This study explored how landscapes are changing as permafrost thaws in the Taiga Plains ecoregion of northeastern British Columbia and southwestern Northwest Territories.
Islands of boreal forest in northern BC and southern NWT are shrinking and disappearing as warmer air temperatures induced by climate change thaw the layer of permafrost supporting them. Without these forested plateaus, water previously trapped in isolated wetlands drains away, impacting the availability and sustainability of freshwater resources.
Long-term and large-scale studies such as this project document how the landscape has changed in recent years and predict how it may change in the future. This is vital for land use planning and water security, and provides necessary baseline information to help make decisions about water management at existing and potential natural resource development projects in the region.
The overall goal of this project was to understand the trajectory of sporadic to discontinuous permafrost environments, with continued climatic warming, by examining the landscape changes at 10 subarctic boreal sites along a latitudinal transect spanning from the southwestern NWT to northeastern BC.
Understanding the water balance in northeastern BC is a priority and challenge for the communities and the energy sector working in the area. This project provides baseline earth science information about the effect that a changing climate is having and will have on the movement, volume and location of water in the region as permafrost melts.
The researchers studied landscape and water balance variations at 10 subarctic boreal sites along a north-south transect established by the Consortium for Permafrost Ecosystems in Transition (CPET). The 200-kilometre transect stretches from south of Fort Simpson in the NWT to the far northeast corner of BC.
Researchers mapped the changes in forest cover and wetland area using remotely sensed imagery collected over many years. Precipitation, water levels and water flow were monitored and used to calculate the amount of runoff. Areal remote sensing imagery was collected in collaboration with NASA who flew their research aircraft over the transect in coordination with ground-based measurements.
As permafrost thaws, the forested plateaus in the landscape shrink, subside and eventually become wetlands as a result of inundation. The water stored in previously isolated bogs is directed to basin runoff. Drying of wetlands through drainage enhances runoff from these environments through the release of water previously impounded behind permafrost, and by the expansion of areas able to contribute to stream and river flow.
Understanding how permafrost-thaw-induced landscape changes in the sporadic to discontinuous permafrost zone affect the hydrology of these environments is important in order to assess the availability and sustainability of freshwater resources.