It was while out fishing for cod one day that my host’s friend saw a disturbing sight. Nudging his motorboat down the finger of a fjord, he saw the sea ahead looked bright red. From a distance, it looked like an ocean of blood.

What could it be, he wondered? The remains of a whale or seal hunt? Mineral deposits leeching from the ancient rocks? As he floated closer, he realised. It was fish. Thousands of dead, floating redfish, a species common to Greenlandic waters. These tomato-hued creatures are adapted to live at such extreme depths that, if they rise to the surface, the change in pressure kills them. It seemed that a colossal iceberg had toppled, pushing the shoal up to their deaths. 

Such...