"We are fighting a giant," he told Reuters during the Earth Summit in Johannesburg of a plan to take on the United States, the outline of which was unveiled in March.

"It is one of the few options we have."

He said he was lobbying other low-lying nations at the World Summit on Sustainable Development join it in lawsuits.

"In the corridors in this conference there are a number of people who have indicated support," he said. "Apart from Pacific islands there are some from the Indian Ocean and the Caribbean."

Australia and the United States, the biggest world polluter, have rejected the Kyoto pact meant to restrict emissions of gases like carbon dioxide which are blamed for blanketing the planet and driving up temperatures.

Higher temperatures could melt the polar icecaps and raise sea levels worldwide, swamping nations like Tuvalu, which is one of the world's smallest states with about 10,000 inhabitants on an area of 27 square kilometres (10 square miles).

SALT SOURS FARMLAND

Paeniu said that sea levels had so far not risen around Tuvalu's palm-fringed islands but that storms seemed to be becoming more fierce, spraying damaging sea salt onto farmland.

Tuvalu produces rice, breadfruit, bananas and taro, a type of starch-rich root vegetable. Its people also rely on fishing.

"Just before coming here to South Africa was the first time I was scared. I saw waves coming right over the land," he said.

"People in some areas were wading up to their thighs."

"I wouldn't rule out people leaving," he said. "But we are not encouraging people to leave because of climate change.

"It's our land. It's where we live."

President George W. Bush argued that Kyoto would be too expensive for the U.S. economy and unfair because it excluded developing nations. Australia has also refused to sign up to the pact under which developed states must cut their gas emissions.

Washington says that natural shifts are boosting temperatures and that no amount of restrictions on human use of fossil fuels, like coal, oil or natural gas, could save Tuvalu.

Paeniu said Tuvalu was not targeting nations like the European Union or Japan because they accepted Kyoto.

He said that Tuvalu could not consider following the Dutch example in building dykes around low-lying land to keep out the sea: "It's one idea," he said. "But how would we afford them?"