(TibetanReview.net, Jul05’23) – A Chinese geologist who has been annually touring the Tibetan Plateau over the last 30 years has spoken of having observed starkly worrying changes in conditions there with serious future implications as a result of global warming. “Climate change means a range of long-term threats for the plateau. We need to recognize that it is at a turning point and respond accordingly,” Geologist Yang Yong, who has been carrying out field studies on the plateau since the 1980s, has said in a report posted on chinadialogue.net Jul 4.
“From what I have seen, the main impacts of climate change on the Qinghai-Tibet Plateau are higher temperatures, a retreating snowline, shrinking glaciers, hydrological changes, degradation of the grasslands, and worsening desertification. Compound disaster chains have a huge impact on the population, while ecosystems are facing unknown hazards.”
“I’ve visited the Qinghai-Tibet Plateau almost annually for over 30 years. I’ve seen the impacts of climate change with my own eyes, and witnessed the environmental and ecological changes that have occurred in a region often known as ‘The Third Pole’ or ‘Asia’s Water Tower’. We are also very likely to see the effects of an El Niño climate pattern over the next few years, possibly leading to temperature spikes. I am extremely worried about the challenges this will bring for the climate, hydrology and people of the plateau.”
On his study of glaciers on the Tibetan Plateau, Yang has said, “Several glaciers at the source of the Yangtze have shrunk significantly between the 1980s and today. For example, comparison of field study findings and satellite images across time shows that the Gangjiaquba glacier has retreated by over 2,000 metres in the last half-century, and the Jianggudiru north glacier by over 500 metres.”
On the glacier which feeds the Yarlung Tsangpo in Tibet, which becomes Brahmaputra in India, Yang has said: “The Jiemayangzong glacier, in the west of the Himalayas, is the source of the Yarlung Tsangpo River (which becomes the Brahmaputra). I have seen how its once-steep face has shattered, becoming a slope of ice leading down to a glacial lake. It has retreated 400 metres over the last 12 years.”
He was startled by the hotness of the weather in the glacial areas at a time when it should have been raining. “It might be hard to imagine, but what has struck me most while studying the glaciers during my recent expeditions is the heat. It should have been the rainy season as we crossed northern Tibet last July. But the sun blazed every day and the ground was parched.”
Yang has spoken of having seen little rain during recent trips during the supposedly flood season months. As a result, rivers were very low compared with a normal year, with parts of the riverbeds exposed. Reservoirs were also low.
On the other hand, over the last 50 years, the number of lakes of one square kilometre or more in size on the plateau had risen from 1,081 to 1,236, with total area increasing from 40,000 square kilometres to almost 50,000.
His explanation for this situation is: “A lot of this extra water comes from melting glaciers, but the melting of permafrost – ground frozen year-round – is also a factor. Research has projected that permafrost on the plateau will shrink 39% by mid-century (2030–2050) and 81% by the end of the century (2080-2100), compared to 1980–2000. It is hard to imagine what the plateau will look like without permafrost.”
The increase in the number and size of lakes is not good news, for it results in changes in river systems and natural disasters. “In 2012, the Zhuonai Lake (in Kekexili, Qinghai) rose and broke its banks, creating a new river. This changed the river system at the source of the Yangtze, with a new lake almost encroaching on the Qinghai-Tibet railway.”
“In 2019, a Chinese Academy of Sciences study found the Qinghai-Tibet Plateau to be one of the parts of the world most affected by global warming, with new types of disasters, such as glacial melting and run-off increasing, lakes expanding, and ice collapsing,” Yang has noted.
The United Nations Environment Programme’s Scientific Assessment of the Third Pole Environment, published in Apr 2022, found that an intensifying water cycle was leading to more frequent glacial lake outburst floods and ice collapses. And by the end of the century, the Qinghai-Tibet Plateau will be warmer and wetter, possibly causing yet more disasters, he has added.
Yang Yong is director of the Hengduan Mountain Research Institute, and was one of the first scientists to investigate the geology and hydrology of the upper reaches of the Yangtze and Yarlung Tsangpo rivers.
(Note: China refers to the Tibetan Plateau as Qinghai-Tibet Plateau)