Climate Change & Landslides
We know climate has been, and is changing, and will do so at an increasing pace unless we dramatically reduce greenhouse gas emissions.
Warming alone has already catastrophic consequences as we noticed so brutally during the Pacific Northwest Heat Wave this year. One of the derivates from global warming are changes in precipitation pattern. Those, in turn affect many land surface and groundwater processes. Surprisingly, a simple link between precipitation and landsliding does not exist. Specific landslide types have their own “hydrological memory”, i.e., the respond differently to changes in precipitation and/or snowmelt. For example, a shallow (less than a metre deep) landslide may respond readily to an intensive rainstorm as long as there has been enough antecedent moisture in the ground (i.e., rain in the preceding weeks). A landslide several tens of metres deep may need weeks or month of well-above average precipitation to “take off” (accelerate).
Understanding the landslide’s response to climate variables is key. Once that is done and a process-response model has been created, we are able to query global climate models and shock the model with climate change projections. This is exactly what Trevor Owen, a Software Developer here at BGC, and I, with the help of a statistics professor from the University of British Columbia, did for shallow landslides on the North Shore in Vancouver, British Columbia, Canada. The resulting study found that regionally speaking landslide frequency could increase by as much as four times and landslide magnitude by as much as 50% by the end of the century. This will have substantial implications in terms of fine sediment input to streams that end up in Metro Vancouver’s drinking water supplies. It can also change the shape of rivers and impact fish habitat.
The results of this study were recently featured on Global News, CBC, Vancouver Sun, and the North Shore News. BGC offers a number of services across geohazard management and climate change. Interested in finding out more? Let’s talk.