China’s chief climate negotiator Su Wei, who was key in helping secure the landmark Paris Agreement last year, has left his position amid a personnel reshuffle, sources say. Su, known among climate diplomats around the world for being tough and direct in his negotiations, left the powerful National Development and Reform Commission’s climate change office after being appointed director of the commission’s international cooperation department, according to two sources close to the NDRC. China and US to ratify landmark Paris climate deal ahead of G20 summit, sources reveal Su’s new appointment does not change his ranking in the official hierarchy, and his previous position is being filled by Xie Ji as acting director of the climate change department, according to the sources. It is not immediately known who will take up Su’s role as China’s chief climate negotiator. The departure of Su – who has been the country’s chief climate negotiator since 2005 – coincides with the international exodus of other senior climate diplomats after the Paris convention. Among them, Todd Stern, the United States’ special envoy for climate change, stepped down in March, and former UN climate chief Christiana Figueres left in July after her term ended. Observers have named Li Gao, a deputy director and another veteran negotiator at the climate change office, as a strong candidate who might fill Su’s shoes. The department’s new chief, Xie, has previously held senior positions in the NDRC’s climate change, resource conservation and environmental protection departments, but has not been directly involved in climate talks. How China, the 'world's largest polluter', is taking on climate change Retired NDRC deputy chairman Xie Zhenhua will remain China’s special representative of climate change. The NDRC’s personnel reshuffle comes after a team sent by the top graft-buster, the Central Commission for Discipline Inspection, completed a review on the commission in June. Following the inspection, the graft-busters urged the commission to “intensify personnel reshuffles” to improve its promotion mechanism. The watchdog has been encouraging reshuffles across and within central ministries as a way to curb nepotism and corruption. Planning agency tangled up by graft Su was one of the key officials who helped secure a historic climate deal in Paris last December . The Paris Agreement established a universal regime to tackle climate change, with representatives from 195 countries agreeing to keep the increase in the global average temperature to well below 2 degrees Celsius above pre-industrial levels. China and the US are likely to ratify the climate deal in the coming days , the South China Morning Post reported on Thursday. Analysts say the priority for China’s new chief climate negotiator will be to ensure effective implementation of what has been agreed on paper, and to convince the world that China – the world’s biggest greenhouse gas emitter – is serious about taking real action against climate change. How a deal was sealed: behind the scenes of historic US-China climate pact Su’s legacy is secure, the analysts say, as he has played an instrumental role in bringing China into accord with the international community, mainly the US, to act jointly on emission controls. After 11 years of steering the country’s climate negotiations, Su is known for his quick wit, especially when China and the US engaged in bitter blame games after the spectacular failure of the 2009 Copenhagen summit. At that time, China was criticised for its stubbornness in clinging to voluntary carbon reduction targets while demanding industrialised nations establish mandatory goals. A climate for change: how China went from zero to hero in fight against global warming in just 6 years Su is also known for his willingness to talk to the media, a rare trait among Chinese diplomats, although he rarely revealed anything unscripted. In 2010, he made international headlines for calling the US “a pig looking in the mirror” during the climate talks, when he compared the US to Zhu Bajie, a pig character in the Chinese classic Journey to the West . Su graduated from Renmin University’s post-graduate course in international law in 1989 after completing a bachelor’s degree in English literature at Shandong University. He joined the Foreign Ministry and immediately became involved in UN climate negotiations, impressing ministry officials with his written reports on those talks.