The dilemma of the dwarf Earth's CO2 degassing: Irrelevant or crucial?

Abstract:

The role of Earth's CO2 degassing is often confined to the definition of its limited absolute value and considered

irrelevant to the global CO2 emission budget. Results reported in literature are contradictory leading to the

evidence that the global Earth's CO2 degassing, independently from its absolute value, is virtually unknown.

Global estimates are inconsistent with point source volcanic degassing and with the new discovered diffuse

degassing sources. In the last twenty years, global Earth's CO2 flux extrapolations increased with the number

of measurements from 110 to 937 Mt/yr. Updated addition of CO2 degassing measurements from less than 10%

of recognized geological sources equals the mostly agreed global estimates. Careful analysis of data shows

evidence of large uncertainties on the estimates of CO2 Earth's degassing, requiring a better understanding of

the physical and geological mechanisms behind climate variability and of processes governing the global carbon

cycle. Beside model uncertainties and stabilization scenarios, an unknown value of the natural Earth's emissions,

with a distinctive C isotopic ratio, leads to inadequate parameterization of unsettled pivotal processes relevant to

studies of the global carbon cycle, atmospheric processes, ocean and land uptake, air–sea exchanges, and mantle

petrology and dynamics.