Xie Zhenhua is returning to his climate diplomacy, a job and passion to which he was dedicated for over a decade, bringing hope that Beijing and Washington will break the ice on climate cooperation amid the rift in their relations, experts said.

A well-known advocate of action to forestall the climate crisis, Xie is widely regarded as the most suitable person for his new job as special climate envoy. He could play a key role in bridging the gap between the two nations not only because of his enthusiasm for the issue, but also the depth and width of his contacts with United States officials, they said.

With the approval of the central authorities, Xie has been named China's special envoy for climate change affairs, Liu Youbin, spokesman for the Ministry of Ecology and Environment, said at a news conference on Thursday.

The ministry has established a special office headed by one of its vice-ministers to facilitate Xie's work, he added. Xie, 71, led the Chinese delegation in global climate negotiations from 2007 to 2018, during which China joined the landmark Paris Agreement on climate change.

Dimitri de Boer, chief representative for China of Client-Earth, an environmental law charity, said Xie's return will make it "quite possible" for China and the US to have "very meaningful and open conversations and dialogues".

"I know him as a very committed official. I think there's no other senior official in China who is as knowledgeable and committed to the climate agenda as Xie Zhenhua," de Boer said. He added that it's "something he doesn't just consider his job. I think he considered it to be his life, his mission".

Xie is capable of making valuable contributions to US-China climate dialogue as well, de Boer said. "He knows the climate negotiators on the US side quite well. For example, John Kerry," he said, mentioning the new US special presidential envoy for climate.

Under the administration of former US president Barack Obama, China and the US were lauded for laying the foundations of international support for the agreement. At the time, Kerry was US secretary of state.

Zhang Jianyu, founder and chief representative of the Environmental Defense Fund's China program, said Xie's widely noted dedication to climate issues, as well as his experience in promoting domestic climate work, makes him a good person to explain China's climate efforts to the world.

As deputy head overseeing climate affairs, Xie worked for the National Development and Reform Commission, the country's top economic planner, from 2006 to 2015. He was then nominated as special representative on climate change affairs.

Zou Ji, president of Energy Foundation China, said Xie's personal charm, diligence and intelligence has won him and also China international trust.

In an interview with Reuters in early February, Kerry said he had heard about the nomination of Xie on Feb 3 and he expected to speak to his new Chinese counterpart soon. He called Xie a "leader" and a "capable advocate" for his country on the issue of global warming.