ATMOSPHERIC CARBON DIOXIDE AND RADIOCARBON: I 



77 



RELATIVE SIZE OF LAND BIOTA 



t 3 



STANDARD 



< N bo + N eo» /N ao] 



Fig. 21 Fraction of industrial C0 2 remaining in the lower atmosphere as a 

 function of the relative size of the land biota, for several values of the 

 atmosphere to ocean transfer time, Tjj,,, and a biota growth factor of 0.25. 

 The average fraction observed from 1959 to 1969 (42%) is indicated by a 

 horizontal line, and the size of the biota used as a standard case 

 (Njj + N eu = 2.656 N ao ) is indicated by an arrow. 



records of industrial production and sunspot numbers to examine in greater 

 detail the properties of the natural carbon cycle and to make time-dependent 

 predictions. 



ACKNOWLEDGMENTS 



We thank Paul Damon, Johann Vogel, George M. Woodwell, and Hans Suess 

 for advice regarding the land biota and radiocarbon, and Peter Guenther and 

 Alex Adams for help in carrying out the computations. The authors are also 

 indebted to Anne Thistle for special help in preparing the typescript. Support 

 was given by the Atmospheric Sciences Division of the National Science 

 Foundation under Grant GA-31324X. 



