中国气候变化信息网 China Climate Change Info-Net

(2017-06-19)Overall ecological system improving despite human activity

China on Saturday began its second scientific expedition to the Qinghai-Tibet Plateau to assess the tremendous changes of the past decades due to climate change and human activities.

Following an expedition in the 1970s, researchers from the Chinese Academy of Sciences (CAS) launched an expedition that will last five to 10 years. They will make a comprehensive survey of the plateau's glaciers, biodiversity and ecological changes, as well as monitor changes to the region's climate.

Their first stop will be Serling Tso, a 2,391-square-kilometer lake that was confirmed to have replaced the Buddhist holy Namtso Lake as Tibet's largest in 2014. CAS will take more than 100 scientists to the lake area and to the source of the Yangtze, China's longest river, the Xinhua News Agency reported.

To provide fundamental data for China's newest national park, the Third Pole National Park, Hou Juzhi, a CAS research fellow, told the Global Times that his team will conduct research on the lake sediments so that they can learn about the lake's climate, environment and ecological changes during the past 200 years.

As the source of several major rivers, the plateau supplies water to nearly 2 billion people. It is facing serious challenges, including glacier melt and land deterioration due to global warming and human activities. Its ecology is fragile and once damaged, it is difficult to recover, said Li Junsheng, an environmental expert at the Chinese Research Academy of Environmental Sciences.

"This expedition will play a significant role in discovering new species. They will also seek to explain more natural mysteries and traces of human development [on the plateau]," Li said.

Retreating glaciers

China's first expedition to the plateau was in the 1970s, covering many fields, including geological structure, prehistoric life, geophysics, climate, zoology and botany. The new round of research will focus on the changes since then.

Zhu Liping, a CAS research fellow leading the lake observation team, told Xinhua that the surface of Serling Tso Lake had expanded 40 percent between 1976 and 2009. Since 1990, water in the plateau's 1,000 lakes has increased by 100 billion cubic meters.

"Glaciers on the Tibetan plateau are in retreat due to rising temperatures. Research shows that glacier ice has decreased by 8,000 square kilometers, or 15 percent, due to climate change. In the long-term, it will have a negative impact on the ecology of the downstream region," Li said, adding that permafrost melting would also lead to desertification and geo-engineering problems.

A 2015 CAS report predicted that more than 80 percent of Tibetan Plateau permafrost could be gone by the year 2100, and that almost 40 percent of it would be gone within the "near future."

The report said the plateau has already shown increasing desertification, mainly around the source region of the Yangtze River, where the desert area has reached 33,200 square kilometers, or 66 percent of the total desert land around all the headwaters of China.

Li added that human activities, such as overgrazing and illegal mining have also affected the plateau's ecosystem.

Despite that, experts agreed that the overall situation of the ecological system on the Tibetan plateau is improving.

The CAS report said the Tibetan plateau remains one of the world's cleanest regions. Pollutant levels recorded on the plateau are similar to those seen across the Arctic, and remain remarkably lower than densely-populated areas. The report attributed it to the efforts of forestry conservation and restoration.

The new national park, another major conservation effort, will be the world's largest, at some 2.5 million square kilometers. Researchers said part of the summer's expedition would be to establish the park boundaries, the South China Morning Post reported.

On the archaeological front, scientists will look for evidence that can prove an earlier archaeological discovery of a Paleolithic ruin at Serling Tso, suggesting that humans might have lived there some 30,000 years ago. Archaeologists will try to answer why humans came to the plateau, where they originated, and how they adapted to high-altitude living, said team leader Deng Tao, deputy director of the Institute of Vertebrate Paleontology and Paleoanthropology, under CAS.