Read at : Google Alert – desertification
http://www.inqua2011.ch/?a=programme&subnavi=abstract&id=1122&sessionid=69
The concept of Natural Desertification – the Global approach
Yoav Avni
In the arid and semi arid regions of the Southern Levant, Inner Mongolia and Southern Australia, located in two different hemispheres, field observations and luminescence dating indicate that major deposition of fluvio-loess sediments, with minor erosion cycles, occurred during the Late Pleistocene glacial period (OIS 4, 3 and 2). These sediments, which were rapidly transformed into loessic soil, support rich natural biomass and have agricultural potential. Severe soil erosion started during OIS 2 and intensified throughout the Holocene, mainly by the action of gullies and upstream migration of headcuts. In the loessic basins of Inner Mongolia, major gullies were found to be long lasting phenomena, initiated long before the Middle Pleistocene. In all sites the present interglacial climate is causing extended soil erosion and reduction in natural biomass and agricultural potential. This process started long before the anthropogenic intervention became significant in the environment and are regarded as clear indicators of Natural Desertification processes, acting on a global scale.
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