When Papua New Guinea & Australia Were One Landmass

The Sahul Land Bridge: 10,000 Years Ago

Yes, Papua New Guinea and Australia were physically connected during the Last Glacial Maximum (LGM), roughly 26,000–19,000 years ago, and remained so until ~8,000–6,000 years ago.

The Sahul Continent

• Sahul = Australia + New Guinea + Tasmania + Aru Islands — single landmass on the Australian continental shelf.
• Sea level: ~120–130 m lower than today (water locked in ice sheets).
• Exposed shelf: Torres Strait (now 150 km wide, 10–20 m deep) was a broad grassy plain with lakes, rivers, and gallery forests.

Human & Biological Consequences

• First Australians: Arrived ≥65,000 ya via island-hopping from Sunda (SE Asia); spread across Sahul.
• Unified gene pool: No genetic separation between New Guinea highlanders and Aboriginal Australians until post-LGM flooding.
• Fauna exchange: Megafauna (Diprotodon, Thylacoleo), marsupials, reptiles, birds moved freely.
• Flora: Shared Antarctic/Austral elements (Nothofagus, Podocarps) in highlands.

Separation

• Meltwater Pulse 1A (~14,600 ya): Rapid rise ~16 m.
• Meltwater Pulse 1B (~11,300 ya): Further rise.
• ~8,000–6,000 ya: Torres Strait fully marine; New Guinea isolated.
• Cultural divergence: Agriculture (taro, banana, sugarcane) developed in New Guinea highlands ~9,000 ya; Australia remained hunter-gatherer. Trade/contact continued via Torres Strait Islanders.

Modern Torres Strait

• 100+ islands (17 inhabited).
• Torres Strait Islanders — distinct Melanesian people, maritime culture.
• Treaty (1978): Australia–PNG maritime boundary; free movement for traditional activities.

Bottom line: For ~90% of human history in the region, PNG and Australia were one continent. The Torres Strait is a recent, shallow flood.