The president of the Cop26 climate summit is warning getting a deal will be “tougher” than the 2015 Paris talks which resulted in a landmark accord.
The summit, which is being held in Glasgow from October 31, is the biggest climate conference since the Paris summit and is seen as crucial in setting worldwide emission targets to slow global warming.
Alok Sharma, the British minister in charge of the talks, says that getting nearly 200 countries to commit to the emission targets to limit global temperature rises to less than 1.5°C above pre-industrial levels is a daunting task.
“What we're trying to do here in Glasgow is actually really tough,” he told the Guardian on Saturday.
“It was brilliant what they did in Paris” but “a lot of the detailed rules were left for the future”, he added.
“It's like, we've got to the end of the exam paper and the most difficult questions are left and you're running out of time
“This is definitely harder than Paris on lots of levels.”
More than 120 world leaders and around 25,000 delegates are expected in Glasgow but China's President Xi Jinping and Russian leader Vladimir Putin have said they are not attending.
The Paris accord saw 197 nations agree to limit global heating to below 2°C but their nationally determined contributions (NDCs) – national plans drawn up to implement the deal – have been deemed inadequate.
Strengthening those plans will be a key part of negotiations.
“What we're potentially saying to countries is that if your NDC isn't good enough, you're going to have to come back to the table,” said Mr Sharma.
He called on the world's biggest emitter China to present its NDC.
“They signed up to the communique in July that we negotiated in Naples, that all the G20 would come up with enhanced NDCs before Cop26. I reminded them they needed to deliver on that,” he said.
UN chief Antonio Guterres said on Thursday that the current climate situation was “a one-way ticket for disaster” as he stressed the need to “avoid a failure” at Cop26.