"These days, the conversation is no longer about growth at all expense, but to have sustainable inclusive growth," says Koh. "ASEAN and East Asia need to ensure that we all grow as a region," she says, referring to the Association of Southeast Asian Nations.

But, says Renat Heuberger, CEO of South Pole Carbon, a social enterprise focused on environmental sustainability, Asia is also the biggest investor in the world in clean technology, which is seen as the best hope of reducing emissions.

"So in both problem and solution of climate change, Asia plays a very important role today," Heuberger says. "On one side, we see Asia exposed to climate change, especially the coastal areas. On the other side, the solution to climate change is in Asia, simply because this area is developing fast, a lot of cash is available, and it is possible to generate profit by solving climate change."

A new report by ratings agency Standard & Poor's said climate change -- and global warming in particular -- is the second most significant major trend likely to impact sovereign credit risk this century. And the impact is not likely to be positive. For example, Typhoon Haiyan, which hit the Philippines last year, was hugely destructive and had a direct impact on economic growth.

"We have taken a view that the size of devastation, while large in absolute terms, has not been sufficient to impact a rating overall," said S&P in the report. "However, assuming that extreme weather events are on the rise in terms of frequency and destruction, how this trend could feed through to our ratings on sovereign states bears consideration."

S&P considers three variables to determine the risk to individual economies posed by climate change: The population living in low-lying coastal areas, the share of agriculture in national GDP, and a vulnerability index.

And Asia is right in the crosshairs of this trend. The 20 most vulnerable nations to climate change are emerging markets and half of them are in Asia Pacific.

Countries like Vietnam, Bangladesh, Fiji, the Philippines, Papua New Guinea and Indonesia that rely heavily on agriculture and employment for growth have "weaker capacity to absorb the financial cost" of shifting or extreme weather events.

In East Asia, the climate has been getting warmer for five decades with mean temperatures expected to rise by almost 2 C or more by 2050 and almost 4 C by 2090. Countries in the region are adapting, says the ADB, and the question is how they are adapting and how much it costs to adapt.

East Asia can afford to adapt to the new climate reality but the bill is likely to be high, at about $23 billion per year for new infrastructure between 2010 and 2050, another $4.2 billion for coastal protection and $9.5 billion for changes in agricultural patterns such as more and newer irrigation systems or consumer subsidies to ensure food remains affordable.

All told, adaptation could cut 5.3 percent from annual GDP growth by 2100, says the ADB.

"Public authorities and civil organizations can contribute to such adaptation by collecting and disseminating information on the impacts of, and potential responses to, climate change," says the ADB. "The essence of planned adaptation is thinking ahead."

Policymakers need to push for a model of economic growth that limits carbon emissions and a more efficient use of resources. Carbon trading schemes are one approach in which countries like China, Japan and South Korea have made some progress.

Gordon Hughes, a professor of economics at the University of Edinburgh and one of the authors of last year's ADB report on climate change in East Asia, says: "Richer countries tend to make more efforts to respond to problems like climate change. Japan and South Korea are doing more than China."

The Philippines is further down the path of dealing with climate change, he adds. "The really important lesson is to invest more in protection like better buildings and castle defense. As countries like China and the Philippines get richer, they need to spend more on protection."

Regional cooperation is also key. Pooling emission targets can cut costs of meeting them by about a quarter. The reality is that climate change and its effects do not respect national borders.

Climate change has a wide impact, and can hit economic growth, the external performance of economies and public finances. And climate change is difficult to plan for because the impact is not even, but poorer and lower-rated countries are hit hardest. This, in turn, is likely to cause more global inequality.

"Rapidly urbanizing and energy-hungry Asia and the Pacific is on the way to becoming one of the world's major producers of greenhouse gas emissions, but it is also home to the largest number of climate-vulnerable people," says Michael Rattinger, a climate change specialist at the ADB's Regional and Sustainable Development Department.

"There is an urgent need to de-carbonize the economy while increasing climate resilience. It is not an exaggeration to say that the global battle against climate change will be won or lost in this region," Rattinger says.

The region must step up efforts to adapt to climate change, he says, as delaying will simply add to the cost. Governments are acting to reduce greenhouse gas emissions but the current targets of these plans are simply not enough.