Degradation of potential winter roads threatens vulnerable communities’ freight accessibility in the pan-Arctic region

Winter roads, which are seasonal roads built on frozen surfaces, serve as a socio-economic lifeline in the pan-Arctic region but are sensitive to amplified Arctic warming. Potential winter roads (PWRs) refer to areas where environmental conditions are suitable for forming the frozen foundation of winter roads. These roads are used to support various vehicles for diverse transportation purposes. However, PWRs for different vehicles (PWRDVs) have not been systematically identified, and the impact of changes in PWRs for freight vehicles on community freight accessibility remains unclear. This study quantified changes in PWRDVs in the pan-Arctic region during the water years 2003–2022 and assessed community freight accessibility under these changes. Results indicate that PWRs for heavier vehicles exhibited smaller areas (ranging from (6.32−8.02) × 10⁶ km² as multi-year averages), shorter durations (ranging from 160 to 180 d for areal and multi-year averages), and more severe degradation. Degraded PWRDVs were primarily observed in the Eurasian Arctic. PWRDV areas decreased by (1.6–3.7) × 10⁴ km² per year (2%–6% per decade). Shortened durations occurred in 8%–21% of PWRDVs, with average reductions of (1.30–2.03) d per year (7%–13% per decade). Some degradation trends were more pronounced than previously documented long-term trends, suggesting accelerated degradation in recent years. Without artificial improvements to other transportation infrastructure, the degradation of PWRs for freight vehicles led to reduced freight accessibility, with improvements in accessibility through PWRs decreasing by 2%–73% per decade in 155 communities, most of which were considered vulnerable due to their relatively large populations and remoteness. These findings provide insights into changes in winter roads and can help enhance the resilience of winter roads and communities to climate change in the pan-Arctic region.