title: Synchronous interhemispheric Holocene climate trends in the tropical Andes.
abstract: Holocene variations of tropical moisture balance have been ascribed to orbitally forced changes in solar insolation. If this model is correct, millennial-scale climate evolution should be antiphased between the northern and southern hemispheres, producing humid intervals in one hemisphere matched to aridity in the other. Here we show that Holocene climate trends were largely synchronous and in the same direction in the northern and southern hemisphere outer-tropical Andes, providing little support for the dominant role of insolation forcing in these regions. Today, sea-surface temperatures in the equatorial Pacific Ocean modulate rainfall variability in the outer tropical Andes of both hemispheres, and we suggest that this mechanism was pervasive throughout the Holocene. Our findings imply that oceanic forcing plays a larger role in regional South American climate than previously suspected, and that Pacific sea-surface temperatures have the capacity to induce abrupt and sustained shifts in Andean climate.
authors: Division of Biology and Paleo Environment, Lamont-Doherty Earth Observatory of Columbia University, Palisades, NY 10964, USA. polissar@ldeo.columbia.edu
authors: Pratigya J
authors: PJ
authors: Polissar
authors: Mark B
authors: MB
authors: Abbott
authors: Alexander P
authors: AP
authors: Wolfe
authors: Mathias
authors: M
authors: Vuille
authors: Maximiliano
authors: M
authors: Bezada
mesh_terms: D000531:Altitude; D002244:Carbon / Q000378:metabolism; D002980:Climate; D005843:Geography; D019015:Geologic Sediments / Q000737:chemistry; D009584:Nitrogen / Q000378:metabolism; D010140:Pacific Ocean; D025341:Principal Component Analysis; D011891:Rain; D012621:Seasons; D012623:Seawater; D013020:South America; D013696:Temperature; D013997:Time Factors
chemical_list: D002244:Carbon; D009584:Nitrogen
keywords: Bolivia; Caribbean; El Niño-Southern Oscillation; Milankovitch; Venezuela
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