'" I II ITI IT 



T7TTT 



II 1 1 1 1 1 pmr 



1 1 1 1 1 1 inn 



lima 



I 



ESTIMATED LIMIT OF ALL KNOWN ICE 



xu_ 



3 



3 



45 



3 



/14 



0_ 



43 



42 



41 



40 



39 



38 



15 JULY 1981 

 FIGURE 3i 



TTT-miii I 11 1 I I I II I I I I I I I 11 I ] I II I I II I J I I I ' I I ■' I I II I 1 I I nil I 1 mH i mil 



57 56 55 54 53 52 51 50 49 48 47 46 45 44 43 



40 



