Obtaining ice core samples from the highest point on Earth can reveal a wealth of information about climate change. As the leader of China's Second Tibetan Plateau Scientific Expedition and Research team, Xu Baiqing climbed almost to the peak of Mt. Qomolangma, to extract ice cores. 

Xu has spent decades working on various mountain glaciers, at different altitudes. He admits that he's not yet done, since although humans can reach the highest point on Earth, the scientific exploration knows no limits.