Study says Warming Poses Peril to Asia

With diminished rice harvests, seawater seeping into aquifers and islands vanishing into rising oceans, Southeast Asia will be among the regions worst affected by global warming, according to a report scheduled for release on Monday by the Asian Development Bank.

The rise in sea levels may force the sprawling archipelago of Indonesia to redraw its sea boundaries, the report said.

All these changes will occur progressively over the next century, the bank estimated, giving countries time to improve their flood control systems, upgrade their irrigation networks and take measures to prevent forest fires, which the report predicts will become more common.

“Our modeling shows that sea levels will rise up to 70 centimeters,” or about 28 inches, said Juzhong Zhuang, an economist at the bank and one of the authors of the report. “That will force the relocation of many millions of people.”

Brackish water seeping into the water table in Jakarta, Indonesia, and the rice paddies of the Mekong Delta in Vietnam is already a growing problem, the report says.

Some of the 92 outermost small islands that serve as a baseline for the claims of coastal waters by Indonesia could disappear, according to the report.

The margin of error of such complex projections so far into the future remains a nagging question but the report’s conclusions are nonetheless sobering for Southeast Asian nations, which have a combined population of more than 563 million.

The report focuses on Indonesia, the Philippines, Thailand, Singapore and Vietnam.

A projected one foot rise in sea levels in the Philippines by 2045 would flood about 5,000 acres, affecting 500,000 people, the report says. Under another sequence of events, sea levels could rise 39 inches by 2080, affecting 2.5 million people in the Manila Bay area.

The authors of the report urged governments to build infrastructure adapted to climate change, arguing that the current economic crisis was not incompatible with combating and adapting to global warming.

“The investment in climate change adaptation can serve as an effective fiscal stimulus,” said Tae Yong Jung, another author of the report.

Southeast Asia is particularly vulnerable to global warming because of the number of people who live near coastlines and the high rate of poverty. About 19 percent of those in Southeast Asian, some 93 million people, live on less than $1.25 a day and are more vulnerable to the projected increase in typhoons, drought and floods.

The region also has a high percentage of agricultural workers, more than 40 percent of the population, who would face a decline in the production of rubber, rice, corn and other crops because of extreme weather, the report said.

The number of fish in the oceans is also likely to decline because of changes in currents caused by a warmer atmosphere.

In cities like Manila, Bangkok and Jakarta, which are already stiflingly hot for several months of the year, average temperatures in 2100 could be nine degrees hotter, the report says, using data from the Intergovernmental Panel on Climate Change.

“If that’s the case, the cities will be like an oven,” Mr. Zhuang said.