Sultan Al Jaber, the United Arab Emirates climate envoy, minister of industry and advanced technology and CEO of the state-owned oil firm ADNOC, will lead the COP28 talks starting in Dubai in November.
It comes as the world faces increasingly stark warnings about the urgency of transitioning away from fossil fuels to have a hope of keeping climate targets in view.
Jaber's oil and gas links are controversial. Dozens of US and European lawmakers say they should disqualify him from the job, with hundreds of climate campaign groups calling for him to quit either COP or ADNOC.
Jaber has done neither.
The 50-year-old bristles at accusations that he has a conflict of interest.
"I'm someone who spent the majority of his career in sustainability, in sustainable economic development and project management, and renewable energy," he told AFP in July.
Indeed, he founded state-owned renewable energy company Masdar a decade before he took the helm of ADNOC with a mandate to "decarbonise" and "future-proof" the gas and petrol giant.
But his oil industry pedigree has raised a lot of eyebrows and questions over the COP presidency, a role that previously attracted a lot less attention.
- Petroleum 'pragmatist' -
"COP28 is beset by a dark cloud of -- entirely warranted -- public scepticism," said US Senator Sheldon Whitehouse, one of a group of US and European lawmakers who last year called for fossil fuel lobbyists to be kept out of the talks.
Whitehouse told AFP that their open letter was sparked by Jaber's saying oil and gas interests would be "at the table."
Others say his links to the oil industry might be an advantage.
One European negotiator, speaking on condition of anonymity, said the COP president needs to help tease out consensus among the world's diverse economies -- including those with stocks of oil, gas and coal.
The stakes are high.
The most ambitious goal of the 2015 Paris Agreement was to limit temperature rise to 1.5 degrees Celsius above pre-industrial levels, although UN climate experts warned this year that we are hurtling towards breaching that guardrail in the 2030s.
Jaber has vowed to "help move the needle in terms of our efforts of keeping 1.5C within reach."
"What I can tell you is that I will work with everyone to develop a plan that is achievable, that is actionable, that is realistic and that is pragmatic, and that will deliver real results," he said.
Surprisingly, he has managed to win over some sceptics during nine months of frenetic travel that has seen him crisscross the planet.
Harjeet Singh, of the influential coalition Climate Action Network International, said a turning point came in July, when Jaber wrote that "phasing down demand for, and supply of, all fossil fuels is inevitable and essential."
"He's very straightforward, he's open to listening," Singh told AFP, adding however that the pair "agree to disagree" on several issues.
Those disagreements include the prominence given to fossil fuel lobbyists and Jaber's endorsement of controversial carbon capture technologies -- like those that trap emissions at source and store them permanently.
ADNOC made a commitment in July to achieve carbon neutrality by 2045 for its own operations.
But that target does not include emissions produced by the oil and gas burned by its customers, which account for the vast majority of its carbon footprint.
- Ambition test -
Will Dr Sultan, as he is known to his teams, be able to use his COP position as a largely behind-the-scenes facilitator, to help deliver an ambitious text acceptable to 198 parties?
His predecessor at COP21 in Paris, Laurent Fabius, said he was "a man who knows his files very well."
But the European negotiator who spoke on condition of anonymity said Jaber was "a little behind the curve" when it comes to negotiating the final text and "much less proactive" than the British were two years ago at COP26 in Glasgow.
Some worry Jaber is too focused on secondary decisions within the UN process and encouraging eye-catching commitments by businesses and countries from the sidelines of the climate talks -- slated to be by far the biggest ever held.
Proof of his ability to shepherd the more important UN text through the negotiations will come on December 12, when COP28 talks are supposed to end.