It was early evening in the Chigertei Valley when I found myself standing on a weathered buttress, cheering the sudden onset of clouds. A fresh weather-front was barrelling in over the Altai massif, and now the clouds were pluming at the mountaintops, some of them wispy and translucent, others dark and throwing shadows, draping columns of rain. By now I understood what this foreshadowed.
Soon, the cloud-cover would fracture the dusk light, and sunbeams would daub chiaroscuro patterns on the land, transmuting the grasslands into prairies of gold. Far away, on the valley floor, smoke spiralled from yurt chimneys; a pair of boy-herders chivvied their sheep alongside a stream. But these were pinpricks of humanity on a floodplain big enough to swallow Manhattan. Up here, I felt certain, the only…