CBSE Class 8 Geography Chapter 7 Asia: Climate, Natural Vegetation And Wildlife Notes

CBSE Class 8 Geography Chapter 7 Asia: Climate, Natural Vegetation, And Wildlife

Asia, a huge continent, stretching from the Equatorial to the Polar regions, has a great diversity of climate. It has some of the coldest and some of the hottest, some of the wettest and some of the driest places on the earth. This diversity of climate is caused by a number of features which interact to give most of Asia a markedly continental type of climate. A continental climate is characterised by extremes of temperature and is generally associated with large landmasses.

Factors Affecting the Climate of Asia

The most dominant features that influence the climate of Asia are the following:

• Its vast latitudinal extent enables the establishment of a wide range of climatic types, ranging from the Equatorial to the Tundra type.
• Several mountain ranges act as effective barriers to air masses or winds.
• The seasonal reversal in the direction of winds.
• The distance from the sea large as parts of the interior are away from the ocean.
• The open nature of the boundary with Europe.
• Several deserts lie in its deep interior.

Asiaextends over 9654 km from east to west and 8527 km from north to south. Due to its vast size, the interiors of the continent do not experience the moderating influence of the oceans.

• The vast interiors absorb more solar energy during summer than the water bodies, and also lose more energy during winter.
• It is because of this that the climate of Central Asia is one of extremes with long and cold winters, chilled by cold winds from the Polar regions, and short and hot summers.

CBSE Class 8 Geography Chapter 7 Asia: Summer Season

The seasonal contrasts between the strong heating of the Asian landmass during the summer (May to September) and chilling in winter (January to March) produce variations in the atmospheric pressure and wind circulation, and in turn affect the climate of the region.

• During the summer season, the rays of the Sun fall vertically on the Tropic of Cancer and heat up the central part of Asia.
• Here, the average temperature remains around 30°C.
• This creates a low-pressure belt centred around the basin of the

Indus river, Tibetan Plateau and Iran.

• However, the main water bodies, the Pacific Ocean and the Indian Ocean, are comparatively cooler, leading to the formation of high pressure over these areas.
• Thus, during the summers, winds laden with moisture blow from the areas of high pressure (seas) towards areas of low pressure (land) and bring heavy rainfall in almost all parts of Asia.
• These winds are called the Summer Monsoons or tropical and subtropical monsoons. In India, they are referred to as the South-West Monsoons

CBSE Class 8 Geography Chapter 7 Asia:  Winter Season

During the winter season, the rays of the Sun fall vertically over the Tropic of Capricorn in the southern Hemisphere, and the interior regions of Asia, which lie at great distance from the sea, become very cold.

• This leads to the formation of a high-pressure area over central parts of Asia.
• High-pressure conditions result in the building up of cold, dry air and winds.
• These winds originating from land are very cold and dry and blow outward from the high-pressure zone.
• Therefore, they do not give rain during the winter season. However, when these winds blow over the Pacific Ocean, they pick up moisture from the ocean and cause rainfall in the coastal areas.
• The southeastern coast of India, Sri Lanka, Japan and Southeast Asia receive rainfall from these winds. These winds are called the Winter Monsoons or North-East winter monsoons

CBSE Class 8 Geography Chapter 7 Asia: Rainfall Pattern

Rainfall conditions in an extensive continent as Asia are wide ranging. It varies from the very rainy areas of the Equatorial belt to practically no rainfall in the deserts of Central Asia and Saudi Arabia.

Mountain ranges are one of the factors, which influence the distribution and pattern of rainfall in Asia. The Himalayas, which have the highest peaks in the world, are imposing barriers.

• They protect South Asia from the extreme cold winds and influence the pattern of rainfall.
• Much of these interior regions of Asia remain in the ‘rain-shadow’ zone as the rain-bearing winds cannot penetrate these mountain barriers. The onshore side of the mountain slopes, on the other hand, receives most of the rainfall.
• That is why the North Indian plains which lies on the ‘leeward’ side of the Himalayas receive rainfall by the summer monsoon, whereas Tibet which lies in the rain-shadow area of the Himalayas remains dry.
• Similarly, heavy rainfall occurs in summer on the west coast of India which lies on the windward side of the Western Ghats but the area east of the Ghats receives scanty rainfall as it is located in the rain-shadow zone.

Thus, the amount and pattern of rainfalls vary from place to place and from season to season. Based on this,

The continent of Asia can be divided into the following categories:

• The Areas of Heavy Annual Rainfall (above 200 cm) lie in the Equatorial region in Indonesia, Malaya Peninsula and the Shiwalik ranges of the Himalayas. Mawsynram in Meghalaya (India) receives the highest average annual rainfall in the world.
• The Areas of Moderate Annual Rainfall (100 cm to 200 cm) lie in parts of India, central and southern China, Japan and Philippines.
• The Areas of Low Annual Rainfall (less than 50 cm) lie in southwest Asia, Central Asia, Siberia and the plateaus of Central Highlands. Many parts of the Arabian Peninsula do not get any rainfall whereas a large part of Central Asia and Siberia being cold deserts get poor rainfall.

CBSE Class 8 Geography Chapter 7 Asia: Types of Climate

The large variety of climatic types that prevail, in Asia can be grouped into following categories:

1. The Tundra Type

This type of climate is found in the northern most part of Asia. It remains frozen for a major part of the year.

• Here the winters are long, very severe, dry and snowbound, whereas summers are short but warm enough for some snow to melt.
• The annual precipitation, including the rainfall in summer season and the snowfall is winter is usually less than 25cm.
• This is because of the low rate of evaporation and the lack of moisture in the cold polar air. Northern Siberia and Kamchatka have Tundra type of Climate.

2. The Taiga or Sub-Arctic Climate

• The Taiga region lies to the south of Tundra.
• The Taiga belt in Asia is characterised by very long cold and severe winters. The summers are short and warm. Rain occurs in summer causing humidity.
• Areas in Asia that experience Taiga type of climate are Russia, northern Kazakhstan, parts of northern Mongolia and northern Japan.

3. The Temperate Type

This type of climate is found in the mid-latitudes, which span between the tropics and the polar regions of the Earth.

In Asia, it can be subdivided into the following types:

Warm Temperate (China Type):

This type of climate is found on the eastern margins of continents in warm temperate latitudes just outside the tropics. Since it is found in most parts of China and is a modified form of monsoonal climate, it is also known as the Temperate Monsoon or China Type of Climate

It is experienced in the eastern part of Asia including China, North Korea, South

• Korea and southern Japan. Here the summers are warm and the winters are cold. Most of the rainfall occurs during the summer months and winters are dry.
• Only Taiwan and some parts of Japan receive rainfall in winter caused by the southeasterly winds which pick up moisture from the Japan Sea, East China sea and the adjoining seas.
• An important characteristic feature of China Type of climate in southern China is the occurrence of typhoons, i.e., intense tropical cyclones that originate in the Pacific Ocean.
• They are most frequent in late summer, from July to September and are quite disastrous.

Cool Temperate (Manchurian Type):

This type of climate is found in the eastern coastal region of Asia, including eastern Siberia, Northeast China, Manchuria, Korea and northern Japan. Here, the summers are warm and wet, whereas winters are cold and dry.

• The annual rainfall ranges between 50 cm and 100 cm and the rain occurs mainly in summer.
• Much of the winter precipitation in northern China, Korea and Hokkaido in Japan is in the form of snow.

Steppe Type:

This type of climate is found in central and western Asia. Due to their location in the heart of continents they have extremeslittle maritimeof temperature.

• Influence and summer thus AKJgg are very warm, and winters are very cold. The amount of annual rainfall is low and it mostly occurs during the summer season.
• Most of the winter months have low precipitation, brought by the occasional depression of the Westerlies and comes in the form of snow.
• Unlike the Taiga region, this region has excessive evaporation and is suitable only for the growth ofshort grasses and does not support the growth of trees. The Steppe grasslands are used for wheat cultivation.

The Mediterranean Type:

This type ofclimate is found along the coast of Mediterranean Sea from Turkey to Syria, Jordan, Lebanon, Israel and Iraq.

• Here the summers are hot and dry, while the winters are mild and wet. Rainfall occurs mostly in winter brought by the cyclonic storms emerging in the west.
• Due to hot and dry summers plants have to adapt themselves to withstand conditions of drought and higher summer temperature.
• So the plants and trees have short thick leaves, long tap roots and thick barks to preserve moisture in the dry season. The most distinctive vegetation of this region consists of evergreen shrubs and trees.
• The trees found in this region include oak, walnut, almond, cedar, pine, fir and myrtle.

4. The Tropical Monsoon Type

It includes a vast region in southern and southeastern Asia covering India, Pakistan, Bangladesh, Cambodia, Laos, Myanmar, southern China, parts Philippines, Thailand, Vietnam, and Sri Lanka.

• This type of climate is characterised by monsoon winds which reverse their direction from season to season and affect the climatic conditions.
• The climate is generally hot and dry during the summers and cool and diy during the winters with a distinct rainy season.
• The rainfall is moderate to high ranging between 50cm to 200 cm annually.

5. The Desert Type

The deserts are mainly of two types —

1. Tropical deserts
2. Temperate deserts.

The type of climate found in these deserts is of the following types:

1. The Tropical Desert Type:

• This type of climate occurs in the Arabian desert in Saudi Arabia and the Thar Desert in India and Pakistan.
• They lie in the western margins of the landmass.
• These desert areas remain hot throughout the year.
• Generally, the summers are hot and the winters are cool.
• The rainfall due to offshore winds is scanty.
• Due to the rapid heating of the land during the day and cooling at night a great difference between the day and night temperatures is experienced in these desert regions.

2. The Temperate Desert Type:

This type of climate is found in a vast territory of high mountains in Central Asia, including the Gobi desert, (China and Mongolia), the Taklamakan desert and the Plateau ofTibet.

• Since this region is located far away from the oceans, it has extreme type of climate with hot summers and severely cold winters with temperatures falling below the freezing point.
• The high mountain barriers in this region keep the rain-bearing winds away from this region and therefore, the rainfall is scanty during the summer, whereas, during the winters it falls as snow.

6. The Equatorial Type

It includes the areas lying between 10° N and 10° S in Indonesia, Malaysia, parts of Sri Lanka and the southern parts ofthe Philippines.

• It is a hot and humid type of climate with high temperatures throughout the year.
• Heavy convectional rainfall accompanied by lightning and thunder occurs almost everyday.
• Humidity is quite high which makes the heat all the more unbearable

CBSE Class 8 Geography Chapter 7 Asia: Natural Vegetation And Wildlife

The large variety of climates in Asia have given rise to different types of vegetation and wildlife.

These include the following:

1. The Tundra Type

Natural Vegetation:

It is a region of cold, treeless plains with permanently frozen subsoil. Due to the growing season of less than three months and the warmest month not exceeding 10°C, there are no trees in this region. Such an environment supports only the lowest form of vegetation like lichens, mosses, sedges and some grasses.

Wildlife:

The animals found in this region include the Arctic fox, the snowy owl, ptarmigan, the polar besu-, polar dog, wolves, lemmings and reindeer. In the Arctic Ocean, seal and walrus are found.

2. The Taiga Type

Natural Vegetation:

Here, the winters are long, dry and among the coldest in the world, whereas summers are warm and short.

• The world’s largest temperature ranges are found in this region. The precipitation is low and mostly in the form of snow.
• The Taiga is a type of Vegetation found in Russia and Siberia. The vegetation of the region comprises a belt of coniferous forests.
• Although precipitation is low in this region, it is sufficient for plant growth due to less evaporation. The main trees are cedar, fir, pine and spruce. These trees yield valuable soft wood.

Wildlife:

In the Taiga region, fur-bearing animals such as arctic fox, mink, sable, reindeer, elk, and bear are found

3. Tropical Deciduous Type

Natural Vegetation:

In the Tropical Monsoon type of climatic region, the natural vegetation varies with the amount of rainfall and the height of land above the mean sea level.

• The areas which receive heavy rainfall have thick evergreenforests whereas, areas with less rainfall have deciduous forests which shed their leaves in the dry winter months.
• The common varieties of trees include teak, sal, sandalwood, eucalyptus, peepal and neem. These forests also have dense growth of bamboos and ferns.

Wildlife:

This region is home to a variety ofanimals including lions, tigers, elephants, leopards, stags, deer, crocodiles and various types of birds. The Asiatic Lion is found only in India.

4. Thorny Vegetation Type

Natural Vegetation:

In the tropical deserts generally conditions are unfavourable for the growth of vegetation. So most of the region is bare with patches of shrubs, grass and thorny bushes. Date palms grow in the oasis.

• In the temperate deserts, vegetation is sparse, comprising shrubs, grasses and thorny bushes. Ferns, bamboos, lianas and palms also grow here.
• However, highlands in Tibet and Mongolia also contain Taiga and Tundra like vegetation depending on the amount of moisture.

Wildlife:

The common animals which live in the harsh climatic conditions of the tropical deserts include camel, ass, gazelle and cheetah. In temperate deserts, the animals found are the

Wildlife In the Tundra Region:

Wildlife In the Desert Region:

Bactrian camel (two humped camel) and horses. Yak is the common animal in the Plateau ofTibet, a cold desert. In Mongolia, Kuland or wild ass is an important animal.

5. Equatorial Type

Natural Vegetation:

Tropical Rainforests are typical of the Equatorial regions. In Malaysia and Indonesia rainforests cover large part of the countries, whereas in southern Sri Lanka these forests have been replaced by agricultural landscape comprising plantations of tea, coconut palms and rubber trees.

• The vegetation consists of evergreen, broad leafed tall, dense trees which form a thick canopy.
• The climatic conditions are ideal for the growth of dense evergreen forests because the region gets high amount of rainfall throughout the year and is constantly warm.
• The important hardwood trees include rosewood, ebony, mahogany, rubber and cinchona. Mangrove swamps are found in the coastal areas. These forests also have a thick undergrowth of shrubs and creepers.

Wildlife:

A number of birds and animals inhabit these dense evergreen forests. The main species of animals include the monkeys, sloths, lizards, snakes, birds, insects and apes like orangutans and gibbons.