Developed countries are not taking their commitment to generate $100 billion in climate finance seriously, experts meeting in the Thai capital said yesterday, possibly jeopardising the 2015 Paris accord.

The Bangkok talks precede a meeting in Katowice, Poland, in December, where government ministers will meet to agree on rules for the 2015 Paris accord. Senior U.N. officials said it is hoped a draft text for negotiation on the rule book will emerge by the end of the week.

Items on the agenda include a promise to raise $100 billion a year in climate finance, from both public and private sources, by 2020 to help developing countries tackle global warming. Discussion on the funding is being "blocked across the board" at the meeting by a group of rich nations led by the United States, said Harjeet Singh, a global climate lead at non-profit ActionAid.

"If they don't commit to real finance, it's all going to fall apart. Developing countries will not be able to implement their targets, which they have put forward in anticipation of the money," Singh told Reuters. "There is a big fear that the $100 billion target will not be met."