The 'Mousterian Pluvial' was an extended wet and rainy period in the
climate history of
North Africa. The pluvial occurred during the
Upper Paleolithic era, beginning around 50,000 years before the present (
ybp), lasting 20,000 years, and ending around 30,000 ybp.
During the Mousterian Pluvial, the now-dessicated regions of northern Africa were well-watered, bearing lakes, swamps, and river systems that no longer exist. What is now the
Sahara desert supported typical African wildlife of grassland and woodland environments: herbivores from
gazelle to
giraffe to
ostrich, predators from
lion to
jackal, even
hippopotamus and
crocodile, as well as extinct forms like the Pleistocene camel. In these respects the Mousterian Pluvial resembled the earlier
Abbassia Pluvial; the later
Neolithic Subpluvial was a weaker re-iteration of the same pattern.
The Mousterian Pluvial was caused by large-scale
climatic changes during the last
ice age. By 50 kybp, the
Wisconsin glaciation ("Wūrm glaciation" in Europe) was well-advanced; growing
ice sheets in North America and Europe displaced the standard climatic zones of the northern hemisphere southward. The temperate zones of Europe and North America acquired an arctic or
tundra climate, and the rain bands typical of the temperate zones dropped to the latitudes of northern Africa.
Curiously, the same influences that created the Mousterian Pluvial also appear to have brought it to a close. In the period of its fullest development, c. 30 to 18 kybp, the
Laurentide ice sheet not only covered an enormous geographic area, but increased its altitude to 1750 meters (more than 1 mile). It generated its own long term weather patterns, which effected the
jet stream passing over the North American continent. The jet stream effectively split in two, creating a new dominant weather pattern over the northern hemisphere that brought harsher conditions to several regions (including parts of
Central Asia and the
Middle East) — changes that included an end to the Mousterian Pluvial and a return to a more arid climate in northern Africa.
References
★ Burroughs, William J., ed. ''Climate: Into the 21st Century.'' Cambridge, Cambridge University Press, 2003.
★ Wilson, R. C. L., S. A. Drury, and J. L. Chapman. ''The Great Ice Age: Climate Change and Life.'' London, Routledge, 2000.