The Duke - who shares Prince George, Princess Charlotte and Prince Louis with his wife, the Duchess of Cambridge - made his comments in an upcoming ITV documentary, Prince William: A Planet For Us All, which will be aired next month.
WATCH: Royal children begin their first days at school
He shared that he has "always loved nature" but said that fatherhood has given him a "new sense of purpose".
"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," the Prince remarked.
Prince William said becoming a father has changed his outlook
"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."
William was joined by a film crew two years ago, as he met people in the UK and abroad who are playing their part in protecting and restoring the environment during the programme, according to Kensington Palace.
The Prince has a passion for protecting the environment
The documentary also charts William's journey from being passionate about conservation to wanting to play a greater global leadership role on the environment.
It comes shortly after the royal shared his thoughts on his children going back to school, admitting it had been something of a "relief".
The Prince was in Belfast to mark Emergency Services Day and met serving blue light responders as part of the visit.
Prince George and Princess Charlotte recently returned to school
Speaking to a police officer, William told her that he suspected other mums and dads were having the same experience as himself.
The father-of-three said: "I think every parent is breathing a sigh of relief that school has started again." He went on: "Five months – it's been wonderful, but it's been a long five months!"
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