Prince William, Duke of Cambridge and Catherine, Duchess of Cambridge speak with glacial expert Dr. Furrikh Bashir (R) as they visit the Chiatibo glacier in the Hindu Kush mountain range in the Chitral District of Khyber-Pakhunkwa Province, Pakistan, October 16, 2019. Getty

The Duke of Cambridge called on Wednesday for "political action" to tackle climate change. He made the appeal as he visited a melting glacier in Pakistan.

Prince William and wife Kate, the Duchess of Cambridge, visited a remote region in the Hindu Kush mountain range in northern Pakistan on the third day of their royal tour of the country. They saw the Chiatibo Glacier in Broghil National Park, and were shown how it has retreated rapidly in recent years as the earth's climate gets warmer.

As William and Kate saw the melting glacier, William, who has long campaigned for environmental causes, said communities "vulnerable to change" needed "more education, more awareness and political action" to deal with the increasing effects of climate change.

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"The young are starting to get engaged in it," he said, calling for a "positive conversation" on climate change among world leaders. During a speech on Tuesday evening in Islamabad, the duke urged leaders in Great Britain and Pakistan to work together amid an "impending global catastrophe."

During the engagement, William, who studied geography at St. Andrew's University in Scotland, joked: "Dr Warren, my geography teacher, would be well impressed that I'm back at a glacier after all these years."

The couple were joined by Dr. Furrukh Bashir of the Pakistan Meteorological Department. William quizzed him during their visit, asking him about what time of year glaciers tend to flood, and the impact locally.

Glaciers in the region's mountains provide water for 1.6 billion people. There are more than 5,000 reasonable sized glaciers in the area, but almost 70% of them are retreating, according to Bashir.

Global warming has seen the Chiatibo Glacier retreat by about 10 yards per year. The first threat that brings, as the glacier melts in the warmer air and the runoff flows downstream toward communities along riverbanks, is flooding.

The second is the depletion of the huge water supply locked away in their ice.

"Scientific communities have agreed global warming is causing glacial retreat," Bashir said. "These glaciers are retreating and telling you that climate change is real, global warming is real. A quarter of humanity are dependent on these glaciers."

Bashir welcomed the visit by the British royals, saying it helped to raise awareness of the changing environment in the region.

"They are highly influential people and they have a permanent position. If we convince them that this is happening because of climate change, global warming, greenhouse gases, hopefully they will advocate to reverse global warming and climate change," he said.

William and Kate arrived by helicopter to the remote location in the Chitral district of Pakistan's Khyber-Pakhtunkhwa Province Tuesday morning, where they received an official welcome and were presented with a book of photographs of William's mother, the late Diana, Princess of Wales' visit to the region in 1991.

Prince William, Duke of Cambridge and Catherine, Duchess of Cambridge speak with flood victims in the village of Bumburet on October 16, 2019 in the Chitral District of Khyber-Pakhunkwa Province, Pakistan. Getty

Following the glacier excursion, the couple met survivors of mass flooding caused by glacial melting in the area in 2015. Buildings and farmland in the valley were destroyed by boulders tumbling down with the flood water. During their visit, they spoke with Diana, a young woman from the area who was named after William's mother.

The young woman is part of a volunteer emergency response team, now funded by U.K. aid money, that helped save lives when the floods hit in 2015. A translator said the royals' visit was "a source of pride" for the group.

"They're glad that people are learning more about this. It's a source of pride," the translator relayed. "They can't forget this day."

Prince William, Duke of Cambridge and Catherine, Duchess of Cambridge visit a settlement of the Kalash people, to learn more about their culture and unique heritage, on October 16, 2019 in Chitral, Pakistan. Getty

For their final engagement of the day, William and Kate visited a settlement of the Kalash tribe, and joined children and young people from the tribe to learn how the Kalash co-exist with other communities in the region.