Curriculum Shule Direct Tanzania Secondary School Form 1 Geography

Geography

CLIMATE
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Geography is the study of places and the relationship between people and their environment. Geographers explore both the physical properties of the Earth's surface and the human societies spread across it.In the context of dynamic and changing world, it is very crucial to study Geography so as to be able to achieve sustainable human development.

CLIMATE

Introduction
In this chapter, you will learn about the concept of climate. Also you will learn the difference between weather and climate. Finally, you will learn about the impact of climate on human activities. The chapter ends with summary of climate, revision questions and a list of references.
Objectives
By the end of this topic, you should be able to define the concept of climate, differentiate between weather and climate, and relate climate to human activities.
Concept of Climate
Define the concept of climate
Climate is the average weather conditions of an area observed and recorded over a long period of time usually about 30 years. The scientific study of climate is called climatology and a person who studies climate is called climatologist
Weather and Climate
Differentiate between weather and climate
There are marked differences between weather and climate. The table below summarizes these differences
<em>Table 5.1 Differences between weather and climate</em>
<em>Table 5.1 Differences between weather and climate</em>
Factors influencing weather and climate
Usually, the elements of weather that affects climate vary from one place to another. While studying about weather, we learned about the elements of weather which affects climate. Therefore, the elements of weather are the same as the elements of climate. The factors that cause variation in weather elements also affect the climate. The factors affecting both climate and weather are presented in the following sub-sections;
1. Latitude
This factor affects temperature and rainfall. Areas around and close to the equator experience higher temperature and receive higher rainfall than those further away. So the rainfall and temperature decrease as one move away from the equator
The amount of heat received at any place on the Earth’s surface depends on the angle at which the Sun’s rays strike the surface of the earth and the duration of the Sunshine. At the equator, the Sun’s rays fall on the Earth’s surface at almost right angles throughout the year, but the angle at which the Sun’s rays strike the Earth’s surface decreases as one moves towards the poles
Therefore, temperatures decrease with increase in latitude because the equator receives vertical rays of Sunlight while the north and the south poles receive slanting rays. Because of this fact, the equator and places near the equator are hotter while places in or near the south and north poles are colder.
2. Altitude
This affects temperature and atmospheric pressure of an area. Temperature decreases with increasing altitude at the rate of 0.6°C for every 100 meters from the sea level. Therefore, low-altitude areas are warmer than high altitude areas. Atmospheric pressure decreases with increasing altitude. Pressure at sea level is higher than pressure at the summit of a high mountain.
3. Ocean currents
The nature of the ocean current influences the temperature of the wind blowing over it and transfers this effect to the land adjacent to the ocean. This will either lead to reduction or increase in the temperature of the land depending on the type of the ocean current. The wind blowing over warm ocean currents will pick moisture from the ocean and often causes heavy rainfall over the land while the wind blowing over the cold ocean current brings little or no rainfall to the land.
4. Distance from the sea
This affects temperature and rainfall. Places located near the sea experience high temperature and receive high rainfall than those located further away. This is because of high rates of evaporation from the water surface, which eventually causes heavy rainfall along the coastal areas. For this reason, coastal regions often experience higher temperatures and rainfall than in inland areas.
5. Aspect
This term refers to the direction in which a slope faces. It influences temperature and rainfall. For example, the south-facing slopes in the northern hemisphere are always warmer than the north-facing slopes. Also, the windward side of the mountain receives heavier rainfall than the leeward side.
6. Wind and air masses
Wind carries moisture with it as it flows. Warm wind blowing over a cold region warms the cold region over which it flows. However, if the wind is cold, it cools the region, Warm, moist wind blowing towards a cold, dry region may lead to formation of rainfall in the destination region. Cold, dry wind blowing over a dry region brings no rainfall and if the blowing is repeated over several years, it may cause aridity in that region
7. Alignment of the coastline
This refers to the arrangement of the region’s coastline in relation to the direction of the wind. If the winds blow across the coastline they cause rainfall. If they blow in parallel to the coastline, they cause drought
8. Inter tropical Convergence Zone (ITCZ)
This is a low-pressure area around the equator. The moist winds meet within this region. Places further away from this zone experience only one rainy season while places close to the zone experience two seasons of heavy rainfall. This is because the winds converge around this region twice a year.
9. Forests
Areas covered with forests normally receive high rainfall as compared to those with little or no vegetation. This is because of high rates of evaporation and transpiration, leading to high humidity. Therefore, these areas often, receive high amounts of rainfall and have a modified climate
10.Human activities
A range of human activities such as agriculture, mining, transportation, construction, etc. affects the climate. For instance, clearing of the forests to get land for agriculture and settlement leads to the loss of biodiversity, making the land arid and unproductive.
Impact of Climate
Relate climate to human activities.
Climate has many impacts on human activities. Various economic activities conducted by man in different parts of the world are determined by the type of climate experienced in a particular region. For example, people living in deserts and semi-arid regions do not practice much agriculture because their environment does not favour crop cultivation or animal husbandry. In these regions, however, a very limited agriculture and animals rearing are conducted. The animals kept include camels, goats, sheep, donkeys and other hardy animals. Only drought-resistant crops such as dates are grown in deserts and arid areas.
In tropical and equatorial regions, a lot of agriculture is carried out. The people of these regions take part in cultivation of crops and keeping of animals. Crops grown include cocoa, banana, horticultural crops and grains. The animals kept in these climatic zones include cattle, pigs, donkeys, horses, poultry and other farmyard animals. Specific types of various economic activities carried out in each climatic region will be discussed in detail in the following section
Climate and Human Activities
The type of human activities undertaken in any part of the world depends on the climate experienced in that place. Each specific climate is suitable for a particular type of human activities. To relate human activities with the type of climate, it is important that to understand the characteristics and location of these climatic regions around the globe.
HOT CLIMATES
These are the type of climates found within the tropics, mainly between 23½° north and 23½° south of the equator. Hot climates include the following climate sub-types;
  1. Equatorial climate
  2. Tropical continental climate
  3. Tropical monsoon climate
  4. Tropical marine climate
  5. Tropical desert climate
Equatorial climate
Location
The region is found approximately between 0° and 5° north and south of the equator. It may extend up to 10° north or south of the equator in some regions. Examples of areas found within this region include the Amazon basin in South America and the Congo Basin, the southern Ivory Coast, south Ghana, western coastal Nigeria, and eastern coastal Malagasy Republic in Africa.
Characteristics of the equatorial climate
  1. There are no marked seasons
  2. High temperature throughout the year; The annual temperature range is about 3°C, The daily mean temperatures are about 26°C throughout the year
  3. The daily temperature range is rarely more than 8°C because of the thick cloud cover
  4. Rainfall is heavy and is usually convection rain
  5. Rainfalls usually occur in the afternoons and they are accompanied by lightning and thunderstorm
  6. Total annual rainfall is about 200 mm with two maximum (peaks)
  7. High humidity and intensive cloud cover throughout the year,
This climate can generally be described as hot and wet throughout the year, with a small annual temperature range, Areas with equatorial climate, the economic activities and vegetation, Highlands located within the equatorial region have their temperatures modified by altitude. The temperature of some of these highland areas includes the East African Highlands which is lowered to about 15°C. These regions are said to have a modified equatorial climate
Variations on the basic type of climate occur in the highland regions of equatorial Africa. The climate of most of these regions has an equatorial rainfall pattern
In areas such as south-eastern Nigeria, Cameroon, the south-east Asian islands of Malaysia, Indonesia and the Philippines, the climate is equatorial monsoon because of the seasonal reversal of winds. This results in even heavier rainfall
Human activities in Equatorial climate
Human activities carried out in the equatorial climate region include shifting cultivation and plantation agriculture. Crops grown in this region include yams, cassava, maize, millet, sweet potatoes, sorghum, beans, watermelons, bananas and groundnuts. Examples of areas where this type of farming is practiced include some parts of West Africa and Asia.
In plantation agriculture, crops such as cocoa, rubber and oil palms are grown on large scale farms. Most rubber plantations are found in Malaysia, Indonesia, Thailand and Sri Lanka. They are also found in Liberia. Cocoa plantations are found in Brazil and West Africa (Ghana, Nigeria and Ivory Coast). Oil palms are grown in Nigeria, Malaysia and Indonesia.
Rainforests are also common in equatorial regions. In Africa, the equatorial forests are found in the Democratic Republic of Congo (DRC), Gabon and some parts of West Africa.
Tropical continental climate
This climate is also known as Sudan type or Savannah climate. In the interior of the continents, it is referred to as tropical continental climate
Location.
This climatic region is found between 5oN and 15oN and 5oS and 15oS though it extends to 25o north or south of the equator. It is best developed in most parts of Africa, and some parts of South America, India and Australia. Characteristics of tropical continental climate are;
  1. Hot summers (32oC) and cooler winters (21oC)
  2. The annual temperature range is about 11oC
  3. The highest temperatures occur just before the rainy season begins
  4. Heavy rains, mainly convection, occur in the summer
  5. Total annual rainfall is around 765mm, though this increases in the areas lying close to the equatorial climate region. Similarly, rainfall decreases towards the tropical deserts
  6. Humidity is high during the hot, wet season.
Areas with tropical continental climate, the economic activities and vegetation
This climate is dominated by tall grass and trees which are found more near the equatorial forest region. The savannah region is suitable for herbivores animals such as giraffes, elephants, buffaloes, rhino, zebras, antelopes, wildebeests and many other animals. There are also carnivorous animals such as lions, leopards, hyenas, etc. The region also supports a variety of species of birds, reptiles and insects
People living in this region mainly engage in livestock keeping, cultivation and tourism. Also, lumbering is practiced. Many tourists come from foreign countries to view the wildlife that lives in the vast grassland. Numerous national parks have been established in this region. In Tanzania, for example, there are national parks such as Serengeti, Mikumi, Selous, Tarangire, Ruaha, Saadani, Ngorongoro, Katavi and Manyara.
The major crops grown in this region are maize, millet, groundnuts, beans, onions, cotton, tobacco, sugarcane, sisal, rice and coffee
Tropical monsoon climate
Location,
The areas which mainly experience monsoon type of climate are South East Asia, Northern Australia, Southern China, and the Indian subcontinent. This type of climate is most marked in India.
Characteristics of Tropical monsoon climate
  1. Seasonal reversal of winds (monsoon winds); onshore during one season and offshore during another season
  2. Onshore wind brings heavy rain to coastal regions while offshore winds bring little or no rain, except where they cross a wide stretch of the sea
  3. Temperatures range from 32oC in the hot season to about 25oC in the cool season, giving an annual range of about 7oC
  4. Annual rainfall varies greatly, depending on relief and the angle at which onshore winds meet the highlands (aspect)
  5. There are three marked seasons namely cool, dry season; hot, dry season; and hot, wet season.
The economic activities
The main human activities carried out in areas experiencing this type of climate include rice growing and livestock husbandry. Apart from rice, other crops grown are wheat, millet, maize, and sorghum.
Sugarcane, cotton and jute are important lowland crops grown in India, Pakistan and Bangladesh. The other crops grown are tea grown in Sri Lanka, Bangladesh and India, and rubber in Malaysia.
Animals kept in this climatic region include pigs, cattle, buffalos, sheep, goats, and poultry.
Tropical marine climate
Location..
Regions with this type of climate are located on the east coasts of regions lying between 10oN and 25oN and 10o S and 25oS. These areas are under the influence of onshore trade winds. The main areas are the east coasts of Brail and Malagasy, the lowlands of Central American and the West Indies the coast of Queen land (Australia) and the southern Islands of the Philippines
Characteristics of Tropical Marine climate
  1. Temperature characteristics are similar to those of the equatorial climate
  2. Hot season temperature is 29oC and cooler season temperature is 21oC
  3. Annual temperature range is about 8oC
  4. Total annual rainfall varies from 1000 mm to 200 mm depending on the location
  5. Rainfall is both convection and topographic (brought by onshore trade winds)
  6. Maximum rainfall occurs in the hot season
  7. High humidity throughout the year
This climate can generally be described as hot and humid throughout the year. However, the climate is cooled by the onshore winds blowing almost every day
Economic activities of Tropical Marine climate
The main human activities carried out in this climatic region include crop cultivation, lumbering and animal rearing. The crops grown include sugarcane, rice, banana and wheat. The animals kept are such as cattle, pigs, sheep, goats and poultry
Tropical desert climate
.Location
The tropical desert climate is found on the western margins of landmasses between latitude 20o to 30o north and south of the equator. The climate is experienced in all the major tropical deserts of the world. The hot deserts occupy about one-third of the Earth’s surface. The tropical deserts found on the continents include the following
  1. Africa: Sahara, Kalahari and Namib Deserts
  2. Asia: the desert of Jordan, Syria, Iran, Iraq, Saudi Arabia and Israel, and the desert of India
  3. North America: Mohave, Colorado and Mexican Deserts.
  4. South America: Atacama Desert.
  5. Australia: Great Australian Desert.
Characteristics of Tropical desert climate
  1. Very little total annual rainfall of less than 120 mm in one year.
  2. Mean monthly temperatures range from 29oC in the hot season to 10oC in the cool season.
  3. In most deserts, daytime temperature can rise to as high as 47oC or more.
  4. Night temperatures can fall to as low as 16oC in summer and 5oC in winter
  5. Very high diurnal temperature range (due to very hot days and very old nights)
  6. The annual temperature range is large. It is about 16oC
  7. Humidity is always low and therefore evaporation is high.
Economic activities in tropical desert climate
Desert environments support very minimal human activities. Agriculture is practiced wherever water is available as in oases (singular oasis) and along rivers. The crops grown include date palms, cotton, rice, sugarcane, vines, millet, tomatoes, tobacco and fruits. Apart from the people who live permanently in oases, there are nomads who move from one place to another in search of pasture. They keep camels, donkeys, goats and sheep. The camel is an animal that has adapted to desert conditions. It can survive for many days without drinking water. It is mainly used for transport in the desert. Other desert people are good hunters and also collect food from the bushes.
The other activities that can be done by desert dwellers include weaving mats, making ropes, and trading
WARM CLIMATES
Location of warm climates
Warm climates border the hot tropical deserts. They occur between 30o and 40o north and south of the equator
There are four broad types of warm climates;
  1. Warm temperature western margin
  2. Warm temperature continental
  3. Warm temperature eastern margin
  4. Warm temperature desert
Warm temperate western margin (Mediterranean type, This is also known as the Mediterranean climate)
Location warm temperature western margin
This type of climate occurs between 30oN and 45oN and 30oS and 40oS on the western sides of the continents. Places experiencing the Mediterranean climate are on the coastal lands around the Mediterranean Sea (the Maghreb, Spain, Italy, Greece, Egypt and Israel), the western sides of North and South America (central California and central Chile), South Australia (Perth and Adelaide) and South Africa (Cape Province).
Characteristics of warm temperature western margin
  1. Temperatures range from 21oC in the summer to 10oC (or below) in the winter
  2. Mean annual temperature is about 15oC
  3. Annual total rainfall varies from 500 to 900 mm
  4. Hot, dry summers and cold, wet winters. This is because westerly winds blow offshore in the summer and onshore in the winter
The Warm temperate western margin or the Mediterranean climate can generally be described as having hot, dry summers and middy, rainy winters.
Economic activities in warm western margin (Mediterranean climate).
The climate permits a wide range of crops to be grown, which include fruits and cereals. It is in this region that much of the world’s citrus fruits are grown. Citrus fruits include oranges, lemons, grapes and limes. Other fruits grown here are peaches, apricots, plums, cherries, olives, almonds and pears.
The cereals include maize, wheat, rice and barley. Agriculture has given rise to specialized industries such as wine-making, flour-milling, fruit canning and food processing industries
Warm temperate continental (steppe type, This type of climate is also known as warm temperate interior region)
Location warm temperature continental.
It is found in the interior of the continents, between 20o and 35o north and south of the equator. The best examples of the areas having this climate are Murray-Darling lowlands of Australia; The high Veldt of South Africa; and the central Paraguay and central Argentina (both in South America); central lowlands of north America (Oklahoma and Texas and in northern Mexico); central European lowlands, and the plains of Manchuria
Characteristics of warm temperate continental climate
  1. Temperatures range from 26oC in the summer to 10oC in the winter
  2. The annual rainfall varies from 380mm to 700 mm, depending on the distance from the sea
  3. Rainfall is convectional type and falls mainly in spring and early summer
Economic activities in warm temperate continental climate
The main economic activities carried out in this region are cattle rearing and crop growing. In Australia, for example, sheep keeping for wool (merino sheep type) is the major economic activity. Sheep rearing is also practiced in South Africa, Argentina and Mexico. Tourism is also practiced in this type of climate
Warm temperate eastern margin (China type)
Location of warm temperature eastern margin
It occurs in the eastern sides of the continents between latitudes 23o and 35o north and south of the equator. The countries having this type of climate are central China, south eastern USA, and Southern Brazil, eastern part of Argentina, South Africa, southern Brazil, and eastern part of Argentina, South Africa, southern Japan, and south eastern Australia.
Characteristics of warm eastern margin
  1. Temperatures are about 26oC in summer and 13oC in the winter
  2. The total annual rainfall varies is about 1000 mm
  3. The rain is convectional and torrential type and it mostly falls in the summer
Economic activities in warm eastern margin
Temperatures and rainfall in this type of climate make it possible to grow crops and keep animals. Lumbering is also practiced in the forested areas.
The crops grown include rice, maize, cotton, sugarcane and tobacco. Animals are extensively kept in Argentina and Australia. The animals produce products such as meat, milk, butter and cheese for consumption and export.
Warm temperate desert( This type of climate is also called mid-latitude desert climate location).
The areas having this type of climate include Nevada and Utah states of North America and Patagonia in South America. It is also found in regions that extend from Turkey, Northern Iran, across the Caspian Sea and Aral areas into former USSR. It is also experienced in the Gobi Desert of Mongolia
Characteristics of warm temperate desert
  1. High summer temperatures (25oC - 37oC)
  2. Cold winters with temperatures as low as -7oC
  3. Diurnal range of temperature is around 35oC and annual range of temperature around 40oC
  4. Unreliable and low rainfall because of continentally effect. Mean annual rainfall does not exceed 250 mm and most of it falls late winter and early spring.
Economic activities in warm temperate desert
The economic activities practiced in this region include nomadic pastoralism which involves the keeping of hardy animals such as donkeys, goats, sheep and camel, Cultivation of crops such as dates, fruits, wheat and vegetables is done in oases and in river valleys
COOL CLIMATES
These climates are experienced in regions between 35o north and 60o south of the equator. They are characterized by definite seasonal variations in temperature. There are four types of cool climates;
  1. Cool temperate western margin (British type)
  2. Cool temperate continental (Siberian type)
  3. Cool temperate eastern margin (Laurentian type)
  4. Temperate desert
Cool temperate western margin (British type)
Location of cool temperature western margin
It is found on the western sides of the continents between 45o and 60o north and south of the equator. Areas with this type of climate include North-West Europe, British Columbia in western Canada, Southern Chile, Tasmania, and the South Island of New Zealand
Characteristics of cool temperate western margin
  1. Winter temperatures range between 2oC and 7oC, while summer temperatures range from 13oC to 15oC
  2. The annual temperature range is between 8oC and 11oC
  3. Rainfalls throughout the year, with maximum in winter
  4. The total annual rainfall is about 760 mm
  5. The rainfall is both conventional and cyclonic in nature
Economic activities in cool temperature western margin
People living in this region engage in a myriad of economic activities which include agriculture, mining, lumbering, manufacturing and commerce
Agriculture is extensively practiced including keeping of beef and dairy cattle and sheep. Also it involves the growing of wheat, barley oats, vegetables and fruits. In British Columbia, lumbering is an important economic activity. In Tasmania and New Zealand, sheep rearing for wool and mutton is an important activity. Fruit farming, especially apples, is practiced throughout the region
Cool temperate continental (Siberian type)
Location of Cool temperate continental (Siberian type)
This type of climate is found extensively in the northern hemisphere. It occurs in the interiors of North America and Eurasia between 35o and 60oN
Characteristics of cool temperature continental
  1. Moderately warm summers (18oC)) and very cold winters (-19oC)
  2. The annual temperature range is very high (37oC)
  3. Most of the rain falls in the summer
  4. The rain is convectional type and is often accompanied by thunder
  5. The annual precipitation (rain plus snow) ranges from 400mm to 500 mm
Economic activities in cool temperate continental
The main economic activities in this region include lumbering, fishing, mining and agriculture
Cool temperate eastern margin (Laurentian type)
Location of Cool temperate eastern margin
It is found on the eastern sides of the continents between 35oN and 5oN and south of 40oS. It is experienced mainly on the eastern sides of North America and Asia.
Characteristics of cool temperature eastern margin
  1. Winter temperatures range from -10oC to 4oC
  2. Summer temperatures range from 12oC to 24oC
  3. The annual temperature range is large and averages 24oC
  4. Precipitation (in the form of rain and snow) is distributed throughout the year
  5. Annual precipitation varies between 700 mm and 1000 mm
  6. Rainfall is both conventional and cyclonic
Economic activities in cool temperature eastern margin
The main economic activities in this region are farming, mining, and manufacturing. The crops grown include wheat, maize, millet and soya beans. Sheep farming is important in Patagonia. Mining and manufacturing are practiced where minerals are found.
Temperate desert
Location of Temperate desert
Characteristics of temperate desert
  1. Winters are very cold with temperatures often below -7oC
  2. Summer temperatures vary between 25oC and 37oC
  3. Diurnal temperature range is about 35oC while the annual temperature range is about 40oC
  4. Rainfall is very low, its averages about 250 mm
  5. Most of the rainfalls in late winter and early spring
Economic activities in temperate desert
The economic activities carried out in this region include mining, animal rearing and agriculture. The animals reared include camels, donkeys, sheep and goats. The main crops grown in this region are date palms, oil palms, and millet. Agriculture is mostly practiced in oases and along river valleys
COLD CLIMATES
Cold climates are mainly experienced in regions between latitudes 60oN and 68oN
There are three types of cold climates;
  1. Cold temperate western margin (British type)
  2. Cold temperate continental (Siberian type)
  3. Cold temperate eastern margin (Laurentian type)
  4. Temperate desert.
Cool temperate western margin (British type).
Location of Cool temperate western margin (British type)
This climate is found to the coastal areas of Scandinavia and Alaska
Characteristics of cold temperate western margin
  1. Short, cold summers with temperatures of about 12oC
  2. Long winters with temperatures ranging from -2oC to 4oC
  3. Annual rainfall is about 750 mm
  4. Rainfalls in most months except the winter when the snow falls
Economic activities of cold temperate margin
The main economic activities practiced in this region include agriculture, mining and manufacturing. Dairy cattle farming is mainly practiced in the Scandinavian countries such as Norway, Denmark and Sweden
Cool temperate Continental
Location of Cool temperate Continental
This climate is found between 55oN and 68oN in the interior of America and Eurasia
Characteristics of cold temperate continental
  1. Cold and long winters with temperatures ranging between -34oC and -45oC
  2. Warm and short summers with average temperatures up to 21oC
  3. Annual precipitation is very low, about 380 mm
  4. Most of the rainfalls in summer, but in winter, precipitation is in the form of snow
Cold temperate eastern margin
This climate is found in the North East pacific of Russia
Climatic characteristics
  1. Long, cold winters with an average temperature as low as -20oC or below
  2. Short, hot summers with an average temperature up to 21oC or higher
  3. Total annual rainfall varies between 500mm and 1000 mm
Economic activities in cold temperate eastern margin
The type of economic activities suitable for this type of climate includes animal husbandry and the growing of crops such as fruits, wheat, and maize, millet, and soya beans.
ARCTIC CLIMATES
These types of climates are experienced in regions beyond the Arctic Circle (661/2oN) and around Arctic Ocean. They are also known as polar deserts. The main features of these climates are low amounts of rainfall, mild summers and very cold winters
Arctic climates comprise of Tundra and Polar climates
Tundra climate
Location of Tundra climate
This region occurs in the northern coast of North America, southern coast Greenland and the Arctic coast of Europe and Asia
Characteristics of Tundra climate
  1. Very long, cold winters with temperatures ranging between -29oC and - 40oC
  2. Short, cool summers with temperatures of about 10oC
  3. Annual rainfall is 250 mm; some of it falls as snow in winter and as rain in summer
Polar climate;
Location of Polar climate
It occurs in the interiors of Iceland, Greenland and Antarctica
Characteristics
  1. Temperatures are permanently below 0oC
  2. Rainfall is in the form of blizzards (now storms)
  3. The winters consist of continuous night, and summers of continuous day. Because temperatures are very low, most these regions are uninhabited
Mountain climate
This type of climate is found in the main mountain areas of the world. The areas that experience such climates include the East Africa Mountains, the Ethiopian highlands, the mountains and plateaus of central Asia, the Alps of Europe, the Andes of South America and the Rockies of North America.
Characteristics.
  1. Pressure and temperature generally decrease with increase in altitude
  2. Rainfall increases with altitude
  3. In areas around mountains within the tropic, temperatures may range from high at the foot of a mountain to very cold at the peak, e.g. Mount Kilimanjaro.
Economic activities.
In the tropics, mountainous regions are famous for cultivation of highland crops such as coffee, tea, banana and maize. The area is also suitable for keeping of animals which include dairy cattle, pigs and other animals.
Relationship between Climate and Human Activities
We have learnt particular climatic conditions influence human activities. Therefore, specific climatic conditions are suitable for given human activities and settlements. The following section presents various economic activities and the way climate has influence it.
Agriculture
Agriculture is strongly influenced by climate. The nature of agriculture and farming practices in any particular location depends on the type of climate experienced in that location.
Crops thrive well in areas with a fertile soil and which receives sufficient rainfall as well as optimum temperature conditions. In such areas, both commercial and subsistence crops are grown.
The equatorial region receives high rainfall and experiences high temperature throughout the year. This climate is suitable for crops that can grow well in moist and hot conditions. The crops that can be grown in this region include cocoa, banana, rubber, sugarcane and yams
Livestock rearing can be practiced in the tropics where rainfall permits the growth of pastures. This area also supports the cultivation of a variety of tropical crops such as fruits, tobacco, sugarcane, tea, maize, rice and a variety of horticultural and cereal crops.
Cooler climates also support crops which grow better in climates like barley, wheat, oats, sugar beet, and fruits such as apples, peaches and apricots. These areas also support the rearing of dairy animals.
In semi-desert and desert climates where very little rainfall is received, there are reduced agricultural activities. However, drought-resistant crops like millet, date palms, oil palms and sorghum can be grown. The keeping of hardy animals such as sheep, camels, donkeys and goats can be practiced.
Settlements
People like to establish settlements in areas with favourable climates and which support a variety of agricultural activities. Such areas are often well-populated. Very hot or extremely cold areas are usually sparsely populated because their climatic conditions are unfavourable for human settlement.
Forests grow well in areas that receive enough rainfall and which have sufficient temperatures. Dense forests of the world are concentrated in the equatorial and tropical climates which experience high rainfall and temperature throughout the year. The presence of forests in these regions stimulate lumbering and growth of other industries such as papermaking and carpentry
Fishing
Most of the world’s fishing grounds are in cooler regions. The cooler water is suitable for the growth of water plants called plankton on which fish feed. Tropical areas are not suitable for fish as compared to regions with temperate climates
Tourism
For tourism industry to flourish, the climate in the host countries must be favourable enough to attract the tourists to visit them. Tropical countries, like Tanzania, are often visited by tourists from cooler climates during winter in their home countries to enjoy the warmth of the tropical countries where they swim in warm waters and Sunbath in tropical beaches
Likewise, the tropical climate supports numerous wildlife which serves as tourist attractions. In Tanzania, for example, there are many national parks with thousands of wildlife species and beautiful sceneries. The animals found in the parks include elephants, buffaloes, zebras, lions, leopards, chimpanzees, monkeys and a variety of reptiles, amphibians, insects and plant species
Industry
The establishment and growth of industries strongly correlate to the climatic conditions. Most industries are established in areas where raw materials are adequately available. For instance, milk, tea, tobacco, meat, fish and fruit processing industries are often located where raw materials are found. Likewise, lumbering industries are built close to forests
Transport
Development of transport systems in some climatic regions is very difficult. For example, the tropical and equatorial regions, which receive much rainfall throughout the year, have poorly developed roads. Routes passing through areas with clay soils become muddy and slippery when it rains hence make transportation a challenge. Roads in desert regions may be blocked by sand blown onto them, making the roads impassable. In very cold regions, precipitation in the form of snow may cover roads, making them impassable during winter
CLIMATE CHANGE
Climate change is the long-term alteration of temperature and other weather patterns in a place. Gases trap heat from the Sun's rays inside the atmosphere causing Earth’s average temperature to rise. The overall effect of climate change is termed as global warming
What is global warming?
Global warming refers to an increase of the Earth’s average surface temperature due to effects of the greenhouse gases. The greenhouse effect is a natural process that warms the Earth’s surface. Greenhouse gases refers to the greenhouse gas, that has the property of absorbing infrared radiation (net heat energy) emitted from Earth’s surface and reradiating it back to Earth’s surface, thus contributing to the greenhouse effect. The greenhouse gases include water vapour (H2O), carbon dioxide (CO2), methane (CH4), nitrogen oxide or nitrous oxide (N2O), ozone (O3) and chlorofluorocarbons (CFCs). These gases trap heat that would otherwise escape from the earth
Since the early 20th century, the global air and sea surface temperatures have increased by about 0.8°C, with about two-thirds of the increase occurring since 1980s. Each of the last three decades has been successively warmer at the Earth’s surface than preceding decades since 1850s
The recent rapid global warming was caused by human activities which contribute to the production of greenhouse gases, such as carbon dioxide, that deplete the ozone layer to trap heat in the Earth’s atmosphere. It is predicted that the continuation of these activities will result in 1.8–4°C average temperature increase over the next century
Causes of global warming
Global warming is mostly caused by increasing concentrations of greenhouse gases in the atmosphere. The following greenhouse gases attributed to human activities are the main causes of global warming.
1. Excessive production of Carbon dioxide
Carbon dioxide is the main greenhouse gas. The gas contributes over 50% of the greenhouse effect
The following are some of the man-made activities that contribute to the production of carbon dioxide in the atmosphere;
  1. Combustion of fuel, Burning of fossil fuel such as wood, coal, petroleum and natural gas, releases carbon dioxide into the atmosphere. The gas is produced during combustion of these fuels in car engines, power stations, industries
  2. Deforestation, Green plants absorb carbon dioxide gas from the atmosphere and use it to manufacture their food through the process of photosynthesis. Cutting down trees means that a few trees are left to absorb carbon dioxide gas from the air. This has led to an increase in the amount of carbon dioxide in the atmosphere
<em>Fig. 5.1 A deforested land</em>
<em>Fig. 5.1 A deforested land</em>
2. Methane
The main source of methane is from agricultural activities. It is released from wetlands such as rice fields and from animals, particularly cud-chewing animals, like cattle. The emission of methane gas into the atmosphere, therefore, increase in agricultural activities contributes to the release of methane to the atmosphere which destroys the ozone layer hence global warming. Methane is also produced by the decomposition of waste materials by bacteria which is the major component of natural gas. The gas is also produced during the mining of coal and oil (as natural gas) and when vegetation is burnt
3. Nitrous oxide (dinitrogen oxide, N2O)
Nitrous oxide is produced from both man-made and natural processes. Human activities which produce nitrogen oxide include combustion of fossil fuels in vehicles and power stations, use of nitrogenous fertilizers and burning of vegetation and animal waste. During combustion of fuel in automobile engines, the air gets so hot that nitrogen reacts with oxygen to form nitrogen oxide. The gas is also produced by digesting bacteria and is part of the nitrogen cycle, one of the most important natural processes on earth
4. Chlorofluorocarbons (CFCs)
The sources of CFCs in the atmosphere include refrigerators, air conditioners and aerosols. CFCs are extremely effective greenhouse gases. One CFC molecule is about 10,000 times more effective in trapping heat than a carbon dioxide molecule. Some of them are up to 14,000 times effective than carbon dioxide, the main greenhouse gas
Effects of global warming
Global warming is expected to have far-reaching, long-lasting and, in many cases, devastating effects on the planet Earth. The following are some effects of global warming
Increase in average temperatures, One of the most immediate and obvious impacts of global warming is the increase in temperatures in the world. The average global temperature has increased by about 0.8°C over the past 100 years. Scientists predict that the Earth’s average temperature will increase by between 1.4 and 5.8°C by the year 2100.
Increase in global temperature affects both the land and ocean environments. The average temperature of the oceans has increased significantly in the past few decades, causing negative effects on marine life
When the ocean water gets warm, the algae in the ocean tends to produce toxic oxygen compounds called super oxides which are damaging for the corals. Global warming threatens the coral reefs to a great extent, and the fact is that if coral reefs are wiped off the planet, it will affect one-third of planet’s marine biodiversity, as well as other ecosystems related to the coral reefs directly or indirectly.
Extreme weather events, Extreme weather events include record-breaking high or low temperatures, floods or intensive storms, droughts, heat waves, hurricanes and tornadoes, etc. Figure 5.2 shows floods as an example of extreme weather event
<em>Fig. 5.2 An example of a flooded area</em>
<em>Fig. 5.2 An example of a flooded area</em>
Scientists project that extreme weather events, such as heat waves, droughts, blizzards and rainstorms will continue to occur more often and with greater intensity due to global warming
Other effects of extreme weather events include;
  1. lower agricultural yields
  2. Melting of arctic ice and snow-caps. This causes landslides, flash floods and glacial lake overflow
  3. extinction of some animal and plant species
  4. Increase in the range of disease vectors, that is, organisms that cause diseases
Change in the world’s climate patterns
It is projected that global warming will alter climate patterns worldwide. Climate change resulting from increasing temperatures will likely include changes in wind patterns, annual precipitation and seasonal temperature variations.
Most of the arable land that once used to be productive is slowly turning arid. With time, farmers will run short of the land for cultivation, a fact that will result in famine
Because high levels of greenhouse gases in the atmosphere are likely to remain high for many years, these changes are expected to last for several decades or longer.
Rise in sea level
Continued increase in the global temperature will cause the melting of ice caps in the poles and mountain glaciers. Melting polar ice and glaciers are expected to raise sea levels significantly. Global sea levels have risen about 8 inches since 1870 and the rate of increase is expected to accelerate in the coming years. If current trends continue, many coastal areas will eventually be flooded.
Scientists predict that by the year 2100 the sea level will rise by at least 25 m, leading to coastal flooding that will displace millions of people. Small islands in the Caribbean, South Pacific, Mediterranean and the Indian Ocean will be totally covered by ocean waters.
Ocean acidification.
As levels of atmospheric carbon dioxide increase, the oceans absorb some of it. This increases the acidity of seawater. Since the Industrial Revolution began in the early 1700s, the acidity of the oceans has increased by about 25%
Because acids dissolve calcium carbonate, seawater that is more acidic has a drastic effect on organisms with shells made of calcium carbonate, such as corals, molluscs, shellfish and plankton. The acid water is likely to dissolve the carbonaceous shells, thus endangering the lives of these sea creatures. Change in ocean acidity will also affect fish and other aquatic animals and plants.
If current ocean acidification trends continue, coral reefs are expected to become increasingly rare in areas where they are now common.
Effects on plants and animals
The effects of global warming on the Earth’s ecosystems are expected to be profound and widespread. Many species of plants and animals are already moving their range northward or to higher altitudes as a result of warming temperatures
Additionally, migratory birds and insects are now arriving in their summer feeding and nesting grounds several days or weeks earlier than they did in the 20th century
Warmer temperatures will also expand the range of many disease-causing pathogens that were once confined to tropical and subtropical areas, killing off plant and animal species that formerly were protected from disease.
These and other impacts of global warming, if left unchecked, will likely contribute to the disappearance of up to one-half of the Earth’s plants and one-third of animals from their current range by 2050
Effects on humans
As dramatic as the effects of climate change are expected to be on the natural world, the projected changes to human being may be even more devastating
Agricultural systems will likely be affected badly. Though growing seasons in some areas will expand, the combined impacts of drought, severe weather, lack of snowmelt, greater number and diversity of pests, lower groundwater tables and a loss of arable land could cause severe crop failures and livestock shortages worldwide
This loss of food security might, in turn, create havoc in international food markets and could spark famines, food riots, political instability and civil unrest worldwide.
The effect of global warming on human health is also expected to be serious. An increase in mosquito-borne diseases like malaria and dengue fever, as well as a rise in cases of chronic conditions like asthma, are already occurring, most likely as a direct result of global warming.
Chapter summary
Climate is the average weather conditions of an area observed and recorded over a long period of time (about 30 years)
Factors influencing weather and climate include latitude, altitude, ocean currents, and distance from the sea, aspect, wind and air masses, alignment of the coastline, inter tropical convergence zone, forests and human activities
The word’s types of climate include the following;
i. Hot climates
  1. Equatorial climate
  2. Tropical continental climate
  3. Tropical monsoon climate
  4. Tropical marine climate
  5. Tropical desert climate
ii. Warm climates
  1. Warm temperature western margin
  2. Warm temperature continental
  3. Warm temperature eastern margin
  4. Warm temperature desert
iii. Cool climates
  1. Cool temperate western margin (British type)
  2. Cool temperate continental (Siberian type)
  3. Cool temperate eastern margin (Laurentian type)
  4. Temperate desert
iv. Cold climates
  1. Cold temperate western margin
  2. Cold temperate continental
  3. Cold temperate eastern margin
v. Arctic climates
  1. Tundra climate
  2. Polar climate
  3. Mountain climate
Climate has a strong influence on the type of human activities that are practiced in any given climatic region
Types of economic activities governed by climate include the following
  1. Agriculture
  2. Settlement
  3. Fishing
  4. Tourism
  5. Industry
  6. Transport
Climate change is a large-scale and long term shift in the planet’s climate. The overall effect of climate change is global warming
Causes of global warming include the following
Global warming is caused by emission of different gases in the atmosphere such as carbon-dioxide, methane, nitrogen oxide (N2O) chlorofluorocarbons (CFCs). The increased emission of these gases is caused by different human activities include burning fossil fuels, cutting down forests and farming livestock
Effects of global warming include the following;
  1. Increase in average temperatures
  2. Extreme weather events
  3. Change in the world’s climate patterns
  4. Ocean acidification
  5. Effects on plants, animals and humans
Revision questions
Question Time 5
A.1. Which of the following tropical climates has the largest diurnal temperature range?
  1. tropical monsoon
  2. hot deserts
  3. Mediterranean
  4. cold deserts
2. Mediterranean climate is also known as .
  1. Warm Temperate continental climate
  2. Cold Temperate Continental climate
  3. Warm Temperate Western Margin climate
  4. Cold Temperate Eastern Margin climate
3. The climatic region which is found between the equatorial and the desert climatic regions is called .
  1. the Monsoon climate
  2. the Mediterranean climate
  3. the Tropical (Savannah) climate
  4. the Tundra climate
4. Tropical desert climate is found between north and south of the equator.
  1. 0° - 5°
  2. 5° - 15°
  3. 15° - 30°
  4. 30° - 45°
5. Which one of the following is not a characteristic of the tropical desert climate?
  1. Low humidity
  2. Very low annual temperature range
  3. Very high diurnal temperature range
  4. Low rainfall
6. One of the main features of a Mediterranean climate is .
  1. The nature of local winds
  2. The influence of ocean currents
  3. The type of rain that falls
  4. The prevailing Westerly winds in winter
7. Which one of the following is a characteristic of both mountain and polar climates?
  1. Ice covering for most of the year
  2. Less than 250 mm of rain annually
  3. Uniform annual temperature range
  4. Cold dry winds
8.The following is the dominant feature of the continent of Africa
  1. Basin
  2. Plateau
  3. Mountain
  4. Coastal plain
9. Which one of the following is not a characteristic of equatorial climate?
  1. High temperature throughout the year
  2. There are distinct seasons
  3. Mean annual rainfall is about 1500 mm
  4. Lightning and thunderstorms are common
10. Each of the following types of vegetation: downs of Australia, veldt of South Africa,pampas of Argentina, the steppes of Eurasia and the prairies of North America, can be given the general name of
  1. temperate grassland
  2. scrubland
  3. tundra
  4. tropical grassland
11. The characteristics of the equatorial climate are _.
  1. heavy rainfall throughout the year and savannah vegetation
  2. heavy rainfall throughout the year and scattered trees
  3. heavy rainfall throughout the year and small annual temperature range about 2°C
  4. seasonal rainfall and scant vegetation
12. Which one of the following best explains why plants can maintain continuous growth in the equatorial climate?
  1. there is an abundance of water
  2. temperatures are always high
  3. evenly distributed heavy rainfall and constant high temperatures
  4. high humidity
13. There is little undergrowth in a tropical rainforest, except along river banks, because
  1. temperatures at ground level are too low
  2. soils are too poor
  3. the soils are often waterlogged
  4. there is not enough Sunlight
14. Many of the plants have long roots and thorny stems. They have few leaves and the foliage is leathery, needle-shaped, waxy or hairy. They are associated with
  1. Mediterranean regions
  2. hot desert
  3. the interior of warm temperate latitudes
  4. Tropical grassland
B. Against each of the following statements, write TRUE if the statement is correct or FALSE if the statment is inccorect.
  1. Weather is the average atmospheric conditions of a place recorded over many years
  2. Weather changes slowly and gradually over many years
  3. Weather varies from one place to another within a region
  4. Areas around and close to the equator experience lower temperature and receive higher rainfall than those further away
  5. Temperature decreases with increasing altitude at the rate of 0.06°C for every 10 metres rise in altitude
  6. Atmospheric pressure at the foot of Mount Kilimanjaro is higher than the pressure at the summit of the mountain
  7. Wind blowing over the cold ocean current towards the land brings little or no rainfall to the land
  8. Places located far away from the sea experience high temperature and receive high rainfall than those located further away
  9. An onshore wind that brings no rainfall may lead to aridity in the long run
  10. Human activities do not lead to climate change
C. Fill in the blanks in each of the following questions
  1. _______climate is found approximately between 0° and 5° north and south of the equator
  2. _______climate experience the largest diurnal range of temperature
  3. Warm temperate western margin climate is also known as ._________
  4. The Maghreb countries experience_________climate
  5. Cold climates are mainly experienced in regions between latitudes_______
  6. TheArctic climatecomprisesof and climates.
  7. _______refers to increase of the Earth’s average surface temperature due to effects of the greenhouse gases
  8. The gases that cause an increase in the Earth’s temperature are called________
  9. The main greenhouse gas is_______
  10. Ocean acidification is caused by dissolved______gas
C. Define the following terms briefly:
  1. Climate
  2. Weather
  3. Climatology
18. List the differences between weather and climate
19. List any five factors that influence weather and climate.
20. In brief, explain two ways in which altitude affects climate
21. List any six effects of global warming
22. Explain briefly how climate affects human activities
23. List the climatic characteristics of the equatorial climate
24. Identify the geographical location of Tropical continental climate
25. Explain the two main sources of carbon diode gas that causes global warming
26. Point out the source Chlorofluorocarbons (CFCs) and explain how they cause global warming
27. Explain how the following factors influence weather and climate:
  1. Altitude
  2. Ocean currents
  3. Distance from the sea
28. Describe the location of Mediterranean climate
29. Explain, in details and with relevant examples, how global warming leads to each of the following phenomena:
  1. Increase in average temperatures
  2. Rise in sea levels
30. Explain how climatic conditions affect each of the following human activities:
  1. Agriculture
  2. Transport
  3. Fishing
31. Describe the characteristics of the tropical desert climate
References
  1. Bunnet, R.B (2005). Physical Geography in Diagrams for Africa (28th edition). Pearson Education Ltd. Essex
  2. Monkhouse, F.J. and Small, J. (1979). A Dictionary of the Natural Environments. Edward Arnold. London.
  3. Mzezele, S. and Kibuuka, P. (2015). Geography In Focus Form One. Oxford University Press Ltd. Dar es Salaam
  4. Philips Certificate Atlas for Eastern Africa (1973). George Philip and Sons. London
  5. Tanzania InstituteofEducation(1986).GeographyforSecondarySchools,BookOne.NPC–(KIUTA).DaresSalaam
  6. Tanzania Institute of Education (2003). Geography Course Book for Secondary Schools Book One. Ecoprint Ltd. Dar es Salaam
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