Prince Charles has spoken of how he was "considered rather dotty" when he began his personal campaign to protect the environment 50 years ago on Wednesday.
The Prince has been reflecting on the speech he made on February 19, 1970, when he spoke about many issues which we are still grappling with today.
In the speech he said:
The number of people "is increasing faster than the resources of the local environment"
How "55 million of us on this island" are using "non-returnable bottles and indestructible plastic containers"
The "growing menace of oil pollution at sea"
Growing pollution from "gasses pumped out by endless cars and aeroplanes"
The Prince of Wales reading out his 1970 speech
Now, the Prince of Wales has given another interview about the danger the world now faces, half a century after his first speech.
"In the sixties, when I was a teenager," said the Prince, "I minded so much about all the things that were gong on."
He spoke of what he called a "complete determination to defeat nature" and how he decided that "this was an area I should look at".
But in the 1970s, when he wanted to install a bottle bank at Buckingham Palace or a reed bed sewage system at his Gloucestershire home, Highgrove, Prince Charles admits he was considered "completely potty" as well as "rather dotty to say the least for even suggesting these things".
Prince Charles reflecting on the climate and his impassioned speech from 1970
The Prince of Wales told the Sustainable Markets Council - an organisation he recently set up to build a bridge between investors and environmental projects - that it is going to cost a lot more to fix climate change issues because "we put the problem off for so long".
It is, he says, because history shows us that "human beings don't take the necessary steps until everybody is hit in the face with the problem".
The Prince launched the Sustainable Markets Council last month at the World Economic Forum in Davos where he urged the world's most powerful business leaders and wealthy companies to work towards decarbonising the world economy.
"We have got this decade left", the Prince said, "everything we are doing has been to destroy our own means of survival, let alone the survival of everything else we depend on".
In other words, this campaigning Prince says we don't have another 50 years to listen to his thoughts, the world must act now.