However inhospitable, one thinks of the Arctic as pristine and elemental, free from the environmental problems that beset more southerly latitudes. So it’s a shock to read reports that the far north is more affected by pollution than almost anywhere else on the planet. Pollutants include polychlorinated biphenyls (PCBs, which cause cancer and birth defects and developmental damage in young children), pesticides such as lindane, toxaphene, chlordane and DDT, and some heavy metals like mercury and cadmium. These originate in lower latitudes, where they evaporate from fields and rubbish dumps or are given off when substances are burned. They travel vast distances on the winds and condense out only when they hit the cold of the far north. In effect the atmosphere is acting as a giant system for vaporising and condensing volatile substances, and so environmentalists have started to call the effect global distillation. The levels of some pollutants are way above international limits: it has recently been reported that some Inuit are eating a hundred times the permitted intake of PCBs in seal skin and blubber each week.