- 80 - 



FIGURE B-5 

 STRUCTURE OF THE ORNL CARBON CYCLE MODEL 



ORNL - DWG B1 6057 ESD 



* THIS FIGURE IS TAKEN FROM AN UPDATED MANUSCRIPT BY W.R. 

 EMANUEL AND OTHER AT OAK RIDGE NATIONAL LABORATORY. 



Net uptake of carbon by the oceans is limited by the avail- 

 ability of carbonate ions. The rate at which gaseous C0 2 dissolves 

 in seawater depends on the rate of reaction with C0 3 " , which is 

 the first step of a process by which C0 2 is incorporated into 

 various seawater carbonate compounds. 



The rate at which carbon flows among the various reservoirs 

 is generally dependent on atmospheric temperatures. Sensitivity 

 to temperature is significant, because a rise in temperature is 

 likely to accompany an increase in atmospheric C0 2 . The original 



