It’s the shuddersome, floppy Greenland shark, which can live to 300, perhaps even longer, its life span slowed and distended by the deep cold of the northern oceans. Since then, measured by weight, 90 percent of the largest creatures sharing the oceans with them have disappeared. This is not just a parable about the warming of the seas. Ninety percent of global marine fish stocks have now been fully exploited or overfished; 81 percent of monitored migratory freshwater populations have declined since 1970. But the story of that warming is nevertheless astonishing, even for those of us anesthetized by exposure to the world’s rapid ecological transformation.

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Persons: preteenagers, Helen Czerski, Czerski, Mike Davis, “ Locations: Atlantic, England, El