Tuvalu Prime Minister Saufatu Sopoanga urged industrialized nations Wednesday to cut greenhouse-gas emissions as soon as possible by shifting to renewable energy sources, fearing his island nation will sink if global warming continues.

"Particularly for us, (global warming) is a matter of life and death," Sopoanga told reporters at a Tokyo Hotel.

Tuvalu, consisting of nine small islands in the South Pacific, is one of the first casualties of climate change.

Global warming, which is believed caused by greenhouse gas emissions, is raising sea levels, which in turn are poisoning the country's soil and threatening to drown it.

Although world scientists are divided over how fast sea levels are rising in the Pacific, Sopoanga, 51, said an analysis presented by Australian scientists shows an average annual rise of 1 cm.

If this is true, Tuvalu islanders have 300 to 400 years before their homeland sinks into the sea, Sopoanga said.

By rendering ground soil infertile, rising sea levels have already taken a toll on the country's main agricultural crop, taro, a main staple of the Tuvalu people.

Over the last 25 years, 2,000 people have migrated from Tuvalu to other neighboring countries, including Australia and New Zealand, Sopoanga said. This is a huge loss for a country with a population of just over 10,000.

Sopoanga said his government does not want to see people leaving Tuvalu, saying they need to protect their homeland as well as preserve their sovereignty, culture and tradition.

Commenting on the 1997 Kyoto Protocol to curb global warming, which has yet to come into force six years after its adoption, he said, "We, the small island countries, are discouraged that it is taking such a long time."

Sopoanga was on a seven-day trip to Japan to discuss bilateral ties with Prime Minister Junichiro Koizumi.