About 2,500 country delegates and observers have gathered in the Thai capital for the penultimate round of negotiations under the UN Framework Convention on Climate Change treaty (UNFCCC), before the UN Climate Change Conference in Copenhagen in December.
Yvo de Boer, UNFCCC Executive Secretary, said hundreds of billions of dollars would be needed annually, but the exact amount of money wealthy countries agree to provide would likely only be agreed at the last minute at Copenhagen.
"The challenge is to get money on the table to meet immediate needs and develop coping strategies. We can then use that to understand better how that figure will rise over time," De Boer told a regional UN briefing held at the sidelines of the talks on 29 September.
A lack of commitment
Delegates from developing nations lined up to complain about the lack of financing and support for adaptation, which would allow countries to implement plans and projects to cope with climate change.
"It is regrettable that no specific numbers have been put on the table for finance," said Ibrahim Mirghani Ibrahim, Sudanese chairman of the Group of 77 plus China, which broadly represents the developing world.
"Even worse, rich countries have shifted responsibility for adaptation on to developing countries themselves. The costs are eating into their mainstream national budgets," he said during the UNFCCC's opening session on 28 September.
The Sudanese government is already going ahead with pilot projects costing about US$300 million to examine ways of responding to an increase in temperature of about one degree centigrade that has brought with it drought, flash floods and increased malaria, officials said.
"Developed countries are not willing to pay but we cannot wait for them," Saadeldin Ibrahim Mohammed Izzeldin, Secretary-General of Sudan's Higher Council for Environment and Natural Resources, told IRIN.
"We will start and hopefully there will be participation from rich countries. We don't expect all the money to come from outside," he said.
India is already paying about 2 percent of its annual budget to combat the effects of climate change, Chandrashekar Dasgupta of the country's Energy and Resources Institute told IRIN.
"The focus of our response has to be adaptation. A traditional farmer lacks the knowledge, the information, the skills and the capital to adapt by bringing in drought-proofing measures such as drip-irrigation or switching crops, for example," he said.
According to preliminary findings from a global World Bank study released on 30 September in Bangkok and Washington, the costs of adaptation to climate change in developing countries are estimated at $75-$100 billion annually for 2010 to 2050.
Billed as the most in-depth analysis of the economics of adaptation to date, the study was financed by the Dutch, Swiss and British governments.
"The World Bank study makes plain that taking action in favour of adaptation now can result in future savings and reduce unacceptable risks," Bert Koenders, the Dutch Minister for Development Cooperation, said in a statement. "At this point, the costs this will entail can still be borne by the international community, to judge by the GDPs of rich countries, but for poor countries they are unacceptably high."
The European Commission earlier this month also estimated that by 2020, developing countries would likely face annual costs of around 100 billion euros ($145.8 billion) to mitigate greenhouse gas emissions and adapt to climate change impacts.
Oxfam and environmental group Greenpeace have said that at least 40 billion euros ($58.35 billion) will be needed annually for adaptation measures for developing countries by 2020.
"Developing countries, which are least responsible for emissions, are being hit with a very large adaptation bill," said Antonio Hill, senior climate policy adviser with Oxfam International.
He also said decision-making about how adaptation money is spent must be firmly lodged with developing countries, because they know best how to respond to the localized challenges they face.
However, countries such as the US, Canada and Australia are stalling over how the cash will be spent, he said.
"These tight-fisted governments see climate change finance as just another form of aid and that therefore poor countries should be accountable to them over how the money is spent," he said.
"But this is not aid money. And aid money is unpredictable; sometimes rich countries make pledges but the money never comes. So we are trying to make sure Copenhagen leads to predictable cash flows. These are real costs. It's not just money, it's human lives."