Regime Shifts in the Sahara and Sahel: Interactions between Ecological and Climatic Systems in Northern Africa

Regime Shifts in the Sahara and Sahel: Interactions between Ecological and Climatic Systems in Northern Africa
  author={Jonathan A. Foley and Michael T. Coe and Marten Scheffer and Guiling Wang},
The Sahara and Sahel regions of northern Africa have complex environmental histories punctuated by sudden and dramatic “regime shifts” in climate and ecological conditions. Here we review the current understanding of the causes and consequences of two environmental regime shifts in the Sahara and Sahel. The first regime shift is the sudden transition from vegetated to desert conditions in the Sahara about 5500 years ago. Geologic data show that wet environmental conditions in this region—giving… 

Climate-Driven Ecosystem Succession in the Sahara: The Past 6000 Years

This gradual rather than abrupt termination of the African Humid Period in the eastern Sahara suggests a relatively weak biogeophysical feedback on climate.

Climate and vegetational regime shifts in the late Paleozoic ice age earth

The oscillatory transition between humid and seasonally dry vegetation appears to demonstrate a threshold-like behavior but probably not repeated transitions between alternative stable states, whereas changes in dominance in lowland equatorial regions were driven by long-term, repetitive climatic oscillations.

Humans as Agents in the Termination of the African Humid Period

  • D. Wright
  • Environmental Science
    Front. Earth Sci.
  • 2017
There is great uncertainty over the timing and magnitude of the termination of the African Humid Period (AHP). Spanning from the early to middle Holocene, the AHP was a period of enhanced moisture

Lowland forest collapse and early human impacts at the end of the African Humid Period at Lake Edward, equatorial East Africa

Abstract In Africa, the early Holocene was characterized by wetter, warmer conditions than today, followed by rapid aridification at ~5.2 ka. However, a lack of lowland vegetation records has

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Palaeoproxy records alone are seldom sufficient to provide a full assessment of regional palaeoclimates. To better understand the possible changes in the Mediterranean climate during the Holocene, a

Disentangling the effects of climate and people on Sahel vegetation dynamics

Abstract. The Sahel belt of Africa has been the focus of intensive scientific research since the 1960s, spurred on by the chronic vulnerability of its population to recurring drought and the threat

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Abrupt changes in rainfall during the twentieth century

Complex interactions in the climate system can give rise to strong positive feedback mechanisms that may lead to sudden climatic changes. The prolonged Sahel drought and the Dust Bowl are examples of

Paleoclimate Variability in the Mediterranean and Red Sea Regions during the Last 500,000 Years

The Mediterranean–Red Sea region has been critical to dispersal of hominids and other species between Africa and the rest of the world, and climate and sea level are thought to be key controls on

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A fully coupled atmosphere‐biosphere model, version 3 of the NCAR Community Climate Model (CCM3) and the Integrated Biosphere Simulator (IBIS), is used to illustrate how vegetation dynamics may be



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FOSSIL pollen, ancient lake sediments and archaeological evidence from Africa indicate that the Sahel and Sahara regions were considerably wetter than today during the early to middle Holocene

Simulation of an abrupt change in Saharan vegetation in the Mid‐Holocene

Climate variability during the present interglacial, the Holocene, has been rather smooth in comparison with the last glacial. Nevertheless, there were some rather abrupt climate changes. One of

The greening of the Sahara during the mid-Holocene: results of an interactive atmosphere-biome model

An asynchronously coupled atmospherebiome model was used to assess the biogeophysical interaction during the mid-Holocene, 6000 years before present. The model determines its own land surface

Relation between century-scale Holocene arid intervals in tropical and temperate zones

CLIMATE records from lake sediments in tropical Africa, Central America and west Asia show several century-scale arid intervals during the Holocene1–10. These may have been caused by temporary

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A conceptual model has been developed for the analysis of atmosphere- vegetation interaction in subtropical deserts. The model can exhibit multiple stable states in the system' a "desert" equilibrium

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The Sahel region in West Africa has been experiencing a persistent drought throughout the last three decades. Here, we present a new perspective on the underlying physical mechanism behind this

Fully coupled climate/dynamical vegetation model simulations over Northern Africa during the mid-Holocene

Abstract The climate and vegetation patterns of the middle Holocene (6000 years ago; 6 ka) over Northern Africa are simulated using a fully-synchronous climate and dynamical vegetation model. The