A VENERABLE CLIMATIC FALLACY 



T. C. CHAMBERLIN 



University of Chicago 



Warm climates within the polar circles and glacial climates 

 on the borders of the tropics are justly regarded as the most out- 

 standing features of geologic climates. That these contrasted 

 climates should have intervened between one another to form an 

 oscillating series adds a feature of the first order of significance. 

 The glaciations on the borders of the tropics seem at first thought 

 the more remarkable, and perhaps they are so, but when it is con- 

 sidered that five miles of ascent brings a greater fall of temperature 

 than a change of 3,000 miles in latitude, there is reason to raise the 

 question whether the transfer of low-latitude warmth to high lati- 

 tudes is not after all the weightier feature. However this may be, 

 mild climates in high latitudes are features of the highest order of 

 interest. 



Now for more than half a century it has been widely maintained 

 that an extension of the sea would at least help explain the mild 

 climates in high latitudes, if indeed it would not furnish a full ex- 

 planation. In addition to this particular application, the doctrine 

 that sea extension contributes to warmth of climate has found many 

 other expressions in geologic literature. 



This habitual association of warmth with sea extension seems 

 to have grown out of the earlier view that in primitive times a warm 

 ocean covered the whole earth. Starting with this concept, the 

 differentiation of climates was held to have grown gradually out 

 of universal warmth by general cooHng attended by the emergence 

 of the land and the reduction of the sea surface. The association 

 of the sea with warmth and the land with lower temperature was 

 natural under these assumptions. 



When the study of the widespread phases of glaciation began — 

 about a century ago — a general extension of glaciation was only 



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