Harp seals and their pups are the subject of the second episode of Frozen Planet II, which is available now on iPlayer. One of the issues with climate change is that it’s really hard to see.

It’s easy to confuse two animals. Believe me, I do it much too often. I’m talking leopard vs. cheetah or emu vs. ostrich. But it doesn’t have to be as difficult to differentiate between two similar ...