Inter-hemispheric linkages in climate change: paleo-perspectives for future climate change

International audience The Pole-Equator-Pole (PEP) projects of the PANASH (Paleoclimates of the Northern and Southern Hemisphere) programme have significantly advanced our understanding of past climate change on a global basis and helped to integrate paleo-science across regions and research discipl...

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Bibliographic Details
Main Authors: Shulmeister, J., Rodbell, D. T., Gagan, M. K., Seltzer, G. O.
Other Authors: Department of Geological Sciences, University of Canterbury Christchurch, Department of Geology, Union College, Research School of Earth Sciences Canberra (RSES), Australian National University (ANU), Department of Earth Sciences Syracuse, Syracuse University
Format: Article in Journal/Newspaper
Language:English
Published: HAL CCSD 2006
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Online Access:https://hal.science/hal-00298056
https://hal.science/hal-00298056/document
https://hal.science/hal-00298056/file/cp-2-167-2006.pdf
Description
Summary:International audience The Pole-Equator-Pole (PEP) projects of the PANASH (Paleoclimates of the Northern and Southern Hemisphere) programme have significantly advanced our understanding of past climate change on a global basis and helped to integrate paleo-science across regions and research disciplines. PANASH science allows us to constrain predictions for future climate change and to contribute to the management of consequent environmental changes. We identify three broad areas where PEP science makes key contributions. 1. The pattern of global changes. Knowing the exact timing of glacial advances (synchronous or otherwise) during the last glaciation is critical to understanding inter-hemispheric links in climate. Work in PEPI demonstrated that the tropical Andes in South America were deglaciated earlier than the Northern Hemisphere (NH) and that an extended warming began there ca. 21 000 cal years BP. The general pattern is consistent with Antarctica and has now been replicated from studies in Southern Hemisphere (SH) regions of the PEPII transect. That significant deglaciation of SH alpine systems and Antarctica led deglaciation of NH ice sheets may reflect either i) faster response times in alpine systems and Antarctica, ii) regional moisture patterns that influenced glacier mass balance, or iii) a SH temperature forcing that led changes in the NH. This highlights the limitations of current understanding and the need for further fundamental paleoclimate research. 2. Changes in modes of operation of oscillatory climate systems. Work across all the PEP transects has led to the recognition that the El NiƱo Southern Oscillation (ENSO) phenomenon has changed markedly through time. It now appears that ENSO operated during the last glacial termination and during the early Holocene, but that precipitation teleconnections even within the Pacific Basin were turned down, or off. In the modern ENSO phenomenon both inter-annual and seven year periodicities are present, with the inter-annual signal dominant. Paleo-data ...