UN climate talks tasked with curbing the threat of global warming are backsliding, delegates from both rich and developing nations said Friday at the close of a week-long session in Bonn.

Even as evidence mounts that deadly impacts are upon us, negotiators said, chances for a compromise deal under the 194-nation UN Framework Convention on Climate Change (UNFCC) are slipping away amid furious finger pointing.

"These negotiations have if anything gone backwards," said the EU's climate action commissioner Connie Hedegaard.

"This imbalance is not helpful and could seriously endanger the prospects of securing the successful outcome the world needs from the Cancun climate conference next December" in Mexico.

"At this pace the world will simply collectively miss the train," she warned.

Record global temperatures, forest fires in Russia, lethal floods in Pakistan "are all consistent with the kind of changes we could expect from climate change, and they will get worse if we don't act quickly," said US negotiator Jonathan Pershing.

"Unfortunately, what we have seen over and over this week is that some countries are walking back from the progress made in Copenhagen," he told journalists, referring to the 11th-hour accord hammered out at the climate summit in December.

The Copenhagen Accord enshrined the goal of capping the increase of global temperatures at 2.0 degree Celsius (3.6 degree Fahrenheit), but did not muster the commitments needed to attain it.

It also pledged long-term financing to the tune of 100 billion dollars a year to help poor countries green their economies and cope with climate change impacts, but without specifying where the money would come from.

Dessima Williams of Grenada, speaking for the 43-nation Association of Small Island States, said she was "greatly concerned" by the slow pace of the talks.