Atmospheric CO2 residence time

As mentioned already, the CO2 cycle has one major problem in the atmosphere -there is no direct chemical sink. In nature, CO2 can only be assimilated by plants (biological sink) through conversion into hydrocarbons (Chapter 2.2.2.3) and stored in calcareous organisms, partly buried in sediments but almost completely turned back into CO2 by respiration hence, CO2 partitions between the biosphere and atmosphere. With respect to time periods being of interest for humankind (from decades to hundreds of years) this natural biogeoehemical recycling can be regarded to be closed or, in other words, the net flux is zero  

Indexes + and - denote sources and sinks relative to the atmosphere. Hence, all concentrations (pools) in the biosphere and atmosphere remain constant (we should 

In Chapter 4.5, the theoretical conception of atmospheric residence time will be developed. 

The river run-off (Tables 2.28 and 2.29) is about 0.46 10 g yr carbon and is much larger than the total wet deposited carbonate (0.13 10 g yr carbon). The global volcanic CO2 emission is uncertain and there is given a value (Table 2.41) of 

1015 g yr 1 carbon. We state that the global carbon wet removal is signifi- 

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