New Zealand responded positively in the true Pacific way of helping one's neighbours, Australia on the other hand has slammed the door in our face

Paani Laupepa, Tuvalu official

And it has condemned Australia for refusing to follow New Zealand's example.

The exodus of Tuvaluans is likely to start in 2002, though the number of islanders who will leave each year has not yet been announced. The two governments expect the scheme to operate for the next 30 years or longer, possibly until 2050.

Tuvalu also asked Australia to help, but to no avail.

Paani Laupepa is assistant secretary of Tuvalu's Ministry of Natural Resources, Energy and Environment.

He told BBC News Online: "While New Zealand responded positively in the true Pacific way of helping one's neighbours, Australia on the other hand has slammed the door in our face.

"Its justification is to compare Tuvaluans with the asylum seekers trying to enter Australia illegally."

Tuvalu is a group of nine islands lying about half-way between Hawaii and Australia. It forms part of the archipelago known formerly as the Gilbert and Ellice Islands.

With a total land area of 26 sq km, and a population of a little over 10,000 people, it is one-tenth the size of Washington DC.

Wild weather

Tuvaluans are convinced that climate change is already a reality for them, and point to several problems they blame on rising global temperatures.

Paani Laupepa told BBC News Online: "We have coastal erosion, droughts, and in the last decade we have also experienced an unusually high level of tropical cyclones. Salt water intrusion is becoming a problem, and this has affected our traditional food crops.

"Perhaps the most pronounced effect of climate change that we are actually seeing is the flooding of low-lying areas. A couple of decades ago the flooding was not so bad as last year's, and to us living on the atolls, this is an increasing sign of the times."

And Mr Laupepa was bitterly critical of the US for abandoning the international agreement on how to tackle climate change, the Kyoto Protocol.

He told BBC News Online: "By refusing to ratify the protocol the US has effectively denied future generations of Tuvaluans their fundamental freedom to live where our ancestors have lived for thousands of years."

Rising tides

The Intergovernmental Panel on Climate Change (IPCC) says it expects global sea levels to rise by between 20 and 90 cm this century, and to rise further after that.

If it proves right, the consequences could be severe not only for island states like Tuvalu, but also for low-lying countries like Bangladesh, which is predicted to lose about 17% of its land to the sea.

The IPCC represents a broad scientific consensus on climate change. But some scientists say our understanding of climate processes is still far too rudimentary to be certain that a problem exists.

They argue that natural climate variability may explain what is happening, and that human activities may be making little or no difference.

A recent reassessment of historical tide-gauge data in the central Pacific found no acceleration in the rise in sea levels.

Pacific-wide sea levels were found to be rising at an average rate of about 0.8 millimetres per year. This trend has been measured using only those recording stations with hourly data stretching back more than 25 years.