LHASA — Describing his relationship with Chinese scientists as "like brothers", Lonnie Thompson, a member of the American Academy of Sciences and a foreign academician of the Chinese Academy of Sciences, has returned to the highest county in China 24 years after his last visit.

In Shuanghu county of Southwest China's Xizang autonomous region, where the average altitude exceeds 5,000 meters, he is working with Chinese scientists to uncover the secrets of the planet.

Located roughly 90 kilometers northeast of the county seat, the Purog Kangri Glacier stands as the largest accumulation of ice outside the polar regions. In September, Thompson and fellow academician Yao Tandong of the Chinese Academy of Sciences arrived there to conduct the second scientific expedition on the Qinghai-Tibet Plateau. Their research primarily focused on crucial ice core drilling.

"It's really striking to go back and see these places that we drilled early in my career. I want to continue documenting the changes we observe in these glaciers," says Thompson.

At 76 and having undergone heart transplant surgery, Thompson expresses his excitement despite facing harsh environmental conditions and physical discomfort.

This visit is part of a scientific expedition to investigate the Qinghai-Tibet Plateau, known as Asia's "water tower". The target region encompasses "one glacier, two lakes and three rivers" and is part of the second scientific expedition and research of the Qinghai-Tibet Plateau, which was initiated by China in August 2017. The goal is to understand the mechanism of environmental change and provide scientific support for the ecological security of the plateau.