lecture_3a - LECTURE 3a - CAUSES OF ICE AGES QUATERNARY...

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LECTURE 3a - CAUSES OF ICE AGES QUATERNARY CLIMATE Current worldwide average temperature is about 14 ° C ( 58 ° F). Deep sea record shows about 30 warm and 30 cold stages within the Pleistocene. During the last 600 ka a cold stage/warm stage cycle had a period of about 100 ka. Before this a 40 ka period was dominant. Some of the coldest periods, which represents the glacial phases, had mean annual temperatures in the order of 10-20 ° C lower than today in areas beyond the ice sheets in Europe and North America. In parts of the subtropics and continental tropics the temperatures during glacial phases were about 4-7 ° C lower than today. Along the marine equator, temperatures during glacial phases were only slightly lower, or no lower, than today Temperatures during interglacials were analogous to present temperatures, but in North America and Europe may have been as much as 2 ° C higher during summer. CONCLUSION: We currently live in an ice age. The present “warm stage” still belongs to cold episode of the earth’s history . ASTRONOMICAL FACTORS
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This note was uploaded on 07/25/2008 for the course GLG 412 taught by Professor Larson during the Spring '08 term at Michigan State University.

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lecture_3a - LECTURE 3a - CAUSES OF ICE AGES QUATERNARY...

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