LONDON, Sept 8 (Reuters) - Britain"s Alok Sharma, president of this year"s United Nations COP26 climate change conference, said on Wednesday he had held constructive discussions with China in recent days ahead of the summit in November. The Glasgow summit is seen as a critical chance to win more ambitious country-by-country commitments on achieving net-zero carbon emissions by 2050 and keeping the global average temperature rise to well below 2 degrees Celsius this century. "I have had constructive discussions on my first visit to China in the COP26 role, but time is running out to prevent a climate catastrophe, and so the discussions I have had here are nothing short of crucial," Sharma said in a statement. China, the world"s biggest emitter of climate-warming greenhouse gas, is coming under pressure to announce more ambitious measures on coal production and consumption. "The choices that China makes, on their energy mix, and on coal specifically, will shape our shared future ... The question that remains is how fast they put these into action, along with other major emitters," Sharma said. The British summary of Sharma"s trip to Tianjin to meet Chinese climate envoy Xie Zhenhua did not set out any new agreements reached during the talks, but said the two discussed China"s commitment to achieve carbon neutrality by 2060, peak emissions before 2030 and reduce its use of coal. "I look forward to more detailed plans being published setting out how China’s targets will be met," Sharma said. They also discussed opportunities for China to go further in areas like renewable energy and zero emission vehicles, the British statement said.