China's president Xi Jinping is yet to confirm his attendance at a major climate conference in Glasgow later this year as fears grow about the outcome of COP26.
World leaders will descend on Scotland's biggest city at the start of November for a crucial summit on the future of the planet.
The world's largest CO2 emitter China is under pressure to slow down its coal production across the country as leaders look to move to cleaner sources of energy.
COP26 President Alok Sharma has said he is "very, very hopeful" that China will send a negotiating team to the international climate change talks in Glasgow.
President Xi has yet to confirm he will attend the gathering which takes place between November 1 and 12, however Sharma told the BBC's The Andrew Marr Show: "I am very, very hopeful that we will have a delegation from China that is coming.
"President Xi Jinping would come for the world leaders' conference which is the first two days of Cop. But of course we want China there as part of the negotiations.
"I do feel that they will come for that. I certainly expect that China will send a negotiating team to Glasgow."
Sharma, who is this week flying with Boris Johnson to New York for the United Nations General Assembly in New York, acknowledged China will have to be a "key" part of any agreement.
He said: "There is no doubt that China is going to be part of the key to all of this. They are the biggest emitter in the world.
"What President Xi Jinping has said is that they are going to strictly restrict the use of coal in this next five-year period, from 2026 they are going to phase down.
"But we want to see the detail of that. That is what we are pressing them.
"They have said to me they want the COP26 to be a success.
"The ball is in their court. We want them to come forward and make it a success together with the rest of the world."
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