The King called for meaningful change as he delivered the opening address at Cop28 in Dubai.
Charles, 75, who has long been an advocate for environmental issues, said the world remains "dreadfully far off track" in key climate targets.
His speech was his first at the conference as King, having previously opened Cop26 in Glasgow in 2021 and Cop21 in Paris in 2015. See some of the highlights in the clip below...
Addressing heads of state, heads of government and business and climate delegates at Expo City Dubai on Friday, the King said: "I pray with all my heart that Cop28 will be another critical turning point towards genuine transformational action at a time when, already, as scientists have been warning for so long, we are seeing alarming tipping points being reached.
"Despite all the attention, there is 30 per cent more carbon dioxide in the atmosphere now than there was back then, and almost 40 per cent more methane.
“Some important progress has been made, but it worries me greatly that we remain so dreadfully far off track as the global stocktake report demonstrates so graphically.
"The dangers are no longer distant risks. I have seen across the Commonwealth, and beyond, countless communities which are unable to withstand repeated shocks, whose lives and livelihoods are laid waste by climate change.
"Surely, real action is required to stem the growing toll of its most vulnerable victims."
Cop28 will be the first time that countries will conduct a “global stocktake” of progress made since the Paris Agreement was signed in 2015, although it is expected that it will not produce a positive result.
The conference began on Thursday and runs until 12 December, with the UK government pledging £1.6 billion for international climate change projects throughout the summit.
Britain's Prime Minister Rishi Sunak, Foreign Secretary Lord Cameron and Labour leader Sir Keir Starmer were among those in attendance at the summit.
Closing his speech, the King said: “Ladies and gentlemen, in your hands, is an unmissable opportunity to keep our common hope alive.
“I can only urge you to meet it with ambition, imagination, and a true sense of the emergency we face, and together with a commitment to the practical action upon which our shared future depends.
“After all, ladies and gentlemen, in 2050 our grandchildren won’t be asking what we said, they will be living with the consequences of what we did or didn’t do.
“So if we act together to safeguard our precious planet, the welfare of all our people will surely follow.
“We need to remember too that the indigenous worldview teaches us that we are all connected, not only as human beings but with all living things and all that sustains life.
“As part of this grand and sacred system, harmony with nature must be maintained.
“The Earth does not belong to us, we belong to the Earth.”
The King also used his two-day trip to Dubai to promote peace in the region in several talks, having also met with the presidents of Nigeria, Guyana and the United Arab Emirates on Thursday.
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