The ADB report -- "Economics of Climate Change in the Pacific" -- focuses on 14 developing Pacific nations: the Cook Islands, Fiji, Kiribati, Republic of the Marshall Islands, the Federated States of Micronesia, Nauru, Palau, Papua New Guinea, Samoa, Solomon Islands, Timor-Leste, Tonga, Tuvalu and Vanuatu.
The bank says most of the countries will see average annual temperatures rise by 3.24 degrees Fahrenheit by 2050.
"If the world were to stay on the current fossil-fuel intensive growth model -- the business-as-usual scenario -- total climate change cost in the Pacific is estimated to reach 12.7 percent of annual gross domestic product equivalent by 2100," the ADB report, released Tuesday, states.
Of the 14 nations studied, Papua New Guinea, or PNG, would suffer the worst economically, with climate change triggering a loss of as much as 15.2 percent of its GDP by 2100. The bank predicts Timor-Leste's GDP to drop by up to 10 percent, followed by Vanuatu at 6.2 percent, Solomon Islands at 4.7 percent, Fiji at 4.0 percent and Samoa at 3.8 percent.
In the meantime, the report says, the region will need $447 million every year until 2050 to prepare for worst-case scenarios caused by climate change.
"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, in a release. "Our findings show that if not adequately addressed, climate change could overturn the region's development achievements."
The study includes assessments of potential impacts on agriculture, fisheries and tourism.
For example, sweet potato crops in Papua New Guinea and the Solomons could fall by 50 percent by 2050. The study predicts catches of skipjack tuna for the western Pacific will decline by an average of more than 20 percent, and for PNG by as much as 30 percent.
Total international tourist arrivals in the region more than doubled from a half million visitors to approximately 1.3 million between 1990 and 2011, but the study estimates the impact of climate change would reduce tourism revenues by 27 to 34 percent by the end of the century.
"By making climate change adaptation truly integral to their policy-making and decision-making
processes, the Pacific island-nations could plan against the adverse impacts of climate change and
continue their efforts to achieve poverty eradication and sustainable development for the region," the report says.