Study Notes: The African Transition Zone

Physical Geography of the Transition Zone (Lesson 1)

Definition of the Transition Zone: - A physical area where properties of the land undergo radical change, such as from arid to tropical. - Total area: Approximately $1,178,800\,\text{square miles}$ ( $3,053,200\,\text{sq. km}$ ). - Extends east to west from Senegal to Somalia (Horn of Africa).
Landforms and Topography: - The Sahel is primarily flat with plateaus ranging from $650\,\text{feet}$ ( $200\,\text{m}$ ) to $1,300\,\text{feet}$ ( $400\,\text{m}$ ) in elevation. - It spans more than $3,000\,\text{miles}$ ( $4,800\,\text{km}$ ) in length and ranges from $125\,\text{miles}$ ( $200\,\text{km}$ ) to $250\,\text{miles}$ ( $400\,\text{km}$ ) in width.
Water Systems: - Lake Chad: Bordered by Nigeria, Niger, Chad, and Cameroon. Once the second-largest wetland in Africa, it has shrunk significantly due to drought, evaporation, and salinity. It is fed by the Chari, Logone, and Yobe rivers. - Lake Volta (Ghana): One of the largest human-made lakes in the world ( $3,275\,\text{sq. miles}$ or $8,482\,\text{sq. km}$ ). Created in the $1960$ s via the Akosombo Dam for hydroelectric power and irrigation. Consequences: Displacement of $70,000$ people from $700$ villages; reduced fertility due to lack of annual silting; increase in standing-water diseases. - Niger River: Known as the "great river," it is $2,600\,\text{miles}$ ( $4,183\,\text{km}$ ) long. It forms an inland delta in central Mali (a large wetland) and a coastal delta in Nigeria ( $150\,\text{miles}$ north to south, $200\,\text{miles}$ wide). - Senegal River: $1,015\,\text{miles}$ ( $1,633\,\text{km}$ ) long. The Manantali Dam ( $1986$ ) controls floods and provides power; the Diama Dam ( $1988$ ) prevents saltwater intrusion. - The Nile River: The Blue Nile (originated in Ethiopia, sources fertile soil) and White Nile (originated in Burundi) meet at Khartoum, Sudan.
Climate and Biomes: - Rainy season: May to August ( $4$ to $8\,\text{inches}$ of rain annually). - Harmattan: A hot, dry wind from the northeast/east (Sahara) occurring in December/January; locally called "the doctor" because it is considered invigorating compared to humid air. - Vegetation: Low-growing grasses, shrubs, acacia, baobab, and jujube trees. - Fauna: Migratory birds, wild dogs, cheetahs, lions, elephants, giraffes, warthogs, and gerbils.
Mathematical Comparisons: - Texas: $268,800\,\text{sq. miles}$ . - Tennessee: $42,180\,\text{sq. miles}$ . - Contiguous United States: $3,718,710\,\text{sq. miles}$ . - Relative size: Texas is roughly $6$ times larger than Tennessee. The Sahel is about $4.4$ times larger than Texas and about $3.15$ times smaller than the United States.

Human Geography of the Transition Zone (Lesson 2)

Early History and Empires: - Around $9000\,\text{B.C.}$ to $4000\,\text{B.C.}$ , Northern Africa was much wetter. A climate shift starting around $4000\,\text{B.C.}$ pushed farming communities south. - Kush: A river civilization in Sudan ( $2000\,\text{B.C.}$ to $\text{A.D.}\,300$ ); capital moved to Meroë. - Axum: Trading empire in Ethiopia ( $\text{A.D.}\,100$ to $\text{A.D.}\,700$ ). - Mali Empire: Founded by Sundiata Keita; most famous ruler was Mansa Musa, who spread Islam and enormous wealth on his pilgrimage to Makkah (Mecca). - Songhai: Grew out of the gold-for-salt trade; eventually overran Mali.
Colonization and The Berlin Conference ( $1884$ – $1885$ ): - European powers met to regulate colonization; no Africans were present. - Resulted in artificial boundaries that merged animist and Muslim societies, leading to religious friction.
Population Patterns: - Average density: $58\,\text{people/sq. mile}$ ( $23\,\text{people/sq. km}$ ). - Population is expected to reach $100\,\text{million}$ by $2020$ and $200\,\text{million}$ by $2050$ . - Major cities: Khartoum ( $5\,\text{million}+$ ), Nouakchott ( $710,000$ ), Timbuktu (Tombouctou).
Society and Culture: - Languages: Afro-Asiatic, Nilo-Saharan, Congo-Kordofanian, and French. - Religion: Dominant Islam; varying degrees of Christianity and animism (belief that nature has spirits). - Family Structure: Primarily patriarchal (headed by a male); organized into clans. Rural areas utilize extended families; urban areas are shifting toward nuclear families (husband, wife, children). - Arts: Dogon ritual masks representing ancestor spirits; talking drums that reproduce linguistic tones; literature (Nafissatou Niang Diallo, Chinua Achebe's Things Fall Apart).
Economics: - Subsistence Farming: Families consume most of what they produce (millet, sorghum). - Resources: Nigeria (OPEC member) has oil; Niger has large uranium deposits; Senegal exports phosphates ( $20\%$ of exports).

People and Their Environment: The Transition Zone (Lesson 3)

Managing Resources and Water Stress: - Population grows at roughly $3\%$ annually, doubling every $20\,\text{years}$ . - Desertification: The destruction of land in arid/semi-arid climates caused by climate variation and human activity (overgrazing, deforestation, overpopulation).
Human Impact: - Overgrazing kills plant roots and compacts soil, reducing water retention. - Pollution: Cotton and rice farmers use agricultural chemicals affecting Lake Chad. - Irrigation Failures: Systems built with humanitarian aid in the $1960$ s– $1980$ s often attracted disease and failed during droughts.
Solutions and Remediation: - International Atomic Energy Association (IAEA): Researching the five large aquifers in the Sahel. - UN Convention to Combat Desertification (UNCCD): Restoration of land productivity. - Perm. Interstate Comm. for Drought Control in the Sahel (CILSS): Created in $1973$ for food security and land management. - Local Innovations: Farmers in Burkina Faso use deepened traditional planting pits with manure to rehabilitate $500,000$ to $750,000\,\text{acres}$ . - The Great Green Wall: A $\$2\,\text{billion}$ UN-backed project to plant a $4,970\,\text{mile}$ ( $8,000\,\text{km}$ ) long, $9\,\text{mile}$ ( $15\,\text{km}$ ) wide wall of trees (such as acacia) from Senegal to Djibouti.