The results of mathematical modeling of the dynamics of fields of thermokarst lakes in the permafrost in Western Siberia until the end of this century is presented. Described geoimitation-regression model of the dynamics of thermokarst-lake fields, whose properties are determined on base of statistics of the location coordinates and lake areas, obtained experimentally using multi-temporal Landsat satellite images for the period 1973-2009 yrs. The model accounts the relationship of thermokarst lake and climate changes, established on the basis of multivariate regression analysis of experimental data. Forecast of field dynamics of thermokarst lakes in West-Siberian permafrost until 2100 with the help of computer simulations on this model based on the predictions of temperature changes, obtained V.V.Klimenko et al for the study territory. It is shown that the gradual increase in temperature by 2100 to 2 - 3,5 ° C will cause a continuous reduction in the area of thermokarst lakes, which is an indicator of the continuing degradation of permafrost and permafrost strength reduction by the end of the century. This research was supported by ESA CAT-1 Project ID:5762 «Cryogenic processes monitoring in Russian permafrost territories using radar data», RFBR Project No. 12-05-90833-mol_rf_nr and Megagrant of Russian Federal Programme Project 14.B25.310001 (BIO-GEO-CLIM).