INDONESIA, the largest archipelago in the world to form a single state consists of five main islands and some 30 smaller archipelagoes, totalling about 17,508 islands and islets of which about 6,000 are inhabited. These are scattered over both sides of the equator. At 1,919,440 square kilometers (741,050 sq mi), Indonesia is the world’s 16th-largest country in terms of land area. Its national territory consists 84% of sea and 16% of land. The Indonesian sea area is four times larger than its land area, which is about 1.9 million sq.km and the sea area is about 7.9 million sq km. The five biggest islands are Kalimantan or two thirds of the island of Borneo (539,450 sq.km); Sumatera (473,606 sq.km); Papua, which forms part of the island of New Guinea (421,952 sq.km), Sulawesi (189,035 sq.km) and Java including Madura (132,035 sq.km). Indonesia shares land borders with Malaysia on the islands of Borneo and Sebatik, Papua New Guinea on the island of New Guinea, and East Timor on the island of Timor. Indonesia also shares borders with Singapore, Malaysia, and the Philippines to the north and Australia to the south across narrow straits of water. The capital, Jakarta, is on Java and is the nation’s largest city, followed by Surabaya, Bandung, Medan, and Semarang.
Its average population density is 134 people per square kilometer (347 per sq mi), 79th in the world, although Java, the world’s most populous island, has a population density of 940 people per square kilometer (2,435 per sq mi). At 4,884 meters (16,024 ft), Puncak Jaya in Papua is Indonesia’s highest peak, and Lake Toba in Sumatra its largest lake, with an area of 1,145 square kilometers (442 sq mi). The country’s largest rivers are in Kalimantan, and include the Mahakam and Barito; such rivers are communication and transport links between the island’s river settlements.
The name “INDONESIA” is composed of the two Greek words: “Indos” meaning India, and “Nesos” meaning islands. The Indonesian archipelago forms a crossroad between two oceans, the Pacific and Indian oceans and a bridge between two continents, Asia and Australia. Because of its strategic position, therefore, Indonesia ‘s cultural, social, political and economic patterns have always been conditioned by its geographical position.
Indonesia’s location on the edges of the Pacific, Eurasian, and Australian tectonic plates makes it the site of numerous volcanoes and frequent earthquakes. Indonesia has at least 150 active volcanoes, including Krakatoa and Tambora, both famous for their devastating eruptions in the 19th century. The eruption of the Toba supervolcano, approximately 70,000 years ago, was one of the largest eruptions ever, and a global catastrophe. Recent disasters due to seismic activity include the 2004 tsunami that killed an estimated 167,736 in northern Sumatra, and the Yogyakarta earthquake in 2006. However, volcanic ash is a major contributor to the high agricultural fertility that has historically sustained the high population densities of Java and Bali.
Lying along the equator, Indonesia has a tropical climate, with two distinct monsoonal wet and dry seasons. Average annual rainfall in the lowlands varies from 1,780–3,175 millimeters (70–125 in), and up to 6,100 millimeters (240 in) in mountainous regions. Mountainous areas—particularly in the west coast of Sumatra, West Java, Kalimantan, Sulawesi, and Papua—receive the highest rainfall. Humidity is generally high, averaging about 80%. Temperatures vary little throughout the year; the average daily temperature range of Jakarta is 26–30 °C (79–86 °F).
The greater part of the country falls with in the boundaries of the equatorial rain belt. It has characteristically a tropical climate. Its geographical make up is an archipelago of mostly small island surrounded by sea. However, it allows an active air circulation. As a result, the climate is closely similar to that of prevailing in the equatorial zones above the world’s oceans. Abundant rainfall, high temperatures and humidity are characteristic to the average Indonesian lowland climate. The lowest average temperature is 18 degree Celsius. Moreover, the proximity of the Asian and Australian Continents brings the Indonesian archipelago well within the Asian characteristic that keeps alternating in accordance with the seasons. The trade and monsoon winds coming from the Indian and Pacific oceans temper the tropical character of the climate.
In Indonesia only two seasons prevail, a dry and wet, or rainy season. In most areas, the rainy season lasts from December up to March and driy season from May to October, with the transition periods characterized by shifting winds and capricious weather occuring in the months of March to May and September to November. The transitional period between these two seasons alternates between gorgeous sun-filled days and occasional thunderstorms. Even in the midst of the wet season temperature could range from 21 degrees (70 degrees Fahrenheit) to 33 degrees Celsius (90 degreed Fahrenheit), except at higher altitudes, which can be much cooler. The heaviest rainfall is usually recorded in December and January each year.
Flora & Fauna
Indonesia’s size, tropical climate, and archipelagic geography, support the world’s second highest level of biodiversity (after Brazil), and its flora and fauna is a mixture of Asian and Australasian species. Once linked to the Asian mainland, the islands of the Sunda Shelf (Sumatra, Java, Borneo, and Bali) have a wealth of Asian fauna. Large species such as the tiger, rhinoceros, orangutan, elephant, and leopard, were once abundant as far east as Bali, but numbers and distribution have dwindled drastically. Forests cover approximately 60% of the country. In Sumatra and Kalimantan, these are predominantly of Asian species. However, the forests of the smaller, and more densely populated Java, have largely been removed for human habitation and agriculture. Sulawesi, Nusa Tenggara, and Maluku—having been long separated from the continental landmasses—have developed their own unique flora and fauna. Papua was part of the Australian landmass, and is home to a unique fauna and flora closely related to that of Australia, including over 600 bird species.
Indonesia is divided into three distinct zoological and geographical zones which includes a transitional area in the central part of the archipelago.
The Western island of the Archipelago display predominantly Asian characteristics of verdant jungles, rare orchids and the giant Rafflesia, (a plant which produces a bloom over 1 meter in diameter). A land where tigers, leopards, elephants, rhinos and thousands of varieties of birds and insects make it their home.
Further east, the central island present a gradual shift from Asian to Australasian flora and fauna. Sulawesi, for example, boasts both monkeys and marsupials, while Komodo is home to a pre-historic giant lizards commonly “dragon” found nowhere else in the world.
The eastern most islands, however, are more indicative of Australasia with bush-like shrubs and hardy plants; brilliantly coloured Lorries, Cukatoos and Australian marsupials become more common place. These wonderfully diverse illustrations of life are protected in numerous nature reserves and National Parks scattered throughout the archipelago.
Indonesia is second only to Australia in its degree of endemism, with 26% of its 1,531 species of bird and 39% of its 515 species of mammal being endemic. Indonesia’s 80,000 kilometers (50,000 mi) of coastline are surrounded by tropical seas that contribute to the country’s high level of biodiversity. Indonesia has a range of sea and coastal ecosystems, including beaches, sand dunes, estuaries, mangroves, coral reefs, sea grass beds, coastal mudflats, tidal flats, algal beds, and small island ecosystems. The British naturalist, Alfred Wallace, described a dividing line between the distribution and peace of Indonesia’s Asian and Australasian species. Known as the Wallace Line, it runs roughly north-south along the edge of the Sunda Shelf, between Kalimantan and Sulawesi, and along the deep Lombok Strait, between Lombok and Bali. West of the line the flora and fauna are more Asian; moving east from Lombok, they are increasingly Australian. In his 1869 book, The Malay Archipelago, Wallace described numerous species unique to the area. The region of islands between his line and New Guinea is now termed Wallacea.
Indonesia’s high population and rapid industrialization present serious environmental issues, which are often given a lower priority due to high poverty levels and weak, under-resourced governance. Issues include large-scale deforestation (much of it illegal) and related wildfires causing heavy smog over parts of western Indonesia, Malaysia and Singapore; over-exploitation of marine resources; and environmental problems associated with rapid urbanization and economic development, including air pollution, traffic congestion, garbage management, and reliable water and waste water services. Habitat destruction threatens the survival of indigenous and endemic species, including 140 species of mammals identified by the World Conservation Union (IUCN) as threatened, and 15 identified as critically endangered, including the Sumatran Orangutan.