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What I find so interesting is why is the oxygen on Earth 21% why not 5%. I can understand why not 90% since it's so reactive but 21% seems so high. Even more s
by dghughes 10y ago
What I find so interesting is why is the oxygen on Earth 21% why not 5%.
I can understand why not 90% since it's so reactive but 21% seems so high. Even more so now in modern times with seven billion people and billions of other animals plus industrialization I'd expect atmospheric oxygen to be falling rapidly.
We humans are pretty lucky to be able to breath, thank you ocean algae! Honorable mention to trees, good job.
- dmd 10y agoJust to give some scale here: A human uses about 0.84 kilograms O2 per day. There is about 5e18 kg O2 in the atmosphere. Excluding all other sources of O2 consumption and replenishment, it would take about 500000 years for the current population of humans to "use up" all the current O2.