Cryospheric changes and their impacts on regional water cycle and ecological conditions in the Qinghai-Tibetan Plateau
YAO Tan-Dong; Qin Da-He;SHEN Yong-Beng; ZHAO Lin;WANG Ning-Lian;LU An-Xin
2013, 35(3):
179-186.
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The Tibetan Plateau is the most concentrated glacier center in the middle and low latitudes of the Earth, also the center of the glacier distribution in China and the High-Asia, feed seven of Asia’s great rivers, is the headwater of rivers that flow down to half of humanity, the called the “Water Tower of Asia”. Consistent with the global climatic warming since 1980, glacier shrinking is more serious with accelerated retreat trend since 1990. All glaciers turned to shrinking status except for some large glaciers in the Tibetan Plateau. Permafrost regions occupy approximately 53% of the land area on the Qinghai-Tibet Plateau, the highest and most extensive high altitude permafrost on Earth. Permafrost in the Qinghai-Tibetan Plateau is highly sensitive to climate change and has experienced significant temperature increases and widespread degradation during the last several decades. Over the past 50 years, the trend of snow-covered areas in the Qinghai-Tibetan Plateau have been decreasing. As temperatures rising, the area of the snowing and snow cover critical state have been greatly increased, resulting in beginning time delay and end date in advance of the snow cover period in the Qinghai-Tibet Plateau. The glacier ablation is accelerating, glacier melting water has been increasing year by year,and leading to the changes in the spatial and temporal distribution of water resources and the water cycle process change, will no doubt give a profound impact on social and economic development in the Qinghai-Tibet Plateau. The alpine meadow and swamp
meadow ecosystem related to permafrost has an important function in water regulation, and to stabilize the local water cycle and runoff in the river systems. Thawing and degrading permafrost will have a significant impact on plateau environments and ecosystem with disastrous consequences. The permafrost thawing due to temperature rise is one of the main factors which led to the degradation of the alpine ecosystem. The ecological degradation and changes of hydrological environment of rivers, lakes, swamps, wetlands are closely related to permafrost degradation in last decades in the river source regions of the plateau. Over the past decade, several times across the board extensive renovations of the Qinghai-Tibet Highway has been carried out due to frost heave and thaw damage. In next several decades, It is predicted that air temperature will increase by 2.6℃ by the mid 2050s, and this will be climate warming transfers into permafrost temperature increases and degradation, the majority of permafrost on the Qinghai-Tibet Plateau will thaw dramatically in the next few decades. Additional human activities, such as operations of the Qinghai-Tibet Highway/Railway and rapid development of economy, will also accelerate permafrost warming, thawing, and eventually disappearing. This process will lead to freeze-thawing disasters related to the permafrost change, such as the thaw slumping, frost heaving, thaw subsidence, frost boil. To adapt the impacts of climate change on the cryosphere of the Tibetan Plateau, we should strengthen the comprehensive and systematic monitoring of changes in glacier hydrological processes and prediction possible future disasters, evaluation of the risk of
disasters on the basis of scientific prediction and census.
