How much dioxygen does the entire population of earth consume in a year?

Answer 1

We consume Oxygen directly by breathing, and causing or allowing it to react in obvious dramatic activities like starting a fire or simply leaving an cut apple to turn brown as is slowly oxidies. We also cause oxygen to be consumed/used by, say turning on a light by burning gas or coal at a power station.

I have no idea of how to calculate the second part of that list but a first approximation of the first part, human respiration, should simply be the product of an estimate of the amount of oxygen used (not simply breathed) per unit time and the population in question.

I have read several sources and it appears that throuhg day/night, winter/summer etc. we use about 10 cubic feet of Oxygen a day.

The population of the Earth is not static but let's take it to be 7.1 billion.

So, in an average year 10 ft3 x 365 x 7,100,000,000 = 7.36*1013 ft3 Oxygen will be consumed by the people of the Earth.

HOWEVER that's not a really useful answer as it's not included the other uses or consumption of Oxygen mentioned at the start. It does not give a context for the vast number we just produced (are we teetering on the edge of our requirements? will the next million trees felled take us into Oxygen decline?)

ADDITIONALLY once you have breathed in Oxygen and used the energy and reactivity in staying alive we eventually (minutes/hours) return it to the atmosphere in several forms including the C2O we breathe out which will, in all likelihood be taken up by vegetative respiration and, in the great roundabout of life, release Oxygen into the atmosphere.

Beano UK