above 15,000’.
The problem is that around that point the “partial pressure” of the atmospheric O2 is too low for effective absorption in the lungs.
“This probably won’t happen for another billion years or so”
I’m so glad they clarified that. I was afraid it was only going to take a million years or so.
Pls. don't assume.
Atmospheric oxygen goes as high as the rest of the atmosphere.
Don’t assume you’re the only one around here that knows about aviation and supplemental oxygen.
Have a nice day.
DuncanWaring is correct.
SkyDancer...if oxygen stops at 20,000 feet, then how do aircraft fly at altitudes much higher than 20,000?
Jet fuel (and avgas) require oxygen to burn.
Let me guess... women and children will suffer first.
Jet fuel (and avgas) require oxygen to burn.
The air is compressed as it enters the engine; ever hear of compressor blades in a jet engine? What do you think they’re for. ever hear of a super charger? What do you think that’s for?
Some people have actually climbed Mt. Everest without using supplemental oxygen.
They are manipulating the stupid and uninformed
LOL
The sky is falling 🥺
In a billion years 😜
They’ll still be trying to pay off all the trillions libtards are squandering now.
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