30 MACHTA 



At this time, I feel we are in a less confident position to forecast the future 

 climate due to the combustion of fossil fuels than to estimate the increase in 

 atmospheric C0 2 concentrations. 



ACKNOWLEDGMENT 



The support of this work by the Division of Biology and Medicine, U. S. 

 Atomic Energy Commission, is gratefully acknowledged. 



REFERENCES 



1. W. Bischof, Carbon Dioxide Measurements from Aircraft, Tellus, 22: 545-549 (1970). 



2. L. Machta, Mauna Loa and Global Trends in Air Quality, Bull. Amer. Meteorol. Soc., 

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3. H. Lieth, Phenology in Productivity Studies, in Ecology Studies, pp. 29-40, Springer- 

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4. L. Machta, The Role of the Oceans and Biosphere in the Carbon Dioxide Cycle, in 

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5. United Nations, World Energy Supply, Statistical Papers, Series J, United Nations, New 

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6. S. Manabe and R. T. Wetherald, Thermal Equilibrium of the Atmosphere with a Given 

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8. C. L. Wilson, W. H. Matthews, W. W. Kellogg, and G. D. Robinson (Eds.), Inadvertent 

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 The MIT Press, Cambridge, Mass., 1971. 



9. J. C. Pales and C. D. Keeling, The Concentration of Atmospheric Carbon Dioxide in 

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10. C. D. Keeling and A. E. Bainbridge, personal communication, 1971. 



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DISCUSSION BY ATTENDEES 



Wallis: If we disallow changes in the accumulation of carbon in the biomass, 

 would you speculate on the climatic change that this would introduce into your 

 model? 



Machta: A run on the computer with all model parameters repeated except 

 for the biota (i.e., no fossil-fuel C0 2 enters the biota) predicts an increase in 



