Alastair Fothergill had been there before, of course, as the series co-producer of Frozen Planet and Planet Earth, but this time was different.

Polar Bear, the family film about a mother polar bear and her young cubs exploring their wintery world for the first time, will be one of the anchors of Disney+’s 2022 Earth Day programming, and it was always supposed that Polar Bear would play to Disney’s traditional family audience for nature films.

The British-born Fothergill was, after all, the producer of the Disneynature film Earth, which was released in movie theatres, along with the follow-ups African Cats and Chimpanzee.

Polar Bear, the film Fothergill set out to make, was not the film he made in the end, though. It still has the family-friendly signature marks familiar to anyone who’s seen a Disney nature film, but this time there’s an edge.

Climate change — or, more accurately, the climate crisis — is reshaping the polar bear’s natural habitat in ways that are both pronounced and profound. The ice melt across the Arctic is more dramatic and happening more quickly than even the most pessimistic projections, and scientists are increasingly concerned about the future survival of the polar region’s apex predator.

In a teleconference call Friday with TV writers and fellow explorers, Fothergill and Polar Bear co-producer Jeff Wilson sounded a note of, if not alarm exactly, disquiet.

What’s happening in the planet’s northernmost regions is already having an effect on the bears’ behaviour, and Fothergill worries about the bears’ prospects in a world where hunting seals on polar ice — seals being bears’ primary source of protein that allows them to withstand winter’s increasingly volatile temperature swings — may no longer be viable.

Bears need ice to reach the seals. If they can’t reach the seals, they can’t hunt the seals. And if they can’t hunt the seals, they starve.

Fothergill is no wet-behind-the-ears dilettante when it comes to nature filmmaking. He majored in zoology at the UK’s Universities of St. Andrews and Durham and joined the BBC’s Natural History Unit in 1983. It was there that he met his mentor and lifelong filmmaking collaborator David Attenborough; he worked on Attenborough’s The Trials of Life in 1990 Fothergill was appointed head of the Natural History Unit just two years later, in 1992. By the end of the decade, though, Fothergill stepped down from administrative duties to focus on producing programs: The Blue Planet, Planet Earth, Frozen Planet and The Hunt followed in quick succession. Fothergill executive-produced Netflix’s landmark Our Planet in 2019, and Attenborough’s autobiographical follow-up, A Life on Our Planet.

Our Planet featured Attenborough’s by now familiar narration and Planet Earth’s narrative style, but it was very different from its predecessors. This time, was on the effects of climate change, human predation on the world’s increasingly fragile ecosystems and looming species extinction.

Polar Bear follows in a similar vein to other Disneynature films, but it’s impossible to make a film about polar bears in this day and age and not focus on their environment. For that reason Fothergill and his co-producer Jeff Wilson opted to tell the story from the vantage point of a mother bear looking back on her 15 years of life in the far North while trying to raise her own cubs to adulthood.

“The reduction in sea ice that we’ve seen over the last 15 years has been dramatic,” Fothergill said. “Polar bears will the first of the A-list of stars in the natural world who may become extinct because of global warming.”

The story always determines what ends up on film in the end, he said, and the story of polar bears is increasingly becoming a story of survival. Advances in camera technology have made nature stories easier to tell — but the stories themselves have become more complex and emotionally demanding.

Biodiversity is not just a buzzphrase. The SARS-CoV-2 pandemic shows that the human biome is regulated the same way the biosphere is regulated, Fothergill said: Everything is connected.

In a strange way, Covid-19 has forced people to realize how connected we are to the natural world, and how easily a disease can be transmitted around the world. It’s not just about polar bears. Polar bears are a symbol, though, because they are one of the most recognizable, familiar animals on the planet.

They also make good material for storytelling.

“The thing about polar bears is they’re probably the ultimate loner, of all the animals you can imagine,” Fothergill said. “They’ll often go for years and years without meeting another bear. The thing about mother bears is they have babies that stay with them for two or three years, and polar bear cubs are possibly the cutest animals on the planet.

“Jeff and I decided very early on that our story would not be just two or three years of a mother brining up one set of cubs. It would be the memories of a 15-year-old bear, looking back from the day she was born until she reached 15.

“That decision was based on the fact that it would allow us to look at global warming changes over that time period. We made the film in Svalbard, just 700 miles south of the North Pole. Over the4 last 10 tom 15 years there has been significant change. That’s why we went for the 15-year narrative.”

Polar Bear streams on Disney+ starting April 22.