Mark Carney, the United Nations’ special envoy on climate action and finance, has said that the achievements of COP28 will depend on the host country’s ability to confront the fossil fuel industry.

“All countries need to be judged on what their contribution is,” Carney told POLITICO’s Power Play podcast, ahead of the summit which is set to begin in the oil-rich United Arab Emirates (UAE) on Thursday.

“And that goes for a country [the UAE] that is a leading oil and gas producer, also a leading renewable producer,” he added.

The UAE, home to some of the largest oil reserves in the world, has attracted criticism for appointing Sultan Ahmed al-Jaber as COP president, in spite of his role as CEO of its national oil company.

Climate activist Greta Thunberg has, for example, said the appointment of al-Jaber — who is also chairman of the board of directors of the UAE’s national renewable energy company — was “completely ridiculous.”

Al-Jaber’s ties to the oil industry made headlines earlier this week as leaked documents — released after the recording of this episode of Power Play — showed the UAE was planning to leverage its position as the talks’ host to discuss oil and gas deals with a dozen countries.

On Wednesday, al-Jaber told reporters that the reports were “false, not true, incorrect” and “an attempt to undermine the work of the COP28 presidency.”

Asked about al-Jaber’s appointment, Carney said, “the COP president is the COP president, and it’s our job to make it work.”

But, he added, this year’s achievements of the world’s top climate summit will also be assessed based on “what part of the leadership of this COP president has been to take the energy industry, the oil and gas industry head on and challenge that industry.”

“Let’s see who stands up in the UAE at COP amongst the oil and gas companies and countries and we’ll start to judge who’s performing and who isn’t,” Carney said.

Carney, who is a former governor of the Bank of England, also criticized the recent changes made by British Prime Minister Rishi Sunak to some key green policies, which critics say jeopardize the U.K.’s goal of reaching net-zero carbon emissions by 2050.

“If you start zigging and zagging on climate policy, calling your commitment into some question, you set yourself up for a tougher adjustment down the road,” Carney said. “There’s the first signs of that in the U.K., which is unfortunate.”

Karl Mathiesen contributed reporting.