The Duke of Cambridge has called on humanity to “speed the pace up” and tackle the growing environmental threat to the planet.

Speaking in a new documentary, William suggests he expects to be criticised for his views, saying: “Someone has to put their head above the parapet and say, I care about this.”

And he highlights how the younger generation – who are typified by the teenage climate change activist Greta Thunberg – are pushing for change and action on the issue.

William and Kate visiting the Chiatibo glacier in the Hindu Kush mountain range to learn about the effects of climate change. Neil Hall/PA Wire
William and Kate visiting the Chiatibo glacier in the Hindu Kush mountain range to learn about the effects of climate change (Neil Hall/PA)

William has been filmed over the past two years in the UK and countries such as Pakistan and Tanzania for the ITV documentary Prince William: A Planet For Us All, which charts his journey from passionate conservationist to wanting to play a greater global leadership role on the environment.

In Pakistan’s Hindu Kush mountains, the duke and his wife saw first hand the effects of climate change on glaciers which are melting at record speeds.

During the official tour last October, William told the documentary: “It’s a huge environmental and humanitarian disaster.

“And yet, we still don’t seem to be picking up the pace and understanding it quick enough. And I think the young are really getting it.

“And the younger generation are really wanting more and more people to do stuff and want more action.

During a visit to Tanzania the duke was shown a stockpile of ivory. Kensington Palace
During a visit to Tanzania, the duke was shown a stockpile of ivory (Kensington Palace/PA)

“And we’ve got to speed the pace up. We’ve got to get on top of it and we need to be more vocal and more educational about what’s going on.”

The documentary follows the duke during a visit to Tanzania in September 2018 and he is filmed feeding a carrot to a rhino called Deborah.

The future king says in the film, which will be screened next Monday: “People might see them and think it’s a big tank, a big hulk of an animal, with a big horn, but they are incredibly vulnerable.

“They have brilliant eyesight and people will take advantage of that and they want this horn, which is effectively nail, and that is all it is, it’s fingernail. This is where the horn belongs, on a live rhino and that’s where it should stay.”

Later William is visibly moved as he visits a heavily guarded secure ivory store in Tanzania where 43,000 tusks with a street value of £50 million have been impounded.

Sir David Attenborough is featured in the documentary with the duke and duchess, the trio are pictured during the naming ceremony of a new British polar research vessel, named after the broadcaster. Peter Byrne/PA Wire
Sir David Attenborough is featured in the documentary with the duke and duchess (Peter Byrne/PA)

He says: “It’s a mind-blowing number of tusks, it really is. You can’t get your head around it.”

William’s interest in protecting the natural world and the environment is reflected in his role as patron of Tusk, a conservation organisation working in Africa which aims to secure a peaceful co-existence for the continent’s wildlife and its people.

And for more than five years the Transport Taskforce of his umbrella organisation United for Wildlife has been working to facilitate collaboration between the transport sector and law enforcement to prevent wildlife trafficking.

In the film, the duke pays tribute to his grandfather the Duke of Edinburgh and father the Prince of Wales for their work supporting the natural world.

He says: “My grandfather, my father have been in environmental work for many years.

Sir David and William watch the broadcaster’s new documentary – sat in the wrong chairs (Kensington Palace/PA)

“My grandfather’s well ahead of his time. My father, ahead of his time. And I really want to make sure that, in 20 years, George doesn’t turn round and say, ‘are you ahead of your time?’ Because if he does, we’re too late.”

The duke and duchess are featured with Sir David Attenborough during the documentary and are filmed when Kate names a new British polar research vessel after the broadcaster and naturalist.

In the documentary, William tells the veteran broadcaster: “Every generation, you know, after yours, David, has grown up listening and seeing all the things that you’ve shown them. And, hopefully, each generation listens a little bit more.”

Sir David, who last week met the Cambridges and watched his new documentary – A Life On Our Planet – with William, shares the duke’s optimism: “The public is becoming extraordinarily well informed it seems to me. Kids know an awful lot now about ecology and what’s happening with the world. It’s remarkable.”

At the end of the programme, William says he believes that 2020 and the coronavirus pandemic has given people a chance to “take stock” of what is important.

He says: “I’ve been really heartened by what I’ve been hearing from other people and how they’ve decided to appreciate nature and experience it and see all the things that they never thought they would.

“Someone has to put their head above the parapet and say, I care about this. To have the belief that if we all work together, we can make a difference.”

Prince William: A Planet For Us All will be screened on ITV at 9pm on Monday October 5.