The continental mainland stretches from the southern
end of the Malay Peninsula to Cape Chelyuskin in
Because of its vast size and diverse character,
The continent may also be divided into two broad cultural realms: that which is predominantly Asian in culture (East Asia, Southeast Asia, and South Asia) and that which is not (Southwest Asia, Central Asia, and Russian Asia). There is enormous cultural diversity within both regions, however.
Rivers, Lakes, and Inland Seas East Asia is the location of the continent's longest river, the Yangtze, which flows about 5470 km (about 3400 mi) eastward from Tibet to the East China Sea. The Huang He (Yellow River) also rises in the Tibetan highlands, flowing east across central China to its mouth at the Yellow Sea. The Zhu Jiang (Pearl River) rises in southwestern China and flows through the southern part of the country on its route to the South China Sea.
In Southeast Asia the major rivers flow southward between mountain ranges. The Mekong rises in eastern Tibet and flows southeast to the South China Sea. The Salween also originates in Tibet, where it is called the Nu Jiang, flowing south to the Andaman Sea. The Irrawaddy, which rises in the mountains of northern Myanmar, also empties into the Andaman Sea.
The major rivers of South Asia have their sources in the Himalayas. The Ganges rises in the western Himalayas and passes eastward through India. Just north of the Bay of Bengal it joins the Brahmaputra River, which rises beyond the Himalayas and then empties into the bay. The Indus River emerges from the western end of the Himalayas and flows through Jammu and Kashmir and western Pakistan into the Arabian Sea.
The only large rivers of Southwest Asia are the Tigris and the Euphrates. Both rivers rise in Turkey and flow southward through Syria into Iraq, where they join before emptying into the Persian Gulf.
The three longest rivers of Russian Asia are the Ob', the Yenisey, and the Lena, all of which are more than 3200 km (2000 mi) long. These rivers rise in southern Siberia and flow northward into the Arctic Ocean.
River basins in tropical and temperate Asia support the highest population densities. The Gangetic Plain, which lies between the Himalayas and the Deccan Plateau; the basins of the Irrawaddy, Mekong, and Chao Phraya in Southeast Asia; and the basins of China's great rivers, especially the Yangtze, Huang He, and Zhu Jiang rivers, are all densely settled. These valleys have fertile soils for agriculture and the rivers serve as a means of transportation.
Some of Asia's important rivers flow into inland lakes. The Jordan River rises in the mountains of Lebanon and Syria and flows southward into the Dead Sea, a saltwater lake seven times more salty than the ocean. At 408 m (1339 ft) below sea level, the surface of the Dead Sea is the lowest point on earth. The Syr Darya and the Amu Darya of Central Asia both drain into the Aral Sea, also a saltwater lake. Since the 1960s the diversion of much water from the Syr Darya and Amu Darya for irrigation has caused the Aral Sea to shrink to less than half its former size. In 1988 the lake split in two, forming the Large Aral Sea, which receives water from the Amu Darya, and the Small Aral Sea, which receives water from the Syr Darya. The decreased water intake has also increased the salt content of the lake. The Caspian Sea is the largest saltwater lake in the world. Lake Balqash in Kazakhstan is another major saltwater lake.
Lake Baikal in southeastern Siberia is the deepest lake in the world and the largest freshwater lake in Asia. The Tônlé Sap, a shallow lake in western Cambodia, is the largest lake in Southeast Asia. It provides a lucrative source of fish for local residents. The Tônlé Sap becomes more than three times its normal size between June and October when floodwaters of the Mekong River empty into the lake.
Vegetation Asia incorporates many different biomes, which are landscapes having similar combinations of climate, vegetation, and animal life.
The northernmost areas of Asia, which experience a subpolar climate, have tundra vegetation consisting of grasses, mosses, and other small plants. Farther inland from the Arctic coast, the tundra gives way to the taiga, a region of vast coniferous forests composed of such trees as spruce, larch, and fir. Farther south, the taiga merges with forests of broadleaf trees, or mixed forests of broadleaf and needleleaf trees.
In Asia's north central interior the forests merge into vast grasslands, much of which is short, steppe grasses. Large portions of Southwest Asia and the continent's interior have semiarid or desert vegetation. Short grasses and other vegetation that require minimal precipitation surround many of the most barren areas in the deserts.
Although tropical rain forest predominates along the southern coastal strip and on the island of Sri Lanka, the eastern side of South Asia is characterized by semiarid tropical vegetation. The Deccan Plateau has mainly tropical dry forest vegetation.
Mainland and island Southeast Asia once supported extensive areas of tropical rain forest, which thrived in the warm, moist climate. Significant tracts of forest remain in most countries, but both legal and illegal harvesting is too rapid to support sustainable regrowth.
Inland from the coastal strips of mainland Southeast Asia and stretching into southern China, tropical seasonal forests predominate. These merge into temperate forests farther north. Around the rim of the Bo Hai gulf the vegetation is chaparral, woody shrubs that grow to about 4 m (about 13 ft) in height.
Asia has three main crop production systems. Across a broad band encompassing the Middle East, Central Asia, much of Russian Asia, and the inner regions of China, subsistence livestock production is the mainstay. Around coastal China, and most of South and Southeast Asia, the major form of agricultural activity is subsistence crop production. Scattered throughout the region-especially in Japan, Southeast Asia, the western parts of Russia, and some fertile patches of the Middle East-are pockets of commercial crop production.
Economically important activities throughout Central Asia and Russia include the production of wheat and other grains, cotton, and vegetables. Southeast Asia and the southern parts of China and India are major rice-growing areas, although grain production and consumption is more common in the northern regions of China and India. Rubber trees and oil palm plantations are significant in Malaysia and Indonesia. Tea plantations are significant in India, Sri Lanka, and Indonesia.
Animal Life The great variety of wildlife in Asia includes many species that are unique to the continent. Orangutans, the second tallest of the ape family after gorillas, are found on Borneo and Sumatra. Giant pandas make their home in southwestern China, and snow leopards roam the plateaus and mountains of Central Asia. A rare freshwater seal lives in Lake Baikal. China's Yangtze River is home to a freshwater dolphin threatened by water pollution and increased numbers of motorized river vessels. The Komodo dragon, the world's largest lizard and among the oldest surviving lizards, inhabits a small island in eastern Indonesia.
Asia's wildlife generally can be classified by the particular vegetation zones they inhabit. Reindeer live in the southern tundra region of northern Siberia. Small fur-bearing animals, such as sables and foxes, are plentiful in the taiga forest of Russian Asia. The grasslands are home to antelope and many rodents, including marmots. In the mountainous areas of Central Asia live tiny musk deer. Tigers, one species of which inhabits northern Siberia, are found throughout the tropical rain forests of South and Southeast Asia. This area is also home to rhinoceroses, monkeys, and several subspecies of elephants.
In the hilly regions of Southwest Asia live gazelles. A rare species of antelope known as the oryx is found on the fringes of the desert areas of the Arabian Peninsula. Other animals commonly found in Southwest Asia include wolves and hyenas.
The remote mountainous region of Vietnam adjacent to the border with Laos has yielded some remarkable discoveries of animals previously unknown by scientists. A new species of cattle-like animal, the sao la (vu quang), was discovered in 1993, only the fourth discovery of this kind in the 20th century. Scientists have discovered other creatures since 1992, including two deer-like animals, the giant muntjac and the quang khem.
Asia's domesticated animals include water buffalo, which are harnessed to plows and carts. Cattle are also used for hauling, especially in India, which has the world's largest cattle population. Most people in India do not eat beef because they belong to the Hindu religion, which considers cows sacred. Pigs are a major source of protein in China, although they are considered unclean in the Islamic countries, which include Pakistan, Afghanistan, and most countries of the Middle East. Sheep are kept across vast areas of semiarid Russian Asia, and reindeer are farmed in the north. People throughout the dry areas of the Middle East use camels.
The bird life of Asia is varied and includes several rare species. In the mountains of northern India lives the lammergeier, a huge bird similar to the vulture, that can obtain a wingspread of almost 3 m (almost 10 ft). Peacocks and birds of paradise are found in the rain forests of Southeast Asia.
The continent of Asia is also home to many of the world's poisonous snakes. Cobras, which are especially common in India, and kraits and vipers, which are found throughout the continent, are the leading poisonous snakes. Numerous other reptiles, such as crocodiles, live in the rivers of Southeast Asia.
Insects and Parasites The tropical climates of large portions of Asia are particularly favorable to the development of insects and of parasites with long, complex life cycles. Tropical walkingsticks can exceed 30 cm (12 in) in length. Malarial organisms and the mosquitoes that carry them are favored by the absence of cold winters and, in rainy tropical areas, by the abundance of precipitation. The deadliest of the malarial organisms, Plasmodium falciparum, can survive year round in tropical areas. Filariae, small parasitic roundworms, are common in India and much of Southeast Asia; the parasite can cause elephantiasis, a disease that produces grotesque swellings. Great swarms of locusts are a periodic menace to farming in various areas of the Asian continent, particularly in Southwest Asia.
Mineral Resources Asia is rich in known mineral resources, and additional resources are suspected in some areas, such as Tibet, which are still unexplored geologically. Asia is particularly endowed with energy resources. Petroleum and natural gas are well distributed, but the greatest concentrations of mapped energy fuels are at the head of the Persian Gulf; in parts of Indonesia, especially Sumatra and Borneo; in northern and interior China; on the shores of the Caspian Sea; and in the West Siberian Plain. Large offshore reserves are believed to exist along the coasts of China, Indonesia, Malaysia, and western India.
Since Vietnam's economy began opening to foreign investment in the late 1980s, offshore oil and gas reserves have been tapped for commercial production. China, Taiwan, Vietnam, Brunei, Malaysia, and the Philippines each claim all or part of the Spratly Islands in the South China Sea, an area thought to contain rich energy and mineral reserves.
Coal exists in great abundance in Siberia, northeastern India, and especially in Shaanxi province in northern China, which contains 30 percent of China's proven reserves. Despite enormous reserves, China is a coal importer because it does not have the capacity to transport sufficient coal from the northern to the southern parts of the country.
With the exception of Turkey, which is a major chromium producer, metallic minerals are relatively scarce in Southwest Asia. China and Siberia are particularly well endowed with mineral resources. Malaysia is rich in tin and India in iron and manganese ores. Indonesia has bauxite, which is used in aluminum production. Gemstones such as diamonds are found in Siberia, and sapphires and rubies occur in South and Southeast Asia. Other important mineral resources include gold, silver, uranium, copper, lead, and zinc. The major manufacturing centers of Asia, such as Japan, Singapore, and Hong Kong, have few or no significant mineral resources.
Agriculture Less than one-third of Asia's land is in agricultural use. The basic unit for organizing production in the rural areas is either the farm or the village, depending on the way in which rural society is structured. In South, Southeast, and East Asia, agriculture is characterized by small farms in alluvial lowlands, too many people on too little land, production largely for subsistence, and a heavy dependence on cereals and other food staples. Farming with simple hand-held tools or plows pulled by draft animals is very common. Many farmers are tenants, not owning the land they work. Communal farming was once common in socialist countries. Most rural communes have disintegrated in China and Vietnam, however, and the rights to use the land have reverted to farm families.
Rice, usually grown under wet conditions, is the staple food crop of South, Southeast, and East Asia. In South and Southeast Asia, controlled irrigation facilities are poorly developed, yields are often low, and double-cropping (two crops planted and harvested in one calendar year) is seldom practiced. Although high-yield varieties of wet rice have been introduced since the 1960s, this has not increased production as hoped.
In India, irrigation schemes have helped stabilize annual yields and increase overall production, but the average rice yield per hectare in the mid-1990s was only about half that of Japan. Nevertheless, Asian countries produce about 90 percent of the world's rice. China and India alone account for nearly 60 percent of the world total.
In addition to subsistence and small-farm agriculture, South and Southeast Asia also have large-scale estate agriculture. These farms produce crops for export, such as rubber, palm oil, coconut products, tea, pineapples, and manila hemp. Estate production originated in the late 18th and early 19th centuries when European colonial powers controlled much of the region. Many estates remain under foreign ownership and control.
In East Asia, agriculture is based on flooded-field cultivation to a latitude of about 35° north in China and about 40° north elsewhere. In contrast to Southeast Asia, yields are high, double-cropping is common, irrigation is highly controlled, and fertilizer is used extensively. These practices make Japan's wet-rice agriculture very productive, despite the small size of Japanese farms.
North of the Huai River in China's Anhui province, rice gives way to wheat and other dry grains, especially sorghum and corn. Fish farming and swine and poultry raising are practiced throughout East Asia. Dairy and beef cattle, though, are commonly raised only in Japan and Korea.
Farmers grow some grains in Asia's dry interior regions, and the raising of cattle, sheep, and horses is important. Semiarid regions of Central and Southwest Asia have agriculture centered around oases. For the most part, however, productivity levels are low.
Forestry and Fishing Although lumbering is an important industry in Southeast Asia, the pattern of commercial production is being altered, due in part to increased concern regarding deforestation. For example, in 1985 Indonesia-a significant source of tropical hardwoods-banned the export of unprocessed logs in an attempt to slow production and increase domestic timber processing industries. The bans were replaced by a high export tax in 1992. Thailand, once a major source of teak timbers, instituted a ban on commercial logging in 1989. Many companies then shifted their attention to the forests of neighboring Cambodia, Laos, and Myanmar, where some firms developed alliances with dissident groups to illegally exploit local timbers.
Slash-and-burn agriculture is still practiced in parts of Southeast Asia, as well as in the more remote parts of humid South Asia and southern China. In the heavily populated areas of India and China, however, the original forest cover has long since been removed.
Lumbering is a major industry in Japan, where large areas of planted conifers have replaced much of the original temperate forests in the south and deciduous hardwoods in the north. Siberian timber reserves are enormous but relatively untapped; the region's inaccessibility and harsh climate prohibit logging, and the quality of the trees is generally insufficient for world markets.
Marine fisheries are extremely important in Asia. Japan is the world's leading fishing country, and China is not far behind. The fishing industry is also important in Russia, Thailand, Indonesia, Korea, and the Philippines. Pisciculture (raising fish in ponds) is also an important activity, especially in China. Although fishing in the less developed countries is largely for domestic consumption, emphasis has increasingly been placed on exports of dried, frozen, and canned fish.
Mining Mining is also an important activity in most Asian countries, and it is a major export industry in several: manganese in India; tin in Malaysia, Thailand, and Indonesia (which combined produce most of the world's supply of this metal); and chromium ore in the Philippines. The most important mineral export, however, is petroleum, with Asian outputs accounting for about half the world's total. Southwest Asia contains the world's largest reserves of oil outside Russia, and most of the production is exported. Indonesia and, more recently, China and Malaysia are also exporters. In South Asia, modest petroleum and natural gas deposits are exploited in Bangladesh, Pakistan, and off the western coast of India. Coal mining is important in China-which contributes about 30 percent to the world's total coal output-and in central and eastern Siberia, northeastern India, Iran, and Turkey. Other significant mineral products include iron, manganese, and tungsten in China; sulfur, zinc, and molybdenum in Japan; and gold in Uzbekistan and Siberia.
