So I was thinking about polar bears the other day. They're not my normal topic for musing while dodging London traffic on my bicycle, but I was thinking about them because a friend told me something I just couldn't believe. She said that polar bears could be the first mammals to lose their entire habitat to climate change. I was shocked. Polar bears have no natural predators. They're on the top of the food chain. They're perfectly adapted to the inhospitable Arctic environment, but now their icy home is disappearing beneath their paws because of our carbon polluting lifestyles.