Letters from Sendai no. 2: risk assessment comes first

The second letter of the ENHANCE series from the Third UN World Conference on Disaster Risk Reduction was posted on 15 March 2015, with no individual byline. Its subject was risk assessment, described as the foundation on which every other part of risk management rests.

The letter made two practical points. Access to data and models was still a problem in many places in 2015. And risk assessments tend to be built around what modellers can compute, when they should be designed around the questions end-users actually need answered.

ENHANCE’s own contribution was methodological. The project worked with statistical methods such as copulas, which capture geographic dependencies between hazards: the chance that rivers in neighbouring basins flood in the same event, for example. Modelling those links improves estimates of low-probability, high-impact risks, the events that drive the largest losses.

The letter named a new ENHANCE policy brief released for Sendai (Botzen et al. 2015) on natural hazard risk assessments for resilience in Europe, and gave three examples of assessments in use:

• an EU-wide flood risk assessment that informed the EU Solidarity Fund;
• local assessments of surface-water flooding in the UK;
• an assessment of drought in the Júcar basin in Spain.

The Solidarity Fund work is covered in the Romania and Eastern Europe case study and the Júcar work in the Júcar drought case study. The next letter turned to partnerships and insurance (no. 3).