【teacher and student sex video】

After landing on teacher and student sex videoBaffin Island, Canada, wildlife photographer and environmental activist Paul Nicklen captured video of a frail polar bear -- dying and foaming from the mouth -- as the weak animal collapsed to the ground. The bear will soon be dead -- if it isn't already.

On Dec. 5, Nicklen posted the grim video to his Instagram account, and since then, it's been stirring emotions around the web. Polar bears are, for better or worse, a symbolic species when it comes to global warming, and many are seeing this video as a new warning sign.

Fortunately, however, the condition of this bear is not representative of most polar bear populations -- at least not yet.

There are 19 different populations of polar bears in the expansive Arctic. The dwindling sea ice here -- which these predators need to hunt fat-rich seals -- is now affecting different groups of bears in different ways.

"It’s tough to see a disturbing image like that and not feel sympathy for the animal," U.S. Geological Survey (USGS) polar bear biologist Todd Atwood said in an interview. "It’s also tough to see an isolated image extrapolated to some kind of population level effect."

The actual cause of the bear's death will remain unknown, but Atwood doubts there's one specific cause. "It’s probably a combination of things -- it could be an old animal -- but it also could be that if it’s still on land, that there’s not enough sea ice," he said.

After posting the video, Nicklen told National Geographicthat "when scientists say bears are going extinct, I want people to realize what it looks like. Bears are going to starve to death. This is what a starving bear looks like."

But while the threat to polar bears is real, all is not yet dire for the Arctic predators.

"It’s worth noting that there are some subpopulations that are believed to be stable," said Atwood.

Polar bears are listed as a threatened species in the United States, which means that while they're not yet on the brink of extinction, they "are likely to be at the brink in the near future," according to the U.S. Fish and Wildlife Service, which maintains the list.

For polar bear populations that are struggling, it's often due to a lack of sea ice. Polar bears can't hunt seals on the open water.

"So as the open water season gets longer, there’s association between the length of the open water seas and body conditions -- body conditions decline," Atwood said.

But this isn't the full story. The physical condition of polar bears is also dependent upon how much fish is available for seals. So in places with more fish and seals -- places that are more "biologically productive" -- there will be more food for bears, and they're likely to be better fed.

Unless, of course, there's no sea ice there, either.

There is a clear solution to polar bears' vulnerability -- and you undoubtedly know it well: Humanity's commitment to limit global warming, which is caused by fossil fuel emissions. These heat-trapping gases warm both the oceans and the air, resulting in vastly diminished sea ice, particularly in the summer and fall.

"This requires changing our behaviors relative to our carbon footprint," Atwood said.