At the end of every summer, scientist Li Zhongqin takes his seasonal hike near the top of a glacier in the Tianshan mountains in China's far northwestern region of Xinjiang.
Li scrambles over a frozen ridge and heads toward a lone pole wedged in the ice. Clouds emerge from a peak above and quickly blow past. He stops to catch his breath. He is at 14,000 feet. The snow is thick. The air is thin.