WAEC SSCE - Geography - 1988 (Essay)

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Reasons for the high volume of trade between Nigeria and Japan

1. Complementary economies: the two countries produce different goods and each needs what the other has. Nigeria supplies primary products (crude oil, rubber, cotton, cocoa, timber and other raw materials) while Japan supplies manufactured goods, so exchange is mutually profitable.
2. Japan's demand for raw materials: being a highly industrialised but resource-poor country, Japan needs large quantities of petroleum and industrial raw materials, which Nigeria can provide.
3. Nigeria's demand for manufactured goods: Nigeria imports vehicles, machinery, electronics and other manufactures in which Japan specialises and which are relatively cheap and of high quality.
4. Japan's advanced technology and industrial capacity enable it to produce goods in large quantities for export to markets like Nigeria.
5. Efficient sea transport and shipping: both countries are well served by ocean routes and modern ports, making the bulk movement of goods between them cheap and easy.
6. Large Nigerian market: Nigeria's big population provides a wide market that attracts Japanese manufactured goods, while its foreign-exchange earnings from oil enable it to pay for imports.

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(a)(i) Latitude and Longitude

Latitude is the angular distance of a place north or south of the Equator, measured in degrees from the centre of the earth. Lines of latitude (parallels) run from west to east, extend from \(0^\circ\) at the Equator to \(90^\circ\)N and \(90^\circ\)S, and are used to calculate distance between places. Longitude is the angular distance of a place east or west of the Greenwich (Prime) Meridian. Lines of longitude (meridians) run from north to south at right angles to the parallels, extend from \(0^\circ\) to \(180^\circ\)E and \(180^\circ\)W, and are used to calculate local time.

(a)(ii) Standard Time and Greenwich Mean Time

Standard Time is the uniform time adopted by a whole country, usually taken from a chosen central meridian, so that the entire country keeps one clock time and avoids the confusion of many different local times from town to town. For example, Nigeria adopts the meridian \(15^\circ\)E and is one hour ahead of GMT. Greenwich Mean Time (GMT) is the local time along the Prime (Greenwich) Meridian, longitude \(0^\circ\). It is the world reference time from which all countries reckon their own time.

(b) Longitude of place X

Step 1: Find the time difference. From 4:48 a.m. on 4th July to 10:00 a.m. on 5th July is \(29\text{ h }12\text{ min}\). Removing the one full day (24 h) that separates the two dates leaves an actual clock difference of:

\[29\text{ h }12\text{ min} - 24\text{ h} = 5\text{ h }12\text{ min}\]

Step 2: Convert the time difference to longitude (\(15^\circ = 1\) hour, \(1^\circ = 4\) minutes):

\[5\text{ h} = 5 \times 15^\circ = 75^\circ\]

\[12\text{ min} = \frac{12}{4}^\circ = 3^\circ\]

\[\text{Total} = 75^\circ + 3^\circ = 78^\circ\]

Step 3: Since the local time at X is behind GMT, X lies west of the Prime Meridian. Therefore the longitude of place X is \(78^\circ\)W.

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(a) Advantages and limitations of water transportation

Advantages:

1. It is the cheapest means of moving bulky and heavy goods over long distances.
2. It requires no expensive track construction - the natural waterway or sea is the route.
3. It can carry very large loads (bulk cargo such as oil, grain and ores) in a single voyage.

Limitations:

1. It is very slow compared with road, rail or air.
2. Waterways are interrupted by rapids, waterfalls, shallow water, sand bars and freezing/silting, limiting where ships can go.
3. It can only serve places near the coast or navigable rivers, and cannot reach inland areas directly.

(b) How the limitations can be overcome

• Slowness: use faster, modern powered vessels and combine water transport with road, rail or air for through movement.
• Rapids, waterfalls and shallows: construct canals, locks, dams and by-pass channels, and carry out dredging to deepen and widen channels; build breakwaters and clear sand bars.
• Limited reach inland: develop ports with good road and rail links (container/intermodal transport) so goods can be moved onward to inland destinations; build inland waterways where possible.

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(a) Sketch map of Africa

Key: The dark-shaded area is the equatorial forest belt of the Congo Basin, with Kinshasa marked in it. The lightly-shaded area is the Sudan tropical grassland (savanna) belt, with Kano marked in it.

(b) Characteristics of the equatorial forest belt

1. It consists mainly of very tall broad-leaved evergreen trees which form a dense, almost continuous canopy.
2. The trees occur in distinct layers, namely emergents, the main canopy, lower storey and shrub layer.
3. There is dense undergrowth, including ferns, shrubs, climbers (lianas), creepers and epiphytes.
4. The trees are closely spaced and competition for sunlight is intense; consequently, many trees grow straight and have buttress roots for support.
5. The forest is green throughout the year because rainfall is high and well distributed.
6. Tree species are numerous and mixed; valuable hardwoods include mahogany, iroko and obeche.

(c) Importance of the equatorial forest belt to man

1. It supplies valuable timber such as mahogany, iroko and obeche for furniture, building and export.
2. It provides fuelwood, poles, fibres, medicinal plants, fruits and other forest products.
3. Lumbering, sawmilling and wood processing provide employment and income.
4. Plantation agriculture is practised, especially cocoa, rubber, oil palm, coffee and bananas.
5. Hunting and fishing provide food and income for many inhabitants.
6. The forest protects soils from heavy rainfall erosion, helps regulate climate and conserves wildlife.

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(a) Permanent drought and seasonal drought

Permanent drought is the condition of continuous, year-round dryness found in desert and semi-desert areas where rainfall is extremely low and unreliable throughout the year; here farming is impossible without irrigation. Example: the Sahara Desert (or the Namib Desert).

Seasonal drought is the regular dry period that occurs every year during the dry season in regions that otherwise have a wet season; the area is watered for part of the year and dry for the rest. Example: the Sudan/Savanna belt of northern Nigeria (or the tropical grasslands generally).

(b) Causes and effects of drought

Two main causes:

• Failure or lateness of the rains caused by shifts in the rain-bearing winds (e.g. the ITD not moving far enough north).
• Human activities such as deforestation and overgrazing that reduce vegetation cover, lower humidity and encourage desertification.

Two effects:

• Crop failure and death of livestock, leading to famine and hunger.
• Drying up of rivers, wells and water sources, causing water shortage and migration of people (environmental refugees).

(c) Methods of minimizing the effects of drought

1. Provide irrigation and construct dams, wells and boreholes to store and supply water.
2. Afforestation and planting of shelter belts, plus growing drought-resistant crops, to check desertification and conserve moisture.

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(a) One cottage industry and one manufacturing industry in a named zone

Taking the Western (Lagos-Ibadan) Industrial Zone of south-western Nigeria:

• Cottage industry: tie-and-dye (adire) cloth making (a small-scale, home-based craft centred on Abeokuta).
• Manufacturing industry: cement manufacturing (a large-scale factory industry, for example the works at Ewekoro and Shagamu).

(b) Account for the location of each industry

Location of the adire (tie-and-dye) cottage industry

• Local raw materials: plain cotton cloth and locally obtained indigo and other dyes are readily available, so the craft needs little imported input.
• Traditional craft skill: the technique has been handed down over generations, especially among the women of Abeokuta, giving a ready pool of skilled labour.
• Low capital requirement: the work is done in the home with simple equipment, so no heavy machinery, large factory building or big money is needed.
• Ready market: a large local population and the demand for traditional and ceremonial cloth provide a steady, nearby market.

Location of the cement manufacturing industry

• Nearness to raw material: the zone lies on extensive deposits of limestone (with clay/shale), the bulky main raw material of cement, so the factory is sited on the source to cut transport cost.
• Availability of power: supply from the national grid and access to fuel keep the energy-intensive kilns running.
• Large market: the densely built-up Lagos-Ibadan belt, with its constant construction of houses, roads and factories, creates enormous demand for cement close by.
• Good transport: the well-developed road and rail network of the zone allows the heavy product to be moved cheaply to markets, and the nearby port at Lagos aids the movement of any imported gypsum and machinery.
• Adequate labour supply: the densely settled south-west provides both skilled and unskilled workers for the plant.

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(a) Combined rainfall and temperature graph

The completed combined graph is shown below. Rainfall is represented by bars against the left-hand vertical scale, while temperature is represented by the line against the right-hand vertical scale.

Month	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Rainfall (mm)	0	0	0	0	60	130	240	300	150	0	0	0
Temperature (°C)	22	25	29	31	32	29	27	26	26	27	25	24

(b) Climatic type

The climatic type is the Tropical Continental (Sudan type) climate.

(c) Reasons

1. The annual temperature range is small: \[32^\circ\mathrm{C}-22^\circ\mathrm{C}=10^\circ\mathrm{C}.\]
2. The mean annual temperature is high: \[\frac{22+25+29+31+32+29+27+26+26+27+25+24}{12}=26.9^\circ\mathrm{C}\approx27^\circ\mathrm{C}.\]
3. Rainfall occurs mainly from May to September, while the remaining months are dry.
4. There is one rainfall maximum, in August, when rainfall reaches 300 mm.

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Lumbering in Zaire (Democratic Republic of Congo)

(a) Areas

• The equatorial rain forest of the Congo (Zaire) Basin, especially along the Congo River and its tributaries and around towns such as Kisangani, Mbandaka and the lower Congo near the coast.

(b) Factors favouring lumbering

• Dense tropical hardwood forest with valuable trees (mahogany, ebony, iroko, obeche) growing over a very large area.
• Hot, wet equatorial climate giving continuous tree growth and quick regeneration.
• The Congo River and its tributaries provide cheap water transport for floating and moving logs to sawmills and ports.
• Labour supply and a demand for timber at home and abroad.

(c) Importance

• Provides timber for building, furniture and fuel.
• Earns foreign exchange from the export of hardwood.
• Gives employment to loggers, sawmill and transport workers.
• Supplies raw material for paper, plywood and other wood industries and yields government revenue.

(d) Problems

• Dense forest and difficult terrain with swamps make felling and haulage hard.
• Mixture of species: valuable trees are scattered among many worthless ones, so much effort yields little.
• Poor transport away from the rivers, and inadequate roads and railways.
• Rapid decay of felled timber by heat, humidity, insects and fungi, and shortage of capital and skilled labour.

(e) Possible solutions

• Build and improve roads and railways and provide modern machinery for felling and haulage.
• Practise selective and scientific forestry with re-afforestation to sustain the forest.
• Treat and preserve timber against decay and pests, and provide capital and training for workers.

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(a) How each factor has affected world population

(i) Improved medical care: better hospitals, drugs, vaccines, sanitation and maternal/child health services have lowered the death rate, controlled epidemic diseases and raised life expectancy. With births still high in many countries, the fall in deaths has produced rapid population growth (a population explosion).

(ii) Advanced technology and industry: mechanised farming and improved storage have increased food supply, while industrialisation created jobs, wealth and better living standards. This has supported larger populations, though in industrialised nations it has also encouraged smaller families and slower growth, whereas in developing nations improved food and health have boosted numbers. Industry also draws people together, raising population in urban areas.

(b) Factors accounting for high population density in Java

1. Fertile volcanic soils that support intensive cultivation of rice and other crops, feeding a large population.
2. Favourable equatorial/tropical climate with abundant rainfall and high temperatures allowing farming all year (double cropping).
3. Intensive wet-rice (padi) agriculture that yields large amounts of food from small areas of land.
4. Good development of industry, trade, transport and towns (e.g. Jakarta), providing employment that attracts and holds many people.

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(a) Labelled diagram of a simple soil profile

(b) Characteristics of two zones in the soil profile

1. A horizon (topsoil or zone of eluviation)
   • It is dark brown or black in colour and contains much humus. This is because dead leaves, plants and animals decay at or near the surface to form organic matter.
   • It contains many plant roots, earthworms and micro-organisms and has high biological activity. This is because it is close to the surface, where air, moisture and decaying organic materials are readily available.
   • It is often leached of clay and soluble minerals. This is because percolating rainwater washes fine particles and dissolved minerals downward into the B horizon.
2. B horizon (subsoil or zone of illuviation)
   • It is usually lighter in colour than the topsoil and contains little humus. This is because most organic matter is concentrated and decomposes in the A horizon.
   • It is richer in clay, iron compounds and other minerals. This is because materials washed down from the A horizon accumulate in this layer.
   • It is more compact and contains fewer roots and soil organisms. This is because it has less humus, less aeration and fewer nutrients than the topsoil.

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(a) On an outline map of Africa, show and name

• (i) Latitude 20 degrees N: a line drawn across the Sahara through southern Algeria, northern Niger, Chad and Sudan.
• (ii) The prevailing winds in July: the moist south-west monsoon (South-West Trade / South-West Monsoon) blowing onshore over West Africa from the Atlantic, and the South-East Trades south of the Equator.
• (iii) One cold ocean current in the north: the Canary Current, flowing south along the north-west coast (off Morocco and Mauritania).
• (iv) One warm ocean current in the south: the Mozambique/Agulhas Current, flowing south along the south-east coast (also the warm Guinea Current off West Africa).

(b) Effects of prevailing winds and ocean currents on the climate of one part of Africa

Taking the West African coast (Guinea coast):

• In July the moist South-West Monsoon blows onshore from the warm Atlantic and warm Guinea Current. It is laden with moisture, so as it rises over the land it brings heavy rainfall and gives the coast a long wet season, high humidity and moderate temperatures.
• The warm Guinea Current keeps coastal water and air warm and adds moisture, reinforcing the heavy rains.

By contrast, on the north-west (Saharan) coast the cold Canary Current cools the onshore air; the air holds little moisture and its lower layers are chilled, so instead of rain it produces fog and aridity, helping to keep the coast of Mauritania and the western Sahara dry and desert-like.

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(a) Four factors that limit the rate of development in the southern coastlands of Nigeria (the Niger Delta and coastal creek belt)

1. Difficult terrain of swamps and creeks: the waterlogged mangrove and freshwater swamps make road and rail construction very difficult and expensive, hindering movement and settlement.
2. Poor, waterlogged soils and flooding: the low-lying, frequently flooded land is not easily farmed or built upon, limiting agriculture and infrastructure.
3. Prevalence of diseases: the hot, wet, swampy environment breeds mosquitoes and other vectors, causing malaria and water-borne diseases that reduce the labour force.
4. Environmental degradation from oil exploitation: oil spillage and gas flaring pollute farmland, creeks and fishing waters, destroying the livelihood of the people.

Also acceptable: dense forest and difficult access, restlessness/insecurity in oil-producing areas, and inadequate potable water.

(b) Four ways the development of the region can be enhanced

• Provision of infrastructure: construction of raised roads, bridges, jetties, electricity and pipe-borne water to improve access and living conditions.
• Control of pollution and land reclamation: enforcing anti-pollution laws, cleaning up oil spills, stopping gas flaring and reclaiming swampland for use.
• Diversification of the economy: developing fishing, agriculture (rice, oil palm), tourism and small industries so the people are not dependent only on oil.
• Investment in health, education and employment: building hospitals and schools, controlling disease, and creating jobs and community-development projects to raise the standard of living.

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(a) Three broad classes of manufacturing industries and one important area for each

(b) Three main characteristics of each class

Heavy industry:

• Uses large quantities of bulky, heavy raw materials (iron ore, coal, limestone).
• Needs much power, capital and large sites, and is located near raw materials or ports.
• Produces bulky basic products (steel, machinery) that serve as inputs to other industries.

Light industry:

• Uses lighter raw materials or semi-finished parts and less power.
• Often market-oriented, located near towns and skilled labour.
• Produces finished consumer goods (cloth, radios, appliances) and needs relatively little space and capital.

Agro-based / processing industry:

• Uses agricultural raw materials (crops, livestock, fish, timber).
• Usually located near the source of the raw material because the produce is bulky or perishable.
• Adds value by converting raw produce into food, drink or other goods (flour, sugar, oil, canned food).

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(a) Sedimentary rock and processes of its formation

A sedimentary rock is a rock formed from the accumulation, compaction and cementation of sediments (fragments of older rocks, mineral particles, or the remains of plants and animals) usually in layers or strata.

Two processes of formation:

• Mechanically formed (clastic): rocks are broken down by weathering and erosion; the fragments (gravel, sand, silt, mud) are transported by water, wind or ice, deposited in layers, then compacted and cemented to form rocks such as sandstone, conglomerate and shale.
• Organically formed: the remains of plants and animals accumulate and are compacted over time; plant remains form coal, while shells and skeletons of marine organisms form limestone. (Chemically formed sedimentary rocks such as rock salt and gypsum arise from evaporation and precipitation of dissolved minerals.)

(b) Importance of sedimentary rocks to man

1. They are the main source of fossil fuels - coal, petroleum and natural gas - which provide energy.
2. They yield valuable minerals and building materials such as limestone (for cement), sandstone, clay, gypsum and rock salt.
3. They weather into deep, fertile soils (e.g. from shales and limestone) that support agriculture, and their porous layers store underground water (aquifers).

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(a) Two types of urban settlements

• An industrial (manufacturing) town
• A commercial/trading (or port) town

(Other acceptable types include administrative/capital towns, mining towns, and route/route-centre towns.)

(b) Characteristic features of each type

Industrial town:

• Dominated by factories, industrial estates and workshops.
• Located near sources of raw materials, power or good transport.
• Has a large working population, worker housing estates and often problems of pollution.

Commercial/trading town:

• Dominated by markets, shops, banks, offices and business districts.
• Usually sited at a route centre, port or route junction where goods are exchanged.
• Has a busy central business district and attracts traders, transporters and a large service population.

(c) Problems facing urban centres

1. Overcrowding and housing shortage, leading to slums and high rents.
2. Traffic congestion and pressure on roads and transport.
3. Unemployment and crime arising from rural-urban migration.
4. Inadequate services and pollution - shortage of water, power, sanitation, and waste and air pollution.

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Irrigation agriculture in the Nile Basin

(a) Need for irrigation

• Egypt and northern Sudan lie in a hot desert climate with very little or no rainfall, so crops cannot grow on natural rain alone.
• The high temperatures cause heavy evaporation, so water must be supplied artificially and continuously.
• Irrigation from the Nile allows farming all year round and makes it possible to feed the dense valley population.

(b) Areas

• The Nile valley and delta in Egypt (from Aswan to Cairo and the delta around Alexandria).
• The Gezira plain in Sudan, between the Blue and White Niles near Khartoum.
• Land along the Blue Nile and around Lake Nasser above the Aswan High Dam.

(c) Methods

• Basin irrigation: the older method of trapping the annual floodwater in basins to soak the land (now largely replaced).
• Perennial (canal) irrigation: water stored by dams such as the Aswan High Dam is led all year through a network of canals to the fields.
• Lift methods: water is raised from the river or canals using the shaduf, the Archimedean screw, the water wheel (sakia) and modern motor pumps.

(d) Crops grown

• Cotton (the leading cash crop of Egypt and the Gezira), sugar cane, rice, wheat, maize, millet, dates and vegetables.

(e) Importance

• Provides food for the dense population and raw material (cotton) for industry.
• Earns foreign exchange from the export of cotton and other produce.
• Provides employment for millions of farmers and supports settlement in an otherwise desert land.
• The dams also supply hydroelectric power and control flooding, aiding overall development.

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Fishing in Nigeria

(a) Areas

• Coastal/marine waters along the Atlantic (the continental shelf off Lagos, the Niger Delta and Calabar).
• Inland fresh waters: rivers Niger and Benue, Lake Chad, the Kainji, Jebba and other reservoirs, creeks, lagoons and floodplains.
• Fish farms (ponds) in many parts of the country.

(b) Methods

• Artisanal (traditional) fishing using canoes, hooks and lines, cast nets, traps and baskets in rivers, lagoons and coastal waters.
• Modern/commercial fishing using motorised trawlers and large nets in the deep sea.
• Fish farming (aquaculture) in constructed ponds, and drying/smoking for preservation.

(c) Types of fish

• Marine/salt-water fish: sardines, mackerel, croaker, shrimps/prawns, shark.
• Fresh-water fish: tilapia, catfish (mudfish), Nile perch, mackerel and bonga.

(d) Importance

1. Provides cheap animal protein in the people's diet.
2. Provides employment and income for fishermen, traders and processors.
3. Supplies raw materials to industry (fish meal, canning) and reduces fish imports, saving foreign exchange.
4. Encourages development of related activities (boat building, net making, transport and marketing).

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As shown on the map above, the required mineral areas and towns are:

(b) Contributions of mining to economic development in West Africa

• Employment: Mining provides direct jobs for miners, engineers, drivers and administrators, as well as indirect jobs in transport, trading and construction. For example, gold mining at Obuasi and Tarkwa in Ghana employs many people.
• Foreign-exchange earnings: Mineral exports earn revenue from abroad. Ghana earns foreign exchange from gold, Guinea from bauxite, Sierra Leone from diamonds and Nigeria from crude petroleum.
• Government revenue: Governments receive taxes, royalties, licence fees and export duties from mining companies. These funds can be used to provide schools, hospitals, roads and other public services.
• Growth of towns and infrastructure: Mining encourages the development of towns and transport facilities. For example, Obuasi and Tarkwa grew because of gold mining, while mining has encouraged roads, railways, power supply and port facilities in mineral-producing areas.
• Raw materials for industries: Minerals supply industries with essential raw materials. Bauxite from Guinea is used for aluminium production, limestone supports cement manufacture, and crude oil from Nigeria supplies refineries and petrochemical industries.
• Improved standard of living: Petroleum products such as petrol, diesel, kerosene and cooking gas are important for transport, domestic use and industrial production. Mining income may also raise the purchasing power of workers and local businesses.

(c) Four environmental problems caused by mining in West Africa

1. Land degradation: Open-cast mining leaves deep pits, heaps of waste rock and uneven land. This destroys farmland and makes some land unsafe or difficult to cultivate.
2. Deforestation and destruction of ecosystems: Vegetation is cleared for mine sites, access roads, settlements and waste dumps. This destroys wildlife habitats and reduces biodiversity.
3. Water pollution: Chemicals used in mineral processing, especially mercury or cyanide in gold mining, may pollute rivers and streams. Oil spills in the Niger Delta contaminate rivers, swamps, groundwater and fishing grounds.
4. Air and noise pollution: Blasting, drilling, crushing and haulage produce dust, smoke and excessive noise. Dust may cause respiratory problems and can settle on crops and nearby houses.

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(a) Factors which determine the direction of flow of ocean currents

1. Prevailing (planetary) winds: steady winds such as the trade winds and westerlies drag the surface water along and set currents moving in their direction.
2. Rotation of the Earth (Coriolis force): the Earth's spin deflects currents to the right in the Northern Hemisphere and to the left in the Southern Hemisphere, giving the circular (gyre) pattern.
3. Shape and position of land masses (coastlines): continents obstruct and deflect currents, forcing them to change direction and follow the coasts.
4. Differences in water density (temperature and salinity): cold, salty, denser water sinks and flows towards warmer areas, while warm lighter water flows on the surface, driving the direction of flow.

(b) Effects of ocean currents on the climate of adjacent coasts (with examples)

• Warm currents warm the coast and bring rainfall. The North Atlantic Drift keeps the coasts of north-west Europe (Britain, Norway) mild and ice-free in winter and gives rain. The warm Mozambique Current gives the south-east coast of Africa a warm, moist climate.
• Cold currents cool the coast and cause dryness/desert. The cold Benguela Current beside south-west Africa produces the arid Namib Desert and coastal fog; the cold Canary Current keeps north-west Africa dry; the cold Peru (Humboldt) Current produces the Atacama Desert on the west coast of South America.
• Where warm and cold currents meet (e.g. off Newfoundland where the warm Gulf Stream meets the cold Labrador Current) fogs form and rich fishing grounds develop.

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(a) Map of Nigeria: climatic belts and towns

On an outline map of Nigeria, from south to north, locate and name the four climatic belts and one town in each:

• Equatorial/tropical rain-forest (maritime) belt (far south) - town: Warri (or Port Harcourt).
• Tropical wet-and-dry / Guinea savanna belt - town: Ilorin (or Ibadan).
• Sudan savanna belt - town: Kano.
• Sahel savanna (semi-desert) belt (far north) - town: Maiduguri (or Nguru).

(A neat sketch map with the belts shown as east-west zones and each town marked is required.)

(b) Seasonal pattern of rainfall (Northern Nigeria)

Northern Nigeria has a single, short rainy season and a long dry season. The rains come with the north-ward advance of the moist south-west (tropical maritime) winds, beginning about May-June and ending in September-October, with a peak around August. Total rainfall is low (about 500-1000 mm) and decreases northwards. For the rest of the year the dry north-east trade wind (harmattan) dominates, giving a long dry, dusty season.

(c) Effects of this rainfall pattern on farming

• Farming is concentrated in the short wet season; planting waits for the first rains and harvesting follows before the dry season.
• Only quick-maturing, drought-resistant crops (millet, guinea corn, groundnut, cotton, beans) can be grown.
• The long dry season limits farming to one crop a year unless irrigation (fadama) is used, and encourages livestock rearing.
• Unreliable or late rains bring the risk of drought and crop failure.

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(a)(i) Area of Nigeria mostly affected by desert encroachment

On an outline map of Nigeria the desert-encroachment (desertification) zone lies in the extreme north, along the border with Niger, covering the Sahel/Sudan savanna belt of the far northern states such as Sokoto, Katsina, Kano, Jigawa, Yobe and Borno. This is the semi-arid belt just south of the Sahara.

(ii) Two important towns within the area: Sokoto and Maiduguri (also acceptable: Katsina, Kano, Nguru, Damaturu).

(b) Major causes of desertification

• Low and unreliable rainfall with long dry seasons and recurrent drought in the Sahel, which reduces vegetation cover.
• Deforestation and removal of vegetation for firewood, timber and building, exposing the soil.
• Overgrazing by too many cattle, sheep and goats, which strips the grass cover and tramples the soil.
• Over-cultivation and poor farming methods that exhaust the soil and leave it bare and loose.
• Bush burning and wind erosion that carry away the fine topsoil, leaving infertile sand.

(c) Two possible ways of combating this hazard

1. Afforestation and shelter belts: planting rows of drought-resistant trees (for example neem) to form the Great Green Wall, which binds the soil, checks wind erosion and restores vegetation.
2. Controlled land use: regulating grazing and farming through rotational grazing, reduced herd sizes, controlled cultivation, and providing alternative fuel to reduce firewood cutting, so that the natural cover can recover.

Also acceptable: irrigation and water conservation, and public education on environmental protection.