Selin Co

Selin Co, located in the Nagqu region of Northern Tibet, is a lake shrouded in mystery. In Tibetan, “Selin Co” means “the demon lake illuminated by dim light.” According to legend, it devours neighboring lakes. In just 40 years, its surface area expanded by nearly 40%, surpassing Lake Namtso to become the largest lake in Tibet. The northern Tibetan plateau is not only a haven for wildlife but also one of the most iconic high-altitude lake regions on Earth. Covering more than 20,000 square kilometers, this area holds a quarter of all lake surface in China, and Tibet’s four largest lakes are all found here.

Selin Co, situated at an elevation of around 4,350 meters, covers an area of approximately 2,391 square kilometers—over 300 square kilometers larger than Shenzhen, a city with more than 17 million residents. In 2001, Selin Co surpassed Lake Namtso to become the largest lake in Tibet. Because its surface area continues to expand every year, it’s often humorously referred to as “the most ambitious lake in Tibet.” This ever-growing body of water offers a rare glimpse into plateau ecological change, drawing explorers and nature enthusiasts from around the world.

On the southern plains of Selin Co, seven isolated stone peaks rise from the earth, resembling silent warriors guarding the lake day and night. According to local legend, they are the incarnations of seven spirits tasked with watching over the demon of Selin Co. Though the tale is mythical, the reason behind Selin Co’s nickname—“Demon Lake”—goes beyond folklore. The lake continues to expand and even absorbs nearby smaller lakes. Among the many lakes of the Qinghai-Tibet Plateau, Selin Co’s rapid growth is unique. Scientific research attributes this expansion to global warming: rising temperatures are accelerating glacier melt, which feeds into the lake.

Although the Qinghai-Tibet Plateau is known as the “Roof of the World,” it is not immune to the effects of global warming. In recent years, rising temperatures have accelerated glacier melt across the plateau. Selin Co lies precisely in a region where meltwater from glaciers converges—and as a closed drainage lake, it has no outlet. This has led to a rapid increase in water volume. The expansion of Selin Co is not only a striking natural phenomenon, but also a vivid example of how climate change is reshaping high-altitude ecosystems.