Sultan Al Jaber, the president of this year's UN climate talks hosted by the United Arab Emirates, on Tuesday called on participants to drastically ramp up their use of renewable energy.

"We will accelerate delivery in sectors like renewables that must triple capacity by 2030 and double it again by 2040," Al Jaber said in a speech at the opening of the Petersberg Climate Dialogue -- a meeting of climate diplomats in Berlin.

Al Jaber's call marked a public endorsement of a target laid out by the International Energy Agency. Last month at a closed-door meeting with G7 leaders in Japan, he had also raised the target.

At the same time, he did not call for a complete end to the use of fossil fuels.

Rather, the COP28 chair said the focus must be on removing the emissions they produce while stepping up renewables.

"We must be laser focused on phasing out fossil fuel emissions, while phasing up viable, affordable zero-carbon alternatives," said Al Jaber in his speech ahead of the climate summit in November.

Earlier this year, the UN's climate expert panel said the world risks crossing the key 1.5-degree Celsius global warming limit in about a decade, urging a dramatic reduction in planet-heating emissions.

While solar and wind power are already increasing dramatically, the UN report said that existing fossil fuel infrastructure will be enough to push the world beyond 1.5C, absent the use of costly and emerging technology to capture and store the carbon pollution.

The COP28 chair also used his speech to call on developed countries to deliver a long promised $100-billion climate package for developing countries.

"This is holding up progress. And as part of my outreach, I am requesting donor countries to provide a definitive assessment on the delivery of this commitment before COP28," Al Jaber said.

In 2009, the chaotic UN climate summit in Copenhagen saw rich nations promise $100 billion a year by 2020 to the Global South, but last year the OECD said the amount delivered was still $17 billion short.

At the same time, the funding needed for developing countries to stop burning planet-heating fossil fuels and prepare for tomorrow's climate disasters has already far outstripped that sum.

Campaigners are pushing for a redesign of the global financial architecture to help countries cope, as many emerging nations grapple with rising costs, soaring debts and extreme weather events.

German Foreign Minister Annalena Baerbock, who is hosting the Petersberg dialogue, however, reported that the pledged sum may finally be in reach.

"The good news is we are on the way to finally reaching this $100-billion sum this year," she said.