Dr Sultan Al Jaber speaks during COP28 at Dubai Expo City on Saturday.

The pledge was among a slew of COP28 announcements on Saturday aimed at decarbonising the energy sector - source of around three-quarters of global greenhouse gas emissions - that included expanding nuclear power, cutting methane emissions, and choking off private finance for coal power.

"This can and will help transition the world away from unabated coal," said Sultan Al Jaber, the UAE's COP28 summit President.

Led by the European Union, United States and UAE, the pledge also said tripling renewable energy would help remove CO2-emitting fossil fuels from the world's energy system by 2050 at the latest.

Backers on Saturday included Brazil, Nigeria, Australia, Japan, Canada, Chile and Barbados.

While China and India have signalled support for tripling renewable energy by 2030, neither backed the overall pledge on Saturday.

Backers including the EU and UAE want the renewable energy pledge included in the final UN climate summit decision, to make it a global goal. That would require consensus among the nearly 200 countries present.

The pledge also called for "the phase down of unabated coal power" and an end to the financing of new coal-fired power plants. It also included a target to double the global rate of energy efficiency by 2030.

Climate vulnerable countries insisted that the goals must be paired with a deal among countries at COP28 to phase out the world's use of fossil fuels.

"We are not making the argument that this is absolutely going to be the sweeping alternative to every other energy source," Kerry said during a launch ceremony at COP28.

"But ... you can't get to net-zero 2050 without some nuclear, just as you can't get there without some use of carbon capture, utilisation and storage," Kerry said.

Global nuclear capacity now stands at 370 gigawatts, with 31 countries running reactors. Tripling that capacity by 2050 would require a significant scaling up in new approvals - and finance.

Meanwhile, several governments, philanthropies, and the private sector said they have mobilised $1 billion in grants to supports countries' efforts to tackle the potent gas.

Two major emitters of methane, Turkmenistan and Kazakhstan, joined the Global Methane Pledge, a voluntary agreement by over 150 countries to slash their methane emissions by 30% by 2030.

The World Bank on Saturday launched an 18-month "blueprint for methane reduction” that will set up 15 national programs aimed at cutting methane emissions from activities like rice production, livestock operations, and waste management.

Reuters