Terrestrial biosphere, carbon dioxide

Prentice, K. C. The Influence of the Terrestrial Biosphere on Seasonal Atmospheric Carbon Dioxide An Empirical Model Ph.D. Dissertation, Columbia University, New York, NY, 1986. 

Future changes in methane are difficult to estimate because we do not yet have complete knowledge of the sources and sinks of methane. The recent slowing down in the increase of methane is not well understood. Another problem concerns possible changes in the future carbon cycle. Will the future uptake of carbon in the terrestrial biosphere increase faster or slower than the emission of carbon dioxide or not To better understand the carbon cycle in a changing climate is one of the big challenges of the future. 

First I want to review some relevant information regarding the global carbon cycle and the processes that affect atmospheric concentrations of carbon dioxide. There are vast reservoirs of carbon in the system (see Figure 3.1) that can exchange fairly rapidly with the atmosphere, which contains about 750 gigatons (1 gigaton = 10 tons) of carbon (GtC). The terrestrial biosphere and soils contain about 2,000 GtC the mixed layer of the ocean contains about 1,000 GtC and the deep oceans, 38,000 GtC. 

In addition, there are vast natural cycles involving two-way exchanges of CO2 into and out of the terrestrial biosphere through respiration, photosynthesis, and decay. Carbon dioxide is also exchanged into and out of the ocean through the mixed layer, by thermodynamic processes of gaseous invasion and... 

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