Prince William used to wonder what his dad was "banging on about" when he discussed climate change.
The 38-year-old royal recently launched a Nobel-style prize to help tackle climate change, and the British royal now feels proud of Prince Charles' efforts to raise awareness of environmental issues.
In an interview alongside Sir David Attenborough on BBC Radio 4, Prince William quipped: "I regularly wonder what my father’s banging on about. I’m sure every son thinks the same.
"Obviously with my father’s environmental credentials, he’s talked about this for a long time and long before people sort of cottoned on to climate change.
"So I’ve always listened to and learnt and believed in what he was saying. But I knew it’s a very hard sell, you know, 40 years ago to kind of predict and see some of the sort of slow moving catastrophes that we were headed towards."
William thinks that attitudes towards climate change have evolved since his dad first spoke about environmental issues.
He said: "I think the dotty person now would be the person who doesn’t believe in climate change."
Meanwhile, William has admitted he feels a responsibility to encourage people to protect the environment.
The royal is determined to ensure that he helps to leave the planet "in a better state then we found it".
William - who has Prince George, seven, Princess Charlotte, five, and Prince Louis, two, with the Duchess of Cambridge - explained: "I really feel we are at a tipping point and I want to make sure that my grandchildren – my children and my grandchildren really, because it’s going to happen relatively fast - that we hand the planet in a better state then we found it."