‘The ice cap is a dynamic thing,’ Pyxeas said, growing breathless as he scrambled. ‘Fresh snow falling on the centre of the cap fails to melt, and compresses to ice, and thus the cap grows. And as it becomes heavier the ice must flow out and away from the centre under its own weight – as a mass of mud will flow out in all directions from under the arse of a big fat man sitting on it. The ice reaches the sea via the glaciers it spawns. And when there is an unusual amount of snow, as there has been on your island the last few years, there is an unusual rate of glacial flow—’

‘Scholar!’ Avatak pulled him back.

They had come to a crevasse, a slice right through the surface of the ice. It was new, it hadn’t been here a few days ago, and the bulk of it was hidden by a thin crust of fresh snow. But Avatak had spotted its extension to either side, thin black cracks. Cautiously he kicked through the snow crust, and they both leaned over to peer into the crevasse. The gathering sunlight caught hard old ice that shone green and blue, as if lit from within, and Avatak could hear a foamy rush of running water from far below.

‘The great weight of the glacier melts its own base,’ Pyxeas breathed. ‘And thus, lubricated, the ice falls ever more readily to the sea. Come on, come on!’ They stepped over the crevasse and hurried on, Pyxeas talking on, endlessly speculating.

It was this curiosity that had prompted Avatak to volunteer to help the scholar from Northland when he had come here three summers ago to make his ‘studies’. The People knew the world changed. They could hardly not know; they depended on these vagaries for their very existence. They knew of the fluttering cycles of day and night, the seasons that swung between bright summers and dark winters, and they knew, thanks to memories stored in folklore and anecdote, of the grander evolutions that spanned generations. But when change came, they just adapted. Went out on the pack ice a little earlier in the summer, or later. Fixed up the winter houses a little later, or earlier. If you got such judgements wrong you starved, and so did your children.

But what they didn’t do, what they had never done, was try to understand. What caused these changes in the world? And what would be the consequence if these changes, such as the increased snowfall in the interior, were to continue, year after year?

It wasn’t because they were in any way less intelligent than the scholar’s Northlander folk, Avatak had come to see. In most ways that counted, his own father, say, was much brighter than Pyxeas, certainly when it came to the brutal business of staying alive. And the people’s shared memory, stored in the epic songs they sang together through the winter, was detailed and accurate. No, it wasn’t a question of intelligence. It was a question of how you thought about the world – not as a plaything of the gods to be accepted without question, but as a puzzle to be solved. And Avatak was drawn to the way Pyxeas’ mind worked as he challenged this huge, baffling, complex, secretive puzzle, and to the sheer delight the man showed when some small piece of it was resolved, and the world made a little more sense.