Lecture_13 - LECTURE 13 ABRUPT CLIMATE CHANGE 1.0 Penultimate Interglacial Phase Warming phase that took Earth out of extreme glacial phase Began

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LECTURE 13: ABRUPT CLIMATE CHANGE 1.0 Penultimate Interglacial Phase - Warming phase that took Earth out of extreme glacial phase. Began sometime between 130,000-140,000 years ago and lead to conditions generally warmer than those today. Warm phase lasted ~10,000 years Referred to in marine record as oxygen isotope stage 5e, in North American terrestrial record known as Sangamon interglacial. In European terrestrial record known as Eemian warm stage. Initial evidence from oxygen isotope records from two ice cores from central Greenland drilled in the early 1990s suggests warm phase punctuated by short-lived cold events. Record prior to 110,000 years, however, in doubt because of folding near the bedrock. . New data from North Greenland ice core drilled between 1996 and 2003 extends back 123,000 years and includes undisturbed record of last interglacial period. Oxygen isotopes published in 2004 imply climate was stable during the last interglacial period, with temperatures in Greenland ~5°C warmer than today. Marine oxygen isotope records from NE Atlantic and Bahama Ridge indicate very little or no climatic variability during warm phase but records from Nordic Seas and west of Ireland show a cooling of several degree and freshening of North Atlantic between 122,000 and 125,000. Phase ended with a rapid cooling about 110,000 years ago that took <400 years.
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2.0 Last Glacial Event - Cooling phase that took Earth out of extreme penultimate warm phase. Marine oxygen isotope records indicates last glacial event began about 110,000 years ago and lead to conditions very much colder than those today. Cold phase lasted until ~18,000 years ago. Possible series of events initiating last glacial event.
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This note was uploaded on 07/25/2008 for the course ISP 203A taught by Professor Larson during the Fall '08 term at Michigan State University.

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Lecture_13 - LECTURE 13 ABRUPT CLIMATE CHANGE 1.0 Penultimate Interglacial Phase Warming phase that took Earth out of extreme glacial phase Began

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