The Prince of Wales has told world leaders humanity faces no greater threat than climate change, as he issued a rallying call for them to take immediate action to tackle rising temperatures.
Charles urged the leaders and negotiators gathered in Paris for the start of crucial UN talks to "think of your grandchildren, as I think of mine", the billions of people without a voice and the youngest generation as they try to secure a new global deal.
Referring to the delegates as the "few", in echoes of Winston Churchill's description of Battle of Britain fighter pilots, he told them their actions over the next two weeks would determine the fate of present and future generations.
Charles began his keynote speech in Paris by expressing, in French, his profound horror at the terror attacks two weeks ago which killed 130 people and his untold sympathy for the grieving families and loved ones of those who died.
"My heart is with the courageous French people in their hour of anguish," he said.
The prince then told the packed hall: "Rarely in human history have so many people around the world placed their trust in so few.
"Your deliberations over the next two weeks will decide the fate not only of those alive today, but also of generations yet unborn."
Over the next fortnight negotiators from 195 countries will attempt to hammer out a deal that will put the world on a path to prevent temperatures rising by more than 2C (3.6F) above pre-industrial levels and avoid dangerous climate change.
Charles said he prayed that in pursuing national interest, countries would not lose sight of international necessity.
Before leaders gathered in Copenhagen in 2009 in an ultimately failed bid to secure a new climate treaty, he had tried to point out the best scientific evidence suggested humanity had 100 months to alter its behaviour "before we risk the tipping point of catastrophic climate change".
The prince, one of only four people to speak in the opening session before leaders start to give their speeches to the summit, questioned whether the world had reached such a "collective inertia" that it could ignore such a warning.
Some 80 of those months had passed, he said, urging the world "we must act now".
"If the planet were a patient, we would have treated her long ago," he said, adding that delegates must start emergency procedures "without further procrastination".
Charles, who recently drew links between climate change and the conflict in Syria, said: "Already we are being overtaken by other events and crises that can be seen as greater and more immediate threats.
"But in reality many are already and will increasingly be related to the rapidly growing effects of climate change."
He warned: "On an increasingly crowded planet, humanity faces many threats - but none is greater than climate change.
"It magnifies every hazard and tension of our existence.
"It threatens our ability to feed ourselves; to remain healthy and safe from extreme weather; to manage the natural resources that support our economies and to avert the humanitarian disaster of mass migration and increasing conflict."
But, he said, humanity has the knowledge, the tools and the money to tackle climate change, and lacked only the will and the framework to do so.
He told the delegations they were here to set the world on the road to a "saner future" and urged them to rescue the planet and people from impending catastrophe in a spirit of enlightened and humane collaboration.
WWF chief executive David Nussbaum said Charles, who is president of WWF-UK, had spoken from the heart and set exactly the right tone for the start of the Paris climate talks.
"As he says, we have the knowledge, the tools and the money to put us on the right low carbon path for 2030.
"I hope the negotiators here in Paris will follow his plea and don't lose sight of international necessities over national interests. The climate talks need to bring us a step closer to a low-carbon future for all."