Scientists and activists have long argued at global climate summits that the only way to slow down global warming is to eliminate its main driver, fossil fuel production.

This year’s United Nations-sponsored climate summit, however, will be hosted in the United Arab Emirates, one of the world’s biggest fossil fuel producers, and the head of the U.A.E.’s national oil company, Sultan al-Jaber, will preside over the meeting. At the summit, which starts in late November, Mr. al-Jaber will be tasked with ironing out the language of its final document.

On Tuesday, speaking at a separate climate-focused conference in Berlin, Mr. al-Jaber gave some of his clearest hints yet on his hopes for what that document will say. Close watchers of climate politics said they were left feeling cautiously optimistic on the ambitions of Mr. al-Jaber, who is also chairman of the U.A.E.’s state-owned renewable energy company, while some of his word choices left room for ambiguity.

“We must be laser focused on phasing out fossil fuel emissions, while phasing up viable, affordable zero carbon alternatives,” Mr. al-Jaber said at the conference in Berlin, which is an annual prelude to the larger U.N. conference later in the year. He also called for a tripling of global renewable energy capacity by the end of this decade and said the world was “way off track” in meeting its emissions reductions pledges.

At a press conference following the speech, responding to questions about his remarks, Mr. al-Jaber said, “We know fossil fuels will continue to play a role in the foreseeable future in helping meet global energy requirements.” Therefore, he said, the aim should focus on “ensuring that we phase out emissions from all sectors whether it’s oil and gas or high emitting industries while in parallel we should exert all effort and all investments in renewable energy and clean technology space.”

The opposite is happening. Despite a lull during the worst years of the pandemic, oil and gas projects are roaring back. Historical producers such as the United States and Saudi Arabia are ramping up production, and the exploitation of new oil blocks in places like Guyana and Uganda is just getting underway.

At last year’s climate summit in Sharm el Sheikh, Egypt, countries couldn’t agree on including “phase out” language for all fossil fuels. A year earlier, in Glasgow, that term was included but pertained only to coal, for which, outside China and India, there have already been major declines in production.

“While it is correct for al-Jaber to focus on emissions, it is also true that meeting our emissions goals means we’re going to have to be using much less fossil fuels than we do today,” said Jason Bordoff, the director of the Center on Global Energy Policy at Columbia University. “It is also true that we will need carbon capture to meet our goals on time. So there’s an element of necessity there. It just can’t be used as cover for a real phasedown.”