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On the remote impacts of mid-Holocene Saharan vegetation on South American hydroclimate: a modelling intercomparison
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  • Shivangi Tiwari,
  • Riovie D. Ramos,
  • Francesco S.R. Pausata,
  • Allegra N. LeGrande,
  • Michael Griffiths,
  • Hugo Beltrami,
  • ILana Wainer,
  • Anne de Vernal,
  • Daniel T. Litchmore,
  • Deepak Chandan,
  • W Richard Peltier,
  • Clay R Tabor
Shivangi Tiwari
University of Quebec in Montreal

Corresponding Author:[email protected]

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Riovie D. Ramos
William Paterson University
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Francesco S.R. Pausata
University of Quebec in Montreal
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Allegra N. LeGrande
NASA Goddard Institute for Space Studies and Center for Climate Systems Research
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Michael Griffiths
William Paterson University
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Hugo Beltrami
St. Francis Xavier University
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ILana Wainer
Universidade de Sao Paulo
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Anne de Vernal
GEOTOP-UQAM
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Daniel T. Litchmore
Columbia University
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Deepak Chandan
University of Toronto
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W Richard Peltier
Department of Physics, University of Toronto
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Clay R Tabor
University of Connecticut
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Abstract

Proxy reconstructions from the mid-Holocene (MH: 6,000 years ago) indicate an intensification of the West African Monsoon and a weakening of the South American Monsoon, primarily resulting from orbitally-driven insolation changes. However, model studies that account for MH orbital configurations and greenhouse gas concentrations can only partially reproduce these changes. Most model studies do not account for the remarkable vegetation changes that occurred during the MH, in particular over the Sahara, precluding realistic simulations of the period. Here, we study precipitation changes over northern Africa and South America using four fully coupled global climate models by accounting for the Saharan greening. Incorporating the Green Sahara amplifies orbitally-driven changes over both regions, and leads to an improvement in proxy-model agreement. Our work highlights the local and remote impacts of vegetation and the importance of considering vegetation changes in the Sahara when studying and modelling global climate.