CLIMATE AND NATURAL REGION
World Climatic Types and their Characteristics
How different Geographical Factors Influence Climate
Explain how different geographical factors influence climate
Usually,
the elements of weather (which make up climate) vary from place to
place. 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 will likewise influence the
climate. The factors influencing climate and weather are discussed below
Latitude
This
factor influences temperature and rainfall. Areas 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 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.
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-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.
Ocean currents
The
nature of the ocean current influences the temperature of the wind
blowing over it and transfers this influence 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.
Distance from the sea
This
influences temperature and rainfall. Places located near the sea
experience high temperature and receive high rainfall than those located
farther 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 inland areas.
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.
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 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.
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.
Intertropical Convergence Zone (ITCZ)
This
is a low-pressure area 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.
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.
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.
The impact of climate
Climate
has many impacts to human activities. Various economic activities
conducted by man in different parts of the world are governed 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 is conducted. The animals kept include camels, goats,
sheep, donkeys and other4hardy 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 inhabitants 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 section below.
Natural Regions of the World
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 hot, warm, cool, cold and arctic (very cold)
climates. Each of these climates is further subdivided into different
subtypes as it will be explained in detail below:
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:
- Equatorial climate
- Tropical continental climate
- Tropical monsoon climate
- Tropical marine climate
- Tropical desert climate
Different Types of Natural Regions
Identify different types of natural regions
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 (South America), and the Congo basin, the southern Ivory Coast,
south Ghana, western coastal Nigeria, and eastern coastal Malagasy
Republic (all in Africa).
Climatic characteristics
- There are no marked seasons.
- 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 of the thick cloud cover.
- Rainfall is heavy and is usually convection rain.
- Rainfalls usually occur in the afternoons and they are accompanied by lighting and thunder.
- Total annual rainfall is about 200 mm with two maxima (peaks).
- High humidity and intensive cloud cover throughout the yearThis climate can generally be described as hot and wet throughout the year, with a 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 in the highland regions of
equatorial Africa. The climate of most of these regions has an
equatorial rainfall pattern.
In
areas such as the 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 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, water melons, 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 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. In the
interior of the continents it is referred to as tropical continental
climate.
Location
This
climatic region occurs 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.
Climatic characteristics
- Hot summers (32oC) and cooler winters (21oC).
- The annual temperature range is about 11oC.
- The highest temperatures occur just before the rainy season begins.
- Heavy rains, mainly convection, occur in the summer.
- 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.
- Humidity 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, 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 practised. Many tourists come from
foreign countries to view the wildlife that live in the vast grassland.
Numerous national parks have been established in this 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
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.
Climatic characteristics
- Seasonal reversal of winds (monsoon winds); onshore during one season and offshore during another season.
- 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.
- Temperatures range from 32oC in the hot season to about 25oC in the cool season, giving an annual range of about 7oC.
- Annual rainfall varies greatly, depending on relief and the angle at which onshore winds meet the highlands (aspect).
- There are three marked seasons: cool, dry season; hot, dry season; and hot, wet season.
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 include rice growing and livestock
husbandry. Apart from rice, the other crops 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 (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.
Climatic characteristics
- Temperature characteristics are similar to those of the equatorial climate.
- Hot season temperature is 29oC and cooler season temperature is 21oC.
- Annual temperature range is about 8oC.
- Total annual rainfall varies from 1000 mm to 200 mm depending on the location.
- 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 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 occurs 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 principal
tropical deserts occur on the continents as follows:
- Africa: Sahara, Kalahari and Namib Deserts
- 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.
- South America: Atacama Desert
- Australia: Great Australian Desert
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:
- Warm temperature western margin.
- Warm temperature continental.
- Warm temperature eastern margin.
- Warm temperature desert.
Warm temperate western margin (Mediterranean type)
This is also known as the Mediterranean climate
Location
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).
General characteristics
- Temperatures range from 21oC in the summer to 10oC (or below) in the winter.
- Mean annual temperature is about 15oC.
- Annual total rainfall varies from 500 to 900 mm.
- Hot, dry summers and cold, wet winters. This 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 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
It
occurs 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.
Climatic characteristics
- Temperatures range from 26oC in the summer to 10oC in the winter.
- 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 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, southern Brazil, eastern
part of Argentina, South Africa, southern Brazil, eastern part of
Argentina, South Africa, southern Japan, and south eastern Australia.
Climatic characteristics
- Temperatures are about 26oC in summer and 13oC in the winter.
- The total annual rainfall varies is about 1000 mm.
- The rain is convectional and torrential type and it mostly falls in the 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. 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.
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:
- Cool Temperate Western Margin (British type).
- Cool Temperate Continental (Siberian type).
- Cool Temperate Eastern Margin (Laurentian type).
- Temperate desert.
Cool temperate western margin (British type)
Location
It
occurs 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.
Climatic characteristics
- Winter temperatures range between 2oC and 7oC, while summer temperatures range from 13oC to 15oC.
- The annual temperature range is between 8oC and 11oC.
- Rain falls throughout the year, with maxima in winter.
- 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 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 practised throughout the region.
Cool temperate continental (Siberian type)
Location
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
Climatic characteristics
- Moderately warm summers (18o) and very cold winters (-19oC).
- The annual temperature range is very high (37oC).
- Most of the rain falls in the summer.
- The rain is convectional type and is often accompanied with thunder.
- The annual precipitation (rain plus snow) ranges from 400 to 500 mm.
The main human activities in this region include lumbering fishing, mining and some agriculture.
Cool temperate western margin (Laurentian type)
Location
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
Climatic characteristics
- (a) Moderately warm summers (18o) and very cold winters (-19oC).
- The annual temperature range is very high (37oC).
- Most of the rain falls in the summer.
- The rain is convectional type and is often accompanied with thunder.
- The annual precipitation (rain plus snow) ranges from 400 to 500 mm.
The main human activities in this region include lumbering fishing, mining and some agriculture.
Cool temperate western margin (Laurentian type)
Location
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
Climatic characteristics
- (a) Moderately warm summers (18o) and very cold winters (-19oC).
- The annual temperature range is very high (37oC).
- Most of the rain falls in the summer.
- The rain is convectional type and is often accompanied with thunder.
- The annual precipitation (rain plus snow) ranges from 400 to 500 mm.
The main human activities in this region include lumbering fishing, mining and some agriculture
Cool temperate western margin (Laurentian type)
Location
It
occurs 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
Climatic characteristics
- Winter temperatures range from -10oC to 4oC.
- Summer temperatures range from 12oC to 24oC.
- The annual temperature range is large and averages 24oC.
- Precipitation (in the form of rain and snow) is distributed throughout the year.
- Annual precipitation varies between 700 and 1000 mm.
- Rainfall is both convectional and cyclonic.
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 practised where minerals are found.
Temperate desert
Location
This climate occurs in the interiors of Eurasia and North America, and in Patagonia (South America).
Climatic characteristics
- Winters are very cold with temperatures often below -7oC.
- Summer temperatures vary between 25oC and 37oC.
- Diurnal temperature range is about 35oC while the annual temperature range is about 40oC.
- Precipitation is very low, it averages about 250 mm.
- Most of the rain falls 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 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:
- Cold temperate western margin.
- Cold temperate continental.
- Cold temperate eastern margin.
Cold temperate western margin
Location
This climate is confined to coastal areas of Scandinavia and Alaska.
Climatic characteristics
- Short, cold summers with temperatures of about 12oC.
- Long winters with temperatures ranging from -2oC to 4oC.
- Annual rainfall is about 750 mm.
- Rain falls in most months except the winter when show falls.
The
main economic activities practiced in this region include agriculture,
mining and manufacturing. Dairy cattle farming is mainly practiced in
the Scandnavian countries such as Norway Denmark and Sweden.
Cold temperate Continental
Location
This climate occurs between 55oN and 68oN in the interior of America and Eurasia.
Climatic characteristics
- Cold and long winters with temperatures ranging between -34oC and -45oC.1
- Warm and short summers with average temperatures up to 21oC.1
- Annual precipitation is very low, about 380 mm.1
- Most of the rainfalls in summer, but in winter, precipitation is 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 -20oC or below.131
- Short, hot summers with an average temperature up to 21oC or higher.1
- Total annual rainfall varies between 500 and 1000 mm.
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 precipitation
(rain), mild summers and very cold winters.
Arctic climates comprises of Tundra and Polar climates
Tundra climate
Location
This region occurs in the northern coast of North America, southern coast Greenland and the Arctic coast of Europe and Asia.
Climatic characteristics:
- Very long, cold winters with temperatures ranging between -29oC and - 40oC.
- Short, cool summers with temperatures of about 10oC.
- Annual precipitation is 250 mm; some of it falls as snow in winter and as rain in summer.
Polar climate
Location
It occurs in the interiors of Iceland, Greenland and Antarctica.
Climatic characteristics
- Temperatures are permanently below 0oC.
- Precipitation is in the form of blizzards (now storms).
- The winters consist of continuous night, and summers of continuous day.
Because
temperatures are very low, most these regions are uninhabited and hence
limited human activities take place here. The natural occupations are
hunting, fishing and herding of reindeer.
Mountain climate
This
type of climate occurs 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 Rockes of North
America.
Climatic characteristics
- Pressure and temperature generally decrease with increase in altitude.
- Precipitation increases with altitude.
- 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.
We
have seen how particular climatic conditions influence human
activities. Now, let us see how specific climatic conditions are
suitable for given human activities.
Agriculture
Agriculture
is strongly influenced by weather and 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 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 in this 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, 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
done.
Settlement
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
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
of the 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 countries to enjoy the warmth of
the tropical countries where they swim in warm waters and sunbath in
tropical beaches.
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 the 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. 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 in the 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 patterns and temperatures). The overall effect of climate
change is termed as global warming.
What is global warming?
Global
warming refers to increase of the earth’s average surface temperature
due to effects of the greenhouse gases. These gases trap heat that would
otherwise escape from the earth. The greenhouse gases include water
vapour (H2O), carbon dioxide (CO2), methane (CH4), dinitrogen oxide or
nitrous oxide (N2O), ozone (O3) and chlorofluorocarbons (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 the increase
occurring since 1980. Each of the last three decades has been
successively warmer at the earth’s surface than preceding decades since
1850.
The
recent rapid warming was caused by human activities which contribute to
the production of greenhouse gases, such as carbon dioxide, that 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
Scientific
understanding of the 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 50% of the
greenhouse effect. It is because of this 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 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 the increase in the amount of carbon
dioxide in the atmosphere.
A deforested land
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,
etc.
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, increases with increase in agricultural
activities. Since 1960s the amount of methane in the air has increased
by 1% per year, twice as fast as the build-up of carbon dioxide.Methane
is also produced by the decomposition of waste materials by bacteria. It
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.
Nitrous oxide (dinitrogen oxide, N2O)
Dinitrogen
oxide is produced from both man-made and natural processes. Human
activities which produce dinitrogen 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 dinitrogen 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.
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 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 1.4 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 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 superoxides which are damaging for the
corals. Global warming is threatening 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 biodivers
Extreme weather events
Extreme
weather events include record-breaking high or low temperatures, floods
or intense storms, droughts, heat waves, hurricanes and tornadoes, etc.
These are effective measures of climate change and global warming.
Floods
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:
- higher or lower agricultural yields;
- melting of arctic ice and snowcaps. This causes landslides, flash floods and glacial lake overflow;2
- extinction of some animal and plant species;
- increase in the range of disease vectors, that is, organisms that cause diseases.
Change in world’s climate patterns
It
is forecasted that global warming will cause climate patterns worldwide
to experience significant changes. Climate change resulting from
increasing temperatures will likely include changes in wind patterns,
annual precipitation and seasonal temperature variations.
Climatic
patterns in most parts of the world have already changed. Rains fall
when least expected and at irregular intervals. This has greatly
affected the timing of planting and harvesting activities. Sometimes the
rains fall so heavily to cause floods, or too little leading to
drought.
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 levels
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 raise by at least 25
m, leading to coastal flooding that will displace millions of people.
Small islands in the Caribbean, South Pacific, Mediterranean and 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 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 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 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 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.
A World Map Showing Different Natural Regions
Draw a world map showing different natural regions
Activity 1
Draw a world map showing different natural region
The Relationship between Human Activities and Climate
Explain the relationship between human activities and climate
Human
activities are human undertakings which are done to earn a living, they
include, fishing, lumbering, hunting and gathering and manufacturing.
Climate influences human activities directly.E.g In agriculture,
different crops have different requirements of temperature and rainfall
as the major climatic element. Therefore it is not advisable to
cultivate permanent crops in deserts.
Ways of Solving Climatic Problems
Propose ways of solving climatic problems
There
are natural and man-made causes of climatic change that bring about
climate problems. There are possible solutions to climatic problems such
as:
- education,
- avoidance of bad methods of farming,
- application of good farming methods,
- application of appropriate technologies,
- land reforms,
- afforestation,
- laws and rules,
- as well as the reduction of carbon dioxide emissions from industries.
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