Shallow landslides in Vancouver’s North Shore mountains are expected to increase in frequency by 300 percent until the end of this century, a new study has found.
Vancouver-based BGC Engineering’s estimates come from new climate modeling and analysis of Metro Vancouver’s historic landslide database.
That’s almost four times more than the consulting firm had previously predicted – similar research in 2009 led to an estimated 10 percent increase from the number of landslides in the past 30 years.
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“When we did the survey in 2009, we had worse models than the ones we have now,” explained BGC’s senior engineering geoscientist Matthias Jakob.
“We also looked at changes in the average landslide size and found that it could also increase by as much as 50 percent.”
The results are important, he added, because landslides can affect not only urban infrastructure but also rural infrastructure such as pipelines, railways and roads. They can also damage critical watersheds and sensitive ecosystems.
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The new study examined the possible frequency, magnitude and intensity of future landslides and waste streams in the North Shore Mountains, and how climate change may affect them.
While some effects of climate change, such as changes in temperature or precipitation, are easier to measure, it is much more complicated to link climate change to landslides, Jakob said.
“It is very important to understand these third or higher order effects of climate change on the Earth’s surface processes,” he told Global News. “It is very important to understand what will happen in the future because the past may no longer be the key to the future.”
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The study was not able to definitively link the likelihood of increased landslides to climate change.
Metro Vancouver’s database showed a doubling of the landslide rate since 1981, it said, but before that the recording was “sporadic”, so it is possible that the increase may be associated with better registration.
Still, Metro Vancouver is preparing for the possibility of increased rainfall and landslides, according to the division chief for environment and water services.
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“On the water supply side, the potential for increased landslides over time is certainly being considered in long-term planning for water infrastructure,” said Jesse Montgomery.
“Vancouver as a region is very fortunate to have a large area with reasonably undisturbed wilderness as their water supply.”
Jakob said it is up to all levels of government to fund risk reduction appropriately, such as updated community plans, added warning systems and new infrastructure to protect existing developments.
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