MANILA -- Climate change could cause countries in the Pacific region to lose as much as 12.7 percent of their gross domestic product (GDP), the Asian Development Bank ( ADB) said Tuesday.

In its latest report titled "Economics of Climate Change in the Pacific," the Manila-based lender said the most significant losses would be felt in Papua New Guinea where climate change could trigger a loss of up to 15.2 percent of its GDP by 2100.

ADB also projected that the change in climate could reduce Timor Leste's GDP by 10 percent, Vanuatu by 6.2 percent, Solomon Islands by 4.7 percent, Fiji by 4 percent and Samoa by 3.8 percent.

"It is critical that countries contributing to the problem of climate change step up to assist Pacific friends and neighbors in the fight to protect their countries against natural disasters, crop losses, and forced migration," said Xianbin Yao, director general of ADB's Pacific Department.

Under a "medium emissions scenario," the ADB report noted that Fiji, Papua New Guinea, Samoa, Solomon Islands, Timor-Leste, and Vanuatu could see temperatures rise by 2 to 3 degrees Celcius by 2070.

This could lead to significant decreases in rain-fed agriculture, reduced fish catches, widespread coral bleaching, and lower tourism numbers.

ADB said the negative effect on agriculture contributes to most of the total economic cost of climate change in the Pacific. It estimates that the Pacific region could require $447 million until 2050, and up to $775 million or 2.5 percent of GDP per year to prepare for the worst scenario.

The report urged policy lenders to take action to mainstream climate change mitigation into development planning and develop forward-looking adaptation strategies. It recommended the "climate- proofing" of infrastructure to improve the capability of Pacific countries to deal with climate change on their own.

ADB also said Pacific countries will need "dramatically improved" access to global and regional climate change funds.