What Would Human Evolution Entail If Oxygen Levels Plummeted to 10%?

The Earth's current atmospheric oxygen content is about 21%. But what if it plummeted to a mere 10%? Would humans evolve in response to this drastic change, or would we simply perish?

Implications for Human Survival

If oxygen levels dropped to 10% quickly, it would have a major existential impact on animal life. The sudden reduction would cause almost everyone to blackout and could result in widespread death. However, those living at high altitudes, such as in Denver, Colorado, which is a mile high, are already acclimatized to low oxygen levels. If these individuals could quickly descend to sea level, they would still be functional. The high-altitude individuals, with more efficient blood and lungs, would likely eventually take over the world.

The Case of the Permian-Triassic Mass Extinction

During the Permian-Triassic mass extinction, which occurred approximately 252 million years ago and is often referred to as "The Great Dying," oxygen levels dropped to around 10%. The synapsid clade, to which humans and their closest relatives belong, was decimated during this time. This mass extinction event was supplanted by archosaurs, which had more efficient respiratory systems.

If the current atmospheric oxygen levels were to persist at 10%, it is very likely that humans would not have evolved at all. The drastic reduction in available oxygen would have severely impacted the development and survival of our species.

What Would Be the Long-Term Effects?

Even if the drop in oxygen levels were gradual and detected early, the global community would likely debate potential solutions. Governments and committees would have to address this issue, but it is likely that some would dismiss the reality of the situation, attributing it to conspiracy theories. Only those individuals with exceptional lung tissue capable of extracting minimal amounts of oxygen would stand a chance of survival.

The survival of the species would depend on the existence of individuals with both opposing genders and the necessary respiratory adaptations. Even without such adaptations, these individuals would have to rely on their remaining oxygen to survive.

Conclusion

The Earth's atmosphere is delicately balanced, and a drop in oxygen levels to 10% would have significant and far-reaching effects on human evolution and survival. Whether we would adapt or succumb to the changed environment, it is clear that such a drastic change would challenge our species in unprecedented ways.