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The impact of climatic changes on permafrost degradation in source region of the Yangtze River

During the past fifty years, permafrost in source region of the Yangtze River (SRYR) has been degrading at a rapid rate due to the influence of increasing human activities and climatic changes. As we all know, the population density in SRYR is not more than one person per square kilometer, so impact of human activities on permafrost is far less than that of climatic changes. Increase of air temperature has resulted in an increase in ground temperature, deepening of permafrost table and shrinkage of permafrost area. In addition to air temperature, many other meteorological factors especially sunshine duration and annual snow cover also have a direct effect on permafrost temperature and can modify the effect of changes in air temperature. In this paper, we analyzed the status of permafrost degradation and the variations of air temperature, sunshine duration and snow cover, pointed out the relationship between permafrost degradation and climatic changes.