Qinghai Lake - China's largest inland saltwater lake - completely froze over in late January, two weeks later than normal. Experts said the delay signals the growing effect of global warming on the fragile ecosystem of the Qinghai-Tibet Plateau.

Apart from being a popular tourist spot, Qinghai Lake is also crucial for maintaining the ecological stability in the region, blocking the spread of deserts to eastern China, and serving as a key research spot for climate change, according to the Qinghai Institute of Meteorological Science.

The lake typically enters a five-month freezing period starting in mid-December, and is completely frozen by mid-January. However, since 2004, the lake is gradually taking longer to freeze over due to an overall rise in temperature around the region, according to institute data.

Li Weijun, a researcher at the National Climate Center, said climate change is slowly warming up the region around the lake, leading to more humidity, more rainfall and more water flowing into the lake's surrounding rivers due to melted glaciers.

Regions around Qinghai Lake have seen a 40 percent increase in average rainfall. The water level of the lake has also risen by around 2 meters since 2005, and the size of the lake reached 4,425 square kilometers, the most in 17 years, according to last year's data from the institute.

At the same time, data shows that around 15 percent of all the glaciers on the plateau have melted in the past three decades.

"These phenomenon are a double-edged sword," said Li. "The living conditions in the region will improve as more water enters the otherwise cold and arid environment."

"However, the extra water might also cause flooding, landslides and other natural disasters that could damage infrastructure and livelihoods in the region."

Li suggested more robust research and the collection of more comprehensive data to understand the effect of climate change on the plateau.