The glacier-filled Tibetan plateau has warmed more over the last 50 years than it has in the preceding 2,000, according to researchers in China.

The Tibetan plateau is covered with tens of thousands of glaciers. The interlinked sheets of ice source the headwaters of the some of the world's largest rivers -- the Yellow and Yangtze in China, the Brahmaputra in India and the Mekong in Southeast Asia -- providing clean drinking water for more than 2 billion people. The snow-covered plateau is sometimes called the "roof of the world."

But researchers say the glaciers are the warmest they've been in two millenniums, their ice melting at a hastening clip.

The alarming new numbers come courtesy of a report by scientists at the Institute of Tibetan Plateau Research, a research division of the Chinese Academy of Sciences.

"Over the past 50 years, the rate of temperature rise has been double the average global level," report authors wrote, as quoted by a local state-run paper called the Science and Technology Daily.

The report says increased human activities on the plateau, as well as global warming, are too blame for the melting ice. They warn that the warming temperatures could lead to an uptick in flooding and landslides in some areas.