Using data and models to infer climate and environmental changes during the Little Ice Age in tropical West Africa

Climate of the past

article

Anne-Marie Lézine¹  Maé Catrain¹  Julián Villamayor¹  Myriam Khodri¹ 

[1]Laboratoire d"Océanographie et du Climat, Expérimentation et Approche numérique/IPSL, Sorbonne Université – CNRS-IRD-MNHN

[2]Department of Atmospheric Chemistry and Climate, Institute of Physical Chemistry Rocasolano

DOI  :  10.5194/cp-19-277-2023

学科分类：社会科学、人文和艺术（综合）

来源: Copernicus Publications

【 摘 要 】

Here we present hydrological and vegetation paleo-data extracted from 28 sites in West Africa from 5 ∘  S to 19 ∘  N and the past1000/PMIP4 IPSL-CM6A-LR climate model simulations covering the 850–1850 CE period to document the environmental and climatic changes that occurred during the Little Ice Age (LIA). The comparison between paleo-data and model simulations shows a clear contrast between the area spanning the Sahel and the savannah in the north, characterized by widespread drought, and the equatorial sites in the south, where humid conditions prevailed. Particular attention was paid to the Sahel, whose climatic evolution was characterized by a progressive drying trend between 1250 and 1850 CE. Three major features are highlighted: (1) the detection of two early warning signals around 1170 and 1240 CE preceding the onset of the LIA drying trend; (2) a tipping point at 1800–1850 CE characterized by a rainfall drop and an environmental degradation in the Sahel; and (3) a succession of drying events punctuating the LIA, the major one of which was dated to around 1600 CE. The climatic long-term evolution of the Sahel is associated with a gradual southward displacement of the Inter-Tropical Convergence Zone induced by the radiative cooling impacts of major volcanic eruptions that have punctuated the last millennium.

【 授权许可】

CC BY