Negotiators in Glasgow are poring over a new draft agreement aimed at averting the worst impacts of climate change.
The COP26 talks were due to finish on Friday, but sticking points – especially on fossil fuels and on financial help to poorer nations – mean they have overrun.
Key language on phasing out coal use has been kept in the latest text.
But it remains unclear if the draft will lead to a deal later on Saturday – or to further negotiations.
Scientists say that limiting temperature rise to 1.5C compared to pre-industrial levels will protect us from the most dangerous impacts of climate change. It is a key part of the 2015 Paris agreement that most countries signed up to.
Meeting the goal requires global emissions to be cut by 45% by 2030 and to zero overall by 2050. One example of the impact of global temperature rise above 2C is the death of virtually all tropical coral reefs, scientists say.
The new version of the agreement released on Saturday continues to refer to “accelerating efforts towards phase-out of unabated coal power and inefficient fossil fuel subsidies” – watered-down commitments that have been criticised by campaigners , even though some observers underlined that it is the first time coal is explicitly mentioned in UN documents of this type.
China and Saudi Arabia are said to be among a group of countries seeking to remove references to fossil fuel subsidies.
Speaking from London, UK Prime Minister Boris Johnson said rich countries must put more “cash on the table” to help the developing world move away from fossil fuels.
Former Prime Minister Tony Blair told the BBC’s Newscast podcast it would be Mr Johnson’s responsibility “to get the thing over the line at the end”, something he said would be “tough to do… when most of the [other] political leaders have gone”.
