12 22 http://en.russian-arctic.info/upload/iblock/51b/51b2842a704c757cadb219dd8ef03deb.pdf Dependence of the modern icebreaker fleet from ice conditions on the Russian seas The article considers the current state of the Russian icebreaker fleet. The possibility of using such a parameter as the sum of degree-days of frost to characterize light, medium and heavy ice conditions in the non-Arctic seas is proved. The analysis of restrictions of the regime of ice navigation of vessels of different ice categories in the waters of the non-Arctic seas for light, medium and heavy ice conditions is carried out. A quantitative assessment of the compliance with technical specifications of the icebreaker fleet on the seas with different ice conditions in these seas. It is shown that the power of the modern icebreaker fleet allows navigation on the Russian seas to be equally successful in conditions of mild and moderate, and in conditions of severe and extremely severe winters. At the same time, the increase in the power of the icebreakers under construction and design and the decrease in the thickness of ice due to sustainable warming in all Russian seas increase the guarantees of safety of the navigation of ships and icebreakers in ice and reduce the dependence of ice navigation on the severity of ice conditions. Based on the analysis of the construction and operation of the icebreaker fleet in the XXI century, it is concluded that the real difficulties of winter navigation in the non-Arctic seas are associated primarily with an increase in the number and size of vessels which participate in icebreaking operations. ice conditions ice cover of the seas ice thickness power of the icebreaker safety of the navigation sum of the degree-days of frost 0 I.O. Dumanskaya