Mass of People
- About one trillion pounds - https://hypertextbook.com/facts/2006/DanielTouger.shtml
- Compare that to mass of iron - 5% * 6^24 kg= 0.05*6 = 3^23 kg of iron
- Trillion is 10^12 - so about one million tons of iron per person.
Ie, if you take a heap of people, each owns about 1 trillion pounds of steel. Carbon availability happens to be 4% of that - so we are perfectly fit for turning all iron into high carbon steel.
Ie, there is no risk of running out of iron on earth.
O, Si, Al, Fe are most abundant.
