Our video of a starving polar bear has been seen by millions of people online over the past few days. For some, it's a symbol of what many polar bears may face in a warming climate. For others, it's a red herring.

So what can one gut-punch of a video really tell us? Quite a lot.

Here we answer some of the most asked questions we've seen about the video on Facebook, Twitter, Instagram, and elsewhere:

Watching the emaciated polar bear struggle to move and desperately dig for food in a trash can is hard to watch on video. For Paul Nicklen and Cristina Mittermeier, two biologists turned photographers turned co-founders of conservation group Sea Legacy, it was even harder to