RECENT DEGRADATION OF PERMAFROST IN CHINA AND THE RESPONSE TO CLIMATIC WARMING

With climatic warming, significant changes are occurring in the permafrost regions in China. On the QinghaiXizang Plateau, the southern limit of permafrost has been degrading at a rate of hundreds of meters per year in recent decades. The thickness of the active layer is increasing by about 2-10 cm/a and the average annual temperature of the frozen ground is increasing by about 0.07-0.21¼C/10a. The changes are approximately the same order of magnitude in the alpine permafrost zone in the Tianshan Mountains. In northeastern China, the changes of permafrost are more evident. The southern limit of permafrost is moving northward at a rate of 1500-3000 m/a, the permafrost table is descending at a rate of 9-11cm/a, and the average annual temperature of the frozen ground is increasing by 0.13-1.6¼C/10a. These changes in permafrost correspond to climatic change in China. During the past decades, a marked rise of air temperatures in the northwestern, and especially in the northeastern region of China correlates with the degradation of the permafrost.