Risk / damage maps

Motivation

In Europe, adapting to changes in the risk of extreme weather is high on the agenda. Losses from extremes, such as floods, droughts and other climate-related events, have risen sharply in recent decades; a rise that cannot be attributed only to increased exposure of economic wealth. The IPCC Fourth Assessment Report concludes that anthropogenic climate change is likely to very likely to lead to increases in intensity and frequency of weather extremes. This is of concern to European policymakers. The recent EU White Paper 'Adapting to Climate Change: Towards a European Framework for Action' has set out an adaptation strategy that, among other things, emphasises the role of disaster risk management. ADAM research has contributed significantly to improving the knowledge base, and identifying knowledge gaps, for managing the changing risks of climate change in Europe.

This section presents research on estimating today's and future flood and drought/heatwave risks. It builds on the results of workpackages 'A2.1 - An assessment of weather-related risks in Europe' which had the following main objective:

Quantify and map weather-related extreme-event risks to public and private capital assets, human lives, and agriculture/forestry/tourism, and identify high-risk areas ("hot spots") on which to focus more detailed analysis.

and 'A2.2 Projections of weather-related extreme event risks to 2025 and 2100' with the following objective:

Develop projections of selected risks [...] to 2025 and 2100 by taking account of scenarios of changed land-use patterns, population/capital and climate. Identify future "hot spots" in the absence of adaptation measures, and  [...] in light of cost-effective adaptation measures.

The overarching methodological approach to this very complex issue relies on the assumption that, although caused by natural events, natural disasters are products of an interaction between nature and the social, economical and political environment which "structures" and configures the lives of individuals, communities and nations (Parker, 2000).

The term risk has been defined in several ways in the natural hazard literature. The work here presented follows the generally accepted risk assessment procedure with "risk" understood as a function of hazard, vulnerability and exposure (see Chrichton, (1999) and Kron (2002)) as follows

• Hazard: the extreme natural event including its probability of occurrence and intensity;
• Exposure: people and assets exposed to hazards;
• Vulnerability: the degree of impact/damage incurred by people and assets due to the intensity of an event.

Based on this definition, the risk may be visualised as the area of a triangle with the three above-defined components as sides. Risk can accordingly be decreased by tackling any of the three contributing variables - the hazard, the elements exposed and/or their vulnerability. The reduction of any one of the three factors to zero would consequently eliminate the risk (which is impossible).

Fig. 1 - The risk triangle

The main task of every operational approach to risk assessment, both in present conditions and in future scenarios, is the modelling of these components, given the constraint in data availability, resolution and consistency. We have produced maps expressed in absolute monetary terms and in relative terms as a ratio of GDP (note: these losses are not GDP losses) for flood risk and of drought/heat stress to agriculture according to specific models, as presented in the following sections.

Keywords: Risk assessment; Hazard; Exposure; Vulnerability; Risk Triangle