The method based on the established quantitative relationship between Budyko's radiative index of dryness and modal values of some regional virgin soils properties was applied to predict the integral soil fertility index alteration at altitudes from 0 to 2500 m above sea level because of expected global climate change during XXI century. The existing data of predicted air temperature, global radiation and precipitation were used in the analysis. Finally, the areas with different levels of agricultural and virgin soils fertility alteration due to the climate change were determined.