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Disputes over when rich and poor nations will set greenhouse gas targets and over climate aid to the developing world threatened to sink UN climate talks on the final day on Friday.
Negotiators from around 195 countries are working to lay the foundations for a new global climate accord that is due to be agreed in 2015 in Paris, and come into force after 2020, but few concrete steps have emerged from two weeks of talks in Warsaw.
"The Warsaw talks, which should have been an important step forward ... are now on the verge of delivering virtually nothing," said China's lead climate negotiator Su Wei.
Around 800 representatives from 13 non-governmental organisations walked out of the talks on Thursday, exasperated at the lack of progress at the meeting, which is likely to run overnight into Saturday.
It was hoped the conference would at least produce a timetable to ensure ambitious emissions cut targets and climate finance pledges are set in time for Paris. But the selection and wording of issues has been politically sensitive.
Rich countries want to emphasise future emission targets for all, while developing nations say industrialised nations must lead in setting targets and foot most of the bill because they have historically accounted for most emissions.
French Development Minister Pascal Canfin said all should submit initial targets for emissions beyond 2020 by early 2015.
"Warsaw will have been a good launch pad for Paris if each state goes away with the principle of putting commitments with numbers on the table ... by the beginning of 2015 at the latest," he said.
The talks have also been sharply divided over aid. Developed nations agreed in 2009 to raise climate aid to $100 billion a year from 2020 from an annual $10 billion for 2010-12.
Hit by economic slowdown, rich countries are now more focused on their own economies and are resisting calls to firm up plans for raising aid from 2013 to 2019.
More urgency
Scientists say warming is causing more heatwaves, droughts, and could mean more powerful storms. The death toll from Typhoon Haiyan in the Philippines has risen to more than 4,000.
A U.N. panel of climate scientists said in September "sustained and substantial" cuts in greenhouse gases are needed to achieve a U.N. goal of limiting warming to less than 2 degrees Celsius (3.6 Fahrenheit) above pre-industrial times - widely seen as a threshold for dangerous change.
U.N. Secretary-General Ban Ki-moon urged world leaders on Thursday to make "bold pledges" for emissions cuts by a summit he will host on September 23 next year but acknowledged many nations would be late.
Many developing nations want that to be a deadline for rich nations to outline initial emissions cuts beyond 2020 but the United States has said it will unveil its plans in early 2015.
A draft document issued on Friday, which still has to be approved by parties, suggested a draft negotiating text be ready at the latest by December 2014 climate talks in Lima, Peru.
Developing nations are also pushing for a new mechanism to deal with loss and damage related to climate change, but developed countries do not want a new institution, fearing that it could pave the way for huge financial claims.
