New Guinea: The World's Second-Largest Island Spans Two Hemispheres

New Guinea, Earth's second-largest island (785,753 km² after Greenland), straddles a unique hemispheric position that shapes its climate, biodiversity, and human geography.

Hemispheric Location

• Southern Hemisphere: Entirely south of the Equator (latitudes ~0°–11°S)
• Eastern Hemisphere: Entirely east of the Prime Meridian (longitudes ~130°–155°E)

This places it in the Australasian realm—biogeographically distinct from both Asia and the Pacific islands.

Political Division

The island is split east-west:

• Western half: Indonesian provinces of Papua, Central Papua, Highland Papua, South Papua, West Papua (formerly Irian Jaya)
• Eastern half: Independent Papua New Guinea (since 1975)

Consequences of Position

Climate: Tropical, monsoonal—no temperate seasons. Biodiversity: 5-10% of Earth's species in <1% of land area—birds of paradise, tree kangaroos, 20,000+ plant species. Cultures: >1,000 languages (most linguistically diverse place on Earth). Geology: Active tectonics (Pacific Ring of Fire)—mountains to 4,884m (Puncak Jaya), copper/gold deposits (Grasberg, Ok Tedi).