Soil degradation, in particular soil erosion, is a major environmental problem in many countries as it can lead to irreversible damage. Contaminated soil has a major impact on the quality of groundwater. Processes relating to industrial and agricultural activities, transport and urbanization contribute substantially to the chemical contamination of soil through the accumulation of waste and pollutants and through acidification by airborne and waterborne pollutants. Desertification and water shortages are a serious environmental problem affecting the most fragile areas. It is affecting the Mediterranean region and some countries in transition. At present, data on recent trends in desertification and on the factors and processes involved are poor. More research on climate change in connection with desertification is needed.