ABSTRACT: Impact of global warming on stability of natural slopes.

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Abstract

Global warming has an increasing impact on many factors that relate directly to the instability of slopes, triggering landslides and causing severe impacts on both the natural environment and humans. Global atmosphere models have indicated that significant changes are expected in the worldwide distribution of magnitude of precipitation and their frequency. Over the next 2 decades many regions will experience either drier or wetter conditions than they ever have in the past several centuries, while others will experience drastic variations in weather events as never before. This has emphasized the need to change current predictive models for assessing natural hazards and their associated risks. It is well known that as a result of various stabilizing factors most slopes stand steeper than their natural angle of repose, and have continued to be stable for centuries. Nevertheless, the positive effect of all of these factors can reduce or disappear altogether. One such factor is matric soil suction, increasing the soil strength. It is lost when excessive rainfall infiltrates into the soil and replaces the air void with water. Natural cementation and other inter-particle forces also provide an effective cohesion, but are susceptible to dissolution and softening as a result of water infiltration. Another factor is root reinforcement and suction provided by vegetation, preventing shallow sliding and surface erosion. The health of this vegetation is particularly dependant on the weather. The groundwater table also has a large impact on slope stability, for example with respect to hydraulic pressure increases, soil weight and internal stress changes, cyclical strength reduction, seepage pressures and internal erosion. All of these factors will be affected by climate change. This paper provides a comprehensive review, with example conceptual models, of natural slope stabilizing factors and how destabilizing processes could be incurred by global warming. In particular, this study will attempt to categorize slopes with respect to these natural stabilizing factors using an existing landslide classification framework, and then develop a predictive model for establishing their land sliding sensitivity to specific global warming changes predicted over the next few decades.

Bibliography of Canadian Geomorphology