the climate of the Sahara and the Sahel started to become drier at an exceedingly fast pace.
The Sahel region is one of primarily agriculture and pastoralism, which is negatively affected by periodic droughts and resultant famines.
Traditionally, most of the people in the Sahel have been semi-nomads, farming and raising livestock in a system of transhumance, which is probably the most sustainable way of utilizing the Sahel.
On its passage over the desert it picks up fine dust particles (between 0.5 and 10 micrometers), delivering them to the Sahel.
The seasonal wetlands of the Sahel are important for migratory birds moving within Africa and on the African-Eurasian flyways.
The people of the Sahel have been both victims and abusers of the environment.
The Conference was organized in response to the food crises of the early 1970s brought on by the Sahelian drought.
The first large Sahelian kingdoms emerged after 750, and supported several large trading cities in the Niger Bend region, including Timbuktu, Gao, and Djennй.
The Sahelian kingdoms were a series of empires, based in the Sahel, which had many similarities.
The Sahel is mostly covered in grassland and savanna, with areas of woodland and shrubland.
Several isolated plateaus and mountain ranges rise from the Sahel, but are designated as separate ecoregions because their flora and fauna are distinct from the surrounding lowlands.
Collectively these states are known as the Sahelian kingdoms.
In 1973, The United Nations Sahelian Office (UNSO) was created to address the severe effects of recurrent droughts in the Sahel.
The topography of the Sahel is mainly flat, and the region mostly lies between 200 and 400 meters (656-1313 ft) elevation.
The first instances of domestication of plants for agricultural purposes in Africa occurred in the Sahel region circa 5000 B.C.E., when sorghum and African Rice began to be cultivated.