The black volcanic rock is bright and glossy in the moonlight; it crunches softly underfoot. Above Karanga Camp, the iconic snow cap is blue-white against a night sky bursting with stars. My breath hangs in the air as small, fluffy clouds and I am chilled to the bone despite the layers under my down jacket. Dome tents huddle in small groups on the mountainside, some glow softly, lit from within by headlamps. The stillness of the night is broken by the shuffle of canvas and the cough of a climber suffering from altitude sickness. It is hard to believe that a mere 2,000m below my camp there is a tropical rainforest.