The evaluation of changes occurring in the dynamics of arid lands and desertification processes is carried out with regard for the influence of the climatic factor on land aridization. The total land area and area of arid lands by continent, including the territory of Dagestan and the southern regions of Russia, are characterized for the first time. It is shown that the problem of arid lands and desertification has both scientific and socioeconomic meanings. In different arid and subarid zones, the origins and dynamic properties depend on region-wide conditions: in warm-temperate and subarid conditions, the processes of desertification are manifested with the leading role of the anthropogenic factor; in tropical and subtropical zones, they occur under the influence of the climatic factor.