Epistemic uncertainties in climate adaptation decision ranking

Climate change adds substantial challenges to the planning, design, operation and integrity management of civil infrastructures and structures. Depending on geographical location, climate changes may result in substantial variations in the environmental loads. These variations are only known to the extent that we believe in the relevance and validity of available climate models, each of which involves assumptions and uncertainties. Consequently, optimal decisions must consider all models and associated uncertainties that are relevant in a given decision context. This paper proposes a decision-making framework for climate adaptation of civil infrastructure and structures, aiming to account consistently for the degree of belief in the different models and their associated uncertainties. The framework represents the degree of belief in different models as epistemic uncertainties, through probabilities assigned in principle subjectively to different relevant climate change scenarios. On this basis, the impact of the different relevant climate scenarios and their probability assignments on decision optimality may be analysed probabilistically. An example of flood risk management is provided, where different adaptation decisions are ranked based on the associated risks. The example shows that the proposed framework provides a different ranking of decision alternatives, compared to common practice approaches in risk-informed decision analysis.