The Prince of Wales has issued a stark warning about the threat of climate change - either the world continues on a path to destruction or creates an inclusive, sustainable and resilient society.
Charles's comments came as he gave the opening address at a conference on Inclusive Capitalism at Mansion House in the City of London.
He told the audience of global business leaders that they face hard choices and will not be popular with their peers.
But they will be able to live with themselves knowing that they have done everything to put "nature and human communities" at the heart of future economic models.
The Prince also highlighted how there needed to be a transformation of global capitalism away from the short term to the long term.
The day-long conference will see the business leaders debate the premise, put forward by some, that the current model of capitalism has broken down and does not benefit society as a whole.
The event was Charles's first major engagement in the UK since his reported comments comparing Russian President Vladimir Putin to Adolf Hitler, made during last week's tour of Canada.
In his address today, the Prince said: "Ladies and gentlemen, we stand at a pivotal moment in history.
"Either we continue along the path we seem collectively determined to follow, apparently at the mercy of those who so vociferously and aggressively deny that our current operating model has an effect upon dangerously accelerating climate change - which I fear will bring us to our own destruction - or we can choose to act now, before it is finally too late, using all of the power and influence, sustainable and resilient society.
"There will, of course, be hard choices to make, and, take it from me, in the short term you will not be popular with your peers, but if you stand firm and take the kind of action that is needed, I have every confidence the rewards will be immense."
Among the speakers during the day will be former US president Bill Clinton and Bank of England governor Mark Carney.
Among the guests were also heads of sovereign wealth and pension funds, senior insurance company executives, asset managers and other significant financiers - with organisers saying they collectively managed 30 trillion dollars (£17.8 trillion).
Charles highlighted some of the changes needed to achieve a transformation of the current form of capitalism, so it focused on lasting and meaningful returns.
He said: "This, for instance, would involve paying due attention to both social and environmental capital.
"It would involve putting young people properly at the heart of companies' employment practices and planning strategies, in order to tackle more effectively the world's growing youth employment crisis.
"It would also go some way to helping those who are most vulnerable in our societies.
"After all, it is perhaps worth bearing in mind that at the end of the day the primary purpose of capitalism should surely be to serve the wider, long-term interests and concerns of humanity, rather than the other way around."
Lynn Forester de Rothschild, wife of the financier Sir Evelyn de Rothschild, was approached by the Mayor of London and the city of London to stage the conference.
She is chief executive of EL Rothschild, a privately funded family investment company which she founded in 2003 with her husband to oversee a variety of the Rothschilds' global investments.
Speaking about Charles, she said: "His Royal Highness was thinking about the proper role of business in society 30 years ago. Many of us woke up with the Occupy Wall Street movement.
"But His Royal Highness understood that if business did not behave for the broader interests of society that not only would business lose its contract to operate, but that the society would be in a worse place."