ABSTRACT
This book presents the approaches adopted by different countries and regions over the world, describing the best practice in four areas: (1) Assessment of the impact of climate change on rainfall patterns and other meteorological events that can cause slope instability; (2) Evaluation of the severity of the impact of climate change on slope instability and landslide risk; (3) Implications of climate change impact on slope design, landslide risk management, risk mitigation strategy and risk adaptation measures; and (4) Need for further work on slope safety preparedness. Thirteen (13) country/region reports covering a total of 17 areas in the world summarize their state-of-practice: Brazil, Canada, Hong Kong, Italy, Japan, Norway, the Russian Federation, the Southeast Asia region (including Indonesia, Malaysia, Singapore, Thailand and Vietnam), Spain, Switzerland, Taiwan, the UK and the USA. In addition, four countries, Australia, China, Columbia and India, filled out a questionnaire on their country’s practice on the same topic. This overview paper consolidates the contributions and key observations made in the country/region reports and summarizes some of the most urgent research needs and emerging trends.
Landslide risk management in a changing or extreme climate context represents a formidable challenge. The insight from the country/region reports reinforces the need for a comprehensive slope safety system that manages landslide risk in a holistic manner using both “hard” engineering measures and “soft” non-engineering approaches. The challenges posed by extreme weather events, which may be exacerbated by climate change, require urgent attention and careful assessment from both a technical and a strategy and policy perspective. Scenario studies indicate that the number, scale and mobility of the landslides associated with extreme weather and climate change could be unprecedented. Slopes in permafrost, mountains with glaciers, coastal slopes, natural slopes underlain by weak granular materials susceptible to debris flows/slides, and slopes prone to progressive deterioration with time (degradation in strength or development of distress) are identified as vulnerable settings and potential critical hazards that will likely respond strongly to climate change with an increase in frequency, magnitude and perhaps runout of landslides. Hence landslide risk will increase. Conventional risk assessment methodologies are not well suited for dealing with the 2risk posed by low probability – high impact (extreme) events. Stress testing provides a complementary approach that may be used for managing the risk to constructed facilities and critical infrastructure. In stress tests, the focus is on the performance of the system under extreme event scenarios. This is a rapidly evolving field of new research initiatives.
The review finds that slope safety preparedness for the impact of climate change varies considerably from one country/region to another. There is much room for cross-fertilization of ideas and insights, as well as joint development of strategies and best practice. Disasters often manifest themselves as fast events, but the vulnerability for disasters is built up slowly, and can be the result of neglecting to be adequately prepared. Focus needs to shift from prevention-mitigation to building resilience and reducing risks. There is an increasing awareness amongst the engineering profession that reliance on engineering works alone in combating the climate change impact is neither practicable nor cost-effective. Instead, due emphasis should be placed on improving warning systems, enhancing emergency preparedness and response, community resilience and recovery. For enhanced preparedness and resilience to take root, the risk management strategy has to be embraced by the community. Hence, effective public education and strong government support are essential.
