Four fairly regular glacial-interglacial cycles occurred during the past 450,000 years. The shorter interglacial cycles (10,000 to 30,000 years) were about as warm as present and alternated with much longer (70,000 to 90,000 years) glacial cycles substantially colder than present. Notice the longer time with jagged cooling events dropping into the colder glacials followed by the faster abrupt temperature swings to the warmer interglacials. This graph combines several ice-core records from Antarctica and is modified from several sources including Evidence for Warmer Interglacials in East Antarctic Ice Cores, 2009, L.C. Sime and others. Note the shorter time scale of 450,000 years compared to the previous figure, as well as the colder temperatures, which are latitude-specific (e.g., Antartica, Alaska, Greenland) temperature changes inferred from the Antarctic ice cores (and not global averages).

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