Estimating drought risk across Europe from reported drought impacts, drought indices, and vulnerability factors

Veit Blauhut,Lena M Tallaksen,Kerstin Stahl,Jürgen Vogt,James Howard Stagge,Lucia De Stefano

doi:10.5194/hess-20-2779-2016

Abstract

Abstract. Drought is one of the most costly natural hazards in Europe. Due to its complexity, drought risk, meant as the combination of the natural hazard and societal vulnerability, is difficult to define and challenging to detect and predict, as the impacts of drought are very diverse, covering the breadth of socioeconomic and environmental systems. Pan-European maps of drought risk could inform the elaboration of guidelines and policies to address its documented severity and impact across borders. This work tests the capability of commonly applied drought indices and vulnerability factors to predict annual drought impact occurrence for different sectors and macro regions in Europe and combines information on past drought impacts, drought indices, and vulnerability factors into estimates of drought risk at the pan-European scale. This hybrid approach bridges the gap between traditional vulnerability assessment and probabilistic impact prediction in a statistical modelling framework. Multivariable logistic regression was applied to predict the likelihood of impact occurrence on an annual basis for particular impact categories and European macro regions. The results indicate sector- and macro-region-specific sensitivities of drought indices, with the Standardized Precipitation Evapotranspiration Index (SPEI) for a 12-month accumulation period as the overall best hazard predictor. Vulnerability factors have only limited ability to predict drought impacts as single predictors, with information about land use and water resources being the best vulnerability-based predictors. The application of the hybrid approach revealed strong regional and sector-specific differences in drought risk across Europe. The majority of the best predictor combinations rely on a combination of SPEI for shorter and longer accumulation periods, and a combination of information on land use and water resources. The added value of integrating regional vulnerability information with drought risk prediction could be proven. Thus, the study contributes to the overall understanding of drivers of drought impacts, appropriateness of drought indices selection for specific applications, and drought risk assessment.

Highlights

Drought is a natural phenomenon that can become a natural disaster if not adequately managed (Wilhite, 2000)
3. map sector-specific drought risk for selected hazard severity levels across Europe. This study addresses these aims through statistical modelling of the combined effect of drought hazard, defined by drought indices, and drought vulnerability, defined by vulnerability factors, on the occurrence of historical drought impacts as extracted from the Europe from reported drought impacts port Inventory (EDII)
Hereby one model is determined for each European macro region and impact category, using annual impact occurrence as a target variable and corresponding hazard and vulnerability observations as predictors

Summary

Introduction

Drought is a natural phenomenon that can become a natural disaster if not adequately managed (Wilhite, 2000). It has a creeping onset and does not have a unique definition (Lloyd-Hughes, 2014), which makes defining the beginning or end of a drought event difficult (Hayes et al, 2004; Wilhite et al, 2007). Wilhite and Glantz, 1985), or by its consequences on socioeconomic and environmental systems, i.e. its negative impacts (Blauhut et al, 2015a). These impacts can either be direct (e.g. reduced crop yields) or indirect (e.g. increased costs for food due to reduced crop yields) and can occur across a wide range of temporal and spatial scales. Blauhut et al.: Estimating drought risk across Europe from reported drought impacts port Inventory (EDII) across 15 different impact categories from agriculture to water quality (Stahl et al, 2016) and financial losses over the last 3 decades were estimated to over EUR 100 billion (EC, 2007)

Methods

Results

Discussion

Conclusion