The South Pacific was the last habitable region on earth to be settled by human beings.
It is now becoming the first to be made uninhabitable.
About 160 million years ago Antarctica, Australia, South America, India and part of South-East Asia formed the single supercontinent Gondwanaland. It gradually broke into ‘tectonic plates’ which are still moving today. Where they pull apart, molten magma sometimes breaks the surface to form ridges. Where they come together, one plate plunges beneath the other, throwing up mountainous ridges to one side and deep oceanic trenches to the other. Most of the islands of the South Pacific are formed by one of these two forces. The Pacific remains the most volatile geological region on earth.
Freeze and flood
During the past two million years there have been at least 20 occasions when the earth’s climate was colder than it is now. At such times, because water cooled and contracted, sealevels fell. The islands of the South Pacific were then larger and fewer. At the height of the last ice age, 18,000 years ago, the sealevel in Fiji was between 120 and 150 metres below the current level. By the end of the Ice Age most of the older island ecosystems became stabilized with grassland, woodland and tropical rainforest. This made them suitable for human settlement.
People probably first moved from Indonesia to New Guinea and Australia between 40,000 and 50,000 years ago, when sealevels were low. With the end of the Ice Age sealevels rose and longer-distance migrations in dug-out canoes began. By the time of the ‘Little Climate Optimum’ between 1200 and 650 BC temperatures were higher than they are now, with persistent trade winds, clear skies and few storms. These were favourable conditions for oceanic migrations: among the greatest feats of navigation ever accomplished. People finally reached the Marquesas Islands to the east about 2,000 years ago. From there they went on to form the ‘Polynesian Triangle’, with Hawai’i to the north and Aotearoa/New Zealand to the south, by about 750 AD – though evidence of earlier settlement is now being examined.
Migration brought great changes to island ecosystems. New crops and animals were introduced and forests were cleared for cultivation. Combined with the effect of tropical storms, these increased soil erosion. The sediment from erosion, in turn, smothered coral reefs. Reefs protect many islands from the ocean and are rich in fish. Most island ecosystems were badly degraded within 1,000 years of human settlement. Pollen records show that forests on Rapa Nui (Easter Island) were completely destroyed. On Aneityum, southern Vanuatu, early settlement and forest clearance on the uplands led to soil erosion and forced a shift of population to the lowlands – similar shifts had to be made on other islands, too.
The initial effect of European intrusion during the seventeenth century was to reduce human impact on the environment. Indigenous peoples, as elsewhere around the world, had no immunity to European diseases and many died, so cultivation and land degradation slowed. But the burning of vegetation increased as commercial farming commenced; repeated burning weakened the soil and led to landslides. Bad management of commercial croplands – such as sugar cane in Fiji – also degraded soils. Native plant and animal species began to disappear and extractive industries ruined entire islands. Phosphate mining rendered much of the islands of Banaba and Nauru uninhabitable.
Wars of the worlds
Occupation by Allied and Japanese troops during World War Two, and the vast scale of the conflict that followed, totally disfigured many of the islands of Melanesia and Micronesia. ‘Strategic’ military bases proliferated. After the war the US, Britain and France (with the ‘loss’ of Algeria in 1962) conducted nuclear tests in the Pacific atmosphere. The great lagoon of Kwajalein in the Marshall Islands became the target zone for missile tests launched from Vandenberg Space and Missile Center in California. Entire populations were removed from Bikini, Enewetak, Rongelap and Wotho atolls, and from Kwajalein and Noi Namur islands. The long-term effects of nuclear testing on ecosystems and human health remain. Since 1977 ‘burnships’ have been incinerating chemical weapons off Johnston Atoll.
For the first time the South Pacific has become vulnerable to global ‘anthropogenic’ (created by humans) climate change. Already, tropical storms have increased in frequency as sea-surface temperatures rise beyond the critical 28ÞC. Degradation by extractive industries has risen sharply with the application of large-scale industrial techniques. Local pollution from combustion engines, power stations, pesticides, fertilizers, plastics and domestic waste has also increased. The construction of roads, airports, causeways and hotels, together with the clearance of mangrove swamps, have all interfered with the fragile ecology of coastal strips and reefs.
The photograph on this page shows Daydream Island, Fiji.
Within the next 20 years it will disappear due to sealevel rise and global warming.
Patrick D Nunn, ‘Recent environmental changes on Pacific islands’, in The Geographical Journal, Vol 156, Part 2, July 1990;
Richard Nile and Christian Clerk, Cultural Atlas of Australia, New Zealand and the South Pacific, Andromeda, Abingdon, 1996;
Minority Rights Group, The Pacific: nuclear testing and minorities, London, 1991.