After years of fruitless appeals for decisive action on climate change, the tiny South Pacific nation of Kiribati has concluded that it is doomed. Yesterday its President, Anote Tong, used World Environment Day to request international help to evacuate his country before it disappears.

Water supplies are being contaminated by the encroaching salt water, Mr Tong said, and crops destroyed. Beachside communities have been moved inland. But Kiribati – 33 coral atolls sprinkled across two million square miles of ocean – has limited scope to adapt. Its highest land is barely 6 feet above sea level.

Speaking in New Zealand, Mr Tong said i-Kiribati, as his countrymen are known, had no option but to leave. "We may be beyond redemption," he said. "We may be at the point of no return, where the emissions in the atmosphere will carry on contributing to climate change, to produce a sea level change so in time our small, low-lying islands will be submerged."

President Tong, a London School of Economics graduate, said emigration needed to start immediately: "We don't want to believe this, and our people don't want to believe this. It gives us a deep sense of frustration. What do we do?"

Kiribati – a former British colony called the Gilbert Islands – is home to 97,000 people, most of them squeezed into the densely populated main atoll, Tarawa, a chain of islets surrounding a central lagoon. Along with other low-lying Pacific island nations such as Tuvalu, the Marshall Islands and Vanuatu, it is regarded as one of the places most vulnerable to climate change.

Erosion, caused partly by flooding and storms, is a serious problem in Kiribati, which straddles the Equator and International Dateline. Most of the land is as flat as a table. "We have to find the next highest spot," said Mr Tong. "At the moment there's only the coconut trees." But even the coconut trees are dying – casualties of an unprecedented drought. The country has had next to no rain for the past three years and meanwhile the freshwater table is being poisoned.

Mr Tong was in New Zealand – which was chosen to host the UN's World Environment Day after committing itself to becoming carbon neutral – for talks with Helen Clark, the Prime Minister, whom he hopes to persuade to resettle many of his people. But he also appealed to other countries to help relocate i-Kiribati.

Achim Steiner, executive director of the UN Environment Programme, said of Kiribati's plight: "It's a humbling prospect when a nation has to begin talking about its own demise, not because of some inevitable natural disaster... but because of what we are doing on this planet." The world must find the "collective purpose" to combat climate change, Mr Steiner said. "Unless everyone... on this planet takes their responsibility seriously, we will simply not make a difference."

New Zealand already has a substantial population of Pacific Islanders, but absorbing another 97,000 would strain its generosity. Besides, that is just Kiribati. A report by Australian government scientists in 2006 warned of a flood of environmental refugees across the Asia-Pacific region. New Zealand is already experiencing significantly increased levels of migration from affected countries.

President Tong said he was accustomed to hearing national leaders argue that measures to combat climate change would jeopardise their economic development. But he pointed out that for Kiribati "it's not an issue of economic growth, it's an issue of human survival". And while scientists were still debating the degree to which the seas were rising, and the cause of it, he said, the changes were obvious in his country.

"I am not a scientist, but what I know is that things are happening we did not experience in the past... Every second week, when we get the high tides, there's always reports of erosion." Villages that had occupied the same spot for up to a century had had to be relocated. "We're doing it now... it's that urgent," he said. "Where they have been living over the past few decades is no longer there. It is being eroded."

The worst case scenario suggested that Kiribati would become uninhabitable within 50 to 60 years, Mr Tong said. "I've appealed to the international community that we need to address this challenge. It's a challenge for the whole global community."

Leading industrialised nations pledged last month to cut their carbon emissions by half by 2050. But they stopped short of setting firm targets for 2020, which many scientists argue is crucial if the planet is to be saved. For Kiribati, it may already be too late.

(By Kathy Marks, The Independent, 06/06/2008)