Ice age

An ice age is a period when for a long time the temperature of Earth's climate is very low. This leads to an expansion of the continental ice sheets, polar ice sheets and mountain glaciers.

'Ice age' is a term used in palaeoclimatology for the period of extensive ice sheets in the recent Pleistocene period. We now know that ice ages have happened a number of times in the past, the greatest and longest of which took place in the Proterozoic era, before multi-cellular eukaryotes evolved.^[1]^[2]

During ice ages the sea level drops as water is held in the great ice sheets at the poles. How much it drops depends on several factors, such as the length of time that a cold period lasts.

↑ Imbrie J. & Imbri, K.P. 1979. Ice ages: solving the mystery. Short Hills NJ: Enslow. ISBN 978-0-89490-015-0
↑ Alley R.B. 2000. The two-mile time machine: ice cores, abrupt climate change, and our future. Princeton University Press. ISBN 0-691-10296-1

[1] Imbrie J. & Imbri, K.P. 1979. Ice ages: solving the mystery. Short Hills NJ: Enslow. ISBN 978-0-89490-015-0

[2] Alley R.B. 2000. The two-mile time machine: ice cores, abrupt climate change, and our future. Princeton University Press. ISBN 0-691-10296-1

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