Wouldn’t it be nice if we could debate climate change for five minutes without hearing about polar bears or being subjected to footage of them perched precariously on a melting ice floe? But that is a little too much to expect. Polar bears have become the pin-ups of climate change, the poor creatures who are supposed to jolt us out of thinking about abstract concepts and make us weep that our own selfishness is condemning these magnificent animals to a painful and hungry end.