Effective monitoring of permafrost coast erosion: Wide-scale storm impacts on outer islands in the Mackenzie Delta area.

Permafrost coasts are extensive in scale and complex in nature, resulting in particular challenges for understanding how they respond to both long-term shifts in climate and short-term extreme weather events. Taking examples from the Canadian Beaufort Sea coastline characterised by extensive areas of massive ground ice within slump and block failure complexes, we conduct a quantitative analysis of the practical performance of helicopter-based photogrammetry. The results demonstrate that large scale (>1 km2) surface models can be achieved at comparable accuracy to standard UAV surveys, but 36 times faster. Large scale models have greater potential for progressive alignment and contrast issues and so breaking down image sequences into coherent chunks has been found the most effective technique for accurate landscape reconstructions. The approach has subsequently been applied in a responsive acquisition immediately before and after a large storm event and during conditions (wind gusts >50 km hr-1) that would have prohibited UAV data acquisition. Trading lower resolution surface models for large scale coverage and more effective responsive monitoring, the helicopter-based data have been applied to assess storm driven-change across the exposed outer islands of the Mackenzie Delta area for the first time. These data show that the main storm impacts were concentrated on exposed North orientated permafrost cliff sections (particularly low cliffs, >20 m in height) where cliff recession was 43% of annual rates and in places up to 29% of the annual site-wide erosion volume was recorded in this single event. In contrast, the thaw-slump complexes remained relatively unaffected, debris flow fans were generally more resistant to storm erosion than the ice-rich cliffs, perhaps due to the relatively low amounts of precipitation that occurred. Therefore, the variability of permafrost coast erosion rates is controlled by interactions between both the forcing conditions and local response mechanisms. Helicopter-based photogrammetric surveys have the potential to effectively analyse these controls with greater spatial and temporal consistency across more representative scales and resolutions than has previously been achieved, improving the capacity to adequately constrain and ultimately project future Arctic coast sensitivity

Towards more inclusive and solution orientated community-based environmental monitoring

Rapid climate-driven environmental change continues to threaten front-line communities that rely on Arctic landscapes to sustain their way of life. Community-Based Monitoring (CBM) can increase our knowledge of environmental change and understanding of human-environment interactions occurring across the Arctic. However, the depth of CBM research outcomes have been limited by an imbalance in contributions from external researchers and community members. A detailed literature analysis revealed that the number of studies documenting CBM approaches in Inuit Nunangat (Inuit homeland in Canada) have increased over the last decade. We identify that bottom-up guiding protocols including the National Inuit Strategy on Research, has increased community engagement in Arctic research processes and equitable outcomes. However, these increases have been concentrated on wildlife-based research where consistent funding streams and pre-existing alignment with community priorities exist. To explore the potential for guiding principles to be more successfully incorporated into impactful CBM, we present a co-developed environmental CBM case study aiming to document and aid understanding of climate-driven landscape change near Tuktoyaktuk, Inuvialuit Settlement Region, Canada since 2018. A foundation of early dialogue and collaborative partnerships between community members and external researchers formed the basis of a community-based climate monitoring program driven by community research priorities. A succession of funded CBM projects at Tuktoyaktuk demonstrated that longer term and resilient climate monitoring can bring together Scientific and Indigenous knowledge systems. Progressing beyond an emphasis on data collection is vital to sustain monitoring efforts, capacity sharing and co-dissemination processes to ensure research is communicated back in a way that is understandable, relevant, and usable to address community priorities. The need for successful CBM is often at odds with current research funding structures, which risks a fragmented mosaic of early-stage initiatives focused on understanding environmental problems rather than sustained and progressive research development towards cooperative solutions