Low-lying and impoverished Asian coastal cities such as Dhaka, Manila and Jakarta are vulnerable to "brutal" damage from climate change without global action, environmental group WWF warned Thursday.
Energy consumption and greenhouse gas emissions must be curtailed in "mega-cities" where global warming will affect everything from national security to water availability, the influential campaign group said.
"Climate change is already shattering cities across developing Asia and will be even more brutal in the future," said Kim Carstensen, head of the WWF Global Climate Initiative.
"These cities are vulnerable and need urgent help to adapt, in order to protect the lives of millions of citizens, a massive amount of assets, and their large contributions to the national GDP (gross domestic product)."
Including their suburbs, Dhaka, Manila and Jakarta now have a combined population of about 49 million, according to WWF.
It said better-off cities such as Shanghai, Hong Kong, Kuala Lumpur and Singapore also faced varying degrees of risk from climate change, such as rising sea levels, excessive rain, flooding and heatwaves.
Hong Kong could see dramatically fewer cold days per year while dengue fever appears to be spreading to previously unaffected parts of Singapore, it noted.
"Asia is the most populous and arguably the most vulnerable continent in the world because of the high risk of climate impacts and relatively low adaptive capacity," the report said.
"Unfortunately, the full extent of climate change has likely not been fully realised," it said, noting that temperatures in Asia have risen by one to three degrees Centigrade (two to five degrees Fahrenheit) in the last 100 years.
WWF issued its report to coincide with a weekend summit here to be attended by US President Barack Obama, Chinese President Hu Jintao and other Asia-Pacific leaders.
The summit takes place three weeks before crucial talks on a new world climate pact open in Copenhagen on December 7.
WWF said that on a "vulnerability" scale going up to 10, Dhaka rated nine points, and Manila and Jakarta eight each.
"Leaders in hotspots of danger like Dhaka, Manila or Jakarta need urgent support from their counterparts in the industrialised world," Carstensen said.
"Effective near-term and long-term adaptation will depend on financial support, technology cooperation, and capacity-building," he said.
Calcutta and Phnom Penh received scores of seven each on the WWF danger scale, Ho Chi Minh City and Shanghai six each, Bangkok five, and Kuala Lumpur, Hong Kong and Singapore four each.
It urged the leaders of the Asia-Pacific Economic Cooperation (APEC) forum to use their summit to promote strategies to reduce carbon emissions across the 21-member organisation.
In a communique to be issued at the end of their annual meeting Sunday, the APEC leaders are expected to declare their support for a global deal at next month's Copenhagen climate gathering.
"We believe that global emissions will need to peak over the next few years, and be reduced to 50 percent below 1990 levels by 2050, recognising that the time-frame for peaking will be longer in developing countries," said a draft of the statement obtained by AFP.
China's Foreign Minister Yang Jiechi said Thursday that it would seek a "fair and reasonable" result at Copenhagen but reiterated that rich nations must bear most of the burden for redressing global warming.
The WWF report said that while they cause many of their own climate-related problems, Asia's big cities are also part of the solution.
It said "cities are hot spots of innovation and technology and have therefore traditionally been the places where many of the solutions to the world's problems have been developed."