understand the remarkable instability of late Quaternary global climate prior to the begin-ning of the Holocene, about 11,000 years ago. This unusual climate behavior was charac-terized by millennial-scale climate oscillations on suborbital timescales, and a distinctive ‘sawtooth ’ pattern of very a...
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| Format: | Text |
| Language: | English |
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| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.651.541 http://walrus.wr.usgs.gov/reports/reprints/Nicholson_Eos_87.pdf |
| Summary: | understand the remarkable instability of late Quaternary global climate prior to the begin-ning of the Holocene, about 11,000 years ago. This unusual climate behavior was charac-terized by millennial-scale climate oscillations on suborbital timescales, and a distinctive ‘sawtooth ’ pattern of very abrupt glacial and stadial terminations (within decades) followed by more gradual global cooling [e.g., Dans-gaard et al., 1993; Hendy and Kennett, 1999]. The fact that both major (glacial) and minor (stadial) cooling periods in Earth’s climate were terminated by similar abrupt warming episodes suggests a common mechanism driving such rapid changes in global climate. Understanding the causes of this instability is crucial given developing concerns about global warming, yet knowledge about this climate behavior has been essentially con-fined to the last 150,000 years or so, owing to the absence of available sequences of suffi-cient age and chronological resolution. The high-resolution paleoclimate record from the Greenland ice cores is limited to about 110 thousand years ago (ka), and although Ant-arctic ice cores now extend back to more than 740 ka [European Project for Ice Coring in Antarctica, 2004], these latter cores primar-ily provide information about high-latitude conditions at much lower resolution than is required to address abrupt climate change. Longer high-resolution paleoclimate records are thus essential to understanding the natural mechanisms of global climate change. Ideally, such records should repre-sent changes in both the atmosphere and oceans, and at low, middle, and high latitude sites. For this reason, high-resolution paleocli-mate records extracted from marine sedi-ment cores are of critical importance. |
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