Fig. 4: Transit times for the fastest trans-Arctic shipping routes during summer (1979–2014).

a–d show results for Polar Class 6 (PC6) ships; e–h for Open Water (OW) ships. Violin plots represent transit times (days) for routes between St. John’s and the Bering Strait (left subplot) and between Rotterdam and the Bering Strait (right subplot), based on both the multi-model mean (MMM) and the reference dataset (REF). In each violin plot, the black solid line indicates the median, and black dashed lines denote the quartiles.