China covers glaciers with blankets to prevent melting

A giant blanket covers part of Dagu, China's most accessible glacier, to slow its melting amid global warming.

A team of researchers at Nanjing University covered a glacier with a cooling blanket. Photo: SCMP — A team of researchers at Nanjing University covered a glacier with a cooling blanket. Photo: *SCMP*

At the Dagu Glacier in the Tibet Autonomous Region of southwest China’s Sichuan Province, thick white blankets now cover an area of more than 400 square metres. Supported by stakes and anchored by wooden planks, the blankets are a newly developed radiation-cooling film that could help slow the rate of melting at the Dagu Glacier, the SCMP reported on July 8.

“Our material is lighter in structure, waterproof, environmentally friendly and can be reused many times,” said associate professor Zhu Bin at Nanjing University. “The cost is also comparable to traditional geotextiles.”

Zhu leads a university research team in collaboration with the Tencent Carbon Neutrality Laboratory, established in 2021. They are racing against time to slow the rate of glacier melt. Glacial lake flooding as the ice melts threatens 15 million people worldwide, including 1 million in the western Chinese regions of Xinjiang, Tibet, Qinghai, Sichuan and Yunnan. About 8,000 glaciers have melted in the past 50 years due to global warming, according to calculations by Kang Shichang, director of the Cryosphere Science Laboratory at the Chinese Academy of Sciences.

Half of the Earth’s 215,000 glaciers could disappear completely by 2100, with dire consequences for the world ’s freshwater supplies and ecosystems, even if humans manage to limit global warming to 1.5 degrees Celsius, according to research published in the journal Science in January. While China has pledged to reduce greenhouse gas emissions to become carbon neutral by 2060, its meteorological agency warned last month that El Nino could bring more extreme weather, including record-breaking temperatures in China.

Evidence of global warming is everywhere, even at Dagu, a glacier that sits 4,860 meters above sea level. There are only 11 glaciers covering 1.46 square kilometers in Dagu, down from 11 glaciers covering 5.6 square kilometers in 1971, according to Huang Shihai, deputy director of the Dagu Glacier Administration. The volume of the glacier on the Heishui River has shrunk by more than 70 percent in more than half a century.

Glacier blankets are not a new idea. Scientists in Switzerland and Italy have been using geotextiles and tarpaulins to shield glaciers in the Alps from the sun for nearly two decades. The technique can reduce the melting of snow and ice by 50 to 70 percent, said Matthias Huss, director of the Swiss Glacier Monitoring Network.

The Nanjing University material reflects more radiation and dissipates more heat, Zhu said. In a 2021 experiment on the Tianshan Glacier No. 1 in Xinjiang, Zhu covered 200 square meters of snow with the new material. Results published in the journal Science Advances last February showed a 1.5 meter reduction in melting depth over 50 days, three to four times better than conventional materials.

The material used at Dagu is even better because of the upgrade. When the Northern Hemisphere summer ends in September, his team will return to Dagu to remove the blanket and assess the results. But as advanced as it is, it is not large enough to save the entire glacier. The cost would be prohibitive and completely uneconomical . Large-scale use of the blanket could also destroy the surrounding ecosystem. The best material would be used to preserve the ice in a specific location. Cutting greenhouse gas emissions is still a much more effective way to preserve glaciers.

An Khang (According to SCMP )

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