 The study analyzes sea ice conditions and navigability along four typical routes of the Northeast Passage using remote sensing data from 1979 to 2019, and finds that the annually averaged sea ice concentration has decreased over the past 41 years, with the fastest rate of decrease occurring in the Kara Sea. The study also shows that air temperature is becoming a significant driving force of melting ice in these routes, while surface winds are crucial for navigability in certain areas. This article was authored by Miao Yu, Peng Lu, Ji Yu and Li, and others.