The rapid melting of China’s glaciers in recent decades threatens the water security of an estimated 1.8 billion people in Asia, according to a new report published Tuesday by the environmental nongovernmental organization Greenpeace.

Nearly one-fifth of China’s total glacier area has disappeared in recent decades and rates of glacial melt have accelerated, with both processes exacerbated by climate change, the report said. Most of China’s glaciers are located in the country’s mountainous far west, which is part of the Asian High Mountain region, an area also known as the “Third Pole” that stores the most ice and snow outside the polar regions. The area is one of the world’s most sensitive to global warming and houses the source waters of many of Asia’s largest rivers, some of which flow as far as Afghanistan, India, and Vietnam.

“This is a wake-up call for China and the world,” said Liu Junyan, Greenpeace East Asia’s climate and energy campaigner and co-author of the report. “It is critical that we speed up the transition away from coal and other fossil fuels and keep global average temperatures at [or below] 1.5 degrees [of warming].”

In some parts of western China, average annual temperatures are now 3 degrees higher than in the early 1960s. (Globally, the average temperature has risen by around 0.8 degrees since 1880.) In addition, more than 80 percent of China’s 48,000 or so glaciers retreated between the early 1950s and 2006, according to the country’s most comprehensive such survey to date. Last year, The Paper — Sixth Tone’s sister publication — documented the decline of Urumqi Glacier No. 1, a much-researched swath of ice in northwestern China that scientists predict may disappear within 50 years.

Rising global temperatures are not the sole cause of glacial melting, Liu told Sixth Tone by phone. “Across [the region], extreme weather events like heavy rain and extreme heat are occurring more frequently,” she said, adding that the problem is worsened by deposits of black carbon in China’s glaciers. Black carbon — fine particulate matter released when biomass and fossil fuels are burned — easily absorbs heat and light, causing ice and snow to melt more quickly.

The complex environmental and social effects of glacial retreat are already becoming apparent. Glacial melt in the economically resurgent Aksu River basin in northwestern China’s Xinjiang Uyghur Autonomous Region has led to increased water runoff since the 1980s. This, in turn, has brought a rise in vegetation coverage, but also more frequent spring floods and summer water shortages, the Greenpeace report says.

The long-term effects of unconstrained melting are much grimmer. If global temperature rises are capped at 2 degrees Celsius, meltwater output from China’s glaciers will peak sometime between 2040 and 2070 before dramatically tailing off — a phenomenon that would have severe implications for water security in Asia, home to more than half of the world’s population.

Already, glacial melting is causing natural disasters in China, scientists say. Last month, a glacier partly collapsed in Tibet, releasing large amounts of debris into a river and causing more than 6,000 residents to be evacuated. And in August, a glacial lake outburst flood — a sudden release of water caused by the collapse of naturally forming dams that contain glacial lakes — inundated the Yarkant River basin in Xinjiang, leading to thousands of evacuations.

Concern about the state of China’s glaciers comes after the United Nations’ Intergovernmental Panel on Climate Change released an alarming report last month warning that humankind only has 12 years left to keep global warming to a maximum of 1.5 degrees above preindustrial levels. Climate scientists warn that any warming above this threshold will increase the likelihood of long-term or irreversible changes to the planet’s ecosystems. The Greenpeace report states that two-thirds of all glaciers in the Asian High Mountain region can be saved if global warming is capped at 1.5 degrees.

Members of the U.N.’s Framework Convention on Climate Change, including China, will meet in Poland next month to work out a deal on the implementation of the 2015 Paris Agreement, which aims to limit global warming to below 1.5 degrees.

Editor: Bibek Bhandari.

(Header image: A view of Glacier No. 1 in the Tianshan Mountains, Xinjiang Uyghur Autonomous Region, 2018. Courtesy of Greenpeace)