Almost all the oxygen we humans and all living animals breathe origins from “lungs of the earth” – the green plants.
Many scholars and students seem to have forgotten that cutting down trees and vegetation leads to/causes more problems than the problem of instabil soil when water in terrain isn’t “looked up” in ecosystem roots. More problems occur when due to deforestation in urban than in rural areas. But each deforestation taking place in old forest areas always causes problems no matter if it’s in rain-forest or up on high levels in mountains/alps.
It is Photosynthesis that gives us humans the oxygen we need. CO2 is “food” for green plants and the photosynthesis produces oxygen at same time it produces needed sugar of the coal for the plants.
Coal is energy (“food”) for the plants.
Formula in words for photosynthesis:
carbon dioxide + water + light energy → sugar + oxygen
Chemical formula for photosynthesis:
6CO2 + 6H2O + hν → C6H12O6 + 6O2
In short: CO2 in the atmosphere (and/or in the form of carbonates from water) and H2O which is absorbed by the roots of green plants gives us humans the oxygen we need to breathe.
The process is called photosynthesis and constitutes one of the basic skills that all should have been taught to understand before passing 7th year in school. Ie everyone should have been taught in order to understand the process before the chemistry lessons that provide chemical formula for the process is taught in later school years.
Source: Kolets kretslopp Fotosyntesens kemi, Magnus Ehinger.nu/undervisning (Swedish text)
Fotosyntes, växten.slu.se (Swedish text)
Photosynthesis is one of the conditions for life on Earth. The process needs solar energy radiation is in addition to carbon dioxide and water, in order to produce oxygen for us to be able to breathe and energy (sugar from coal)for the green plants to live on.