Speaking to the CERAWeek energy conference via video on Tuesday, Al Jaber said 52 international and national oil companies had already joined the Oil and Gas Decarbonization Charter, representing 44% of oil production.

"This is major progress. But it is not enough," Al Jaber said, calling on other oil and gas firms to "step up and sign up."

Al Jaber's COP28 presidency announced the charter with Saudi Arabia in December during the United Nations climate summit in Dubai, where nearly 200 countries agreed to transition away from fossil fuels.

CNPC did not immediately respond to a request for comment. Previously, CNPC said it aims for a peak in its carbon emissions by around 2025, reaching near-zero emissions by 2050, a decade ahead of China's carbon neutrality target of 2060.

Among the charter's signatories are BP, Eni, ExxonMobil, Aramco and ADNOC, which Al Jaber leads as chief executive.

Climate activists had criticised the summit being held in the United Arab Emirates, a leading oil exporter and member of the Organization of Petroleum Exporting Countries (OPEC).

Jaber, who also chairs UAE renewable energy firm Masdar, said his background in all forms of energy was ultimately beneficial.

(Reporting by Yousef Saba; Editing by David Gregorio)