The 38-year-old royal previously revealed has a "new sense of purpose" in protecting the planet now he has children - Prince George, 7, Princess Charlotte, 5, and Prince Louis, 2.
He said: "Now I have got George, Charlotte and now Louis in my life - your outlook does change.
You want to hand over to the next generation, the wildlife in a much better condition. I always believe it is possible to give young people hope and belief that things can get fixed.
I have the belief that if we all work together, we can make a difference and champion action on conservation and climate change."
And Prince William admitted parenthood has changed his "outlook" on life.
"I think you realise a lot more when you become a father," he said.
I was quite a happy-go-lucky young guy, enjoyed parties and then all of a sudden you go 'well hang on a second, there's a little person here. I'm responsible for that person'."