Collapse of the California Current During Glacial Maxima Linked to Climate Change on Land

• DOI: 10.1126/science.1059209
• Publication Date: 2002-07-27T09:53:24Z
• Authors: T. D. Herbert; J. D. Schuffert; D. Andreasen; L. Heusser; M. Lyle; A. Mix; A. C. Ravelo; L. D. Stott; J. C. Herguera
• Keywords: Deglaciation; Alkenone; Last Glacial Maximum; Milankovitch cycles; Paleoclimatology; Orbital forcing

Time series of alkenone unsaturation indices gathered along the California margin reveal large (4° to 8°C) glacial-interglacial changes in sea surface temperature (SST) over past 550,000 years. Interglacial times with SSTs equal or exceeding that Holocene contain peak abundances pollen redwood, distinctive component temperate rainforest northwest coast California. In region now dominated by Current, warmed 10,000 15,000 years advance deglaciation at each five glacial maxima. did not rise south modern Current front. Glacial warming therefore is a regional signal weakening during when ice sheets reorganized wind systems North Pacific. Both timing and magnitude SST estimates suggest Devils Hole (Nevada) calcite record represents but global paleotemperatures, hence does pose fundamental challenge orbital (“Milankovitch”) theory Ice Ages.