Desertification occurs from climate change and human activities. It occurs primarily to semi-arid areas where the natural vegetation is stripped, thus causing the desert to expand. An example of desertification is the expansion of the Gobe desert in Mongolia. As the Gobe desert expands, it blows large dust clouds over parts of China and impacts on the total world's climate. One of the causes of the expansion of the Gobe desert is the raising of sheep in Mongolia in order to provide the demand for cashmere wool clothing. This is an example of how what seem to be insignificant human activities can, in fact, have large regional and world-wide impacts.