Papua New Guinea's Carteret islanders are destined to become some of the world's first climate change refugees. Their islands are becoming uninhabitable, and may disappear below the waves.

A decision has been made to move the islanders to the larger nearby Bougainville island, four hours' boat ride to the southwest. Ten families at a time will be moved, over one to two years, once funds are allocated for the resettlement programme.

"It's a pretty hard life out there on the islands. Some of the homes have been washed away," Joe Kaipu, the senior district co-ordinator of Bougainville, told Reuters by telephone.

"The only action now is to resettle them," he said.

A United Nations panel of more than 2,000 scientists has predicted that average sea levels are likely to rise between 9 and 88 cm (3.5 to 35 inches) by 2100, mainly because of a build-up of heat-trapping greenhouse gases in the atmosphere from the burning of fossil fuels, such as oil and coal.

Sea levels are expected to rise because of a melting of ice caps and because water expands when it warms. If the entire Greenland ice sheet melted in coming centuries, for instance, sea levels would rise by seven metres.

Many scientists say a 50 cm rise in sea levels could cause a 50 metre retreat of the coastline in low-lying areas.

At the higher end of the forecast, the sea would overflow the heavily populated coasts of countries such as Bangladesh, and cause low-lying island states like the Indian Ocean's Maldives and South Pacific's Kiribati and Tuvalu to disappear.

SINKING ISLANDS

"It's a matter of survival for us. If our islands go under, we all go under," said President Anote Tong of Kiribati, 33 low-lying islands covering 5 million sq km (1.9 million sq mile) in the South Pacific and home to about 100,000 people.

"We move back from the shoreline, (but) how far can we move back? We are in danger of falling off the backside of our islands," Tong told Reuters at a recent Pacific leaders' summit in Port Moresby, capital of Papua New Guinea.

Kiribati's highest point is 87 metres (261 ft) above the sea. Most islands are coral atolls covered with just 2.5 metres (just over 8 ft) of hard sand and meagre soil. There are no rivers and most islands enclose a lagoon.

Two uninhabited Kiribati islands, Tebua Tarawa and Abanuea, disappeared underwater in 1999, according to the South Pacific Regional Environment Programme, and the island of Tepuka Savilivili no longer has any coconut trees due to salination.

Tong said the world's big polluters, like the United States and Australia who have remained outside the United Nations' Kyoto Protocol on reducing greenhouse gases, must face the moral consequences of their inaction.

"That is a question that they have to ask themselves -- are they willing to see us go under?" Tong said.

The United States pulled out of Kyoto in 2001 when President George W. Bush said it was too expensive and wrongly excluded poor nations from the first round of cuts to 2012. Australia has also refused to ratify the protocol.

ENVIRONMENTAL REFUGEES

Scientists say rising sea levels would also foul freshwater supplies for millions of people and spur mass migrations.

A recent UN study forecast that some 50 million people could became environmental refugees by 2010, driven from their homes by desertification, rising sea levels, flooding and storms linked to climate change.

Tuvalu Prime Minister Maatia Toafa hates the term "environmental refugee" but admits his 11,600 people may have to abandon their South Pacific island homes.