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Comment by bongobingo1 | Hacker News Reader

Are we likely to discover in (* x 10) years that an over saturation of O2 in the atmosphere is damaging in some kind of way, on a global scale? AFAIK breathing pure O (or O2? Not a chemist) isn't great for your health?

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It is famously damaging, so much so that the event that led to the current high concentration of oxygen in the atmosphere is called the https://en.wikipedia.org/wiki/Oxygen_Catastrophe

Luckily, all the damage is already done, and our ecosystem is now well adapted to living in a bath of toxic gas.

I've always found it funny that oxygen, commonly pictured as the benevolent stuff of life, is actually such so dangerous biologically. It's really a change in perspective when you realize that the reason we can't survive for five minutes without it is that we're running countless tiny power plants that use volatile chemicals and constantly struggle to dispose of the toxic byproducts.

> I've always found it funny that oxygen, commonly pictured as the benevolent stuff of life, is actually such so dangerous biologically.

Water is similar.

The essence of life is turning things into other things; doing so is difficult and dangerous.

Earth atmosphere is 21% O2 vs. 0.04% CO2 (up from ~0.03% CO2 prior to the human era.) Had all the gigatons of CO2 pumped into the atmosphere by human activities instead been O2, the effect would be negligible.

Atmospheric O2 is about 21%. CO2 is about 0.042% currently. It's 2 orders of magnitude difference, which is also why human activity can have a relatively large impact on CO2 concentration.

I would assume all the methanol produced this way is burned, taking the generated O2 from atmosphere to CO2.

Medical oxygen tanks are over 85%.

That said everything would be more flammable.

Such a high level makes the terrifyingly large insects of the dinosaur era possible again

Here's a funny posting by the Terminix (bug spray) folks: https://www.terminix.com/blog/bug-facts/giant-prehistoric-bu...

It was actually before dinosaurs (Devonian and Cambrian Periods).

Probably not. Those large insects and other bugs could flourish because they didn't have effective competition. But increasing the oxygen level today isn't going to remove the ecosystem that prevents giant bugs from developing again.

Analogously, there's nothing about the atmosphere preventing giant ground sloths from existing, but they nevertheless can't exist because they're not compatible with humans.

They can't exist because they were exterminated in the comet strike of 10,818 BCE.

We don't know whether they would have coexisted with us. E.g., hippo population in Columbia is exploding. Megatherium sp. coexisted with hunter-gatherer humans for at least thousands of years.

Horses and camels can coexist with humans. They too were obliterated in the Americas by the comet strike.

But we anyway know people did hunt all of them, before that.

It's certainly not good for newborn babies - look up retinopathy of prematurity.

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