Rapid Warming Turning Banks Island to Mush, Triggers 60-Fold Increase in Landslides
Rapid regional warming is turning Banks Island in the Canadian High Arctic to mush, according to a new study in the journal Nature Communications, triggering a 60-fold increase in landslides over the last three decades and putting the Inuvialuit population on Sachs Harbour at risk.
“The evidence is there for anyone to see, scientists say, thanks to the web-based app Google Earth Engine, which offers time-lapse views of the globe, as seen through the eyes of remote sensing satellites, from 1984 onward,” the Globe and Mail reports. “When trained on Banks Island, those views reveal a terrain in the throes of a rapid transformation,” showing permafrost that “softens and collapses into a slurry of mud and gravel as the years speed by.”
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The findings match up with the results of past local studies, and with reports from residents of Sachs Harbour, the only permanent settlement on the island, located at the western end of Canada’s Arctic Archipelago.
“Our analyses totally back them up,” said lead author and University of Ottawa geographer Antoni Lewkowicz, who started the study two years ago as an exercise for his fourth-year students. “We now have a very clear linkage, not just with general climate change, but with warm summers and reactions in the permafrost landscape.”
“In hard numbers, the satellite data reveal that the rate of landslides on Banks island has increased 60-fold during the past three decades,” the Globe states. “To date, that change corresponds to a loss of roughly 100 million tonnes of ice that was previously locked in place as a relic from the last ice age.”
The study also concludes that “the loss was not gradual, but, rather, concentrated in sharp spikes following on the heels of unusually warm summers that occurred in 1998 and a three-year stretch in 2010, 2011, and 2012,” the paper adds. “This suggests that the ground stability in many areas of the High Arctic is closely coupled to the local climate and may weaken rapidly when temperatures reach a critical threshold.”
Permafrost scientist Steve Kokelj of the Northwest Territories Geological Survey said the results underscore the more dramatic climate change occurring in colder, more northerly Arctic locations. “It tells us that these parts of Banks Island and other parts of the Canadian Arctic are going to change dramatically in our lifespans,” he told the Globe. “It’s important to define where those areas are and to understand the downstream effects…through aquatic systems and communities.”