Lima: UN climate talks went deep into overtime on Friday as negotiators struggled to break a deadlock between rich and developing nations on the underpinnings of a world carbon-cutting pact.
A years-old dispute over sharing responsibility for curbing greenhouse gases saw the 12-day negotiations enter a familiar phase of poker-like holdout, darkening prospects for the ambitious environmental accord.
Hours after the scheduled close of the session, officials and ministers were engaged in frantic haggling over a draft outlining a variety of country approaches -- trying to whittle it down to a consensus text.
"We are almost there. We need to make just a final effort," Peruvian Environment Minister Manuel Pulgar-Vidal pleaded with negotiators.
"We need to take political decisions."
Countries disagree on how a principle called "differentiation" will apply in a process next year of declaring national pledges for curbing Earth-warming fossil fuel emissions.
Developing nations insist the West must bear a bigger burden for the carbon cuts, having started decades earlier to pollute their way to prosperity.
But rich countries point the finger at developing giants like China and India furiously burning coal to power their rapid growth.
Developing nations further demand that pledges incorporate not only action on reducing carbon emissions, but also financial help and adaptation aid to shore up their climate defenses.
A format for the pledges must be agreed in the Peruvian capital to allow countries to start their submissions from the first quarter of next year.
They will be at the core of a global climate pact that nations have agreed to sign in Paris in December 2015, to enter into effect by 2020, seeking to limit average global warming to two degrees Celsius (3.6 degrees Fahrenheit) over pre-Industrial Revolution levels.Campaigners in Lima said they feared a weak-willed compromise.
"The latest text which countries are working on has been stripped down to its bare bones to accommodate the whims of the lowest common denominator," said Christian Aid`s Mohamed Adow.
"Right now we are facing the prospect of being no further forward than we were when we left last year`s meeting in Warsaw."
Green group WWF, also observing the annual negotiations round, said the new draft "contains a mixed bag of options."
"It`s crunch time for negotiators here in Lima and everything is still up in the air," WWF said.
The goal of the pact was set down in Durban in 2011, but negotiations on its scope and scale have been a minefield.
"Some key elements fell to the cutting room floor and are not in the text at all," Union of Concerned Scientists analyst Alden Meyer said of the latest draft.
Dropped text included language on absolute, economy-wide mitigation targets for developed countries.
The current range of options on key points "go from weak or minimal, to barely acceptable, to OK," said Meyer.
And he predicted differentiation would remain a tough issue, having been "pretty much scrubbed out of most of the text."
"That may not be acceptable to some" developing countries, he said.
Another major blocking point is whether or not to have a process to assess the pledges` global impact on the two degrees goal -- with China a key opponent.
Pope Francis also weighed in on the debate, saying in a letter to Pulgar-Vidal that "time to find global solutions is running out."
"We can only find adequate solutions if we act together," the Pope said in a message Thursday.
There was a "moral imperative to act," he said. Climate change "affects all of humanity, in particular the poorest, and future generations."
Scientists say two degree Celsius warming is relatively safe but still no guarantee against damage to the climate system.
On current carbon trends, the planet is on course for around four degrees Celsius warming this century, dooming future generations to a planet of worsening drought, flood, storm and rising seas, they say.