Melanesia stretches in a 5600-km (3500-mi) arc off the northern and eastern coast of Australia. From northwest to southeast, Melanesia includes New Guinea, lying just north of Australia; the Bismarck Archipelago, belonging to Papua New Guinea; smaller archipelagos of Papua New Guinea; the Solomon Islands, some of which belong to Papua New Guinea but most of which are part of the nation of Solomon Islands; the many islands of the nation Vanuatu; the islands of New Caledonia and Dependencies, a French territory; and the Fiji Islands (an island nation commonly known as Fiji).
The tiny islands and atolls of Micronesia are scattered widely across a large area north of Melanesia and east of Asia. Micronesia has four main island groups. The Caroline Islands lie north of the equator from New Guinea and belong mostly to the Federated States of Micronesia, a self-governing country in free association with the United States. A small portion of the Carolines belongs to Palau, also a self-governing country in free association with the United States. To the north of the Carolines are the Mariana Islands, which make up the Commonwealth of the Northern Mariana Islands, a self-governing U.S. commonwealth, and Guam, an unincorporated U.S. territory. To the east of the Marianas are the Marshall Islands, an island group and republic in free association with the United States. Southeast of the Marshalls is the nation of Kiribati, which straddles the equator. The tiny nation of Nauru, a single island west of Kiribati, is also counted as part of Micronesia. Micronesia’s islands are so small that their land area totals just 3240 sq km (1250 sq mi). Even among the smaller islands of Oceania—that is, Oceania excluding New Guinea, New Zealand, and Hawaii—Micronesia makes up just 3.6 percent of the total land mass.
Polynesia, lying in the central and southern Pacific, encompasses a vast triangle stretching east from Melanesia and Micronesia. Polynesia is larger than both Melanesia and Micronesia combined. The southwestern tip of the Polynesian triangle is the nation of New Zealand, lying southeast of Australia and far south of the tropic of Capricorn. The southeastern tip is Easter Island, part of Chile lying just south of the tropic of Capricorn three-fourths of the distance from Australia to South America. The triangle’s northwestern tip is Hawaii, straddling the tropic of Cancer halfway between North America and Asia. These three tips, however, are outliers: Most of Polynesia is clustered just east of Melanesia south of the equator. From north to south, the Polynesian islands immediately east of Melanesia form the nation of Tuvalu; Wallis and Futuna, a French territory north of Fiji; and the nation of Tonga. Farther east, from north to south, are Tokelau, a territory of New Zealand; the independent nation of Samoa (formerly Western Samoa); American Samoa, a U.S. territory; Niue, a self-governing island in free association with New Zealand; and the Cook Islands, a self-governing island group also in free association with New Zealand. Still farther east lie the five archipelagos of the French territory French Polynesia: the Austral Islands, the Society Islands (with well-known Tahiti and Bora-Bora), the Tuamotu Archipelago (including the Gambier Islands), and the Marquesas Islands. Beyond French Polynesia is Pitcairn Island, a dependency of the United Kingdom.
Climate of Oceania
The climate of Oceania's islands is tropical or subtropical, and range from humid to seasonally dry. Wetter parts of the islands are covered by Tropical and subtropical moist broadleaf forests, while the drier parts of the islands, including the leeward sides of the islands and many of the low coral islands, are covered by Tropical and subtropical dry broadleaf forests and Tropical and subtropical grasslands, savannas, and shrublands. Hawaii's high volcanoes, Mauna Kea and Mauna Loa, are home to some rare tropical Montane grasslands and shrublands.