Geography Form One Notes – Climate

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The Concept of Climate

Define the concept of climate

Climate isthe average weather conditions of an area observed and recorded over along period of

time (abou 30 years).

The scientific study of climate is called climatology and a person who studies climate is called

climatologist.

Weather and Climate

The Difference between Weather and Climate

Differentiate between weather and climate

There are marked differences between weather and climate, The table below summarizes these

differences.

Weather Cumate

Describe the atmospheric condtons at a specific place and Desc the average atmospheric conto of «place

tine ver aspect period of tine.

Clint is defined a statistical weather inflation hat

Weather i defined a the day to day sate of he stmosphere, describes the variation of weather a a given pce for a

and tis shor erm (ines to week) variation specified tie itera

Weather condons re measured vera shor period eg. few Clini contions are mesued over many years, €

tors or day. 30 years

Determined by real time measurements of atmospheric Detemined by averaging weather dts ver prods of 30

ress, wind spend and ition, Monit, pecipation, | yur

cod cover, and other variables.

‘Weather changes abruptly within a short period (Climate changes slowly and gradually over many years.

‘Weather varies ftom one place to another within a region Climate remain uniform over alge aca.

(Climatic lemons are not measured but clcubted fom

‘Most weather elements are measured by weather instruments, the recorded weather data

Factors influencing weather and climate

Usually, the elements of weather (which make up climate) vary from place to plac. In the lesson

‘on weather we learned about the elements of weather. Because climate is influenced by weather,

the elements of weather are the same as the elements of climate. Therefore, the factors that cause

variation in weather elements wil likewise influence the climate. The factors influencing climate

and weather are discussed below:

1. Latitude: This factor influences temperature and rainfall, Ateas around and close to the

‘equator experience higher temperature and receive higher rainfall than those farther away. So the

rainfall and temperature decreases as one moves away from the equator:The amount of heat

received at any place on the eart’s surface depends on the angle at which the sun’s rays strike

the surface ofthe earth and the duration ofthe sunshine, At the equator, the sun’s rays fall onthe

[Earth’s surface at almost right angles throughout the year, but the angle at which the sun’s rays

strike the Barth’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 ofthis 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 influences temperature and atmospheric pressure of an area. Temperature

decreases with increasing altitude at the rate of 0.6°C for every 10 metres rise in altitude.

Therefore, low-altiude 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 ofthe ocean current influences the temperature of the wind

blowing over it and transfers tis influence to the land adjacent tothe 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

borings ltl or no rainfall to the land

4, Distance from the sea:This influences temperature and rainfall. Places located near the

sea experience high temperature and receive high rainfall than those located father away. This is

because of high rates of evaporation fiom the water surface, which eventually causes heavy

rainfall along the coastal areas, For this reason, coastal regions often experience higher

temperatures and rainfall than inland areas,

5. Aspect: This term refers tothe direction in which a slope faces. I influences temperature

and rainfall. Fr 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 carves moisture with it as it flows. Warm wind blowing over

1 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

“ainfall in the destination region. Cold, dry wing 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 tothe direction ofthe wind. I’the winds blow across the coastline they cause rainfall. IF

they blow in parallel to the coastline, they cause drought

8. Intertropical Convergence Zone (ITCZ):This isa low-pressure arca around the equator.

The moist winds meet within this region. Places farther 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 litle or no vegetation. This is because of high rats 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: range of human activities such as agriculture, mining, transportation,

construction, ete 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

Relationship between Climate and Human Activities

Relate climate to human activities

Climate has many impacts to human activities. Various economic activities conducted by man in

diferent parts of the world are governed by the type of climate experienced in a particular

region. For example, people living in desers and semi-arid regions do not practice much

agriculture because their environment does not favour erop cultivation or animal husbandry. In

these regions, however, avery limited agriculture and animals rearing is conducted. The animals

kept include camels, gots, sheep, donkeys and other hardy animals. Only drought resistant crops

such as dates are grown in deserts and arid areas.

In topical and equatorial regions, a lot of agriculture is carried out. The inhabitants of these

regions take part in cultivation of crops and keeping of animals. Crops grown include cocoa,

banana, horticultural erops and grains. The animals kept in these climatic zones include cal,

pias, donkeys, horses, poultry and other farmyard animals. Specific types of various economic

activities carried out in each climatic region wll be discussed in detail inthe section below.

THE MAJOR WORLD CLIMATIC REGIONS

Different regions of the world experience different amount of temperature and rainfall. The

differences in the amount of rainfall and temperature experienced in different regions of the

world make them have different climatic characteristics. This gives rise to various climatic

regions around the globe. Temperature and rainfall are the main elements that determine the type

of climate. Both elements vary considerably from one region to another and form a basis for

classifying climate, The five broad types of climate are ot, warm, cool, cold and arctic (very

cold) climates, Each ofthese climates is further subdivided into different subtypes a it willbe

explained in detail below:

HOT CLIMATES:

‘These are the type of climates found within the tropics, mainly between 237° north and 232°

south ofthe equator. Hot climates include the fllowing climate sub types:

1, Equatorial climate

2. Tropical continental climate

3. Tropical monsoon climate

4. Tropical marine climate

5. Tropical desert climate

Equatorial climate

‘The region is found approximately between O° 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 (South America) and the Congo basin, the southern Ivory

Coast, south Ghana, western coastal Nigeria, and eastern coastal Malagasy Republic (all in

Aftica)

Climatic characteristics

There are no marked seasons.

b. High temperature throughout the year: – The annual temperature range is about 3°C. –

The daily mean temperatures are about 26°C all the year round,

©. The daily temperature range is rarely more than 8°C because ofthe thick cloud cover.

4. Rainfall is heavy and is usually convection rain,

©. Rainfalls usually occur in the aflernoons and they are accompanied by lighting and

thunder

Total annual rainfall is about 200 mm with two maxima (peaks),

8 High humidity and intensive cloud cover throughout the year This climate can generally

be described as hot and wet throughout the year, witha small annual temperature range.

Highlands located within the equatorial region have their temperatures modified by altitude. The

temperature of some of these highland areas, e.g, the East African Highlands, is lowered to

about 15°C. These regions are said to have a modified equatorial climate,

‘Variations on the basic type of climate occur inthe highland regions of equatorial Africa. The

climate of most ofthese regions has an equatorial rainfall pattern

In areas such asthe 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 heaver rainfall

Human activities cartied 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, water melons, bananas and groundnuts. Examples of areas where this

{ype of farming is practiced include some part of West Aftica 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 Srilanka. 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 (RDC), Gabon and some parts of West Africa

Tropical continental climate

‘This climate is also known as Sudan type or Savannah climate, Inthe interior of the continents it

is referred to as topical continental climate

Location: This climatic region occurs between SoN and ISON and SoS and 150S though it

extends to 250 north or south of the equator. It is best developed in most parts of Africa, and

some parts of South America, India and Australia.

Climatic characteristics

Hot summers (320C) and cooler winters (210C),

b. The annual temperature range is about 110C.

4 Heavy rans, mainly convection, occur in the summer.

Total annual rainfall is around 76Smm, though this increases in the areas lying close to

the equatorial climate region. Similarly rainfall decreases towards the tropical deserts.

Humility is high during the hot, wet season

This climate is characterized by tall grass and trees which are more numerous near the equatorial

forest region. The savannah region is suitable for herbivores animals such as giraffes, elephants,

bufloes, rhino, zebras, antelopes, wildebeests and many other animals. There are also

camivorous animals such as lions, leopards, hyenas, ete. The region also support 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 practised. Many tourists come from forcign countries to view the wildlife that live

inthe vast grassland. Numerous national parks have been established inthis region. In Tanzania,

for example, there are established 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

“The areas which mainly experience monsoon type of climate are South East Asia, Norther

‘Australia, Southern China, and the Indian subcontinent. This type of climate is most marked in

India.

Climatic characteristics

Seasonal reversal of winds (monsoon winds); onshore during one season and offshore

during another season.

b. Onshore wind brings heavy rain to coastal regions while offshore winds bring litle o no

rain, except where they cross a wide stretch ofthe sea.

Temperatures range from 32°C in the hot season to about 25°C in the cool season, giving

an annual range of about 7

4. Annual rainfall varies greatly, depending on relief and the angle at which onshore winds

‘meet the highlands (aspect),

This climate can generally be described as having a hot, wet season and cool, dry season, The

‘main human activities carried out in areas experiencing this type of climate includ rice growing

and livestock husbandry. Apart from rice, the other erops grown are wheat, millet, maize, and

sorghum,

Sugarcane, cotton and juice are important lowland crops grown in India, Pakistan and

Bangladesh. The other crops grown are tea (Srilanka, Bangladesh and India) and rubber in

Malaysia. Animals kept in this climatic region include pigs, cattle, buffalo, sheep, goats, and

poultry

‘Tropical marine climate

Regions with this type of climate are located on the east coasts of regions lying between 100N

and 250N and 100 $ and 2508. 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 Philipines.

Climatic characteristics

a. Temperature characteristics are similar to those of the equatorial climate,

b. Hot season temperature is 29°C and cooler season temperature is 21°C. (¢) Annual

temperature range i about §°C.

4. Rainfall is both convection and topographic (brought by onshore trade winds).

Maximum rainfall occurs in the hot season.

£ 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 everyday.

The main human activites carried out inthis climatic region include erop 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 poulty.

“Tropical desert climate

‘The tropical desert climate occurs on the western margins of landmasses between latitude 200 10

300 north and south ofthe equator. The climate is experienced in all the major tropical deserts of|

the world, The hot desers occupy about one third of the earth’s surface. The principal tropical

deserts occur on the continents as follows

1, Affica: 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

Climatic characteristics

a. Verylittle total annual rainfall (less than 120 mm in any one year),

b, Mean monthly temperatures range from 29°C in the hot season to 10°C in the cool

€ In most deserts, daytime temperature can rise to as high as 47°C of more

4. Night temperatures can fall to as low as 16°C in summer and $°C in winter

©. Very high diurnal temperature range (due to very hot days and very old nights,

£ The annual temperature range is large. It is about 16°C.

& Humidity is always low and therefore evaporation is high

Desert environments support very minimal human activities. Wherever water is available asin

cases (singular oasis), and along rivers, agriculture i practised. The erops grown include date

palms, coton, 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

cof pasture, They keep camels, donkeys, goats and sheep. The camel isan animal that has adapted

to desert conditions. It can survive for many days without drinking wate. It is mainly used for

transport in the desert. Other desert people are good hunters and also collect food fiom the

bushes.

The other activities that can be done by desert dwellers include weaving mats, making ropes, and

trading,

WARM CLIMATES

‘Warm climates border the hot tropical deserts. They occur between 300 and 400 north and south

ofthe equator.

‘There are four broad types of warm climates:

1, Warm temperature western margin;

2. Warm temperature continental;

3. Warm temperature eastern margin; and

4. Warm temperature desert

‘Warm temperate western margin (Mediterranean type). This is also known as the Mediterranean

climate

This type of climate occurs between 300N and 4S0N and 300S and 400S 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).

General characteristics

Temperatures range from 21°C in the summer to 10°C (or below) in the winter.

b. Mean annual temperature is about 15%.

Annual total rainfall varies from S00 to 900 mm.

4. Hot, dry summers and cold, wet winters. Ths is because westerly winds blow off shore in

the summer and on shore in the winter.

The Mediterranean climate can generally be described as having hot, dry summers and middy,

rainy winters. The climate permits @ wide range of crops to be grown, which include fruits and

cereals, It sin 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 10 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: It occurs inthe interior ofthe continents, between 200 and 350 north and south of the

equator. The best examples of the areas having this climate are Murray-Datling lowlands of

‘Australia; The high Veldt of South Africa; andthe central Paraguay and central Argentina (both

in South America); central lowlands of north America (Oklahoma and Texas and in northem

Mexico); central European lowlands, and the plains of Manchuria,

Climatic characteristics

a. Temperatures range from 26°C in the summer to 10°C in the winter

b, The annual rainfall varies from 380 to 700 mm, depending on the distance from the sea,

©. Rainfall is convectional type and falls mainly in spring and early summer. The main

«economic activities carried out in this region are cattle rearing and crop growing. Tourism is also

practised,

‘Warm temperate eastern margin (China type)

Location: It occurs inthe easter sides of the continents between latitudes 230 and 350 north

and south of the equator. The countries having this type of climate are central China, south

eastem USA, southem Brazil, easter part of Argentina, South Aftica, southern Brazil, eastem

part of Argentina, South Africa, southern Japan, and south eastern Australia,

Climatic characteristics

Temperatures are about 260C in summer and 130C in the winter.

b. The otal annual rainfall varies is about 1000 mm.

€ The rains convectional and torrential type and it mostly falls inthe summer

‘Temperatures and rainfall in this type of climate make it possible to grow crops and keep

animals. Lumbering is also practised 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. The areas having this type of

climate include Nevada and Utah states of North America and Pentagonia in South America. Itis

also found in regions that extend from Turkey, northem Iran, across the Caspian sea and Aral

areas into former USSR. It is also experienced inthe Gobi desert of Mongolia,

COOL CLIMATES

“These climates are experienced in regions between 350 north and 600 south of the equator. They

are characterized by definite seasonal variations in temperature, There are four types of cool

climates:

1. Cool temperate continental (British type);

2 Cool temperate continental (Siberian type);

3. Cool temperate eastern margin (Laurentian type); and

4. Temperate desert

Cool temperate western margin (British ype)

It occurs on the western sides of the continents between 450 and 600 north and south of the

‘equator. Areas with this type of climate include North West Europe, British Columbia in western

(Canada, Souther Chile, Tasmania, and the south Island of New Zealand,

Climatic characteristics

Winter temperatures range between 2°C and 79C, while summer temperatures range from

IC w IFC.

b. The annual temperature range is between §°C and 11°C.

Rain falls throughout the year, with maxima in winter.

4. The total annual rainfall is about 760 mm,

The rain is both convectional and cyclonic in nature

People living in this region engage in a myriad of economic activities which include agriculture,

‘mining, lumbering, manufacturing and commerce. Agriculture is of extensive type and includes

keeping of beef and dairy cattle and sheep and the growing of wheat, barley oats, vegetables and

{uits In British Columbia lumbering isan important economic activity. In Tasmania and New

Zealand, sheep rearing for wool and mutton is an important activity. Fruit farming, especially

apples, is practised throughout the region,

Cool temperate continental (Siberian type)

This type of climate is found extensively in the northern hemisphere, It occurs inthe interiors of|

North America and Eurasia between 35° and 60°N

Climatic characteristics

Moderately warm summers (18°) and very cold winters -19°C).

b. The annual temperature range is very high (37°C)

©. Most of the rainfalls inthe summer.

4. The rains convectional type and is often accompanied with thunder

The annual precipitation (rain plus snow) ranges from 400 to $00 mm.

‘The main human activities in this region include lumbering fishing, mining and some agriculture

Cool temperate western margin (Laurentian type)

11 oceurs on the easter sides ofthe continents between 3S0N and SON, and south of 4008. It is

experienced mainly on the eastem sides of North America and Asia,

Climatic characteristics

a. Winter temperatures range from -10°C to 4°C.

b. Summer temperatures range from 12°C to 24°C

The annual temperature range is large and averages 24°C.

4. Precipitation (in the form of rain and snow) is distributed throughout the year.

€ Annual precipitation varies between 700 and 1000 mm. (f) Rainfall is both convectional

and cyclonic

The main economic activities inthis region are farming, mining, and manufacturing, The crops

srown include wheat, maize, millet and soya beans. Sheep farming is important in Patagonia

“Mining and manufacturing are practised where minerals ae found

‘Temperate desert

This climate occurs in the interiors of Eurasia and North America, and in Patagonia (South

America)

Climatic characteristics

a. Winters are very cold with temperatures often below -7*C

b. Summer temperatures vary between 25°C and 37°C.

©. Diurnal temperature range is about 35°C while the annual temperature range is about

aoc.

4. Precipitation is very low, it averages about 250 mm,

©. Most of the rainfalls in late winter and early spring,

The human activities carried out in this region include mining, animal rearing and some

agriculture. The animals reared are such as camels, donkeys, sheep and goats. The main crops

grown in this region are date palms, oil palms, and millet Agriculture is mostly practised in

cases and along river valleys.

COLD CLIMATES

Cold climates are mainly experienced in regions between latitudes 60°N and 68°N

There are thre types of cold climates:

1. Cold temperate western margin,

2 Cold temperate continental; and

3. Cold temperate eastern margin,

Cold temperate western margin

This climate is confined to coastal areas of Scandinavia and Alaska.

Climatic characteristics

Short, cold summers with temperatures of about I2%C

b. Long winters with temperatures ranging fiom -2°C 0 4°C.

4. Rain falls in most months except the winter when show falls.

‘The main economic activites practiced in this region include agriculture, mining and

‘manufacturing. Dairy catle farming is mainly practiced in the Scandnavian countries such as

‘Norway Denmark and Sweden.

Cold temperate Continental

‘This climate occurs between SSoN and 680N in the interior of America and Eurasia.

Climatic characteristics

Cold and long winters with temperatures ranging between -34°C and -45°C.

b. Warm and short summers with average temperatures up to 21°C.

in winter, precipitation i in the form of snow

Cold temperate eastern margin

‘This climate occurs in the north east pacific of Russia

Climatic characteristics

Long, cold winters with an average temperature as low as -20°C or below.

. Short, hot summers with an average temperature up to 21°C or higher.

Total annual rainfall varies between $00 and 1000 mm,

ARCTIC CLIMATES

‘These types of climates are experienced in regions beyond the Arctic Circle (661/20N) and

around Arctic Ocean, They are also known as polar deserts. The main features of these climates

are low amounts of precipitation (rain), mild summers and very cold winters.

Arctic climates comprises of Tundra and Polar climates

Tundra climate

This region occurs in the northern coast of North America, southem coast Greenland and the

Arctic coast of Europe and Asia,

Climatic characteristics

a. Very long, cold winters with temperatures ranging between -29°C and – 40°C.

Short, coo! summers with temperatures of about 10°C

Annual precipitation is 250 mm; some of it ils as sow in winter and as rain in summer

Polar climate

1eoccursin the interiors of Ieland, Greenland and Antarctica

Climatic characterisis

a. Temperatures are permanently below OFC

b. Precipitation isin the form of lizards (now storms)

The ines consist of continuous night, and summers of continuous day.

Because temperatures are vey low, mos these regions are uninhabited and hence limited human

activities take place ere. The natural occupations ae hunting, ishing and herding of reindsr.

Mountain climate

‘This type of climate occurs in the main mountain areas of the word. The areas that experience

such climates include the East Affica Mountains, the Ethiopian highlands, the mountains and

plateaus of central Asia, the Alps of Europe, the Andes of South Ameria and the Rockes of

North America

Climatic characterises,

4. Pressure and temperature generally deerease with increase in atte.

. Precipitation increases with tude

foot oF a mountain to very cold a the peak, e.g. Mount Kilimanjaro

We have cen how particular climatic conditions influence human activities. Now, let us see how

specific climatic conditions are suitable forgiven human activities

Asrcultre

Agriculture is strongly influenced by weather and climate. The nature of agriculture and farming

practices in any particular location depends onthe type of climate experienced in that location.

CCrops thrive well in any area with a fertile soil and which receives sufficient rainfall as well as

‘optimum temperature conditions. In such areas both commercial and subsistence crops may be

grown

‘The equatorial region receives high rainfall and experiences high temperature throughout the

year This climate is suitable for crops that can thrive well in moist and hot conditions. The crops

that can be grown inthis region include cocoa, banana, rubber, sugarcane and yams.

Livestock rearing can be practised 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, maiz, rice anda varity 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 dary

animals

In semi desert and desert climates where very litle 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 done

Settlement

People like to establish settlements in areas with favourable climates and which support a varity

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 thrive well in areas that receive ample rainfall and which have adequate 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 paper-making and carpentry.

Fishing

Most ofthe world’s fishing grounds are in cooler regions. The cooler water is thought to support

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 counties 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 serve 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 tothe 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 ofthe 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

itrains. This makes it hard to travel on earthy and murram roads. Roads in desert regions may be

blocked by sand blown onto them, making the roads impassable. In very cold regions

precipitation inthe form of snow may cover roads, making them impassable during winter.

CLIMATE CHANGE

Climate change is a large-scale, long term shift in the planet’s climate (weather pattems and

temperatures). The overall effect of climate change is termed as global warming.

What is global warming?

Giobal warming refers o increase ofthe cath’ average surface temperature due to effects ofthe greenhouse

fess, These ses trap heat hat would otherwise escape fom the cath. The greenhouse gases include water

‘vapour (H20), carbon dioxide (C02), methane (CHA), dinitrogen oxide or nitrous oxide (N20), ozone (03)

and chloroftorocarbons (CFCS),

Since the early 20th century, the global air and sea surface temperature has increased by about

(0.8°C, with about two-thirds of te increase occurring since 1980. Each ofthe last three decades

has been successively warmer atthe earth’s surface than preceding decades since 1850.

‘The recent rapid warming was caused by human activities which contribute tothe production of|

greenhouse gases, suchas carbon dioxide, tht trap heat in the earth’s atmosphere. Its predicted

that the continuation ofthese activities will result in 1.8-4°C average temperature increase over

the next century

Causes of global warming

‘Scientific understanding ofthe cause of global warming has been increasing. Global warming is

mostly caused by increasing concentrations of greenhouse gases in the atmosphere, The

following greenhouse gases are the main contributors to global warming. They are the main

causes of global warming

Carbon dioxide

Carbon dioxide is the main greenhouse gas. The gas contributes over S0% of the greenhouse

effect. I is because ofthis reason that man is struggling to reduce carbon dioxide emissions. The

following are some of the man-made sources of carbon dioxide in the atmosphere:

Deforestation: Green plants absorb carbon dioxide gas ftom the atmosphere and use it to

‘manufacture their food through the process of photosynthesis. Cutting down trees means that @

{ew trees ate left to absorb carbon dioxide gas from the air. This has led to the increase inthe

amount of carbon dioxide in the atmosphere.

oS Oe b thus ch

PAE cae,

A deforested land

Combustion of fuel: Burning of fossil fuel such as wood, coal, petroleum and natural gas,

reeass ctbon donde ino the stephere. The gas is prodoed daring combustion of these

fos in car engines, power stations, indus,

Methane

The main source of methane is from agricultural activites. I i relensed from wetlands such as

tice fields and fom animals, particularly cud-chewing animals, like cate, The emission of

iettane gut ito the stoepere, therefie, increases wih increase in apical actives,

Since 1960s the amount of methane inthe sha increased by 1% per year, twice a ist a the

build-up of carbon dioxide, Methane sao produced by the decomposition of waste materials

by bacteria, shear component oF aber]. Th gat it lo proce org teeing

of coal and oi (natura ga) and when vegetation i burt

itrous oxide (nitrogen oxide, NSO)

Diniuogen oxide i produced fiom both man-made and natual processes Human activities

wich produce dinirogen oxide include combustion of fossil fuels in vehicles and power

suns, ese of irogenous frtlizes and taming of vegetation and nial waste, During

combustion of uel in automobile engines, the sr get oho tha nitrogen reacts with onygen to

form dinitrogen oxide

‘The gas is also produced by digesting bacteria, and is part ofthe nitrogen cycle, one of the most

important natural processes on earth,

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-eaching, long-lasting and, in many cases, devastating

consequences for 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 on 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 and 5.8°C by the year 2100,

Increase in global temperature will affect both the land and the ocean environments. The average

temperature of the oveans has increased significantly inthe past few decades, eausing negative

effects on marine life

When the ocean water gets warm, the algac in the ocean tends 0 produce toxic oxygen

‘compounds called superoxides which are damaging forthe corals. Global warming is threatening

the coral reefs toa 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 indiretly

Extreme weather events

[Extreme weather events include record-breaking high or low temperatures, floods or intense

storms, droughts, heat waves, hurricanes and tomadoes, ete. These are effective measures of

climate change and global warming.

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ods

Seiemis projet that exteme weather even, such as eat waves, ought, Mizzards and

fintoms wil continue to occur mote fen and with reer ntensity de to global warming

(ter feta extreme weather vet ince

+ bigher or lower agricul yields;

+ mehing of tiie and snowcap. This cases andes, Nash Moos and glacial Ike

+ extn of sme aia and plan species; and

+ increase in the range ofisease vectors, hat i oransms tha cause diseases,

Ws forecasted that global warming will cause climate pats worldwide 10 experince

sinfcantchangss Cliate change resuing fm increasing temperatures willy incade

change in win pater, anual precipitation and seasonal temperate vaitons

Climatic pater inmost part the wor have lead changed Rais il when les expected

and at iegular intervals. This has gray feed the timing of plating and harvesting

scivites Sometimes the ans als heavily to cause Nos, or ite leading to drought.

“Most ofthe arable land that once used to be productive is slowly turning arid. With time, farmers

will rn short ofthe land for cultivation, a fat 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 levels

Continued increase in the global temperature wll cause the melting of ice caps in the poles and

‘mountain glaciers. Melting polar ice and glaciers ate expected to raise sea levels significantly

Global sea levels have risen about & inches since 1870 and the rate of increase is expected to

accelerate in the coming years. Ifcurrent trends continue, many coastal areas will eventually be

flooded.

‘Scientists predict that by the year 2100 the sea level will aise by atleast 25 m, leading to coastal

Aooding that will displace millions of people. Small islands in the Caribbean, South Pacific,

Mediterrancan and Indian Ocean willbe 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 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, mollusks, shellfish and

plankton. The acid water is likely to dissolve the carbonaceous shells, thus endangering the lives

ofthese 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 of 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 eatlier 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 let unchecked, will likely contribute to the

disappearance of up to one-half ofthe 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 society 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 tur, create havoc in intemational food markets and could

spatk famines, food rots, political instability and civil unrest worldwide.

“The effect of global warming on human health is also expected to be serious. An increase in

‘mosquito-bome diseases like malaria and dengue fever, as well as arise in cases of chronic

conditions like asthma, ae already occurring, most likely asa direct result of global warming.

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