The Emirati president of the UN's COP28 talks said Monday he respects climate science, after a leaked video showed him declaring that no science says phasing out fossil fuel will achieve climate goals.

Sultan Al Jaber also repeated his past statements that a phase out of fossil fuels was "inevitable" as he hit out at "repeated attempts to undermine" the work of the COP28 presidency.

"We're here because we very much believe and respect the science," Jaber, who is also the head of UAE national oil company ADNOC, told reporters.

"Everything this presidency has been working on is focused on and centred around the science," Jaber said.

He acknowledged that global greenhouse gas emissions must be cut by 43 percent by 2030 as part of efforts to achieve the goal of limiting warming to 1.5 degrees Celsius from pre-industrial levels.

The Guardian newspaper published a video on Sunday showing Jaber having a testy exchange with former Irish president Mary Robinson during an online forum.

"I'm not in any way signing up to a discussion that is alarmist," Jaber told the SHE Changes Climate online conference on November 21.

"I am factual and I respect the science, and there is no science out there, or no scenario out there, that says that the phase-out of fossil fuels is what's going to achieve 1.5 (degrees)."