A Flood Damage Allowance Framework for Coastal Protection With Deep Uncertainty in Sea Level Rise
A Flood Damage Allowance Framework for Coastal Protection With Deep Uncertainty in Sea Level Rise
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DOI：
10.1029/2019ef001340
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发表时间：
2019-08
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影响因子：
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通讯作者：
D. Rasmussen;M. Buchanan;Robert E Kopp;M. Oppenheimer
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文献类型：
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作者：
D. Rasmussen;M. Buchanan;Robert E Kopp;M. Oppenheimer
深度不确定性描述了在(1)用于描述关键系统过程的模型和(2)用于表征关键变量和参数的不确定性的概率分布方面存在无知或不一致的情况。对南极冰盖(AIS)质量损失的未来预测仍然具有很大的不确定性。这使得在决定实施何种安全边际时，对长期沿海保护项目的决策变得更加复杂。如果选定的安全边际没有适当考虑海平面上升的不确定性，防洪的有效性可能会随着时间的推移而下降，可能会使生命和财产面临更大的风险。为了解决这一问题，我们制定了一个洪灾损失限额框架，用于计算确保维持一定水平的金融风险所需的防洪战略的高度。损害允许框架考虑了决策者的偏好，如规划视野、保护战略和对AIS稳定性的主观看法。我们使用曼哈顿--人口和建筑环境在时间上固定--来说明我们的框架如何根据AIS融化的多种可能情景来计算一系列损害限额。在温室气体排放量较高的情况下，我们发现结果对AIS对海平面上升贡献上限的选取很敏感。明确财务风险目标的设计指标，如预期的洪灾损失，允许计算避免的洪灾损失(即收益)，这些损失可以与建筑成本的估计相结合，然后整合到现有的财务决策方法中(例如，收益-成本分析)。
Deep uncertainty describes situations when there is either ignorance or disagreement over (1) models used to describe key system processes and (2) probability distributions used to characterize the uncertainty of key variables and parameters. Future projections of Antarctic ice sheet (AIS) mass loss remain characterized by deep uncertainty. This complicates decisions on long‐lived coastal protection projects when determining what margin of safety to implement. If the chosen margin of safety does not properly account for uncertainties in sea level rise, the effectiveness of flood protection could decrease over time, potentially putting lives and properties at a greater risk. To address this issue, we develop a flood damage allowance framework for calculating the height of a flood protection strategy needed to ensure that a given level of financial risk is maintained. The damage allowance framework considers decision maker preferences such as planning horizons, protection strategies, and subjective views of AIS stability. We use Manhattan—with the population and built environment fixed in time—to illustrate how our framework could be used to calculate a range of damage allowances based on multiple plausible scenarios of AIS melt. Under high greenhouse gas emissions, we find that results are sensitive to the selection of the upper limit of AIS contributions to sea level rise. Design metrics that specify financial risk targets, such as expected flood damage, allow for the calculation of avoided flood damages (i.e., benefits) that can be combined with estimates of construction cost and then integrated into existing financial decision‐making approaches (e.g., benefit‐cost analysis).