When filmmakers from the conservation group Sea Legacy arrived in the Arctic, they captured a haunting scene. And more than anything, it highlights the dangers of climate change.

On a stretch of ice somewhere in the Arctic Circle, an emaciated polar bear struggles across the frozen terrain. Fast approaching death, the starving creature picks listlessly through trash cans, hoping to find enough food to keep going. But as a crew film this heartbreaking tragedy, a far more terrifying drama is unfolding behind the scenes.

From snow-covered tundras and soaring mountains to white sand beaches and open savannas, nature has no shortage of wonders that inspire and delight. But while our planet’s stunning landscapes often takes center stage in documentaries and on travel brochures, many of us are ignorant about just how fragile this Earth really is.

Covering 5.5 million square miles, the Arctic stretches across a region more than 1.5 times bigger than the continental United States. Home to a surprisingly diverse ecosystem of flora and fauna, it’s often thought of as one of the last true wildernesses on planet Earth. However, its future is far from guaranteed.

As global warming causes temperatures to rise, the ice in the Arctic has been melting at an alarming rate. And even though thaws are a natural, seasonal occurrence here, most scientists agree that the process has accelerated far beyond its normal range. So where does this leave the animals that call this region home?

Today, one of the most potent symbols of climate change is the polar bear. Native to the Arctic Circle, these fearsome beasts can grow to weigh up to 1,600 pounds. Related to the brown bear, they have developed strong, powerful bodies that are perfectly adapted to suit the harsh environment.

But with their impressive bulk, polar bears have to take in plenty of food. And with little for them to eat on land, they spend most of their time prowling the ice that floats on top of the Arctic Ocean. From there, they are able to sneak up on and catch seals, their preferred source of nutrition.

On Canada’s Baffin Island, the resident polar bears depend on fluctuating levels of sea ice to provide their hunting grounds. During the summer months, the ice disappears completely, and the creatures must wait until fall before they can feed. In the meantime, they survive off reserves of stored fat.

But as the Arctic ice continues to shrink, these polar bears are being forced to go longer and longer without access to food. And while populations in other regions, such as Russia, are not believed to be at risk, the bears of Baffin Island are thought to be declining in number. As a result, the entire species has been classified as vulnerable by the International Union for Conservation of Nature.

In the summer of 2017, wildlife photographers Paul Nicklen and Cristina Mittermeier found themselves on Somerset Island, an uninhabited region that lies close to Baffin Island off the Canadian coast. Nicklen, who works for National Geographic, was originally a biologist, but in recent years he has become increasingly concerned with issues of conservation.

In 2014 Nicklen and Mittermeier founded Sea Legacy, an environmental group dedicated to conserving the planet’s oceans. And three years later, the couple brought a team of filmmakers to Somerset Island, ready to document the fragile ecosystem of the Arctic Circle. But what they found was even more powerful than they could have imagined.

In fact, what Nicklen and Mittermeier ended up recording would become a significant piece of evidence in the global debate surrounding climate change. While on the island, the team spotted an emaciated polar bear struggling to survive. Without the ice that would have enabled it to hunt, the animal had been reduced to a shadow of its formerly majestic self.

Their cameras rolling, the team watched as the painfully thin bear dragged itself weakly across the island. Eventually, it managed to find its way to some trash cans, where it rummaged desperately for something to eat. And even though it was lucky enough to uncover a snack, it was nowhere near enough food to sustain such a large animal.

At the end of the footage, the bear is shown lying down, apparently unwilling or unable to move. Eventually, the changing seasons forced the Sea Legacy team to move on, and they abandoned Somerset Island without knowing what would ultimately become of the beleaguered bear. However, Nicklen believes that it died soon after their encounter.

On December 7, 2017, National Geographic published an article featuring footage of the struggling polar bear. And within days, it had gone viral. But while some media outlets dubbed the animal the “Face of Climate Change,” Mittermeier was quick to stress that they did not know for sure what had caused the bear’s condition.

Speaking to Canadian radio station CBC in 2017, she explained her take on the footage. “We are not certain that it was because of climate change,” she admitted. “It is impossible to tell why he was in this state. Maybe it could have been an injury or a disease, but the point is that it was starving and we want people to know what a starving polar bear looks like, because as we lose the ice in the Arctic, polar bears will starve.”

Detractors suggested that the bear might simply have been ill. However, National Geographic supported the conclusion that the animal was starving. Pointing to the animal’s atrophied muscles as a sign of prolonged malnutrition, it also drew attention to its lack of scars or any other signs of injury.

As the video’s popularity grew, the Sea Legacy team found themselves facing some difficult questions about what they had witnessed. For example, many people wanted to know why they had not intervened and rescued the bear. However, the filmmakers knew that it is illegal to feed a polar bear in Canada and couldn’t help at all.

Talking to National Geographic in 2017, Nicklen discussed the idea of somehow saving the bear. “Of course that crossed my mind,” he said. “But it’s not like I walk around with a tranquilizer gun or 400 pounds of seal meat.” Furthermore, Mittermeier pointed out the dangers inherent in approaching a starving polar bear without a weapon.

Instead, the filmmakers chose to document the bear’s struggle in the hope of raising awareness about the species’ uncertain future. “In the end, I did the only thing I could,” Mittermeier told the National Geographic. “I used my camera to make sure we would be able to share this tragedy with the world.

And while the jury is still out on whether this particular bear was a victim of climate change, the environmental message, Nicklen says, remains the same. “When scientists say bears are going extinct, I want people to realize what it looks like,” he said. “This is what a starving bear looks like.”