The paleoclimate evolution curve of the South Kara Sea basin over the past 250 Myr, which is necessary for numerical reconstruction of its thermal history, was plotted using data from a large number of works devoted to studying of the paleoclimate of the Arctic sector of the West Siberian Basin. For the period from 260 to 65 Mya, the construction of the paleoclimate curve was based on a series of paleotectonic reconstructions of the studied area. The reconstruction of the climatic history of the Cenozoic was based on a detailed study of climate variations in Eurasia over the past 65 Myr. The history of sharp climate fluctuations in the last 3.5 Myr was based on information from a large number of works devoted to studying of the regional paleoclimate in the Pliocene-Quaternary. Studies published in the literature speak in favor of the limited size of the glacial covers formed within the South Kara basin. This makes it possible to neglect the effect of the porosity of sedimentary rocks from the glacial cover load in comparison with the similar effect of the load of sediments removed by erosion in the Miocene. Any correction to the paleoclimatic data due to the thermal influence of the ice sheet with its limited thickness should not exceed the error in determining the data themselves. Peculiarities in the change in temperature and the salinity of pore waters with depth determine the existence of various forms of permafrost in the shelf areas of the Arctic seas.