The Geography of Oceania – Pacific Islands

By Matt Rosenberg

Updated January 20, 2016.

Oceania is the name of the region consisting of island groups within the central and South Pacific Ocean. It spans over 3.3 million square miles (8.5 million sq km). Some of the countries included in Oceania are Australia, New Zealand, Tuvalu, Samoa, Tonga, Papua New Guinea, the Solomon Islands, Vanuatu, Fiji, Palau, Micronesia, the Marshall Islands, Kiribati and Nauru. Oceania also includes several dependencies and territories such as American Samoa, Johnston Atoll and French Polynesia.

Physical Geography of Oceania

In terms of its physical geography, the islands of Oceania are often divided into four different sub-regions based on the geologic processes playing a role in their physical development. The first of these is Australia. It is separated because of its location in the middle of the Indo-Australian Plate and the fact that due to its location there was no mountain building during its development. Instead, Australia's current physical landscape features were formed by mainly by erosion.

The second landscape category in Oceania is the islands found on the collision boundaries between the Earth's crustal plates. These are found specifically in the South Pacific. For example at the collision boundary between the Indo-Australian and Pacific plates are places like New Zealand, Papua New Guinea and the Solomon Islands. The North Pacific portion of Oceania also features these types landscapes along the Eurasian and Pacific plates. These plate collisions are responsible for the formation of mountains like those in New Zealand which climb to over 10,000 feet (3,000 m).

Volcanic islands such as Fiji are the third category of landscape types found in Oceania. These islands typically rise from the seafloor through hotspots in the Pacific Ocean basin. Most of these areas consist of very small islands with high mountain ranges.

Finally, coral reef islands and atolls such as Tuvalu are the last type of landscape found in Oceania. Atolls specifically are responsible for the formation of low-lying land regions, some with enclosed lagoons.

Climate of Oceania

Most of Oceania is divided into two climate zones. The first of these is temperate and the second is tropical. Most of Australia and all of New Zealand are within the temperate zone and most of the island areas in the Pacific are considered tropical. Oceania's temperate regions feature high levels of precipitation, cold winters and warm to hot summers. The tropical regions in Oceania are hot and wet year round.

In addition to these climatic zones, most of Oceania is impacted by continuous trade winds and sometimes hurricanes (called tropical cyclones in Oceania) which have historically caused catastrophic damage to countries and islands in the region.

Flora and Fauna of Oceania

Because most of Oceania is tropical or temperate there is an abundant amount of rainfall which produces tropical and temperate rainforests throughout the region. Tropical rainforests are common in some of the island countries located near the tropics, while temperate rainforests are common in New Zealand. In both of these types of forests there is a plethora of plant and animal species, making Oceania one of the world's most biodiverse regions.

It is important to note however, that not all of Oceania receives abundant rainfall and portions of the region are arid or semiarid. Australia for example, features large areas of arid land which have little vegetation. In addition, El Nio has caused frequent droughts in recent decades in Northern Australia and Papua New Guinea.

Oceania's fauna, like its flora is also extremely biodiverse. Because much of the area consists of islands, unique species of birds, animals and insects evolved out of isolation from others. The presence of coral reefs such as the Great Barrier Reef and Kingman Reef also represent large areas of biodiversity and some are considered biodiversity hotspots.

Humans and Oceania

Most recently in 2005, Oceania's population was around 33 million people, with the majority centered in Australia and New Zealand. Those two countries alone accounted for more than 24 million people, while Papua New Guinea had a population of over five million. The remaining population of Oceania is scattered around the various islands making up the region.

Like its population distribution, urbanization and industrialization also vary in Oceania. 89% of Oceania's urban areas are in Australia and New Zealand and these countries also have the most well established infrastructure. Australia in particular has many raw minerals and energy sources, and manufacturing is a large part of its and Oceania's economy. The rest of Oceania and specifically the Pacific islands are not well developed. Some of the islands have rich natural resources, but the majority do not. In addition, some of the island nations do not even have enough clean drinking water or food to supply to their citizens.

Agriculture is also important in Oceania and there are three types which are common in the region. These include subsistence agriculture, plantation crops and capital intensive agriculture. Subsistence agriculture occurs on most of the Pacific islands and is done to support local communities. Cassava, taro, yams and sweet potatoes are the most common products of this type of agriculture. Plantation crops are planted on the medium tropical islands while capital intensive agriculture is practiced mainly in Australia and New Zealand.

Finally, fishing and tourism are important to Oceania's economy and its development. Fishing is a significant source of revenue because many islands have maritime exclusive economic zones that extend for 200 nautical miles and many small islands have granted permission to foreign countries to fish the region via fishing licenses. Tourism is also important to Oceania because many of the tropical islands like Fiji offer aesthetic beauty, while Australia and New Zealand are modern cities with modern amenities. New Zealand has also become an area centered on the growing field of ecotourism.

To learn more about Oceania and its countries visit the Countries of Oceania page on this website.

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The Geography of Oceania - Pacific Islands