Guest “not in a billion years” by David Middleton
Earth’s Oxygen is Rapidly Running Out, Dropping Levels Will Eventually Suffocate Most Life on Planet
MARCH 03, 2021, Buzz Staff
Elon Musk may be talking about sending humans to Mars, and Bill Gates may be talking about reversing climate change – but the very air we breathe may run out soon.
/our oxygen-rich atmosphere may only last another billion years, finds a new study. Published in journal in Nature Geoscience, called “The future lifespan of Earth’s oxygenated atmosphere,” explains that even if it won’t happen in the near future, when the change comes, it’s going to happen fairly rapidly.
[…]
The article features this “representative image”…
Is “/our” a typo? Or some arcane journalistic technique? Did Buzz Staff (if that is his real name) think that “soon” and “going to happen fairly rapidly” meant the same thing?
After starting off with, “Earth’s Oxygen is Rapidly Running Out” and “the very air we breathe may run out soon”… They go on to write, “our oxygen-rich atmosphere may only last another billion years.” As a geologist, I tend to think of “soon” as thousands or maybe even a few million years. One billion years is not “soon”… The Phanerozoic Eon is only about 540-560 million years old.
Phanerozoic
Its name derives from the Ancient Greek words φανερός (phanerós), meaning visible, and ζωή (zōḗ), meaning life; since it was once believed that life began in the Cambrian, the first period of this eon. The term “Phanerozoic” was coined in 1930 by the American geologist George Halcott Chadwick (1876–1953).[5][6]
I suppose the Proterozoic Ediacaran critters were alive; but they were weird and hadn’t been noticed in 1930.
“Our oxygen-rich atmosphere may only last another billion years.”
This caveat to the statement that “Earth’s oxygen is rapidly running out… the very air we breathe may run out soon” lacks context.
- Is a billion years a long or shore period of time compared to how long our atmosphere has been oxygen-rich?
- For that matter… How long has our atmosphere has been oxygen-rich?
- When did our atmosphere become oxygen-rich?
- How do you define oxygen-rich?
The “Great Oxidation Event” only took O2 from about zero-point-zero to about 0.1 bar, before it fell back to 0.001 bar. The Cambrian Explosion brought it up to 0.035 bar. The Devonian oxygenation brought it up its current partial pressure of 0.21 bar…
| Billion Years Ago | Atmospheric Oxygen (bar) |
| 0.420 | 0.210 |
| 0.560 | 0.035 |
| 1.000 | 0.001 |
“Earth’s Oxygen is Rapidly Running Out“
This will certainly take care of that wildfire thingy. The “fire window” is defined as an atmospheric oxygen content range of 13-15% to 35%. Below 13-15% fire will not ignite and above 35% fire cannot be extinguished (which would really suck!).
Oddly enough, Earth’s oxygen is running out… Just not “rapidly.”
The atmospheric oxygen level has been slowly declining over time. O2/N2 ratios from Greenland and Antarctic ice cores indicate that atmospheric oxygen has declined by 0.7% over the past 800,000 years (Stolper et al., 2018). At this rate, fire will become extinct in only 8-9 million years. Which will be good because we’ll lack the strength to start fires, much less put them out…
Not Enough Oxygen: Side Effects
Serious side effects can occur if the oxygen levels drop outside the safe zone. When oxygen concentrations drop from 19.5 to 16 percent, and you engage in physical activity, your cells fail to receive the oxygen needed to function correctly. Mental functions become impaired and respiration intermittent at oxygen concentrations that drop from 10 to 14 percent; at these levels with any amount of physical activity, the body becomes exhausted. Humans won’t survive with levels at 6 percent or lower.
Only about 18 million years until we get down to 6% O2…
In other news…
World Leaders Pledge To Cut Emissions By As Much As They Can Realistically Back Out Of
Tuesday 10:15AMBONN, GERMANY—Agreeing that public perception of how they were handling the climate crisis had never been more important, world leaders signed a major new accord Tuesday in which they pledged to cut carbon emissions to the extent that they could realistically back out of a few years from now.
[…]
References
Catling, David & Kevin Zahnle. (2020). The Archean atmosphere. Science Advances. 6. eaax1420. 10.1126/sciadv.aax1420.
Glasspool, Ian & Andrew Scott. (2010). Phanerozoic atmospheric oxygen concentrations reconstructed from sedimentary charcoal. Nature Geoscience. 3. 10.1038/ngeo923.
Ozaki, K., Reinhard, C.T. The future lifespan of Earth’s oxygenated atmosphere. Nat. Geosci. (2021). https://ift.tt/3b9PDW1
Rimmer, S. M., Hawkins, S. J., Scott, A. C., & Cressler, W. L. (2015). The rise of fire: Fossil charcoal in late Devonian marine shales as an indicator of expanding terrestrial ecosystems, fire, and atmospheric change. American Journal of Science, 315(8), 713-733.
https://ift.tt/2LMhbFc
Stolper D, Bender M, Dreyfus G, Yan Y, Higgins J. A Pleistocene ice core record of atmospheric O2 concentrations. Science. 2016;353:1427–1430. doi: 10.1126/science.aaf5445.
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