CLIMATE
 identify and locate on the map, the climate types of Botswana
Botswana’s Climate
Botswana is generally described as a semi-arid country because this type of climate covers the largest area of the
country.
Temperature
Botswana lies on both sides of the Tropic of Capricorn. The country experiences hot summers with mean monthly
temperatures of about 12oC. Temperatures of over 40oC have been recorded on some summer days especially in
the west and south western parts of the country. The highest temperatures are usually recorded in December and
January. Winter temperatures range between 2oC and 19oC. Lower temperatures below the freezing point are
often recorded in June and July. Large diurnal (daily) temperature range is often recorded in winter. This is because
of the clear skies and absence of clouds and lack of moisture. During the day, temperatures are high because of
direct insulation and during the night the ground loses heat very rapidly.
Rainfall
It ranges from 250mm in the south western part of the country to 650mm in areas around Kasane. Botswana is
generally a low rainfall (semi-arid) country. The northern parts of the country, especially the Chobe district gets the
highest amount of rainfall. The Chobe district has a tropical sub-humid type of climate. The south-eastern part or
area around Gaborone and Lobatse get more than 500 mm. Rainfall gradually decreases from these areas to the
west and south-western parts of the country. The south-western part of the country receives the least amount of
rainfall. It has a desert or arid type of climate. Botswana’s rainfall is low and unevenly distributed. Rain mainly falls
between November and April, which are summer months and therefore, we can say that Botswana has summer
rainfall with very little or no rainfall in winter, that is May, June and July. Rainfall does not always start or finish as
expected. There are times when it comes as early as September and finishes as late as April. The annual amount
changes from year to year and therefore we cannot be sure of how much rain will fall in a year. Because of this, we
can conclude that Botswana’s annual rainfall varies a lot. Because of these variations in rainfall, we sometimes
have periods of droughts which sometimes may be long. Droughts sometimes alternate with periods of heavy
rainfall.
Natural Vegetation
Vegetation in any place is controlled by the climatic and soil conditions. The vegetation found in Botswana can be
grouped into the following categories:
1.
Deciduous Forest
This vegetation is found in the extreme north eastern part of the country, that is, the Chobe District.
Deciduous trees shed their leaves during the dry season to reduce transpiration. Examples of such trees are
Mukwa (blood wood), Mukusi (Rhodesian teak) and Tsaudi (Rhodesian mahogany). In between these grows
bushes and scattered grasses.
2. Savanna Vegetation
Botswana has different types of savanna vegetation. This is due to difference in the climatic and soil
characteristics. Savanna types of vegetation in Botswana are:
i.
Tree Savanna
This vegetation occurs in semi-arid regions with a rainfall amount of 400 – 600 mm. This vegetation
consists of acacia thorn trees and trees like Mokoba, Moloto which have long tap roots. The vegetation is
also characterized by tall trees with thick trunks such as Mokoba, Morula and Mowana. From Mahalapye
northwards the mophane tree savanna is the most common type of tree savanna vegetation.
ii.
Shrub Savanna
This occurs in the driest parts of the country where rainfall is below 250 mm. The vegetation is
characterized by scattered thorny bushes, cactus plants and scattered grasses.
iii.
Bush and Shrub Savanna
This is also found in the semi-arid environments but with lower rainfall of about 300 – 400 mm. shrubs
grow closer together.
iv.
Grass Savanna
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This is found at Mababe depression, Lake Ngami and Makgadikgadi saltpans. Grass savanna consists
mainly of short coarse or wiry grasses. During the rainy season, the soils here become waterlogged. There
are a few trees and bushes in this area.
v.
Aquatic savanna
This consists of water loving plants like reeds, water lilies and palm trees (Mokolwane). Aquatic vegetation
occurs in the swampy areas of Okavango Delta and also on the banks of the Chobe River.
Human Activities
Human activities are greatly influenced by the environment. In Botswana human activities include;
1. Crop Cultivation
Crop cultivation is confined to the eastern and northern parts of the country. These are the wetter parts of the
country with fertile soils. A variety of crops including maize, sorghum, millet, beans, groundnuts, melons and peas
are grown. Commercial arable farming also takes place on freehold and leased land. Intensive irrigation is
practiced in the Tuli Block and Gaborone Block areas. Crops grown include vegetables and fruits. Extensive dry land
farming also takes place at Pandamtenga and Barolong farms. The main crops produced here are sorghum, maize
and watermelons.
2. Pastoral Farming
Climatic conditions and the vegetation have made most parts of Botswana ideal for livestock farming. Pastoral
farming is practiced in most parts of the country. The extreme northern part of the country has fewer livestock
because of pests and diseases such as Foot and Mouth and wild animals. Livestock kept in Botswana include cattle,
sheep, goats, poultry and in small numbers donkeys, horses and pigs. Cattle farming are very important and have
led to the establishment of a beef industry in Botswana.
3. Tourism
Vegetation in many parts of the country provides a good habitation for wildlife. Wildlife and wilderness are the
main tourist attractions in the country. There are game parks and reserves with a considerable variety of wildlife.
These together with wilderness areas such as Okavango Delta and Makgadikgadi Pans are frequented by tourists.
Tourism brings money to the country through recreational hunting (hunting for sport or pleasure) and hotel
accommodation.
Impact on Human Activities on the Environment
Some of the consequences of human activities on the environment in Botswana are
 Deforestation
It is caused by uncontrolled cutting of trees, especially fuel wood. In some cases, vegetation has been removed or
cleared for crop cultivation, to provide fencing material for the fields, used as building materials and timber.
 Soil Erosion and Land Degradation
The problem of soil erosion is due to poor methods of farming such as ploughing up and down the slope, intensive
cultivation of land, overgrazing which is increasing intensity every year.
 Veld fires
Burning of bushes has also contributed to problems of soil erosion and desertification especially in semi-arid
regions.
 Decline in wildlife
The wildlife population has been reduced due to overhunting. To save the animals from extinction and to protect
the tourist industry wild animals are now protected by law and permit have to be obtained before any killing is to
be done. However, animals continue to be illegally killed for subsistence use (for food), for their skins and other
trophies.
 Pollution
The tourism industry contributes to pollution. In some of the tourist areas there is indiscriminate littering by
tourists. Poor management of wastes by hotels and tourist resorts may cause water pollution in rivers.
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identify and locate on the map, the climate types of Africa the following climatic regions: Deserts, SemiDesert, Savannah, Warm Temperate continental, Equatorial and Mediterranean
 discuss the climate types under the following: location/distribution, climate, natural vegetation and human
activities

discuss the impact of human activities on the environment
Africa’s Climatic Regions
Africa has the largest tropical area of all continents. The seasons for areas south of the equator are the opposite of
areas north of the equator. Most of Africa has a warm or hot climate. The highest temperatures have been
recorded in the Sahara Desert and the lowest in high mountains where snow or frost occurs. Rainfall varies
significantly from one area to another. Areas like the Congo Basin receive high rainfall of up to 2500 mm whilst
others like deserts get little or no rain at all. Africa can be divided into six climatic regions. These are the Equatorial
Climate, the Tropical Savanna Climate, Semi Desert, Hot Desert Climate, Warm Temperate Continental and the
Mediterranean Climate.
The Equatorial Climate
Location and Distribution
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The Equatorial Climate as its name suggest occurs along the equator between latitude 5 o south and 5o north of
the equator.
 In Africa this climate occurs in the Congo basin and the lowlands of West Africa.
 Areas are western coastal Nigeria, southern Cote D’ Vore, Cameroon, Gabon, eastern Uganda, south central
Ghana, DRC
Climatic Characteristics of the Equatorial Region
 It is hot and wet throughout the year hence there is only one season/The region is hot and wet all year round
 It receives high rainfall of between 1250mm and 3000 mm per year.
 Temperatures are high because the sun is always overhead at the equator.
 Daily mean temperatures are about 26oC all year round.
 The daily temperature range is rarely more than 8oC
 Annual temperature range hardly exceeds 3oC.
 Abundant/extensive cloud cover prevents temperature from rising above 32 oC during the day and from
dropping below 22oC at night.
 Heavy convectional rain falls almost every day. It mostly comes in the afternoons and is accompanied by
lightning and thunder.
 The air is always moist/the air is always humid above 80%
 The prevailing winds are trade winds- winds that blow from the sub-tropical high pressure towards the
doldrums
 The region lies in a low pressure belt called the doldrums.
The diagram below is a good example of a climate graph for an equatorial region.
Climatic chart of Equatorial areas
Notice that the temperature curve is almost a straight line. This indicates that temperatures are almost the same
all year round. The bar graphs in figures show that there is no month without rainfall. There are no seasons like
summer and winter.
Natural Vegetation
The natural vegetation of the area has tall, broad leaved and evergreen trees called the tropical rainforest/selvas.
Characteristics of the tropical rainforest
The main features of the rainforest are:
i.
It is consists of three layers:
a) Top/upper layer - These are very tall trees that go up to 50 m high with buttress roots that may go up to 3
m high. They form a continuous canopy above the forest. The canopy provides shade for plants and
animals from the scorching sunlight. Many tropical birds, monkeys, apes, reptiles and snakes live in the
canopy.
b) Middle layer – tree ferns, lianas/creepers or climbing plants that use tree trunks for support. These are
trees that grow up to between 19m and 34 m high.
c) Bottom/lower layer – ferns, herbaceous plants and saprophytes that grow up to 17 m in height.
The vegetation has adapted to the wet and hot environment in the following ways:
 Trees grow very tall in an effort to reach for sunlight.
 Creepers/lianas/climbers/climbing plants climb large trees to reach the top for sunlight.
 Little undergrowth due to shortage of sunlight/there is little growth at the forest floor because of lack of
sunlight
 They have broad leaves for rapid transpiration.
 Trees have thin and smooth trunks as there is neither the need to store moisture in their trunks or to protect
themselves from cold weather.
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The trees have leathery leaves to withstand great heat
They have drip tip leaves to shed off rain water
Plants grow in layers to compete for sunlight
Tree leaves have many stomata to increase transpiration
Human Activities
Tropical rainforests have few people due to thick forests and unfavourable climatic conditions. The climate
influences the way in which people live. Major activities of the equatorial region include:
1.
2.
3.
4.
5.
Fishing, Hunting and Gathering - the pygmies of the Congo basin are traditional inhabitants of this region. They
live by hunting, fishing and gathering as there are plenty of foods like leafs, nuts, fruits, birds, animals and fish.
Shifting Cultivation - some communities of subsistence farmers in the rainforest practice shifting cultivation
which is also called the slash and burn technique. These people clear the surrounding vegetation. The
vegetation is left to dry and then burned. The land is planted with crops like bananas, pineapples, yam,
cassava, cocoyam and coconuts until it loses its fertility. Once the fertility of the soil is exhausted they shift to
another fresh area.
Plantation Agriculture - large scale farming of cash crop is done in plantations. The equatorial climate is good
for growing a variety of crops for commercial purposes such as rubber, cocoa, palm oil, coffee, tea, tobacco
and bananas. Some of the plantations are owned by international companies. After harvesting crops are sent
to processing industries or for export.
Lumbering/logging - lumbering is the commercial cutting of trees for purposes of making timber. There are
many valuable trees that grow in the rainforest that are used to make good timber such as mahogany and
ebony. Timber is used to manufacture wood products such as plywood, paper and boats. It is used in housing
construction and for making railway sleepers.
Industries - agriculture and lumbering contribute to the establishment of processing industries in the region.
There are a number of industries that process agricultural products. Some plantations have their own
processing plants.
Impact of human activities on the environment
Some of the negative human impacts on the rainforest include:
 Deforestation – it is the cutting down of trees without replacement. The felling or clearing of land is done for
the purpose of cultivating crops, for extracting timber, for expanding settlements as the population increases
or to create space to build infrastructure. The tropical rain forest is fragile. Once destroyed it is not easy to
replace the original vegetation.
 Loss of wildlife - some of the animal species in the region is threatened by extinction due to overhunting.
 Destruction of the ecosystem - vegetation is part of the ecosystem and if removed the ecosystem is disrupted
and the habitat and food for wildlife is destroyed and this has negative effects on wildlife.
 Soil erosion and land degradation occurs as a result of deforestation.
 Pollution - the use of fertilisers and pesticides as well as processing industries cause pollution of surface and
underground water, and air pollution with negative effects on people, plants and animals.
Factors affecting human activities
The rainforest makes it difficult for people to carry out some of the human activities in the region include:
 The hot and wet conditions of the rainforest are good for the spread of diseases and insects that affect man,
his crops and animals.
 Dangerous pests such as tsetse fly and deadly diseases such as malaria and yellow fever are common in this
region.
 The region has high temperature. Hot and humid condition causes sweating and sometimes even sunstroke.
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The dense forest makes it difficult and expensive to clear the land for developments. For instance forest has
led to the development of timber industries. However, it is difficult to construct roads and the task of
transporting logs from the forests is also difficult.
The thin soil of the equatorial region loses its fertility very quickly once the forest is removed. If the soil is
exposed heavy rains make it lose its nutrients through leaching and soil erosion.
Veld fires
Steep slopes
The Savanna Climate/Tropical Continental or Sudan
Location and Distribution
 It is called Tropical continental because it is found within the tropics, between the Tropic of Cancer and the
Tropic of Capricorn inside continents.
 It is also called Sudan type because it is best developed in Sudan.
 It is found on both sides of the equatorial between 5o and 15o North and 5o and 15o South of the equator.
 It stretches from the equatorial zone to the desert and covers West, East and Central Africa (about one-fifth of
the area of Africa).
Climatic Characteristics
The Savanna climate is characterized by a hot and wet season during the summer months and a dry and cold
season during the winter months.
 Monthly temperatures ranges between 21oC (cool winter) and 32oC (hot summer)
 The annual temperature range of about 11oC.
 The highest temperatures occur just before the rainy season begins i.e. April in the northern hemisphere and
October in the southern hemisphere
 Rain falls in summer (when temperatures are high). In the northern hemisphere the hot rainy season begins in
May and lasts until September while in the southern hemisphere it starts from October and lasts until April.
 These rains are caused by the prevailing winds that blow onshore in summer/doldrums which move over the
region in this season/south-west monsoon
 There is no rain/very little rain in winter due to off shore Trade Winds. In West Africa the North East Trade
Winds blow off shore from the Sahara desert. This dust laden wind is locally called the Harmattan.
 The annual rainfall is about 765 mm and is mainly convectional; however, rainfall differs from place to place.
Around the borders of the equatorial region, rainfall is quite high and decreases gradually towards the desert
borders.
 Humidity is high in summer due to high temperatures and rainfall.
Climatic chart of Tropical Continental areas
Vegetation
Tropical grassland is the natural vegetation of regions with this climate. It has different name according to their
location, e.g. campos (Brazil), llanos (Guiana Highlands) savanna (Africa and Australia). Its main features are as
follows:
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Tall grass may grow up to a height of 2 meters and scattered trees. This vegetation is sometimes referred to as
savanna parkland vegetation. This dominate in areas where the dry season lasts for six to seven months
In areas bordering the rain forest, trees dominate because the dry season lasts for only three months. This
type of vegetation is sometimes called savanna woodland.
As one move further away from the equatorial rain forest the dry season becomes longer and the vegetation
in areas bordering the desert consists of thorn bushes, low shrubs and thorn trees because the dry season
lasts for nine months. This vegetation is called savanna scrub.
Most of the grasses wither and turn brown in the dry season and fires are common. The roots remain dormant
and when the rains come they produce new shoots and leaves
The vegetation have adapted to the long dry season in the following ways:
o Some trees have small leaves - to prevent loss of moisture through transpiration/reduce
transpiration.
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Some trees lose their leaves in winter - to prevent loss of moisture through transpiration/reduce
transpiration. Trees that lose their leaves in winter are called deciduous trees.
Some trees have few leaves to reduce transpiration
Some trees such as the acacia tree have long roots - to reach for water deep underground.
Acacia trees also have an umbrella shaped canopy - to provide shade for the roots and trunk thus
conserving moisture.
Some trees like cacti and the baobab tree have thick succulent trunks and stems –to store water/for
storing water.
Grasses wither during the dry season and their roots remain dormant - and when the rains come they
spring back to life.
Trees grow separate from each other - thus avoiding competition for water.
How savanna vegetation benefits people
 Savanna parkland – pastoral farming, building material, home for wild animals/tourism
 Savanna woodland – building material, raw material, food, medicine, shade, firewood
 Savanna scrub – medicine, food
1.
2.
3.
4.
5.
6.
Human Activities
Pastoral Farming - As grassland, the savannah is ideal for pastoral (livestock) farming. There are a number of
subsistence pastoralists in this region who keep enough livestock to meet their family needs. For instance, the
Masai of East Africa and the Fulani of West Africa keep large herds of cattle, goats and sheep that graze on the
savanna grasslands. Both groups are nomadic pastoralists, in that they move from place to place in search of water
and pastures for their livestock. Commercial cattle ranching also take place in this region.
Arable farming - Many people in the savannah have practiced crop cultivation for a long time. Crops grown include
sorghum, maize, millet, cotton, and tobacco. The Hausa people of Nigeria are an example of settled cultivators of
the savanna.
Commercial plantation farming has become established in the savanna. Crops grown include sugarcane, tobacco,
maize, cotton, and sisal. Most of these plantations and large commercial farms are found in Kenya, Tanzania,
Nigeria, Malawi, Uganda and Zimbabwe. The first white settlers introduced Plantation Agriculture in this climatic
region during the colonial era. Crops from plantations are mainly grown for export.
Industries - Agriculture has led to the establishment of agro-based industries that process agricultural products.
There are industries in countries such as Kenya and Tanzania that process and package sugar, coffee, tea,
chocolate and milk products.
Tourism - Tourism is an important source of income for a number of countries in this region. Savannah has a wild
variety of wildlife that includes herbivores (grazing animals) like buffaloes, wildebeests, warthogs, zebras, rhinos,
giraffes and elephants. Large variety of herbivore supports carnivores (predators) like lions, leopards, cheetahs,
wild dogs and hyenas. For this reason national parks and game reserves have been set up in many countries in the
region and facilities like lodges and camp sites have been developed to attract tourists. Masaimara and Serengeti
plains are famous for tourism.
Fishing - In parts of the savannah climate where there is high rainfall, there are perennial rivers. In some countries
such as Malawi, Tanzania and Uganda there are perennial lakes. Fishing is an important activity in these areas.
Impact of Human Activities on the Savannah
 Overgrazing - Pastures for livestock have been greatly affected by overstocking and overgrazing. This poor
management of rangelands, which is worsened by drought, has led to soil erosion and invasion of thorny
grazing lands and drought resistant bushes.
 Deforestation - In the savanna both trees and grasses are being exploited for various purposes. This includes
cutting trees for fuel wood, clearing land for farming and veld fires. It exposes the soil to weather elements
like wind and rain. Bare soil is easily eroded and huge dongas and gullies may develop, resulting in land
degradation.
 Desertification - The savanna regions bordering the desert are slowly turning into deserts. Desertification
usually occurs when dry land is used intensively. Human activities like over cultivation, over-grazing of
livestock and deforestation all degrade the soil. Drought can also accelerate this problem of desertification.
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Desertification does not only affect people and animals. It also has a significant effect on climate and
vegetation.
Pollution - The use of pesticides for instance, kills many other living organisms some of which are essential for
soil formation. Indiscriminate dumping of toxic wastes kills both plants and animals.
Loss of Wildlife - Overhunting threatens many animals with extinction. Animals such as the rhino have become
endangered species because of overhunting. The destruction of vegetation also affects animals because it
destroys their natural habitats. The growing demand of wildlife souvenirs such as livery ornaments has led to
indiscriminate killing of animals and poaching.
Veld fires - Littering and burning of the veld through the careless use of fires are some of the common
problems associated with tourists in game parks and game reserves.
Factors affecting human activities
However there are a number of challenges that affect agricultural developments in the savanna region. These
include:
 Drought - Farming in the Savanna is often affected by long drought periods. Rainfall in this region is unreliable.
Drought affects both crop and livestock farming. It also increases the problem of desertification.
 Pests and Diseases - In some parts of the savanna, farming is limited by pests and diseases. Tsetse fly brings
sleeping sickness to man and trypanosomiasis (nagana) to cattle. Large areas have been neglected or
abandoned due to the presence of pests like tsetse fly and mosquitoes. Locusts also have a devastating effect
on both vegetation and crops.
 Poor Infertile Soils - Heavy rains cause both soil erosion and leaching which removes silica from the upper soil
layers, leaving behind the red coloured oxides of aluminium and iron. These red soils are compacted or
cemented forming a hard layer known as laterite. The laterites are poorly drained and plant roots cannot
penetrate them easily. Such areas are better suited to animals than crop farming.
Tropical/Hot Desert Climate
Location and Distribution
 In Africa, the tropical deserts occur approximately between latitude 15°N and 30°N of the Equator and also
between 15°S and 30°S of the Equator.
 These deserts are called tropical deserts because they are confined to the Tropic of Cancer and Capricorn. The
Sahara desert, which is the largest, stretches from the west coast, across the continent to the east coast in
North Africa along the Tropic of Cancer and The Kalahari and Namib Deserts along the Tropic of Capricorn
Climate characteristics
 The tropical desert experiences cool winters
 Extremely hot summers.
 The mean monthly temperatures range from 29°C in summer to 10°C in winter.
 The diurnal temperature range is always high. In summer, maximum day temperatures of over 40°C have been
recorded and a night minimum of 15°C while in winter they range from about 5°C (night) to 20°C (day).
 These daily temperature extremes are caused by clear or cloudless skies and dry air. This results in large
amounts of heat reaching the ground during the day hence the high temperatures. The absence of clouds also
lets much heat out at night hence low temperatures.
 The sky in the tropical desert remains cloud-free due to the subsiding air of high pressure.
 Desert areas get very little or no rainfall/Rainfall exceeds 250 mm in a year
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The small amount of rain that occurs is usually of convectional type. It occurs as violent thunderstorms
sometimes causing flash floods
 Low rainfall in deserts is caused by the following factors:
o Deserts lie in high pressure belts called the Horse latitudes. The descending air of the subtropical high
warms causing the air to dry out and prevent condensation. Humidity is very low in desert regions.
o The continental location of many tropical deserts places them far from a source of moisture, which is
the sea or ocean. This situation is called continentality. Warm and moist air travelling long distances
from the sea loses much of its moisture by the time it reaches the desert region.
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The coasts of some desert areas are washed by cold currents. The Sahara is washed by the cold
Canary Currents whilst the Namib is washed by cold Benguela Currents. The cold waters of these
currents do not readily evaporate, thus depriving these coasts almost completely of rain. The little
moisture that occurs is from the fogs that form when the cold current chills the warm air above and
causes its moisture to condense.
In the Sahara, the small amount of rainfall is also due to the effects of offshore winds, called the
Sirrocco, which blows to the Mediterranean Sea and the Hamattan which blows towards the Equator.
All these winds are hot, dry and dusty. There is little or no permanent surface water because of high
evaporation rates. Other than rivers that pass through deserts the only other permanent source of
water in deserts are oases which are found where the groundwater table is near the surface.
Climatic chart of Tropical /Hot Desert areas
Natural Vegetation
The vegetation is generally described as scrub. Plants found here are shrubs, coarse grasses, cactus like plants and
thorn bushes.
 Plants growing in this region have adapted to the harsh conditions. the characteristics of the vegetation of this
region that makes it survive in these dry and hot conditions include:
o Long roots which reach for water and plant nutrients deep underground
o Few or no leaves with a thick skin and waxy surface to reflect heat and reduce transpiration.
o Storage of water by succulent plants like cacti and aloes in their thick stems or roots.
o Green stems that can photosynthesize even when in leafless
o Small hard leaves that close their pores during the dry season
o The shedding of leaves to reduce transpiration.
o Seeds with tough skins and hard shells to protect them while lying dormant for years before
germination
o Thorns for protection against herbivores.
 For this reason desert plants are also known as Xerophytes.
 Intense evaporation in the desert increases salinity of the soils. Salts accumulate on the surface forming hard
saltpans. Plants, which grow in these pans, are called halophytes (salt lovers).
Human Activities
The desert regions are sparsely populated due to these harsh physical conditions. Human activities in this
environment include:
1. Nomadic Herding/Nomadic Pastoralism - Some desert dwellers keep livestock and move from place to place in
search of water and pastures. For example, the Tuaregs of the Sahara traditionally kept sheep, goats and
camels. Camels provided transport across the desert. The camels are well adapted to this environment and
provided them with some of their basic needs like meat, milk and skins. The skins were used for making tents,
clothes, bags and carpets. They traded these animals and their products for necessities like grain, firearms and
ammunition.
2. Crop cultivation/Settled Cultivators - Crop cultivation takes place around oasis and river valleys. Here crops are
grown under irrigation, for example, more than 40 million people are concentrated along the Nile River where
crops are grown under irrigation. Crops grown extensively include wheat, barley, cotton, rice and maize. The
Nile floods do not only provide water for irrigation, but also deposit fertile soils on the flood plains
3. Caravan Trading - This was common in the Sahara Desert. The desert merchants travelled in caravans using
camels and horses. They carried a wide range of goods like clothes, firearms, ammunition, and beverages,
household utensils, grains and tobacco. They bartered these for goods produced by nomadic pastoralists like
carpets and rugs.
Impact of Human Activities on the Environment
 Overgrazing: Little vegetation cover has resulted in overgrazing in this area
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Desertification is caused by overgrazing
Deforestation
Soil erosion
Salinization caused by irrigation because not all irrigation water is absorbed into the soil. Some of it
evaporates leaving behind dissolved salt in the topsoil. The accumulation of salts in the soil is known as
salinization. This ruins the land and often results in crop failure.
Factors affecting human activities
The tropical desert makes it difficult for people to carry out some of the human activities in the region. Factors that
impact on human activities include:
 Lack of water, there are a few water sources in the desert such as oasis and this is where the population is
concentrated.
 Poor or infertile soils: Deserts have sandy soils, which lack plant nutrients and have a poor water holding
capacity. The soils are not ideal for crop cultivation.
 Little or no vegetation cover: lack of vegetation means lack of pastures for livestock
Semi Deserts
Distribution and location
 Semi deserts lie on the edge or border of true/hot deserts.
 They form a transitional zone between the desert and wetter climates like savanna and temperate grassland.
 As their name suggests, semi-deserts are not as dry as true deserts.
 Like deserts, semi deserts are areas of high pressure which has hot and dry air. Few people live here because
the region receives low and unreliable rainfall and has infertile soils.
 Areas that experience this type of climate are the Kgalagadi Desert on the edge of the true Namib Desert. The
Kgalagadi Desert spreads into 3 countries; Botswana, Namibia and South Africa.
 On the edge of the Sahara is the Sahel, a region transitional between semi-desert and savannah.
Climate characteristics
 The semi desert region generally has warm summers and cold winters.
 Although the conditions are not as harsh as those of desert, day temperatures may be very high in summer.
 There is a large difference between day and night temperatures (high diurnal temperature range). This is
because of the cloudless skies.
 Semi-deserts are regions of low rainfall and high evaporation rates.
 The average rainfall is between 250-500 mm per year.
 Rainfall is mainly of convectional type.
 The region experiences long droughts and dry winds.
Climatic chart of Semi- Desert areas
Natural Vegetation
 The major type of vegetation is scrub, thorny short acacias and bushes, short coarse grasses and cactus.
 During the rainy season grasses and flowering plants may cover a wide area. These plants however last only
for a short time during the rainy season.
 Grass withers and flowers soon fade away as the long dry season arrives.
 Plants here have to cope with high heat, intense sunlight, and prolonged drought in much the same way as
those in desert regions.
 Vegetation in semi deserts is very sparse or scanty.
Human Activities
The traditional inhabitants of this region were largely hunter-gatherers and nomadic pastoralists. However, there
are other human activities such as crop cultivation, irrigation and tourism.
1. Hunting and Gathering - In Southern Africa, Basarwa are traditional inhabitants of this region. They lived by
hunting wild animals with bows and arrows and gathering wild fruits, berries, melons and nuts, as well as
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insects. They obtained water from dew, sip wells, plant roots and desert melons. They used tortoise and
ostrich shells for storing water. Their clothes were made from animal skins. Fire was used for roasting meat
and for keeping them warm in winter.
Nomadic Pastoralism - Livestock are raised in semi-arid regions. Farmers rear cattle, goats, sheep, camels and
donkeys. The Tuaregs of Sahel are shepherds who move from place to place looking for water and pastures.
They ride camels and keep sheep and goats.
Tourism - The presence of wild animals has led to the establishment of game parks such the Kalahari Trans
frontier Park and Central Kgalagadi Game Reserve. There are game ranches in the region, as wild animals can
adapt to the dry desert conditions better than domestic animals.
Crop Production - Cultivation of drought resistant crops like sorghum, beans, millet and watermelons is done.
Crops that need more water like vegetables, fruits and cotton can only be grown under irrigation in oases.
Impact of Human Activities on the Environment
 Desertification, whereby these regions are slowly being turned into true deserts. The Sahel and the Kgalagadi
Desert are becoming true deserts due to land degradation caused by a combination of drought, overgrazing by
livestock and firewood collection.
 Overgrazing of livestock
 Deforestation
 Soil erosion
 Salinization
Mediterranean Climate/ Warm Temperate Eastern Margin
Location and Distribution
 It occurs between latitudes 30°N and 45°N and 30°S and 40°S on the western sides of the continents,
especially lands bordering the Mediterranean Sea. In Africa, it is best developed in the coastal northern parts
of Algeria, Morocco, Tunisia and Egypt in the northern hemisphere and also in South Western Cape (South
Africa), in the southern hemisphere.
 The Mediterranean climate is so named because most of the areas with this type of climate are found along
the Mediterranean Sea.
 The Mediterranean climate is found in relatively few areas.
Climatic Characteristics
 There is a relatively small difference between summer and winter temperatures because Mediterranean
regions are located near large bodies of water.
 The temperature ranges from in summer 21oC (hot) to in winter 10oC (mild/cool)
 Rainfall occurs when temperatures are low- in winter.
 On shore westerly winds blow in winter bringing cyclonic rainfall/ the mistral-cold wind blows down the Rhone
valley in the winter season.
 Dry off shore winds from deserts blow in summer/ The hot, dry and dusty winds called Sirocco winds blow
from the Sahara across towards the Mediterranean in summer season
 In summers skies are cloudless
 The summers are dry with low humidity
 The region receives annual rainfall of about 500 mm to 900 mm.
 Rainfall may come as heavy showers which sometimes cause floods.
 Fogs occur off the coast where the onshore winds cross cold currents
Climatic chart of Mediterranean areas
Natural Vegetation
 The natural vegetation of the Mediterranean region is the evergreen open forest/woodlands, woody scrub
and grasses.
 Evergreen trees are found in areas that receive more rainfall. They include cork oak, pine, cypress and
eucalyptus. Under the trees are shrubs.
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Woody scrub dominates in drier areas. These scrub lands are called marquis in North Africa and fynbos in
South Africa. They include sweet smelling herbs such as lavender, rosemary, thyme and oleander. They are
used for making sweet scents used in perfumes, lotions and bath soaps.
Tough grasses and flowers also grow in this region.
The natural vegetation of Mediterranean lands has adapted to survive long, hot and dry summers. They have
many of the characteristics of desert plants hence they are also called xerophytes. The following
characteristics enable them to survive:
o Plants tend to be less than a meter tall and relatively shrubby in appearance.
o They grow briefly after winter rains, and then survive the dry summer in the form of seeds.
o The leaves are often small, curled, and waxy with the few stomata to reduce transpiration
o stomata hidden among numerous hairs on the bottom side of the leaf/some plants roll their leaves to
reduce transpiration
o Many of the plants contain numerous volatile chemicals such as turpentine that prevent herbivores
that retard their growth.
o Many species are fire resistant. Some like cork trees have thick heavy bark others have underground
roots and seeds that survive fires.
o Long roots to reach water deep underground
o Bulbous roots to store up water
o Thick back to reduce transpiration.
Human Activities
Agriculture is an important activity in the Mediterranean region as the climate permits a variety of crops to be
grown.
1. Orchard Farming -The Mediterranean is well known for orchard farming and as a result it is often referred to
as the world’s orchards land. A wide range of fruits, especially citrus fruits such as oranges, lemons, limes,
citrons and grape fruits are grown. Olive trees are also grown extensively to produce olives that are processed
into olive oil. These develop long roots to tap water during the dry summers
2. Winter crop cultivation - Cereals are grown extensively, especially wheat and barley. A wide variety of nuts like
chestnut, walnut, hazelnuts and almonds are grown. Other crops include tobacco, cotton and figs.
3. Viticulture - The Mediterranean specialises in viticulture/cultivation of grapes which are supported by the long
sunny summers. Most grapes are used for making wine, while some are dried into raisins, currants and
sultanas.
4. Pastoral/sheep, goat and a few cattle are kept in the cooler mountain areas of the Mediterranean region.
5. Tourism - The bright sunny weather attracts tourists, particularly from cold countries. The Mediterranean
coastal areas are therefore densely populated and more developed than the interiors.
6. Market gardening – due to moderate temperatures/long sunny summers
7. Agro industries - Agriculture has given rise to specialised industries such as wine making, flour milling, fruit
canning and food processing.
Impact of Human Activities on the Environment
 Deforestation - Most natural vegetation in the Mediterranean areas has long since been cleared. Some trees in
the region have been cut down because they are valued for their softwoods. Vegetation has been cleared to
give way to farms and for human settlement.
 Overgrazing - Overgrazing by goats and sheep has led to the dominance of scrub vegetation
 Soil erosion for this reason the natural evergreen open woodland has been reduced to scattered woodland
and shrubs.
Warm Temperate Continental Climate/ Temperate Grasslands/Steppe
Location and distribution
 Found inside the continents between latitudes 20 oN and 35oN and 20oS and 35oS.
 In Africa it is best developed in South Africa between the Drakensberg Mountains and the Kgalagadi Desert in
an area that includes Gauteng Province, North West, Free State, Lesotho, Mpumalanga, Swaziland and
Limpopo Province. It covers 30% of South Africa’s land area and is popularly known as the High Veldt.
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Climatic Characteristics
 Temperate grasslands have cold winters and warm summers.
 The annual temperature range is high. The temperatures ranges from 10oC in winter to 26oC in summer
 The South East Trade Winds blow in the region bringing cyclonic rainfall
 Annual rainfall varies between 400 mm and 780 mm.
 Rainfall is higher in eastern areas close to the sea but decreases westwards towards the desert.
 Convectional rainfall also falls with the passage of summer low pressure systems
 Evaporation is high in summer.
 The wettest months are from November to January while from June to August are the driest.
Climatic chart of the Warm Temperate Continental Climate areas
Vegetation
 The natural vegetation is mainly grass, sometimes called temperate grassland or steppe. In Southern Africa it
is called the veldt.
 The veldt has a few scattered trees.
 Grasses are much shorter, tough and less nutritious, especially in the drier areas.
 The grasses, along with other plants, such as herbs, form a continuous cover, except in areas where there is
sufficient ground water to support clumps of trees.
 Grass withers and dies in the dry season. The roots do not die but produce new stems during the rainy season.
 In the wetter regions and along rivers and streams the grasses are tall and nutritious.
Human Activities
1. Crop Production - The temperate grassland is a good area for wheat production. The flatland is good for
ploughing and harvesting using machines. Most of the world wheat is produced in these regions. Crops grown
in the Highveld include wheat, maize, sorghum, citrus fruits, groundnuts and sunflower. Vegetables are grown
in irrigated areas and farmland closer to urban areas.
2. Pastoral Farming - The grassland is ideal for pastoral farming. Animals such as beef cattle, sheep, goats, pigs
and horse are kept in ranches. Dairy cattle are kept for the production of milk, butter, cheese, cream and
skimmed milk. Fodder crops like Lucerne and Alfalfa grow well in this region and are grown to feed livestock.
Human Impact on the Environment
All activities we have discussed have a great impact on the environment. In the drier parts of the veldt, there is a
problem of overgrazing which is caused by overstocking. The resulting environmental problem is soil erosion.
Intense use of land for crop cultivation and the use of heavy machinery have led to soil erosion too. Droughts and
veldt fires have worsened this problem.
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