Rising water temperatures, sea levels and acidity are threatening to destroy the vast region of Southeast Asia known as the Coral Triangle, labelled the ocean's answer to the Amazon rainforest, the WWF said in a new report.

Collapse of the reefs would send food production in the region plummeting by 80 percent and imperil the livelihoods of over 100 million people.

With too little action on climate change, "you get a world in which you have perhaps tens of millions of people homeless by the inundation of coastlines through rapid sea level rises," report lead author Ove Hoegh-Guldberg said.

"You see the erosion of food security and you see a world by the end of this century which is, I think, pretty much a nightmare."

WWF Coral Triangle Initiative Network head Lida Pet Soede said the seas in the triangle -- bordered by East Timor, Indonesia, Malaysia, Papua New Guinea, the Philippines and the Solomon Islands -- were vital sources of biodiversity.

"Some of the locations in the Coral Triangle are really important areas for all sorts of fish. The migration of tuna and turtles that spawn in the Coral Triangle are not going to have a next generation," she told AFP.

Saving the Coral Triangle will require countries to commit to deep cuts in greenhouse gas emissions.

Heat-trapping carbon gases -- notably from burning fossil fuels like coal, oil and gas -- are blamed for warming Earth's atmosphere and driving changes to weather patterns, as well as creating acidic seas hostile to much marine life.

The warnings come ahead of tough negotiations over a successor agreement to the Kyoto Protocol in the Danish capital Copenhagen in December.

Emissions cuts of 80 percent below 1990 levels by 2050 will be needed to avert the worst effects on the region, home to more than half the world's coral reefs and a linchpin for ocean life, the WWF said.

Local communities and governments will also have to curb over-fishing and pollution, the report said.

"If you continue down the path of the over-exploitation of resources, even if you get an incredible reduction in emissions, there will still be a threat," WWF climate campaigner Richard Leck said.

The report was released as ministers and officials from over 70 countries meet in the Indonesian city of Manado for the World Ocean Conference, the first global meeting on the relationship between oceans and climate change.

Delegates say delays over past years in dealing with climate change mean the Earth could face a series of "tipping points" that could trigger irreversible melting of sea ice and cripple the ocean's ability to absorb carbon from the atmosphere.

"It is clear that the oceans perform a very important climatic regulation function and if that is ... disturbed further then all of humanity is likely to be affected by that," United Nations Environment Programme deputy head Angela Cropper said.

"Time is not a luxury many of the world's islands and coastal communities have. At stake are millions of island and coastal peoples from the Arctic to the tropics," US-based University of Delaware marine scientist Biliana Cicin-Sain said.

"The current global economic crisis should not take attention away from dealing with climate change and from maintaining the unique role of the oceans in sustaining life on Earth."

Nations at the conference hope to pass a joint declaration aimed at influencing the direction of the Copenhagen talks.

A meeting Friday will also see leaders from the six Coral Triangle nations pass a joint plan on conserving the region.

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