"We need some of the world's greatest brains and minds fixed on trying to repair this planet, not trying to find the next place to go and live," William told the BBC in an interview airing Thursday. "I think that ultimately is what sold it for me - that really is quite crucial to be focusing on this [planet] rather than giving up and heading out into space to try and think of solutions for the future."
He said he is also concerned about the carbon cost of space flights.
The Duke of Cambridge spoke as "Star Trek" actor William Shatner became the oldest person to go to space onboard a Jeff Bezos’ Blue Origin rocket on Wednesday.
Bezos, Virgin’s Richard Branson and SpaceX founder Elon Musk have all competitively ventured into space tourism as of late and Musk frequently talks about the importance of making humankind "interplanetary" especially if Earth becomes uninhabitable.
The prince will also be awarding £1 million grants on Sunday through his inaugural Earthshot Prize to innovators working to solve climate change.
Williams’ father, Prince Charles, has also long been an advocate for climate change awareness and William said it would be an "absolute disaster" if his son Prince George, 8, was still having the same conversation about global warming in "like 30 years' time whatever, still saying the same thing, because by then we will be too late."