COP28 the closing act for Xie Zhenhua in a role he had played since 2007. Hou Liqiang reports.

Xie Zhenhua was like a COP28 superstar, often finding himself surrounded by a crowd at the United Nations climate change conference in Dubai, United Arab Emirates.

People greeted the veteran Chinese climate diplomat everywhere he went, and he would respond with a smile, nodding his head.

The 74-year-old was busy. Aside from participating in the COP28 agenda's many multilateral conferences, he also addressed many sessions at the China pavilion and elsewhere.

Xie also made full use of the gaps between those events to engage in bilateral meetings. He tried to move quickly from one event to another, despite having had slightly limited mobility for many years.

At a news conference in Dubai, Xie described COP28 as the "most difficult COP" he had participated in since he began to steer China's climate diplomacy in 2007.

Every single minute of Xie's time at each COP had been scheduled, people close to him said when explaining why he was so popular at home and abroad.

The gray-haired veteran might now be able to enjoy a well-earned rest, with the Ministry of Ecology and Environment announcing on Jan 12 that Xie had stepped down from his position as China's special envoy for climate change for health reasons.

Liu Zhenmin, a former vice-minister of foreign affairs, has been appointed as his successor.

Jia Feng, former head of the Center for Environmental Education and Communications affiliated with the Ministry of Ecology and Environment, said of Xie that it would be difficult to find another person who had led negotiations on one topic for so many years in Chinese diplomatic history, and especially in environmental diplomacy.

"It seems that everybody knows him once he enters a conference room, no matter where it is," Jia said.

After graduating from Peking University in 1988, Jia joined the national environmental watchdog's department for institutional reform and human resources, which was headed by Xie, and worked directly under him for over two years.