Nigeria

I

Introduction

Nigeria, republic in western Africa, with a coast along the Atlantic Ocean on the Gulf of Guinea. Most of Nigeria consists of a low plateau cut by rivers, especially the Niger and its largest tributary, the Benue. The country takes its name from its chief river. Until 1991, the capital was the largest city, Lagos, on the southwestern coast; at that time, the city of Abuja, in the country’s interior, became capital.

Nigeria is by far the most populated of Africa’s countries, with more than one-seventh of the continent’s people. The people belong to many different ethnic groups. These groups give the country a rich culture, but they also pose major challenges to nation building. Ethnic strife has plagued Nigeria since it gained independence in 1960.

Nigeria has a federal form of government and is divided into 36 states and a federal capital territory. The country’s official name is the Federal Republic of Nigeria. Lagos, along the coast, is the largest city and the country’s economic and cultural center, but Abuja, a city in the interior planned and built during the 1970s and 1980s, is the capital. The government moved from Lagos to Abuja in 1991 in the hope of creating a national capital where none of the country’s ethnic groups would be dominant.

Nigeria long had an agricultural economy but now depends almost entirely on the production of petroleum, which lies in large reserves below the Niger Delta. While oil wealth has financed major investments in the country’s infrastructure, Nigeria remains among the world’s poorest countries in terms of per capita income. Oil revenues led the government to ignore agriculture, and Nigeria must now import farm products to feed its people.

---

---

The area that is now Nigeria was home to ethnically based kingdoms and tribal communities before it became a European colony. In spite of European contact that began in the 16th century, these kingdoms and communities maintained their autonomy until the 19th century. The colonial era began in earnest in the late 19th century, when Britain consolidated its rule over Nigeria. In 1914 the British merged their northern and southern protectorates into a single state called the Colony and Protectorate of Nigeria. Nigeria became independent of British rule in 1960. After independence Nigeria experienced frequent coups and long periods of autocratic military rule between 1966 and 1999, when a democratic civilian government was established.

II

Land and Resources

Nigeria covers an area of 923,768 sq km (356,669 sq mi). At its greatest expanse, it measures about 1,200 km (about 750 mi) from east to west and about 1,050 km (about 650 mi) from north to south. Nigeria is bounded by Cameroon to the east, Chad to the northeast, Niger to the north, Benin to the west, and the Gulf of Guinea on the Atlantic Ocean to the south.

The country’s topography ranges from lowlands along the coast and in the lower Niger Valley to high plateaus in the north and mountains along the eastern border. Much of the country is laced with productive rivers. The Nigerian ecology varies from tropical forest in the south to dry savanna in the far north, yielding a diverse mix of plant and animal life. Human population and development pose serious threats to both the ecology and the human environment.

A

Topographic Regions

The broad, mostly level valleys of the Niger and Benue rivers form Nigeria’s largest physical region. The Niger enters the country from the northwest, the Benue from the northeast; they join at the city of Lokoja in the south central region and continue south, where they empty into the Atlantic at the Niger Delta. Together, they form the shape of a Y. Population densities and agricultural development are generally lower in the Niger and Benue valleys than in other areas.

North of the Niger Valley are the high plains of Hausaland, an area of relatively level topography averaging about 800 m (about 2,500 ft) above sea level, with isolated granite outcroppings. The Jos Plateau, located close to Nigeria’s geographic center, rises steeply above the surrounding plains to an average elevation of about 1,300 m (about 4,200 ft). To the northeast, the plains of Hausaland grade into the basin of Lake Chad; the area is characterized by somewhat lower elevations, level terrain, and sandy soils. To the northwest, the high plains descend into the Sokoto lowland.

Southwest of the Niger Valley (on the left side of the Y) lies the comparatively rugged terrain of the Yoruba highlands. Between the highlands and the ocean runs a coastal plain averaging 80 km (50 mi) in width from the border of Benin to the Niger Delta. The delta, which lies at the base of the Y and separates the southwestern coast from the southeastern coast, is 36,000 sq km (14,000 sq mi) of low-lying, swampy terrain and multiple channels through which the waters of the great river empty into the ocean. Several of the delta’s channels and some of the inshore lagoons can be navigated.

Southeastern coastal Nigeria (to the right of the Y) consists of low sedimentary plains that are essentially an extension of the southwestern coastal plains. In all, the Atlantic coastline extends for 853 km (530 mi). It is marked by a series of sandbars, backed by lagoons of brackish water that support the growth of mangroves. Large parts of Africa’s Bight of Benin and Bight of Biafra fall along the coast. Because of the Guinea Current, which transports and deposits large amounts of sand, the coastline is quite straight and has few good natural harbors. The harbors that do exist must be constantly dredged to remove deposited sand.

Inland from the southeastern coast are progressively higher regions. In some areas, such as the Udi Hills northwest of Enugu, escarpments have been formed by dipping rock strata. Farther east, along Nigeria’s border with Cameroon, lie the eastern highlands, made of several distinct ranges and plateaus, including the Mandara Mountains, the Shebeshi Mountains, the Alantika Mountains, and the Mambila Mountains. In the Shebeshi is Dimlang (Vogel Peak), which at 2,042 m (6,699 ft) is Nigeria’s highest point.

B

Climate and Vegetation

Nigeria has a tropical climate with sharp regional variances depending on rainfall. Nigerian seasons are governed by the movement of the intertropical discontinuity, a zone where warm, moist air from the Atlantic converges with hot, dry, and often dust-laden air from the Sahara known locally as the harmattan. During the summer, the zone of intertropical discontinuity follows the Sun northward. As a result, more and more of the country comes under the influence of moisture-laden tropical maritime air. Thus, much of the country experiences a rainy season during summer. As summer wanes, the zone shifts southward, bringing an end to the rainy season. Temperatures are high throughout the year, averaging from 25° to 28°C (77° to 82°F). In the higher elevations of the Jos Plateau, temperatures average 22°C (72°F). Northern Nigeria typically experiences greater temperature extremes than the south.

Rainfall varies widely over short distances and from year to year. Parts of the coast along the Niger Delta, where the rainy season is year-round, receive more than 4,000 mm (160 in) of rain each year. Most of the country’s middle belt, where the rainy season starts in April or May and runs through September or October, receives from 1,000 to 1,500 mm (40 to 60 in). Within this region, the Jos Plateau receives somewhat more rain, due to its higher elevation. In the dry savanna regions, rainfall is especially variable. The region along Nigeria’s northeastern border receives less than 500 mm (20 in) of rain per year, and the rainy season lasts barely three months.

Vegetation also varies dramatically at both the national and local level in relation to climate, soil, elevation, and human impact on the environment. In the low-lying coastal region, mangroves line the brackish lagoons and creeks, while swamp forest grows where the water is fresh. Farther inland, this vegetation gives way to tropical forest, with its many species of tropical hardwoods, including mahogany, iroko, and obeche. However, only in a few reserves—protected from the chainsaw and the farmer—is the forest’s full botanic diversity intact. Elsewhere, forest is largely secondary growth, primarily of species like the oil palm that are preserved for their economic value. Forests cover only about 12 percent (2005) of the country’s total land area.

Immediately north of the forest is the first wave of savanna: the Guinea, or moist, savanna, a region of tall grasses and trees. The southern margins of the Guinea savanna—which has been so altered by humans that it is also called the derived savanna—were created by repeated burning of forest until only open forest and grassland were left. The burnings destroyed important fire-sensitive plant species and contributed to erosion by removing ground cover. Tropical forest is giving way to the Guinea savanna at such a rate that the only forests expected to survive the next generation are in reserves. Beyond the Guinea savanna lies the drier Sudan savanna, a region of shorter grasses and more scattered, drought-resistant trees such as the baobab, tamarind, and acacia. In Nigeria’s very dry northeastern corner, the semidesert Sahel savanna persists. Throughout these drier savannas, drought and overgrazing have led to desertification—the degradation of vegetation and soil resources.