Partnership Workshop: Impacts of permafrost thaw in mountain areas of Canada and beyond
From 22–25 October 2014, 30 senior experts from academia, industry and government met near Whistler in order to develop priorities for research and knowledge transfer related to permafrost thaw in Canadian and other mountain environments. The workshop organized by Stephan Gruber, Marten Geertsema, and Lukas Arenson received support from the Natural Sciences and Engineering Research Council of Canada (NSERC), BGC Engineering Inc., the British Columbia Ministry of Forests, Lands and Natural Resource Operations, and Carleton University.
More information: Participants
Discussions addressed four key questions and the results are similarly grouped around these themes: (1) What is noteworthy about permafrost in mountains? (2) What is the relevance of permafrost in mountains? (3) What research and development needs exist? (4) What is a good way forward?
What is noteworthy about permafrost in mountain regions?
Spatial extent: About one third of the global permafrost region is situated in mountainous terrain and a significant proportion of Canada’s permafrost region has high-relief topography. For example, more than half of British Columbia’s permafrost occurs in mountains, extending southward far beyond permafrost in lowlands and valleys. But also Alberta, the Yukon, the Northwest Territories, Nunavut, Quebec, and Labrador have permafrost in their mountain areas. Although permafrost (being a subsurface thermal condition) cannot be directly observed, the significant reduction in mountain glacier and snow cover is a clear indicator of climate change that, invariably, will also result in widespread thaw of permafrost. Thaw is understood here as the state of losing ice content through melt.
Inclusive view: Permafrost in mountainous areas is governed by the same basic processes as permafrost in other environments. Although, mountain topography and terrain related mass movements yield a much greater diversity of materials and temperatures per unit area, than is encountered in cold lowlands, the governing principles are the same. Permafrost in mountainous regions thereby enriches the variety of phenomena encountered beyond what is found in lowland areas. A combined view on permafrost in differing environments is useful for informing research and engineering. The expression “permafrost in mountainous regions” is preferred over “mountain permafrost” as it avoids implying separate entities.
Distinct characteristics: Permafrost in mountains is special in terms of: (a) Extreme environmental gradients (due to elevation change, insolation, avalanches, etc.) resulting in the juxtaposition of conditions that would otherwise be found at distances of hundreds or thousands of kilometers. (b) Permafrost and glacial environments often coexist and interact. Outside mountainous regions, glacial and permafrost research is more often related in the context of Quaternary history, only.
Distinct phenomena: A number of phenomena related to permafrost are most prominently or exclusively observed in mountainous areas: thermal effects of air advection in slopes composed of coarse materials, compaction of avalanche snow and debris into ice-rich permafrost, slow, gravity driven mass movements of ice-rich sediments, rock glaciers, intense sediment dynamics including rock fall and debris flows, as well as strong ground water flow and extended unsaturated zones. These phenomena originate from the high potential energy available in mountain terrain causing gravity to have a greater effect on many processes compared to lowland environments.
What is the relevance of permafrost in mountain regions?
Hazards: Permafrost thaw in the mountains will increase the probability of geohazards such as debris flows, rock falls, rock avalanches, and displacement waves. Due to the high potential energy and possible process transformations, these phenomena can have a very far reach that frequently extends to lower-lying areas without permafrost. For lack of established best practices, hazard mapping for linear infrastructure (roads, rail, pipelines, transmission lines) on valley floors often under-appreciate these risks. A number of geohazards without historic precedence in terms of location, frequency, magnitude and processes have been observed to originate from permafrost areas in mountains. Permafrost in mountains adds an additional element of uncertainty to the identification and quantification of geohazards.
Water: Permafrost thaw can strongly affect the quantity, timing, geochemistry, and sediment concentration of runoff and thus affect aquatic ecosystems, growing conditions for vegetation, and drinking water safety. Increased sediment input by rock fall and debris flows can have long lasting effects on bed load and channel geometry of rivers. In the subsurface, groundwater flow and permafrost interact and correspondingly, hydro-thermal effects of e.g. mining can be difficult to predict.
Landscape evolution: Permafrost and glaciers often coexist in mountains. Glaciers respond to climate change much more rapidly than permafrost. Many mountain landscapes will likely be devoid of glaciers while permafrost lingers and its geomorphic effects take over. Permafrost is relevant in shaping mountain topography where frost weathering and glacial erosion and sediment transport work in concert.
International: Many mountain regions in South American and in Asian mountain ranges have extensive permafrost areas that we know rather little about. Especially in the Hindu Kush Himalayan region, many of these areas are densely populated. Broadening Canadian permafrost expertise to also include mountain environments outside Canada can provide important insight, an advantage for Canadian engineering supporting large projects in the areas, and, it can become a distinctly Canadian aspect of foreign aid.
What research and development needs exist?
Improved understanding of processes and phenomena is required in key areas: (a) How runoff and water quality are affected by changes in permafrost and seasonally frozen ground. (b) How ground temperatures and the ground ice contents vary spatially and in the future beneath mountain slopes. (c) How and how much carbon is incorporated into frozen deposits by e.g., solifluction, in peatlands, or with valley fills. (d) How vegetation and permafrost interact in mountains. (e) How rock slopes and their stability respond to permafrost degradation. (f) How permafrost and groundwater flow interact in mountains.
Methods and technology are required for simulation studies and site investigations. This includes: (a) Back analysis of major geohazard events and the role of permafrost. (b) Identifying priority areas for detailed geohazard investigation, e.g. permafrost in proximity or upslope of infrastructure. (c) Simulation of permafrost characteristics in mountain terrain and their transient changes. (d) Development of technologies that allow an efficient and reliable identification of areas susceptible to permafrost thaw. This is important for prediction and for investigating which regions and configurations are most sensitive to change. (e) Homogenous data repository for permafrost monitoring data.
Long-term monitoring of permafrost and related phenomena in mountains is required for informing research, industry and governments, for understanding environmental changes, and for developing and testing computer models and other new technical developments.
Baseline data that are suitable for supporting permafrost research in mountains. This includes high-elevation meteorological stations, snow observations, stream flow and water quality measurements, and meteorological models and re-analyses.
What is a good way forward?
Coordination: As data in mountains is sparse, coordinated and co-located research activities as well as data exchange between diverse actors and domains such as hydrology, avalanche warning, glacier research, national parks, and provincial/territorial governments is indispensable.
Supersites: The establishment of focus areas for long-term measurements is important for the execution of long term research programs, monitoring of environmental changes, and for the testing of computer models and other innovations.
Collaborative research to address the research and development needs outlined will develop the Canadian knowledge base and community towards more and more interconnected and multi-disciplinary expertise on permafrost in mountainous areas.
Dissemination of information about permafrost in mountains and its relevance to stakeholders towards government agencies, industry, and professional organizations is important.
Representation in national (e.g. via the Canadian Geotechnical Society and the Canadian National Committee of the International Permafrost Association) and international organizations (e.g. via an Action Group in the International Permafrost Association) will provide further visibility and points of contact.