Under global climate change, what changes will occur to the ecological environment of the Qinghai-Tibet Plateau? Chao Shijun said

The Qinghai-Tibet Plateau is an important part of the earth's ecosystem. In recent years, climate change is having an increasing impact on its ecosystem.

In the context of global climate change, what changes will occur to the ecological environment of the Qinghai-Tibet Plateau? At the ecological and environmental protection exchange meeting in the upper reaches of the Yangtze River recently held by the Yangtze River Ecological and Environmental Protection and Restoration Joint Research Center (hereinafter referred to as the Yangtze River Center), the reporter interviewed Chao Shijun, the person in charge of follow-up research in Qinghai Province, vice president and senior engineer of the Qinghai Province Environmental Science Research and Design Institute.

China Environment News: What results have been achieved so far in the follow-up research in Qinghai Province?

Chao Shijun:The joint research on ecological and environmental protection and restoration of the Yangtze River is an important measure to promote the implementation of the central government's precise, scientific and legal pollution control requirements. Two phases of the Yangtze River resident tracking research have been carried out as an important part of the joint research. The second phase of the research in Qinghai Province is aimed at improving the quality of the water ecological environment and taking scientific and technological innovation and the transformation and application of scientific and technological achievements as the main line, supporting the Yangtze River source region to coordinate and promote the coordinated management of water resources, water ecology, and water environment, and strengthening source protection and comprehensive river basin management. Use scientific and technological support to deepen the battle against pollution. The main tasks include: finding out the current situation of water ecology in the source area of the Yangtze River, carrying out water ecological surveys and assessments, preparing technical plans for water environment issues and comprehensive management, updating the list of pollution sources, environmental issues and ecological environment information in typical areas of the basin, and carrying out a direct flow of the Yangtze River. Tracing the causes of water quality fluctuations at the national control water quality monitoring section of the Menda National Control Water Quality Monitoring Section, etc., special investigations and analysis were conducted in particular on the impact of climate change in the source area of the Yangtze River.

At present, the research team has carried out three on-site surveys from 2023 to 2024, established a database for ecological and environmental protection and restoration of resident cities, clarified the current situation of the water ecology in the source area of the Yangtze River, and compiled a water ecology survey and evaluation report. There are also problems in the source area of the Yangtze River, such as uneven regional distribution of urban sewage treatment facilities, imperfect pipe network facilities, difficulty in collecting urban sewage, sensitive and fragile ecosystems, and overall improvement of the ecological background but the basic pattern of local degradation has not been reversed. We have formed the "Pollution Control Plan for the Tongtian River Basin (called Multiple Sections) in Yushu Prefecture, Qinghai Province","Plan for Improving Water Conservation Function of Yushu Batang River Basin","Water Ecological and Environmental Problems and Comprehensive Management Technical Plan in the Source Area of the Yangtze River","Climate Change Driven" Research on Underlying Surface Changes and Runoff Effects and Prediction in the Three River Source Areas "and other technical plans, as well as the" Sanjiangyuan National Park Climate Change Monitoring Bulletin "and" Qinghai Province Action Plan Research Report on Adaptation to Climate Change " Special Report on Climate Change Monitoring and Evaluation in Qinghai Province and other decision-making consultation reports. Among them, in terms of traceability of water quality fluctuations at the Zhimenda section, our research believes that water quality fluctuations at Zhimenda may be related to natural factors such as climate warming and humidification of the Qinghai-Tibet Plateau.

It can be said that in providing policy advice (scientific and technological special reports) to ecological and environmental protection authorities at all levels, we have given full play to the scientific and technological assistance role of the second phase of the Yangtze River Joint Research Working Group, actively participated in the preliminary consultation and demonstration of relevant decisions by local people's governments, and provided policy suggestions on water environment issues and water pollution prevention and control in the source region of the Yangtze River for ecological and environmental protection authorities at all levels.

China Environment News: What impacts does climate change have on the Qinghai-Tibet Plateau?

Chao Shijun:The impact of climate change on the Qinghai-Tibet Plateau is mainly reflected in two aspects: one is warming and the other is humidification. According to research by other scholars, the Qinghai-Tibet Plateau has been the region with the fastest climate warming in my country in the past 60 years, with an obvious warming trend. From 1961 to 2020, the warming rate reached 0.34℃/10 years, more than twice the global warming rate during the same period, and was more significant in winter. The temperature rise on the Qinghai-Tibet Plateau has obvious spatial differences, and the temperature rise on the Qiangtang Plateau and the Qaidam Basin exceeds 0.40℃/10 years. The annual precipitation on the Qinghai-Tibet Plateau generally fluctuates and increases, especially in the near future. From 1961 to 2020, the annual precipitation on the Qinghai-Tibet Plateau increased by an average of 7.9 mm every 10 years. Among them, Sanjiangyuan and other places in the central plateau have benefited the most, with annual precipitation increasing by an average of 5-20 mm every 10 years.

From 1961 to 2019, the average temperature in the source area of the Yangtze River showed a significant upward trend, with an average increase of 0.41℃ every 10 years, which was significantly higher than that of the whole country and the Qinghai-Tibet Plateau; in terms of precipitation, the annual precipitation from 1961 to 2019 showed an increasing trend, with an average increase of 1.37mm every 10 years. After entering the 21st century, the overall increase was relatively large, especially from 2011 to 2019.

From 1980 to 2019, the number of snow cover days in Sanjiangyuan area showed an overall downward trend. Every 10 years, the number of snow cover days decreased by about 22 days. The first day of snow cover in Sanjiangyuan area showed a slow upward trend, and the first day of snow cover every 10 years The day of snow cover was postponed by about 3.5 days, and the day of snow cover showed a downward trend, and the day of snow cover was advanced by about 12 days every 10 years.

China Environment News: In the context of climate change, what challenges will the ecological environment of the Qinghai-Tibet Plateau encounter?

Chao Shijun:Snow mountains and glaciers are widely distributed in the Sanjiangyuan area, with a glacier resource reserve of 200 billion cubic meters. Ice and snow melt water in this area has become the main source of supply for the three rivers and one of the most sensitive areas to global climate change. Against the background of global warming, snow and glaciers in the Sanjiangyuan area have accelerated melting, and freshwater resource reserves have gradually decreased, resulting in the destruction of the already extremely fragile ecological environment.

Based on remote sensing data and two periods of glacier cataloging data in my country, statistics and analysis were carried out on the distribution status of glacier resources, spatio-temporal change trends of glaciers, and abnormal change characteristics of glaciers in Qinghai Province. We found that the number, area, average length and ice reserves of glaciers in Qinghai Province all showed a decreasing trend from 2000 to 2020. The number of glaciers decreased by 128, the area decreased by 464.63 square kilometers, and the length decreased by 0.08 kilometers. Ice reserves have been reduced by 29.58 cubic kilometers. Rising temperatures during the ablation season will greatly enhance the ablation rate of glaciers, accelerate the retreat of the glacier end and the shrinkage of the area. Rising temperatures in winter and spring will cause a larger proportion of precipitation to land on the glacier in the form of rainfall. Surface, accelerating the melting of glaciers in winter and spring.

Climate change has also led to the expansion of lakes on the Qinghai-Tibet Plateau. In recent years, the lake area in some areas of the Qinghai-Tibet Plateau has significantly expanded and the water volume has increased. The lake area of the Qinghai-Tibet Plateau accounts for 57.2% of China's lake area. Among them, 80% of the lakes have expanded, and the area has increased by 5676 square kilometers in the past 50 years. Rising temperatures and increased precipitation are the main reasons. The lake area of Selincuo, the largest lake in Xizang, increased by 650.70 square kilometers from 1988 to 2020.

Based on remote sensing data and monitoring data, algorithms such as normalized difference water body index were used to analyze and evaluate the impact of climate change on the water area and water level of key lakes such as Qinghai Lake, Zhaling Lake, Eling Lake and Hala Lake. Affected by the combined impact of the increase in glaciers, snow melt water, and increased precipitation, the area of lakes in Qinghai has continued to increase. After 2000, the area of lake water has shown an increasing trend, with Qinghai Lake showing a change trend of shrinking first and then expanding.

Climate change also affects river runoff changes on the Qinghai-Tibet Plateau. Based on hydrological, meteorological and other data, climate statistics and SWAT models were used to analyze and evaluate the impact of climate change on runoff in the source area of the Yellow River, the source area of the Yangtze River, the source area of the Lancang River, and the inland rivers of the Qaidam Basin. From 1961 to 2022, the average annual flow in the source area of the Yellow River generally showed a decreasing trend, with frequent alternation of abundant and dry; the average annual flow in the source area of the Yangtze River generally showed an increasing trend. In the 21st century, the continuous increase in precipitation has led to a significant increase in annual flow; Affected by the increase in temperature, the increase in ice and snow melt water and the significant increase in precipitation, the runoff of inland rivers in the Qaidam Basin has increased; Climate factors affecting river runoff mainly include precipitation, evaporation and air temperature. Climate change has the most significant impact on river runoff in the source area of the Yangtze River and inland river in the Qaidam Basin, followed by the source area of the Yellow River and Lancang River.

In the context of global warming, the increase in glacier melt water and the increase in runoff into lakes will cause greater disturbance to the sediment and increase the turbidity of the water body, which will easily cause adverse effects on benthos. The desalination of water accompanying the expansion of lake area may reduce or even eliminate some salinity-sensitive species that are only distributed in a small area, and are replaced by other species.

Climate change affects the carbon sequestration capacity of vegetation in the Sanjiang Source Area. Through the assessment of the productivity impact of vegetation carbon sequestration, the carbon sequestration capacity of vegetation ecosystems will continue to increase from 2001 to 2022. The carbon sink and carbon source area of the vegetation ecosystem account for 85.3% and 14.7% of the total area respectively. The carbon sink area continues to increase, while the carbon source area gradually decreases. Under the future global temperature rise of 1.5℃, the carbon sequestration of vegetation ecosystems in this region will increase overall; under the temperature rise of 2.0℃, there will be certain risks to the carbon sequestration capacity of the eastern part of Sanjiangyuan District.

China Environment News: How will Qinghai's stationed work be carried out next?

Chao Shijun:Combined with the first and second phase of the on-site tracking research in Qinghai Province, in the next step, we will use the gradually improved data to carry out high-resolution climate simulation and data assimilation to explore the feedback process between climate change and the plateau ecological environment in different regions.

The research team will also further study the important impact of human activities on the ecological environment, couple climate change and human activities, and explore the response degree and process of ecosystems to human activities and climate change on different spatio-temporal scales. The spatial modal analysis and physical mechanism interpretation of altitude-dependent warming are still controversial, and there is still much room for research on the impact of climate change on the plateau ecological environment.

In addition, the permafrost region of the Qinghai-Tibet Plateau has huge carbon reserves. The research team will quantitatively assess the role of permafrost ecosystem activities in reducing emissions and increasing sinks, accurately simulate organic carbon emissions in permafrost regions, and provide scientific basis for effectively managing ecosystem carbon sinks. Achieve carbon peak and carbon neutrality.

In the next step, under the guidance of the Ministry of Ecology and Environment and the Yangtze River Center, we will continue to improve the scientific and technological assistance mechanism based on the first and second phases of the on-site follow-up research and combined with the actual situation of Qinghai Province, and continue to make efforts in the scientific research team construction of "Sanshui Co-governance", the overall and collaborative management of "Sanshui", the research and development of ecological restoration technologies to address climate change, and the construction of provincial scientific and technological innovation platforms to effectively promote the application and transformation of results, and use science and technology to support the aquatic ecological environment in the source area of the Yangtze River. Protection and restoration.