Deserts are moving closer to where humans live. This means sand is spreading closer to villages and cities. This process is called desertification. A big cause of desertification is overgrazing By animals and burning the grassland for farming. Animals hooves pack the dry arid dirt. This makes it much harder for rain to support erosion. This increases vegetation The only way to stop desertification is to help vegetation grow by giving land more water. But some oppose this idea.