The lakes on the world’s highest plateau showed a trend of delayed freezing and melting that took place earlier than usual over the four decades up until 2017, a new study found, underscoring the impact of climate change on some of the planet’s most vulnerable regions.

Around four-fifths of the 132 lakes monitored on the Qinghai-Tibet Plateau saw the length of time they were covered by ice shortened by a certain period ranging from a few days to over 50 days between 1978 and 2017, according to the study published Friday. It was published in Scientific Data, Nature’s open access scientific journal, by researchers from the state-backed China Academy of Sciences.

Known as Asia’s “water tower,” the Tibetan Plateau is home to many glaciers and lakes. It is the source of 10 major rivers in Asia, providing water supply to almost 2 billion people.

But warming global temperatures have led to the disappearance of some 6,000 glaciers on the Qinghai-Tibet Plateau over the decades, studies show. The average temperature in the region increased by 0.42 degrees Celsius per decade from 1980 to 2018, twice the global average rate, according to a separate June study by the Chinese Academy of Sciences.

Zhang Bing, co-author of the study, told Sixth Tone that the study is the first of its kind to look at lake freezing patterns on the Tibetan Plateau in the 40-year period, which could offer projections of future changes and help make policies in terms of production and life, such as water supply in downstream areas.

“In addition to the temperature and rainfall monitored by meteorological stations, the lake ice data serves as another indicator, which helps reflect the impact of global warming on the plateau in a comprehensive way,” Zhang said.

Friday’s study also offers an annual dataset of the freezing-up and breaking-up of lake ice on the high-altitude plateau through remote sensing and mathematical modeling supported by meteorological data. Researchers said such figures had rarely been recorded before, given ground-based observation on the Tibetan Plateau is “challenging and costly” due to high altitudes and the harsh natural environment.

The study also added new evidence about how climate change could add new risks to the ecologically vulnerable region. Previously, scientists had warned of the supply and quality of water deteriorating due to accelerated warming in the area.

Editor: Bibek Bhandari.

(Header image: Frozen Qinghai Lake on the Tibet Plateau, May 11, 2011. VCG)