June 30, 2022
Check out “Rivers of Change” a new StoryMap* that will help people visualize NWT’s changing permafrost landscape. The StoryMap was produced through collaboration between the Northwest Territories Geological Survey (NTGS) and Carleton University Northern Studies MSc student Sarah Simpkin.
“Rivers of Change” acts as an introductory portal to key research published by Kokelj et al. last year in The Cryosphere. That paper represents the first time a research team led by several NWT-based scientists has brought together permafrost information from so many quarters, including hard-won data gleaned through collaboration with academic and Indigenous partners. The team has coupled tireless fieldwork, collection of novel drone survey data, and interpretation of satellite imagery to gain new insights on the impacts of permafrost thaw on the lakes and streams of northwestern Canada.
Check out a summary of that work.
A Little Background
In the western Canadian Arctic, remnants of the melting Laurentide ice sheet were buried in sediment and have been preserved as ice-rich permafrost for over 12,000 years. Research shows that the thawing of this icy permafrost is dramatically modifying Arctic landscapes, causing large landslides with cliff-like headwalls up to 30 m high to develop. The largest of these massive disturbances, also known as retrogressive thaw slumps, can exceed 800 meters in diameter and displace millions of cubic meters of thawed, muddy sediments, which can flow downslope creating thick tongues of debris up to 2 km long. These huge debris deposits obstruct the normal flow of streams and rivers, fill lakes with sediment, threaten roads, and create obstacles for wildlife and land users.
In addition to changes in the landscape, the water quality of downstream environments is also greatly affected by the thawing of ice-rich permafrost slopes. Impacted lakes and streams become increasingly muddy, and the concentrations of dissolved materials such as calcium, sulphate, and metals can significantly increase. Thawing permafrost also releases carbon into the atmosphere.
This research developed models and maps that help identify the locations and severity of permafrost landslide effects, and which downstream lake and stream networks and coastal zones are being most impacted. The mapping products enable environmental managers, communities, land users, and scientists to visualize the impacts that permafrost thaw and retrogressive thaw slumps have on northern landscapes and water bodies.
The research has shown that permafrost landslides across the study area have increased by 10 to 100-fold over the last 3 decades. Once a landslide initiates, the removal of vegetation and the organic moss layer that insulates permafrost can make these slopes even more susceptible to future land disturbances. While mitigating the largest disturbances is impossible, identifying and avoiding sensitive slopes or remediating sites before major landslides develop could be implemented as management tools. In addition, installing monitoring equipment on roadsides that provides real-time information can help infrastructure managers monitor land movements and ensure public safety.
Dr. Kokelj from the NTGS notes that this work is not an endpoint but rather just a beginning. A deeper understanding of this climate change-related process can help us to better predict how the landscape will evolve in the future, which can inform infrastructure planning, and can lead to better prevention and management strategies. Numerous researchers are also paying attention to the team’s research results, and the work has sparked rapidly growing interest from national and international scientists. Climate-driven permafrost thaw is expected to increase in the coming decades, and a better knowledge base will inform decision making and ensure a more resilient northern society.
*StoryMap is a tool that helps to integrate dynamic maps with story elements and images to help immerse viewers in geographic information.