Almost half the world's population gets its water from glaciers and rainfall in Asia's highest mountains and deserts. Geologist Aaron Putnam of Columbia University's Lamont-Doherty Earth Observatory, his father David Putnam, an archaeologist at the University of Maine at Presque Isle, and their colleagues recently visited some of these areas on study expeditions, snapping these striking photos. Above: Looking north toward the high Tien Shan mountains of western China. At center is the highest peak in the Tien Shan: Tomur peak (or Jengish Chokusu in Khirgiz).
Snow on high peaks above Thampe Chhu, Bhutan.
Tshewang Rigzin (Department of Hydromet Services, Royal Government of Bhutan) and guides sampling boulder on moraine.
Tshewang Rigzin (Department of Hydromet Services, Royal Government of Bhutan) and Aaron Putnam (Columbia) tinkering with a weather station.
Prof. Summer Rupper (Brigham Young University) and colleagues descending Drukso Gangri after emplacing stakes that would monitor melt over the following year.
Drukso Gangri ('Dragon-Tooth Glacier'), Bhutan.
Rinchen Zoe plateau, Bhutan Himalaya.
Himalayan Bharal ('Blue Sheep') on high cliffs near Tampe La.
Camp beneath the high mountain pass of Tampe La.
Nomadic yak herders in the Nikka Chhu valley, Bhutan.
Looking north toward the spine of the Himalaya, featuring the high peaks of Makalu (right) and Everest (left).
Blowing sand in the Taklamakan.
Ancient lake bed of Lop Nor.
Cookie cut from an ancient 'sub-fossil' poplar discovered deep in the Taklamakan Desert.
David Putnam describing ancient poplars rooted in waterlain sediment surfaces in the Taklamakan Desert.
Aaron Putnam investigating sediments that indicate the presence of water in the Taklamakan Desert.
Shells associated with ancient, now-dry riverbeds in the Taklamakan Desert, south of the Tarim River.
Ancient waterlain sediments littered with wood being exposed from beneath migrating sand dunes.
Ancient mud cracks on the surface of waterlain sediments in the Taklamakan Desert show that wet conditions prevailed in the past.
Sand dunes in the Taklamakan Desert.
Red dots indicate the locations of our field sites where Putnam and colleagues are investigating past climate and glaciers.