Paving the Way for Climate-Resilient Infrastructure - UN CC:Learn

Chapter 7: A Framework for Risk Assessment and Risk-Informed Decision-Making for Infrastructure DevelopmentWithin this hierarchy systems approach, the level of the system determines what decisions are made tomaximize its functionality. Decisions to ensure sufficient performance of the components of the system(e.g. a bridge for System 1 or the wires of that bridge for System 2) contribute to the overall reliability ofthe system.Updating risksAfter the creation of risk models, it is possible to update risks by inputting improved exposures, vulnerabilityor robustness information into the models, reassessing risks and re-evaluating benefits of changingthe system. This type of Bayesian updating includes both spatial and temporal changes. For spatialrelatedrisk updates in large-scale hazard risk management, real-world data and observations based ona geographic information system (GIS) interface platform (e.g. satellite observations, airplane observations,insurance data, on-site observations) can contribute to indicators for models and optimization ofrisk management strategies. Risk updates based on temporal changes take into account different stagesof risk management depending on the timing of risk-based decision-making relative to the occurrence ofthe exposure event.Risk management with regard to any kind of exposure is a problem that constitutes three different situations:before, during, and after hazards take place. There is a significant difference in risk managementdepending on whether there is time to deal with a hazard before or during its impact, or whether impactsare being addressed during or after they affect society. Before a hazard hits, risk management is basedon prioritization, capacity strengthening and being prepared. For example, risk reduction resources areoptimally allocated for retrofitting and rebuilding in light of possible earthquakes. During the presenceof a hazard, risk management focuses on doing the right thing (i.e. carrying out the appropriate actions)according to plan, based on the evolution of the exposure event. Monitoring and control of damage, emergencyhelp and rescue, aftershock hazard assessment, and identification of the seismic event comprisepossible components of this stage. After a hazard hits, risk management means reinvesting in recovery ofconsequences. Activities in this situation include rehabilitation of infrastructure functionality, conditionassessment and updating, and (again) optimal allocation of resources for retrofitting and rebuilding.UncertaintyIn the context of climate change and its many uncertainties, adaptable, robust decision-making is necessary.There are two types of uncertainties associated with climate change: (1) uncertainty due to naturalvariation (‘regulatory uncertainty’) and (2) uncertainty due to the fact that knowledge about climatechange and its potential impacts is lacking (‘knowledge uncertainty’). Knowledge uncertainty can bereduced; regulatory uncertainty cannot. Reducing knowledge uncertainty — through quantifying informationand knowledge — contributes to better optimization of risk reduction. Decisions must thereforebe robust with regard to assumptions and adaptability to future reality.Climatic changes will evolve over the next 50 years. Newly built infrastructure could have a lifetime of50 to 100 years. Therefore, given uncertainty about climate change—regarding whether outcomes willmimic best-case or worst-case scenarios—risk-based decisions need to be robust and ensure protectionof systems independent of predictive assumptions.86Paving the Way for Climate-Resilient Infrastructure: Conference Proceedings