Speaking a day after COP28 president Sultan Ahmed al-Jaber proposed embracing fossil fuels into the future, Guterres said "we cannot save a burning planet with a fire hose of fossil fuels".
"The 1.5-degree limit is only possible if we ultimately stop burning all fossil fuels - not reduce; not abate," he said, referring to nascent technologies to capture and store carbon emissions.
My message to leaders at — António Guterres (@antonioguterres) #COP28:Protecting our climate is the world's greatest test of leadership.I urge you to lead.Humanity's fate hangs in the balance.Make this climate conference count.December 1, 2023 UN chief Antonio Guterres has addressed the COP28 climate summit.
The duelling visions summed up the most divisive issue facing world leaders at this year's UN climate summit in the oil-producing country of the United Arab Emirates.
King Charles pleaded with world leaders to make progress in the global climate agenda.
"Scientists have been warning for so long - we are seeing alarming tipping points being reached," he said, warning that failing to rein in emissions would result in catastrophe.
"Unless we rapidly repair and restore nature's economy, based on harmony and balance, which is our ultimate sustainer, our own economy and survivability will be imperilled."
The comments from Charles, whose role as Britain's head of state is largely ceremonial, appeared to be at odds with his government.
UN Secretary-General Antonio Guterres had a dire warning for delegates at the COP28 climate summit. (AP PHOTO)
British Prime Minister Rishi Sunak, who was expected at COP28 on Friday to announce Stg1.6 billion ($A3.1 billion) in climate finance, has rolled back several domestic measures that had been set by previous governments to help the country meet its 2050 net-zero targets.
Later on Friday, world leaders including Kenya's President William Ruto and Ukraine's Volodymyr Zelenskiy were scheduled to speak to the conference.
Away from the main stage, delegations and technical committees set to work on Friday with the mammoth task of assessing their progress in meeting global climate targets, specifically the Paris Agreement goal of limiting global warming to within 2C above pre-industrial temperatures.
Scientists say a global temperature rise beyond this threshold will unleash catastrophic and irreversible impacts worldwide.
The UN on Friday published its first draft for what could serve as a template for a final agreement from the COP28 summit, which ends on December 12.
Sultan Ahmed al-Jaber has urged countries to work with oil companies to reach common ground. (AP PHOTO)
The draft offers "building blocks" for a political outcome and includes several options for addressing one of the thorniest issues at the summit - deciding whether, and to what extent, fossil fuels should play a role in the future.
One of the options involves including commitments to phase down or phase out the use of fossil fuels, to quit coal energy and to triple renewable energy capacity by 2030.
Also on the table for discussion is whether to phase out fossil fuel subsidies, which totalled some $7 trillion last year, and whether to include provisions for carbon capture and removal technology.
On Thursday, the UAE's Jaber urged countries to work together with oil companies to reach common ground.
The summit also clinched an early victory by adopting a new fund to help poor nations cope with costly climate disasters.
