A draft agreement at the COP26 climate summit has watered down commitments to end the use of coal and other fossil fuels, as countries race to reach a deal after two weeks of talks.
While the language around fossil fuels has been softened, the inclusion of the commitment in a final deal would be seen as a landmark moment.
A deal must be agreed upon by the end of the summit, which is in its final hours.
The UN meeting is seen as crucial for limiting the effects of global warming.
The draft agreement, which was published early on Friday following all-night talks, also asks for much tighter deadlines for governments to reveal their plans to reduce greenhouse gas emissions.
And it also strengthens support for poorer countries fighting climate change.
Negotiations over a final deal could stretch late into Friday, or potentially even longer.
Scientists say that limiting warming 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 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.