By Yousef Saba and Saeed Azhar

RIYADH: The crown prince of Saudi Arabia said on Saturday that the world's top oil exporter aims to reach zero-net emissions by 2060 and more than doubled its annual target to reduce carbon emissions to almost 280 million tonnes.

Crown Prince Mohammed bin Salman was speaking in recorded remarks at the Saudi Green Initiative, which comes ahead of the 26th UN Climate Change Conference of the Parties, or COP26, in Glasgow from Oct. 31 - Nov. 12, that hopes to agree on deeper emissions cuts to tackle global warming.

"The Kingdom of Saudi Arabia aims to reach zero-net emissions by 2060 under its circular carbon economy programme in accordance with the kingdom's development plan ... while maintaining the kingdom's leading role in strengthening security and stability of global oil markets," Prince Mohammed said.

Riyadh, a signatory to the Paris climate pact, on Saturday set out details of its nationally determined contributions (NDCs) - goals for individual states under global efforts to prevent average global temperatures from rising beyond 1.5 degrees Celsius above pre-industrial levels.

The United States and the EU want Saudi Arabia to join a global initiative on slashing emissions of methane by 30% from 2020 levels by 2030. U.S. climate envoy John Kerry will attend a wider Middle East green summit Riyadh is hosting on Monday.

Prince Mohammed said the Saudi Green Initiative aims to eliminate 278 million tonnes of carbon emissions per year, up from a previous target of 130 million tonnes.

Saudi Arabia in March pledged to reduce carbon emissions by more than 4% of global contributions through initiatives including generating 50% of its energy needs from renewables by 2030 and planting billions of trees in the desert state.

Fellow Gulf OPEC producer the United Arab Emirates earlier this month announced a plan for net-zero emissions by 2050.

Saudi Arabia has been criticised for acting too slowly, with Climate Action Tracker giving it the lowest possible ranking of "critically insufficient".

The kingdom's economy remains heavily reliant on oil income as economic diversification lags ambitions set out by Crown Prince Mohammed bin Salman. Saudi officials have argued the world will continue to need Saudi crude for decades to come.

And experts say it is too early to tell what the impact of Saudi's nascent solar and wind projects will be. Its first renewable energy plant opened in April and its first wind farm began generating power in August.

Megaprojects, such as futuristic city NEOM, also incorporate green energy plans including a $5 billion hydrogen plant, and Saudi state-linked entities are pivoting to green fundraising.

Some investors have expressed concerns over the kingdom's carbon footprint. Others say Saudi Arabia emits the least carbon per barrel of oil and that de facto ruler Prince Mohammed is serious about economic diversification.

"Obviously the carbon footprint is an issue. However, we would highlight that realistically carbon is going to be slow to phase out, and oil is here for some time yet," Tim Ash at BlueBay Asset Management said in emailed comments.