New research shows that the expansion of the tropics and associated changes in Pacific Ocean wind patterns facilitated the Polynesian migration to the far eastern and southern ends of the Pacific including Easter Island, New Zealand and subantarctic Auckland Islands.

Macquarie University’s Associate Professor Ian Goodwin and colleagues reconstructed wind-field patterns from modeled Pacific sea level pressure at 20-year intervals spanning the period 800 AD to 1600 AD.

Voyaging to Easter Island was possible as early as 800 to 910 AD, and voyaging to New Zealand as early as 940 to 970 AD. However, they revealed climate windows where the most favourable sailing conditions for travel between central East Polynesia and New Zealand occurred between 1140 and 1260 AD, and for travel to Easter Island between 1250 and 1280 AD.

The paleoclimate changes accords well with the archaeological evidence that suggests a rapid colonisation of Polynesian islands by sea-faring peoples, including the colonisation of New Zealand between 1100 and 1300 AD.

Off-wind or down-wind sailing between central East Polynesia and New Zealand was unusually possible during this period, when intensification and poleward expansion of the Pacific subtropical anticyclone strengthened tradewinds toward New Zealand.

The paleo-wind patterns revealed that New Zealand was potentially colonised by voyaging from the Tonga/Fiji Islands, the Southern Cook Islands, and the Austral Islands further east. Similarly, the wind patterns revealed that Easter Island might have been colonised from both Central East Polynesia and from Chile.

“This research fits in the Polynesian folklore, which refers to multiple migrations – our mapping of the climate conditions at that time they were travelling confirms the possibility,” said Professor Goodwin.

It also indicates that Polynesian sailing-canoes did not need a capability to sail to windward, and that all passages could have been made downwind over the immense ocean tracts.

“These are fantastic new insights into prehistoric maritime migration, and opens doors for marine climatologists to work with anthropologists and archaeologists, to piece together the evolution of maritime societies.”

Ian D. Goodwin, Stuart A. Browning, and Atholl J. Anderson (2014) Climate Windows for Polynesian Voyaging to Easter Island and New Zealand PNAS (Proceedings of the National Academy of Science, USA).

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