GEOG M109 Lecture Notes - Lecture 10: Water Cycle, Fluid Dynamics, Longwave
Document Summary
Drylands: areas that experience a deficiency in water availability on an annual basis. Precipitation is characterized by high variability in both time and space. First definition by aubreville (1949): describe the change towards more desert-like conditions in humid areas adjacent to the sahel desert in west. There has been some variability in how desertification" is defined, mainly different in impacts and causes. Impacts: some definitions emphasize the economical impacts, and others refer to it as degradation of landform and destruction of vegetation cover. Causes: some stress the importance of human causes. Others admit the possible importance of climate control but give them a relative inferior role. Others are more open-minded with respect to natural causes. According to un convention to combat desertification: desertification is land degradation in arid, semi-arid and dry subhumid areas resulting from various factors, including climate variations and human activities.
