Earth CO2 dynamics: from CO2 to organic matter and organic matter back to CO2 – an estimate of fluxes

Abstract

The Earth CO2 is constantly changing. During photosynthesis CO2 is assimilated and immobilized in the form of organic matter. In the other way around, under the action of chemical and biochemical processes, the CO2 of the organic matter is released again into the atmosphere. The current concentration of CO2 in the atmosphere is about 390 ppm. Based on information from the literature, it is possible to estimate the amount of organic matter produced from the CO2 available in the atmosphere. On the other hand, by incinerating all the plant and animal organic matter on the Earth, it is possible to estimate the amount of CO2 produced and released to the atmosphere. In order to test these hypotheses, mathematical models were developed. By the models it is possible to estimate that if all CO2 in the atmosphere is assimilated via photosynthesis, it would produce 296 Mg.ha-1 of organic matter. On the other hand, by incinerating all vegetable and animal organic matter from the Earth, excluding petroleum, coal and other carbon sources, and considering an average value of 100 Mg.ha-1 the CO2 concentration in the atmosphere would increase by 131.8 ppm. This value added to the existing 390 ppm would raise CO2 concentration to 521.8 ppm. According to the models and results presented, forests may not be as important as carbon accumulators, making the environment conducive to life on Earth, but according to literature they are essential in the formation of rainfalls and maintenance of humidity, especially in areas far from the oceans and seas.