Arctic climate change has the potential affect access to semi-permanent trails on land, water, and sea ice, which are the main forms of transport for communities in many circumpolar regions. Focusing on Inuit Nunangat (the Inuit homeland in northern Canada), trail access models were developed, drawing upon a participatory process that connects Indigenous knowledge and science. We identified general thresholds for weather and sea ice variables that define boundaries that determine trail access, applying these thresholds to instrumental data on weather and sea ice conditions to model daily trail accessibility from 1985-2016 for 16 communities. We find that overall trail access has been minimally affected by >2°C warming in the last three decades, increasing by 1.38-1.96 days, differing by trail type. Across models, the knowledge, equipment, and risk tolerance of trail users was substantially more influential in determining trail access than changing climatic conditions.The Arctic is undergoing transformative climate change, with profound implications for transportation 30,31 . Studies seeking to understand these impacts have primarily focused on quantifying how transport-relevant climatic conditions are changing and modeling future climate trends, focusing on shipping and winter roads 32,33 . A smaller body of research focuses on unmaintained semi-permanent trails on the sea ice, lakes, rivers, ocean, and the frozen ground (referred to as 'trails'), which are critically important for travel between settlements, to cultural sites, and for practicing traditional hunting, fishing, and gathering activities 34,35 . This work catalogues local observations of changing climatic conditions and examines how they are affecting access 36,37 , but does not assess regional trends or quantify how climate affects transportation. An absence of integrative approaches that cross scales and incorporate qualitative and quantitative methods has been noted to constrain understanding of how climate change affects Arctic transportation systems 33,38 .This paper develops a modeling framework to connect Indigenous knowledge (IK) and science to quantify how climate change affects trail access, focusing on the Inuit Nunangat. The 50 permanently inhabited communities of the Nunangat are primarily coastal, accessible year-round by air, with marine transportation possible in the summer. Travel outside of settlements by all-terrain vehicle (ATV), small watercraft, and snowmobile is common year-round, involving the use of extensive networks of trails on the land, water, or sea ice, often involving traveling hundreds of kilometers in remote regions. The region is witnessing rapid warming, with Inuit one of the most sensitive populations globally to climate impacts 39 .
Three decades of trail access trendsTrail access models were created using the modeling framework described in Online Methods based on indepth research in 9 communities, and specify quantitative thresholds for weather and sea ice variables that determine trail access. Models were cre...