Fate of Paris accord hangs in balance as UN talks go down to wire

Observers said delegates were struggling to resolve the question of whether big emitters will signal their intent to raise their emissions-cutting targets next year

Big polluting countries faced last-ditch pressure from smaller nations to show serious commitment to fighting climate change as negotiators battled into the early hours of Saturday to salvage a result from a fraught UN summit in Madrid.

With the two-week gathering mired in interlocking disputes over how to implement the 2015 Paris Agreement on global warming, Chile, presiding over the talks, had earlier attempted to inject a note of optimism.

"Today is the day when we must show the world that we are capable of delivering the agreements that are needed to tackle the unprecedented challenge before us," Andrés Landerretche, a Chilean