0655 GMT February 29, 2020
Experts from around the world wrapped up discussions in Bangkok geared towards creating a comprehensive rulebook for countries to implement the landmark Paris Agreement on climate change, AFP reported.
But talks foundered over the key issue of how efforts to limit climate change are funded and how contributions are reported.
Delegates representing some of Earth's poorest and smallest nations said on the final day of the summit that the US and other Western economies had failed to live up to their green spending commitments.
"Developed countries are responsible for the vast majority of historic emissions, and many became remarkably wealthy burning fossil fuels," said Amjad Abdulla, the head of a negotiating bloc of small island states.
"Yet, we face devastating climate impacts and some of us could be lost forever to rising seas" without progress on the Paris deal by the end of the year, he added.
The Paris deal, struck in 2015, aims to limit global temperature rises to less than two degrees Celsius and to below 1.5 degrees if possible by the end of the century.
To do this, countries agreed to a set of promises, including to establish an annual $100-billion fund to help developing nations react to our heating planet.
But the details of the final rulebook are subject to intense debate.
The US and other developed economies want less oversight on how their funding is gathered and more flexibility over how future finance is structured.
But developing nations insist they need predictable and open funding in order to effectively plan their fight against the fallout from climate change.
A senior climate negotiator, who spoke on condition of anonymity, told AFP Sunday that the US and rich nations were asking poorer ones to trust them to self-regulate climate financing.
"We want to do our bit, but how can we trust them? Show us the money," the negotiator said.
Delegates ended talks Sunday with an agreement to hand over technical discussions to a panel of experts, who will continue to meet before a summit kicks off in Katowice, Poland, at the start of December.
Patricia Espinosa, the UN's climate change secretary, told reporters progress had been made in Bangkok "on most issues" but that "no issues have been fully resolved yet".
Paris deal 'on brink'
The Bangkok talks were organized as an emergency negotiating session after little progress was made at previous rounds towards a final rulebook.
Under the timeframe set in Paris, the guidelines for nations must be finalized by the end of 2018.
While delegates made some headway on areas such as new technology and carbon markets, activists said the US – with Western acquiescence –had stonewalled any momentum on the key funding issue.
Harjeet Singh, global lead on climate change for NGO ActionAid, said Sunday the Paris deal was "on the brink".
"Developed countries are going back on their word and refusing to agree clear rules governing climate finance," he told reporters.
"If they remain stuck in their positions and fail to loosen their purses, this treaty may collapse."
The US under President Donald Trump will leave the Paris process in 2020, but multiple delegates in Bangkok told AFP that it was still actively hindering progress in talks.
One senior negotiator said the US was "poisoning" the atmosphere of trust that led to the Paris accord.
Activists also called out the European Union, Britain and Australia for falling into line with Washington's position.
Alden Meyer, director of strategy and policy at the Union of Concerned Scientists, said the rate of climate change was rapidly outstripping the political effort to curb it.
"As this summer's devastating wave of heat waves, wildfires, floods, and other extreme weather events across the world makes abundantly clear, the Earth's climate system is unimpressed by politicians' rhetoric."