264 



ANNUAL REPORT SMITHSONIAN INSTITUTION, 1950 



These figures are regarded as being somewhat liberal and the quan- 

 tity of oil may actually be considerably less.' 



In addition to the above, the Athabaska Tar Sands (10) are esti- 

 mated to contain about 30 X 10^ cubic meters of oil. 



The amount of natural gas may be estimated at 400 cubic meters 

 of gas per 1 of oil, or at an energy content of 40 percent that of oil. 



The oil shales of the world are less well known. Those of the United 

 States, especially the Green River shales, are estimated to contain at 

 least 55X10^ cubic meters of oil. Assuming that the rest of the 

 world has about three times as much oil shale as the United States, 

 we would obtain, for an order of magnitude, 160X10^ cubic meters 

 (1,000 billion barrels) of oil from this source. 



TOTAL ENERGY OF FOSSIL FUELS 



ENERSY (IO'*Kg-Cal) 



FiGUBE 5. 



The results of these estimates are given in table 1 and shown graph- 

 ically in figure 5. It will be noted in particular that 92 percent of 



" Since the foregoing was first published the author has obtained directly from Dr. L. G. 

 Weeks his own estimate of the total world supply of petroleum, which is more conservative 

 than the figures cited above. For the land areas Dr. Weeks estimates an amount of about 

 600 billion barrels (96x10" m.'), and for the continental shelves about 400 billion barrels 

 (64X10» m.3), giving a total of 1,000 billion barrels, or 160Xl0».m.5, which is just half 

 the figure employed above. 



These figures were also given in a written discussion, by Dr. Weeks, of a paper by Prof. 

 A. I. Levorsen on "Estimates of Undiscovered Petroleum Reserves" read before the United 

 Nations Scientific Conference on the Conservation and Utilization of Resources at Lake 

 Success, August 22, 1949. (See Weeks, L. G., Highlights on 1947 developments In foreign 

 petroleumi fields. Bull. Amer. Assoc. Petrol. Geol., vol. 32, No. 6, p. 1094, June 1948 ; 

 Levorsen, A. I., Estimates of undiscovered petroleum reserves, Proc. U. N. Scientific Con- 

 ference on the Conservation and Utilization of Resources, vol. 1, Plenary Meetings, pp. 

 94-99, and discussions, pp. 103-104, by M. King Hubbert, and pp. 107-110, by L. G. 

 Weeks, 1950.) 



