ANTARCTIC experts have warned there is a chance of a dramatic rise in sea level during the 21st century - which would have disastrous consequences for Bermuda.

The airport and many other low-lying areas of the island are likely to end up underwater if the nightmare scenario put forward by scientists becomes reality.

There is a one in 20 chance of a major disintegration of part of the Antarctic ice sheet leading to a global sea-level rise of 1.5 metres (around five feet) over the next century, according to a survey carried out jointly by the British Antarctic Survey and the Norwegian environmental safety organistaion, Det Norske Veritas.

Ocean levels rose by ten to 12 inches in the 20th century and scientists expect a further rise of 20 inches this century due to the effects of global warming - and that's even if the possible ice collapse does not take place.

The study was based on the stability of the massive Western Ice Sheet, which accounts for 13 per cent of the ice on the frozen continent.

The sheet is currently attached to rock, but scientists calculated there is a five per cent chance of it breaking free and disintegrating during the next century, releasing a flotilla of enormous icebergs into the ocean and gradually adding a metre to the sea level.

Bermuda Natural History Museum curator Dr. Wolfgang Sterrer said the implications for Bermuda would be serious.

"I would think that large areas would be flooded," said Dr. Sterrer. "The airport is the first large area that comes to mind. But many other areas would be flooded too.

"There will be other effects. With every increase in sea level, it means the ocean will reach much further inland whenever there is a hurricane. Erosion will be accelerated. Rising ocean temperatures will lead to more frequent and more severe hurricanes."

The rising sea level is already having dramatic effects on low-lying islands. Dr. Sterrer cited the example of the tiny Pacific island country of Tuvalu, midway between Hawaii and Australia. Two months ago, the 11,000 inhabitants of Tuvalu gave up their fight against rising sea level and decided to abandon their homeland.

Lowland flooding and saltwater intrusion into the water supply as well as rapid coastal erosion had left them with little choice.

Sea levels have risen and fallen over the millennia and Bermuda holds solid proof that sea levels were once much higher than they are now.

"At the Government Quarry, there is incontrovertible evidence that the sea level was once as high as 21 metres (70 feet) above the present level," said Dr. Sterrer. "This was about 420,000 years ago.

"We have found a beach and fossils of creatures like clams and barnacles." At that time, Bermuda would have been made up of a cluster of small, elevated areas protruding from the sea.

"During the Ice Age, the sea level was 120 metres lower," added Dr. Sterrer. "So we are now a lot nearer to highest than the lowest levels, which suggests we are in a warm period between ice ages.

"When the sea was at its lowest, you could have walked from here to North Rock."

Much of the earth's fresh water is frozen in the Antarctic ice and scientists believe the Western Ice Sheet is the most vulnerable to collapse, because part of it is attached to rock below sea level.

The Eastern Ice Sheet is considered much more stable because it sits on rock above sea level. The ice sheet is five kilometres thick in places.

Scientist David Vaughan, of the British Antarctic Survey, said: "You have to balance the likelihood against the severity of the impacts and in this case, even a five per cent chance of this happening is really damn serious."