Evaluation of adaptation scenarios

1. Evaluation of adaptation scenarios Follow-up committee meeting 6 October, Leuven

2. Need to adapt to new conditions • The current level of flood risk (making abstraction of possible future climate change effects) is probably not optimal • Climate change alters current conditions Requires reassessing flood risks and current flood riskmanagement strategies

3. What is the optimal level of adaptation? • Autonomous adaptation is not likely to be optimal • Policy makers are ought to invest the limited resources in an optimal manner, maximising welfare … this requires • Reliable data on the likely impacts (costs) of climate change • Information on costs and effectiveness of adaptation options • Information on indirect effects of adaptation options

4. What is the optimal level of adaptation?

5. Decision support model – computation of values for the evaluation criteria • Avoided flood risks calculated with the model • Possibility to account for economic growth, population growth and number of people per household • Project horizon of 30, 50 and 100 years • Select the appropriate discount factor for calculating the NPVs

6. Decision support model – extended CBA • Development of the decision matrix • Standardisation • Attributing weights to the effects • Ranking • Implicit CBA and benefit-cost ratio

7. Decision support model – sensitivity analysis • Sensitivity of the results to changes in the weights • Sensitivity of the results to changes in the decision matrix

8. Decision support model – uncertainty analysis • Uncertainty analysis is broken down into: • Identification of the various sources of uncertainty • Quantification of the uncertainties identified • Reassessment and discussion of the results in the light of uncertainty

9. Concluding remarks • Added value for prioritising flood control measures described by multiple, not readily comparable effects • Combination of a completely automated MCA with an implicit CBA • Standardisation and the weighting are somewhat arbitrary • Reducing the arbitrary of the results thus requires enquiring the public about their preferences • Popularisation of the tool by the determination of a set of criterion weights that can be used in any assessment in Belgium